Prechamber Mod "Flame" Front
Prechamber Mod "Flame" Front
05-16-2016, 10:54 AM
#351
(05-13-2016, 07:06 PM)Torkey Put the car on the dyno after reamng out to .125" on all the holes except for the drain and the large hole. Results were 13 more ft/lbs torque, 3 more HP. I recommend doing this. Quick, easy and cheap way to get more go.
Did you throw any more timing at it after opening up the holes?
(05-13-2016, 07:06 PM)Torkey Put the car on the dyno after reamng out to .125" on all the holes except for the drain and the large hole. Results were 13 more ft/lbs torque, 3 more HP. I recommend doing this. Quick, easy and cheap way to get more go.
Did you throw any more timing at it after opening up the holes?
The timing was advanced a few degrees. I'm not exactly sure how much though. I advanced it until it sounded right. Not a scientific method.
05-18-2016, 04:07 AM
#353
The 606 one seems to be designed for central mounting in the cylinder, not the best idea for use in the older engines? Wonder where the GP hole is etc. And if the upper part would fit in the older engines
1978 300D, 373,000km... OM617.912 with a Holset HX30W, 7.5mm IP, 711.113 5 speed (project car, 7 years off the road and counting ;/)
1977 250 270,000km (parts car)
1977 300D (ex 280) 500,000km
1981 240D 498,000
1975 HJ45 ???,000
2001 2.8TD Rodeo 4x2 - 456,000 - DD
Soooooo, MB100 upper PC with 617.95 fire duct would be the ideal? They're pretty rare though, what if you had a Late 602/3 upper PC and rotated it. You'd need some jig to do it properly...and special welding rods I guess. Also would need a lathe to clean things up....
The 606 one seems to be designed for central mounting in the cylinder, not the best idea for use in the older engines? Wonder where the GP hole is etc. And if the upper part would fit in the older engines
1978 300D, 373,000km... OM617.912 with a Holset HX30W, 7.5mm IP, 711.113 5 speed (project car, 7 years off the road and counting ;/)
1977 250 270,000km (parts car)
1977 300D (ex 280) 500,000km
1981 240D 498,000
1975 HJ45 ???,000
2001 2.8TD Rodeo 4x2 - 456,000 - DD
05-18-2016, 04:20 AM
#354
there is no gain in changing the pre cups of your 617 A engine.
If your engine is 617 N/A u have a lot of things to change before reaching needs of best suited cups....
As of my experience the 605/6 injector wich uses the famous 315 nozzle can be used as drop in . Pre cup work best with around holes opened by 20/100 and the neck to 8mm , but this for turbo cups.... the na cups are too week to mod.
Good luck.
FD,
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Scott
there is no gain in changing the pre cups of your 617 A engine.
If your engine is 617 N/A u have a lot of things to change before reaching needs of best suited cups....
As of my experience the 605/6 injector wich uses the famous 315 nozzle can be used as drop in . Pre cup work best with around holes opened by 20/100 and the neck to 8mm , but this for turbo cups.... the na cups are too week to mod.
Good luck.
FD,
Powered by tractor fuel
05-19-2016, 09:10 PM
#355
The 605+6 have all the angled injection already, I think retrofitting angled injection PCs into a 617 would get a touch more efficiency out of the old dog as well as the enlarged burn holes
1978 300D, 373,000km... OM617.912 with a Holset HX30W, 7.5mm IP, 711.113 5 speed (project car, 7 years off the road and counting ;/)
1977 250 270,000km (parts car)
1977 300D (ex 280) 500,000km
1981 240D 498,000
1975 HJ45 ???,000
2001 2.8TD Rodeo 4x2 - 456,000 - DD
One day, I hope to soup up a 617 to 300-400hp..my NA conversion is just practice at this stage...(although I do have 315 nozzles in it)
The 605+6 have all the angled injection already, I think retrofitting angled injection PCs into a 617 would get a touch more efficiency out of the old dog as well as the enlarged burn holes
1978 300D, 373,000km... OM617.912 with a Holset HX30W, 7.5mm IP, 711.113 5 speed (project car, 7 years off the road and counting ;/)
1977 250 270,000km (parts car)
1977 300D (ex 280) 500,000km
1981 240D 498,000
1975 HJ45 ???,000
2001 2.8TD Rodeo 4x2 - 456,000 - DD
05-20-2016, 10:54 AM
#356
regards
FD,
Powered by tractor fuel
hehe, the seat of the injector at 15º angle is more a aesthetics and practicallity mixed with german ingenuity and ability to complicate than anything else, the 606 cups can´t be used in a 617 or in a 603 head unless heavy mods are done , so i belive it does not worth the assle...
regards
FD,
Powered by tractor fuel
05-22-2016, 09:59 AM
#357
(05-19-2016, 09:10 PM)NZScott One day, I hope to soup up a 617 to 300-400hp..my NA conversion is just practice at this stage...(although I do have 315 nozzles in it)
The 605+6 have all the angled injection already, I think retrofitting angled injection PCs into a 617 would get a touch more efficiency out of the old dog as well as the enlarged burn holes
Hey NZScott - How much would you say the 315 nozzles increased your power? Was it noticeable?
(05-20-2016, 10:54 AM)barrote hehe, the seat of the injector at 15º angle is more a aesthetics and practicallity mixed with german ingenuity and ability to complicate than anything else, the 606 cups can´t be used in a 617 or in a 603 head unless heavy mods are done , so i belive it does not worth the assle...
regards
Hehe - the German engineer strikes again.
