Prechamber Mod.
Prechamber Mod.
Taper the transfer tube 10mm down to 8mm Results: cold start better than stock,stronger idle,much improved cold performance
improved low,mid. and high rpm.same or less smoke. Good for high or low altitude,engine is smoother in operation.
No down side that I can determine Easy mod. to do. Do remember to cut a small chamfer leading in to the taper,but no wider than
3/32 of an inch or there will be a small amount of momentary low end loss.
Prechamber Mod.
Taper the transfer tube 10mm down to 8mm Results: cold start better than stock,stronger idle,much improved cold performance
improved low,mid. and high rpm.same or less smoke. Good for high or low altitude,engine is smoother in operation.
No down side that I can determine Easy mod. to do. Do remember to cut a small chamfer leading in to the taper,but no wider than
3/32 of an inch or there will be a small amount of momentary low end loss.
im not saying not to modify the pre-chambers. i have bored out the expansion holes by around.020" and chamfered the at around 15*. this did noticeably help with output and smoking however i am running significantly more boost and fuel. as such im not sure what effect it might have on a stock engine.
if by the transfer tube you mean the exterior of the lower tube that is a very bad idea. this would help cold performance due to the lowered heat rejection from the tip increasing the combustion temps. however at WOT it would likely melt or crack the head. the lower half of the pre-chamber is made of Nimonic 80A a early predecessor to the Hastelloy series and somewhat similar to the 600 series of Inconel. while these alloys are quite resistant to thermal creep, oxidation, and carburization they cant take that kind of punishment forever. in the SAE paper on the development of the 617.95 engines they recorded the pre-chamber temps at various zones while in operation. the peak temp at the tip was 970*C. while Nimonic 80A would survive up to around 1600 the mechanical strength reduction is an almost exponential curve past 1100*C. the reduced heat rejection tothe head from the tips would result in rapid thermal failure