1984 300D with Monark nozzles, GT2256V w/ Synkooppi/Arduino controller, W123 n/a intake, air/water intercooler, precup holes reamed, IP & valve timing = fac + 2 degrees, upgraded leather interior, 140A alternator, electric lift pump, 3" aluminum radiator w/ electric fan, HID headlight conversion, bilsteins, stock MW IP turned up 3 turns on tq module per OM616, 2.65 rear end, ventilated front rotors, dual rear swaybar mod + W116 springs - https://www.youtube.com/watch?v=4zPSyCMkkk0
kestreltom
05-22-2016, 09:59 AM #357(05-19-2016, 09:10 PM)NZScott One day, I hope to soup up a 617 to 300-400hp..my NA conversion is just practice at this stage...(although I do have 315 nozzles in it)
The 605+6 have all the angled injection already, I think retrofitting angled injection PCs into a 617 would get a touch more efficiency out of the old dog as well as the enlarged burn holes
Hey NZScott - How much would you say the 315 nozzles increased your power? Was it noticeable?
(05-20-2016, 10:54 AM)barrote hehe, the seat of the injector at 15º angle is more a aesthetics and practicallity mixed with german ingenuity and ability to complicate than anything else, the 606 cups can´t be used in a 617 or in a 603 head unless heavy mods are done , so i belive it does not worth the assle...
regards
Hehe - the German engineer strikes again.
1984 300D with Monark nozzles, GT2256V w/ Synkooppi/Arduino controller, W123 n/a intake, air/water intercooler, precup holes reamed, IP & valve timing = fac + 2 degrees, upgraded leather interior, 140A alternator, electric lift pump, 3" aluminum radiator w/ electric fan, HID headlight conversion, bilsteins, stock MW IP turned up 3 turns on tq module per OM616, 2.65 rear end, ventilated front rotors, dual rear swaybar mod + W116 springs - https://www.youtube.com/watch?v=4zPSyCMkkk0
05-22-2016, 06:23 PM
#358
FWIW later 603s got the angled injection as did the 616. Good point about whether it's worth the hassle though- you never know til you try I guess?
1978 300D, 373,000km... OM617.912 with a Holset HX30W, 7.5mm IP, 711.113 5 speed (project car, 7 years off the road and counting ;/)
1977 250 270,000km (parts car)
1977 300D (ex 280) 500,000km
1981 240D 498,000
1975 HJ45 ???,000
2001 2.8TD Rodeo 4x2 - 456,000 - DD
Haven't quite got to that stage yet - car isn't running...
FWIW later 603s got the angled injection as did the 616. Good point about whether it's worth the hassle though- you never know til you try I guess?
1978 300D, 373,000km... OM617.912 with a Holset HX30W, 7.5mm IP, 711.113 5 speed (project car, 7 years off the road and counting ;/)
1977 250 270,000km (parts car)
1977 300D (ex 280) 500,000km
1981 240D 498,000
1975 HJ45 ???,000
2001 2.8TD Rodeo 4x2 - 456,000 - DD
05-23-2016, 12:48 AM
#360
DiseaselWeasel
05-23-2016, 12:48 AM #360I always felt like the angled injection engines run smoother and smoke less...
05-26-2016, 01:03 PM
#361
(05-22-2016, 09:03 PM)MFSuper90 I've got 315's, and the power increase is hardly noticeable if any.
Thanks!
1984 300D with Monark nozzles, GT2256V w/ Synkooppi/Arduino controller, W123 n/a intake, air/water intercooler, precup holes reamed, IP & valve timing = fac + 2 degrees, upgraded leather interior, 140A alternator, electric lift pump, 3" aluminum radiator w/ electric fan, HID headlight conversion, bilsteins, stock MW IP turned up 3 turns on tq module per OM616, 2.65 rear end, ventilated front rotors, dual rear swaybar mod + W116 springs - https://www.youtube.com/watch?v=4zPSyCMkkk0
kestreltom
05-26-2016, 01:03 PM #361(05-22-2016, 09:03 PM)MFSuper90 I've got 315's, and the power increase is hardly noticeable if any.
Thanks!
1984 300D with Monark nozzles, GT2256V w/ Synkooppi/Arduino controller, W123 n/a intake, air/water intercooler, precup holes reamed, IP & valve timing = fac + 2 degrees, upgraded leather interior, 140A alternator, electric lift pump, 3" aluminum radiator w/ electric fan, HID headlight conversion, bilsteins, stock MW IP turned up 3 turns on tq module per OM616, 2.65 rear end, ventilated front rotors, dual rear swaybar mod + W116 springs - https://www.youtube.com/watch?v=4zPSyCMkkk0
05-27-2016, 04:09 AM
#362
Have tried to heat them red hot then let them cool slowly down. After that i tried with quality cobolt drill bits 2.5mm (holes is 2.2mm) that is designed for stainless steel drilling but they gets round almost right away. I am drillig at very low rpm
EDH_Performance
05-27-2016, 04:09 AM #362Can anyone give me some advice how to drill bigger holes in these prechambers? Have tried after some help, but drillbits can not handle 606 prechambers.
Have tried to heat them red hot then let them cool slowly down. After that i tried with quality cobolt drill bits 2.5mm (holes is 2.2mm) that is designed for stainless steel drilling but they gets round almost right away. I am drillig at very low rpm
05-27-2016, 05:41 AM
#363
(05-27-2016, 04:09 AM)EDH_Performance Can anyone give me some advice how to drill bigger holes in these prechambers? Have tried after some help, but drillbits can not handle 606 prechambers.
Have tried to heat them red hot then let them cool slowly down. After that i tried with quality cobolt drill bits 2.5mm (holes is 2.2mm) that is designed for stainless steel drilling but they gets round almost right away. I am drillig at very low rpm
I used a small, gradual tapered carbide bur in my dremel tool - and set the dremel to it's lowest speed. I didn't try to anneal the prechamber and I did not use coolant or oil. I pushed the bit in with moderate pressure to prevent chatter. It went pretty quick. I used the butt end of the appropriate sized drill bit as a go/no-go gauge to determine the holes sizes as I reamed them.
kestreltom
05-27-2016, 05:41 AM #363(05-27-2016, 04:09 AM)EDH_Performance Can anyone give me some advice how to drill bigger holes in these prechambers? Have tried after some help, but drillbits can not handle 606 prechambers.
Have tried to heat them red hot then let them cool slowly down. After that i tried with quality cobolt drill bits 2.5mm (holes is 2.2mm) that is designed for stainless steel drilling but they gets round almost right away. I am drillig at very low rpm
I used a small, gradual tapered carbide bur in my dremel tool - and set the dremel to it's lowest speed. I didn't try to anneal the prechamber and I did not use coolant or oil. I pushed the bit in with moderate pressure to prevent chatter. It went pretty quick. I used the butt end of the appropriate sized drill bit as a go/no-go gauge to determine the holes sizes as I reamed them.
05-27-2016, 06:57 AM
#364
But my engine is a Turbo so i have bigger holes then N/A engines from factory.
This post was last modified: 05-27-2016, 06:58 AM by EvoPeter.
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Mercedes 190 -92, om605 Stroker 2.75L, Dieselmeken 7,5mm (160cc) EDC with Baldur DSL1 ECU, Garrett GTX3576R A/R 1.06 without WG, SMF, 716.661 (SG-S370/6) Gearbox
I tryed several different drills. Untill i went to the local tools shop an bought reamers. After that it took me 20min do drill my chambers. But i only enlarged every second hole to 2,4 or 2,5mm according to the Suomi tuners recommendations.
But my engine is a Turbo so i have bigger holes then N/A engines from factory.
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Mercedes 190 -92, om605 Stroker 2.75L, Dieselmeken 7,5mm (160cc) EDC with Baldur DSL1 ECU, Garrett GTX3576R A/R 1.06 without WG, SMF, 716.661 (SG-S370/6) Gearbox
05-27-2016, 09:55 AM
#365
since people can´t loose some time Reading , here it goes again,
"durasteel" bits or "carbide" i have access to a brand called "maykestag, 6,000 rpm for 2.5mm .
but the best is use a portable hand drill , those battery type, use care this bits can be sharpened if need be, since they are very hard the may brake easily , but nothing that a half skiled tech can´t handle.
BTW the moderator could post a thread on how to drill cups , wich type of holes people use.. dadda those fancy things
FD,
Powered by tractor fuel
somewhere in the previous threads i explained how it can be done easy and cost efective,
since people can´t loose some time Reading , here it goes again,
"durasteel" bits or "carbide" i have access to a brand called "maykestag, 6,000 rpm for 2.5mm .
but the best is use a portable hand drill , those battery type, use care this bits can be sharpened if need be, since they are very hard the may brake easily , but nothing that a half skiled tech can´t handle.
BTW the moderator could post a thread on how to drill cups , wich type of holes people use.. dadda those fancy things
FD,
Powered by tractor fuel
05-27-2016, 01:34 PM
#366
PanicButton
05-27-2016, 01:34 PM #366Yep. Whether burrs, bits, or reamers... carbide is the way to go. I reamed mine with carbide reamers to the proper diameter, then conically "ported" them with a carbide burr. All in all 25 bucks on ebay.
03-06-2017, 06:16 PM
#367
(11-25-2015, 12:43 PM)Captain America(11-25-2015, 11:42 AM)MTUPower How big did you enlarge the holes to? How temps have you seen on your EGT? For how long? How much fuel are you putting in? Which all leads to - why do you think your head has cracks? ...and lastly- if the engine is running fine are you going to reinstall the head or a buy a new one?
3 Front holes are at .203
2 Rear holes are at .157
Bottom Hole at .126
Highest temp Ive seen is right at 1250f for a few seconds, and that is right before the turbo is spooled (running 16 psi with pump turned up by me)
Making a looooooooong pull temps sit at just over 1200f
the engine got hot a few times enough to boil water out of the reservoir tank that may have done it. that's the only thing I can think. I will acquire a new head and port it
![[Image: IMG_20140111_101408.jpg]](http://i64.photobucket.com/albums/h183/foxcrf450rider/Mobile%20Uploads/IMG_20140111_101408.jpg)
Not to be out done my Captain America, I have finally gotten around to the next phase in the evolution...
I am considering tapering the inside of the burn tube and back cutting under the injector heat shield seat in order to help keep the injector area cleared out. MB says to increase the seat hole to 14mm and to lower the seat 1mm to reduce smoke, but I got a little over zealous when I did the first set of turbo 616 PCs and lowered the seat to the point where the PC broke when I torqued down the injector. After that I would feel much better about angling the back side of the seat instead of lowering the seat surface.
(11-25-2015, 12:43 PM)Captain America(11-25-2015, 11:42 AM)MTUPower How big did you enlarge the holes to? How temps have you seen on your EGT? For how long? How much fuel are you putting in? Which all leads to - why do you think your head has cracks? ...and lastly- if the engine is running fine are you going to reinstall the head or a buy a new one?
3 Front holes are at .203
2 Rear holes are at .157
Bottom Hole at .126
Highest temp Ive seen is right at 1250f for a few seconds, and that is right before the turbo is spooled (running 16 psi with pump turned up by me)
Making a looooooooong pull temps sit at just over 1200f
the engine got hot a few times enough to boil water out of the reservoir tank that may have done it. that's the only thing I can think. I will acquire a new head and port it
Not to be out done my Captain America, I have finally gotten around to the next phase in the evolution...
I am considering tapering the inside of the burn tube and back cutting under the injector heat shield seat in order to help keep the injector area cleared out. MB says to increase the seat hole to 14mm and to lower the seat 1mm to reduce smoke, but I got a little over zealous when I did the first set of turbo 616 PCs and lowered the seat to the point where the PC broke when I torqued down the injector. After that I would feel much better about angling the back side of the seat instead of lowering the seat surface.
03-06-2017, 09:33 PM
#368
Looking forward to some test results...
1978 300D, 373,000km... OM617.912 with a Holset HX30W, 7.5mm IP, 711.113 5 speed (project car, 7 years off the road and counting ;/)
1977 250 270,000km (parts car)
1977 300D (ex 280) 500,000km
1981 240D 498,000
1975 HJ45 ???,000
2001 2.8TD Rodeo 4x2 - 456,000 - DD
Mmmmmmm nice. You yanks are so lucky to have lots of these engine lying around that you can do experiments like this.
Looking forward to some test results...
1978 300D, 373,000km... OM617.912 with a Holset HX30W, 7.5mm IP, 711.113 5 speed (project car, 7 years off the road and counting ;/)
1977 250 270,000km (parts car)
1977 300D (ex 280) 500,000km
1981 240D 498,000
1975 HJ45 ???,000
2001 2.8TD Rodeo 4x2 - 456,000 - DD
02-01-2018, 11:27 PM
#369
How have they gone?
I got a random thought about trying something like this, if only I could find some cheap as NA (post about 1979) prechambers
1978 300D, 373,000km... OM617.912 with a Holset HX30W, 7.5mm IP, 711.113 5 speed (project car, 7 years off the road and counting ;/)
1977 250 270,000km (parts car)
1977 300D (ex 280) 500,000km
1981 240D 498,000
1975 HJ45 ???,000
2001 2.8TD Rodeo 4x2 - 456,000 - DD
....so
How have they gone?
I got a random thought about trying something like this, if only I could find some cheap as NA (post about 1979) prechambers
1978 300D, 373,000km... OM617.912 with a Holset HX30W, 7.5mm IP, 711.113 5 speed (project car, 7 years off the road and counting ;/)
1977 250 270,000km (parts car)
1977 300D (ex 280) 500,000km
1981 240D 498,000
1975 HJ45 ???,000
2001 2.8TD Rodeo 4x2 - 456,000 - DD
02-03-2018, 07:00 PM
#370
(02-01-2018, 11:27 PM)NZScott ....so
How have they gone?
I got a random thought about trying something like this, if only I could find some cheap as NA (post about 1979) prechambers
I really really like them... One of those things where I wished I had just made the time and put them in earlier lol..
I should note that I have the camshaft advanced 10* and currently have the static timing (start of injection) at 28* BTDC. As soon as it gets warmer here I am going to bump it up to 30* and see how it takes it.
Also, for some reason, these PCs wanted a min of 26* or it would miss at idle, I am at a loss as to why, but when I put them in the timing was stock at 24* and it missed and the cold idle was ruff & smokey. I had a little adjustment left in the slots, so I advanced the pump as much as I could (got me to 26*) and it eliminated the miss and smoke. It does sound different though, more like a real diesel, but softer if that makes any sense..
I have had them in for about 6,000 miles so far. The funny part is it idles quieter at 28* than it did with the stock PCs at 24* lol.. Based on that I want to give it more and see how it does.
(02-01-2018, 11:27 PM)NZScott ....so
How have they gone?
I got a random thought about trying something like this, if only I could find some cheap as NA (post about 1979) prechambers
I really really like them... One of those things where I wished I had just made the time and put them in earlier lol..
I should note that I have the camshaft advanced 10* and currently have the static timing (start of injection) at 28* BTDC. As soon as it gets warmer here I am going to bump it up to 30* and see how it takes it.
Also, for some reason, these PCs wanted a min of 26* or it would miss at idle, I am at a loss as to why, but when I put them in the timing was stock at 24* and it missed and the cold idle was ruff & smokey. I had a little adjustment left in the slots, so I advanced the pump as much as I could (got me to 26*) and it eliminated the miss and smoke. It does sound different though, more like a real diesel, but softer if that makes any sense..
I have had them in for about 6,000 miles so far. The funny part is it idles quieter at 28* than it did with the stock PCs at 24* lol.. Based on that I want to give it more and see how it does.
02-06-2018, 05:53 AM
#371
1978 300D, 373,000km... OM617.912 with a Holset HX30W, 7.5mm IP, 711.113 5 speed (project car, 7 years off the road and counting ;/)
1977 250 270,000km (parts car)
1977 300D (ex 280) 500,000km
1981 240D 498,000
1975 HJ45 ???,000
2001 2.8TD Rodeo 4x2 - 456,000 - DD
Well that's a pleasant surprise, think everyone was counting on them running like crap. Think everyone now wants to know the power gain this gives...
1978 300D, 373,000km... OM617.912 with a Holset HX30W, 7.5mm IP, 711.113 5 speed (project car, 7 years off the road and counting ;/)
1977 250 270,000km (parts car)
1977 300D (ex 280) 500,000km
1981 240D 498,000
1975 HJ45 ???,000
2001 2.8TD Rodeo 4x2 - 456,000 - DD
02-08-2018, 12:04 PM
#373
(02-06-2018, 05:58 PM)R-3350 i would be interested in the effects with much more fueling. also would be interested in the BSFC with the new chambers.
Adding more fuel is just one way to make more power. The more timing you can run the better, but the stock PCs only fill so fast so they are limited to about 26* of lead time.. Increasing the diameter of the burn holes allows the PC to fill faster, thus reaching ignition temp sooner, allowing injection to happen sooner.
I went a step further and advanced my cam 10* so I am building pressure even sooner. I am currently at 28* and will go to 30* as soon is it gets warm out.. (too cold to work one the car lol). There is a considerable amount of power that can be had by tuning.
Once I find the limit timing wise and settle on a number, I am really tempted to dyno it. I would be really happy if I could see 160 ish at the wheels with stock elements. I have heavily modded the governor (eliminated the high speed governor spring and torque control function) so it does not back off fuel as it revs up.
Larger elements deliver fuel faster, so I will be interested to see what kind of timing I can run when I switch to 10mm elements.
(02-06-2018, 05:58 PM)R-3350 i would be interested in the effects with much more fueling. also would be interested in the BSFC with the new chambers.
Adding more fuel is just one way to make more power. The more timing you can run the better, but the stock PCs only fill so fast so they are limited to about 26* of lead time.. Increasing the diameter of the burn holes allows the PC to fill faster, thus reaching ignition temp sooner, allowing injection to happen sooner.
I went a step further and advanced my cam 10* so I am building pressure even sooner. I am currently at 28* and will go to 30* as soon is it gets warm out.. (too cold to work one the car lol). There is a considerable amount of power that can be had by tuning.
Once I find the limit timing wise and settle on a number, I am really tempted to dyno it. I would be really happy if I could see 160 ish at the wheels with stock elements. I have heavily modded the governor (eliminated the high speed governor spring and torque control function) so it does not back off fuel as it revs up.
Larger elements deliver fuel faster, so I will be interested to see what kind of timing I can run when I switch to 10mm elements.
02-09-2018, 10:47 AM
#374
85 300D om617: 8mm M pump 175cc 5200rpm, holset he221w @ 30psi, large A2W ic, compounds on the way.
i just wonder how they would handle a 2-3X increase in fueling. they may behave in a non linear way much past stock fueling. still its quite nice to see its working as intended i may be tempted to try these at some point.
85 300D om617: 8mm M pump 175cc 5200rpm, holset he221w @ 30psi, large A2W ic, compounds on the way.
02-09-2018, 12:18 PM
#375
(02-09-2018, 10:47 AM)R-3350 i just wonder how they would handle a 2-3X increase in fueling. they may behave in a non linear way much past stock fueling. still its quite nice to see its working as intended i may be tempted to try these at some point.
The ones I am running (and posted pictures of) have more done to them than just cutting a slot across the burn holes. I did a lot of internal work too. I am pretty sure I described what all I did though.
I think this is more of a hybred between DI and IDI.
(02-09-2018, 10:47 AM)R-3350 i just wonder how they would handle a 2-3X increase in fueling. they may behave in a non linear way much past stock fueling. still its quite nice to see its working as intended i may be tempted to try these at some point.
The ones I am running (and posted pictures of) have more done to them than just cutting a slot across the burn holes. I did a lot of internal work too. I am pretty sure I described what all I did though.
I think this is more of a hybred between DI and IDI.
02-09-2018, 11:42 PM
#376
85 300D om617: 8mm M pump 175cc 5200rpm, holset he221w @ 30psi, large A2W ic, compounds on the way.
i have been following this thread and your work closely so i am aware of the mods you have shared publicly at least. my concern circles around what would they behave like/do if fed 175cc/1k fueling with boost to match? while i am loathe to agree with FI in any manner i do have some concerns about the thermal rejection and integrity of these if subjected to significantly more than stock fueling and boost and the associated temperatures and pressures. that being said i would still try them i would just likely wait till the long block i am assembling is finished in case it lunched itself due to dropping a tip or burning a piston. all that aside i have to commend you for you work and the interesting progress you have made.
85 300D om617: 8mm M pump 175cc 5200rpm, holset he221w @ 30psi, large A2W ic, compounds on the way.
02-11-2018, 01:00 PM
#378
I do not see how this is a good thing..
whipplem104
02-11-2018, 01:00 PM #378So let me get this straight. You had to add timing with this mod? If so then you are slowing down the flame front. Or effecting quench.
I do not see how this is a good thing..
02-12-2018, 11:40 AM
#379
(02-11-2018, 01:00 PM)whipplem104 So let me get this straight. You had to add timing with this mod? If so then you are slowing down the flame front. Or effecting quench.
I do not see how this is a good thing..
That's funny..... All the carving and reaming I did totally changed everything..
The stock PC is designed to try to maintain pressure after ignition for as long as possible by restricting the exiting gas flow. What I have now is more like a large port swirl chamber where the primary combustion chamber volume stays the same, but the pressure rise and fall are not restricted very much.
My goal is to run as much timing as possible. This mod allows me to do that. It is not something for the meek to try
(02-11-2018, 01:00 PM)whipplem104 So let me get this straight. You had to add timing with this mod? If so then you are slowing down the flame front. Or effecting quench.
I do not see how this is a good thing..
That's funny..... All the carving and reaming I did totally changed everything..
The stock PC is designed to try to maintain pressure after ignition for as long as possible by restricting the exiting gas flow. What I have now is more like a large port swirl chamber where the primary combustion chamber volume stays the same, but the pressure rise and fall are not restricted very much.
My goal is to run as much timing as possible. This mod allows me to do that. It is not something for the meek to try
02-13-2018, 10:15 AM
#380
I had assumed that the larger holes were allowing a larger amount of fuel to burn at a quicker rate. Because the holes were to small and causing a restriction for the volume.
whipplem104
02-13-2018, 10:15 AM #380My point is that if you are having to run increased timing that you are slowing down the flame front. The fact that you are increasing timing means that you are taking longer to reach peak cylinder pressure. So I do not see how the mod is doing what you want, assuming you want more power. If your flame front was faster from the larger holes then you should decrease timing.
I had assumed that the larger holes were allowing a larger amount of fuel to burn at a quicker rate. Because the holes were to small and causing a restriction for the volume.
02-13-2018, 12:04 PM
#381
85 300D om617: 8mm M pump 175cc 5200rpm, holset he221w @ 30psi, large A2W ic, compounds on the way.
while i would agree that timing is best kept as little as is practically possible. i am not entirely sure that this is slowing down the flame front. i suspect that with it being closer to DI that it is experiencing more of an ignition delay like most other diesels. the PC impingement ball tends to cancel most of that delay at operating temps in the standard PC. but potentially with this opened set up it could be running a bit cooler so it takes a bit of time to get going while still increasing the combustion propagation speed into the chamber. thats why i was wondering about the BSFC it should be relatively evident if the BSFC goes up appreciably that the slower combustion Delta P means more time spent BTDC fighting it reducing efficiency. in a gas engine the less timing needed the better the burn however you don't have to factor things like ignition delay and PC to main chamber transfer times so im still watching this to see the results in data.
85 300D om617: 8mm M pump 175cc 5200rpm, holset he221w @ 30psi, large A2W ic, compounds on the way.
02-13-2018, 12:09 PM
#382
(02-13-2018, 10:15 AM)whipplem104 My point is that if you are having to run increased timing that you are slowing down the flame front. The fact that you are increasing timing means that you are taking longer to reach peak cylinder pressure. So I do not see how the mod is doing what you want, assuming you want more power. If your flame front was faster from the larger holes then you should decrease timing.
I had assumed that the larger holes were allowing a larger amount of fuel to burn at a quicker rate. Because the holes were to small and causing a restriction for the volume.
Increasing the burn hole size is not done to "burn at at quicker rate", it is done to increase the fresh air charge in the PC, which allows more fuel to be burned.
One side affect of reducing / eliminating the restriction between the cylinder and the PC is that the PC and cylinder pressures will rise closer to the same rate, and the PC charge will reach ignition condition sooner than the stock restricted PC will, which allows the injection to start sooner without nailing.
Reducing / eliminating the restriction between the PC and the cylinder has a dramatic effect on the pressures in each at every point during each cycle. The restrictions between the PC and the cylinder causes the cylinder pressure to be higher than the PC pressure prior to injection. Once injection starts, the PC pressure is higher than the cylinder pressure that is already pre-loaded (for lack of a better term, (think of a preloaded spring)) and the added volume from combustion goes to work. For small fuel volume injection, low power, this is efficient. But it limits how much fuel can be injected and requires high boost pressure to force more air into the PC to keep the EGTs in check, which generates crazy high pre injection cylinder pressures (pumping losses), crazy high post injection PC pressures, Smoke, and high EGTs.
Reducing / eliminating the restriction between the PC and the cylinder means that the effective pressure volume (the volume that has to be pressurized to a point where work will start, (how far does the spring have to be compressed before it is solid)) has increased, and the static pressure in the cylinder is lowered, so when ignition starts, the initial fuel is used to bring the cylinder pressure up to working levels (compresses the spring), where as before with the small holes, the cylinder pressure was at that point of work because of the restriction between the PC and cylinder.
What I have done is almost totally eliminate the aspects of the Prechamber design, and made it into more of a high flow Swirl Chamber with the pressure characteristics closer to a DI engine, so to expect that this set up would want the same timing as the stock set up is not reasonable. It is a totally different engine now, and it wants what it wants.
I have also gone a step further and changed the cam timing to further enhance the pumping efficiency which changes the cylinder / pc pressure rise timing. With the current settings, (cam + 10*, and static timing at 28*) the engine idles quieter than it did before the mod, EGTs are way lower, smoke is non existent, and the engine is significantly more responsive and runs stronger. I can tell by how it comes to life when the advance starts to come in that it wants more timing, so once it warms up I will set it to 30*. (I also want to replace my DVs as I have a bad one so I am also waiting until I get them)
I get the impression that you are thinking that I had to advance it 10* or something to make it run lol... I gave it 2*, from 24* to 26*.. who knows, it may have been happy at 25*.. Even an injector change can require that if one really wants to tune the engine. I laugh every time I hear someone quotes a timing speck from a manual as if that is the end all be all, when in reality from a tuning perspective, they are good starting points; each engine will want what it wants.
To your point, have I changed something? Yes.. Did it have a negative effect with a stock tuning? Yes... Did it allow me to run more aggressive fueling and timing, while lowering EGTs and Smoke, making more power, and increasing mileage when not driving like a maniac? Yes... Is this something that everyone should do? No
(02-13-2018, 10:15 AM)whipplem104 My point is that if you are having to run increased timing that you are slowing down the flame front. The fact that you are increasing timing means that you are taking longer to reach peak cylinder pressure. So I do not see how the mod is doing what you want, assuming you want more power. If your flame front was faster from the larger holes then you should decrease timing.
I had assumed that the larger holes were allowing a larger amount of fuel to burn at a quicker rate. Because the holes were to small and causing a restriction for the volume.
Increasing the burn hole size is not done to "burn at at quicker rate", it is done to increase the fresh air charge in the PC, which allows more fuel to be burned.
One side affect of reducing / eliminating the restriction between the cylinder and the PC is that the PC and cylinder pressures will rise closer to the same rate, and the PC charge will reach ignition condition sooner than the stock restricted PC will, which allows the injection to start sooner without nailing.
Reducing / eliminating the restriction between the PC and the cylinder has a dramatic effect on the pressures in each at every point during each cycle. The restrictions between the PC and the cylinder causes the cylinder pressure to be higher than the PC pressure prior to injection. Once injection starts, the PC pressure is higher than the cylinder pressure that is already pre-loaded (for lack of a better term, (think of a preloaded spring)) and the added volume from combustion goes to work. For small fuel volume injection, low power, this is efficient. But it limits how much fuel can be injected and requires high boost pressure to force more air into the PC to keep the EGTs in check, which generates crazy high pre injection cylinder pressures (pumping losses), crazy high post injection PC pressures, Smoke, and high EGTs.
Reducing / eliminating the restriction between the PC and the cylinder means that the effective pressure volume (the volume that has to be pressurized to a point where work will start, (how far does the spring have to be compressed before it is solid)) has increased, and the static pressure in the cylinder is lowered, so when ignition starts, the initial fuel is used to bring the cylinder pressure up to working levels (compresses the spring), where as before with the small holes, the cylinder pressure was at that point of work because of the restriction between the PC and cylinder.
What I have done is almost totally eliminate the aspects of the Prechamber design, and made it into more of a high flow Swirl Chamber with the pressure characteristics closer to a DI engine, so to expect that this set up would want the same timing as the stock set up is not reasonable. It is a totally different engine now, and it wants what it wants.
I have also gone a step further and changed the cam timing to further enhance the pumping efficiency which changes the cylinder / pc pressure rise timing. With the current settings, (cam + 10*, and static timing at 28*) the engine idles quieter than it did before the mod, EGTs are way lower, smoke is non existent, and the engine is significantly more responsive and runs stronger. I can tell by how it comes to life when the advance starts to come in that it wants more timing, so once it warms up I will set it to 30*. (I also want to replace my DVs as I have a bad one so I am also waiting until I get them)
I get the impression that you are thinking that I had to advance it 10* or something to make it run lol... I gave it 2*, from 24* to 26*.. who knows, it may have been happy at 25*.. Even an injector change can require that if one really wants to tune the engine. I laugh every time I hear someone quotes a timing speck from a manual as if that is the end all be all, when in reality from a tuning perspective, they are good starting points; each engine will want what it wants.
To your point, have I changed something? Yes.. Did it have a negative effect with a stock tuning? Yes... Did it allow me to run more aggressive fueling and timing, while lowering EGTs and Smoke, making more power, and increasing mileage when not driving like a maniac? Yes... Is this something that everyone should do? No
02-13-2018, 02:44 PM
#383
I would think that you would want a cam specifically designed for the injection pump for this in order for it to be of benefit?
whipplem104
02-13-2018, 02:44 PM #383So you are saying that the holes are enough of a restriction to keep the prechamber from reaching compression ignition as fast as the rest of the cylinder? So with larger holes it gets there sooner and you can start injection earlier because of this? And this is good for a more complete combustion and it does not shift peak cylinder pressure. Rather than speeding up actual combustion speed and the rate at which the flame front enters the combustion chamber.
I would think that you would want a cam specifically designed for the injection pump for this in order for it to be of benefit?
02-14-2018, 03:37 PM
#384
(02-13-2018, 02:44 PM)whipplem104 So you are saying that the holes are enough of a restriction to keep the prechamber from reaching compression ignition as fast as the rest of the cylinder? So with larger holes it gets there sooner and you can start injection earlier because of this? And this is good for a more complete combustion and it does not shift peak cylinder pressure. Rather than speeding up actual combustion speed and the rate at which the flame front enters the combustion chamber.
I would think that you would want a cam specifically designed for the injection pump for this in order for it to be of benefit?
Bigger elements will deliver fuel at a faster rate. My goal this summer is to finally get the pump machine built, so I can build a 10mm pump for it, and a couple others that I said I would. That will totally change things again timing wise, and I will have to find out how much timing it wants all over again.
This set up is not for low emissions or minimizing fuel consumption, I consider this in line with putting bigger valves and a high lift and overlap cam in a V8. The more air I can get into the PC and the sooner I can inject it, the more fuel I can burn. The more fuel I can burn, the more power it will make.
(02-13-2018, 02:44 PM)whipplem104 So you are saying that the holes are enough of a restriction to keep the prechamber from reaching compression ignition as fast as the rest of the cylinder? So with larger holes it gets there sooner and you can start injection earlier because of this? And this is good for a more complete combustion and it does not shift peak cylinder pressure. Rather than speeding up actual combustion speed and the rate at which the flame front enters the combustion chamber.
I would think that you would want a cam specifically designed for the injection pump for this in order for it to be of benefit?
Bigger elements will deliver fuel at a faster rate. My goal this summer is to finally get the pump machine built, so I can build a 10mm pump for it, and a couple others that I said I would. That will totally change things again timing wise, and I will have to find out how much timing it wants all over again.
This set up is not for low emissions or minimizing fuel consumption, I consider this in line with putting bigger valves and a high lift and overlap cam in a V8. The more air I can get into the PC and the sooner I can inject it, the more fuel I can burn. The more fuel I can burn, the more power it will make.
02-14-2018, 05:09 PM
#385
I really want to hear how the engine sounds with the modified prechambers. Make a video if you can. Does it still have the specific sound of MB prechamber engines ?
It's pretty interesting though that it wants advanced timing. It goes againstexperience in DI and IDI engines. DI engines often run timing as low as 5-10 degrees BTDC, up to 20 degrees BTDC. Swirl and prechamber engines are similar and run timing advanced compared to DI - 20-30 degrees BTDC.
I really want to hear how the engine sounds with the modified prechambers. Make a video if you can. Does it still have the specific sound of MB prechamber engines ?
02-15-2018, 11:16 AM
#386
(02-14-2018, 05:09 PM)Petar It's pretty interesting though that it wants advanced timing. It goes againstexperience in DI and IDI engines. DI engines often run timing as low as 5-10 degrees BTDC, up to 20 degrees BTDC. Swirl and prechamber engines are similar and run timing advanced compared to DI - 20-30 degrees BTDC.
I really want to hear how the engine sounds with the modified prechambers. Make a video if you can. Does it still have the specific sound of MB prechamber engines ?
It sounds the same at idle.. I would say a little softer rattle maybe.. or less harsh.. There is a difference in its sound when you are driving though. A stock set up rattles at idle and then quiets down once you start to take off, but with this set up as you take off, it has a nice soft, subtle, rattle like a Cummins or a regular diesel for that matter, but it is really soft, nothing harsh like a crackle or nailing. By 2K it is quite like normal.
The original poster who recommended tapering the inside of the burn tube also commented that he had to add a little advance, and I do not think he touched the burn holes, but I may be mistaken about that... These days I am more interested in results than why lol..
(02-14-2018, 05:09 PM)Petar It's pretty interesting though that it wants advanced timing. It goes againstexperience in DI and IDI engines. DI engines often run timing as low as 5-10 degrees BTDC, up to 20 degrees BTDC. Swirl and prechamber engines are similar and run timing advanced compared to DI - 20-30 degrees BTDC.
I really want to hear how the engine sounds with the modified prechambers. Make a video if you can. Does it still have the specific sound of MB prechamber engines ?
It sounds the same at idle.. I would say a little softer rattle maybe.. or less harsh.. There is a difference in its sound when you are driving though. A stock set up rattles at idle and then quiets down once you start to take off, but with this set up as you take off, it has a nice soft, subtle, rattle like a Cummins or a regular diesel for that matter, but it is really soft, nothing harsh like a crackle or nailing. By 2K it is quite like normal.
The original poster who recommended tapering the inside of the burn tube also commented that he had to add a little advance, and I do not think he touched the burn holes, but I may be mistaken about that... These days I am more interested in results than why lol..
03-08-2018, 11:04 AM
#387
I like what the 10* did for me, and by the way it runs, I think there is more to be had by advancing it a little more. I think one tooth is 20* but I need to confirm that. I also want to check for valve clearance, so I will advance the cam one tooth on a donor engine I have and see how much intake valve movement there is first.
Also getting ready for a bigger turbo and advancing the injection timing to 30* BTDC.
From the testing that other members have done, there is definitely a difference in the set up for a "restricted PC" (with holes) and with an "open PC" (Open slot).
I think I am going to try advancing the cam 4 more degrees for a total of 14* advanced over stock and see what that does.
I like what the 10* did for me, and by the way it runs, I think there is more to be had by advancing it a little more. I think one tooth is 20* but I need to confirm that. I also want to check for valve clearance, so I will advance the cam one tooth on a donor engine I have and see how much intake valve movement there is first.
Also getting ready for a bigger turbo and advancing the injection timing to 30* BTDC.
From the testing that other members have done, there is definitely a difference in the set up for a "restricted PC" (with holes) and with an "open PC" (Open slot).
03-09-2018, 06:31 AM
#388
2005 CDI heavily modified 1984 300TD - Myna pump/TMIC/enlarged PC's/HX30Super/W126 II front brakes/Vogtland springs/EGT +Boost gauges/H4 Hella's
I just bought a wagon block with the head and it's sitting in the grosch. My current PC's are enlarged but I think I'm going to pull the ones in the "new" block and make them even more enlarged. The head's intake ports will be enlarged as well as the exhaust ports and with all this timing will be advanced even more than it is now. More air to get in and out should see the engine more responsive and make more power.
2005 CDI heavily modified 1984 300TD - Myna pump/TMIC/enlarged PC's/HX30Super/W126 II front brakes/Vogtland springs/EGT +Boost gauges/H4 Hella's
03-09-2018, 11:20 AM
#389
(03-09-2018, 06:31 AM)MTUPower I just bought a wagon block with the head and it's sitting in the grosch. My current PC's are enlarged but I think I'm going to pull the ones in the "new" block and make them even more enlarged. The head's intake ports will be enlarged as well as the exhaust ports and with all this timing will be advanced even more than it is now. More air to get in and out should see the engine more responsive and make more power.
Yep.
More air will support more fuel. More timing will allow more of the fuel to be burnt by the time the connecting rod big end goes over center.
(03-09-2018, 06:31 AM)MTUPower I just bought a wagon block with the head and it's sitting in the grosch. My current PC's are enlarged but I think I'm going to pull the ones in the "new" block and make them even more enlarged. The head's intake ports will be enlarged as well as the exhaust ports and with all this timing will be advanced even more than it is now. More air to get in and out should see the engine more responsive and make more power.
Yep.
More air will support more fuel. More timing will allow more of the fuel to be burnt by the time the connecting rod big end goes over center.
03-14-2018, 08:52 AM
#390
Anyone who is looking at a custom cam should really be careful. The valve relief pockets need to be made deeper if any significant changes in cam geometry are being considered.
If anyone has a bad 617a piston, I would be interested in it to cut apart to see how much deeper I can make the valve relief pockets without making the piston too thin, (I have no idea what the oil cavity looks like).
I wanted to advance the cam another 5 degrees at the crank, but there is no way without cutting the pistons.
There are 40 teeth on the cam gear, so each tooth is worth 9 degrees at the cam, 18 degrees at the crank. I advanced the cam one tooth on a donor engine, and checked for valve clearance. There was interference at the intake valve that prevented rotation. Right now I am running the cam advanced 5 degrees at the cam which is 10 degrees at the crank and that is all that there is to be had.
Anyone who is looking at a custom cam should really be careful. The valve relief pockets need to be made deeper if any significant changes in cam geometry are being considered.
If anyone has a bad 617a piston, I would be interested in it to cut apart to see how much deeper I can make the valve relief pockets without making the piston too thin, (I have no idea what the oil cavity looks like).
I wanted to advance the cam another 5 degrees at the crank, but there is no way without cutting the pistons.
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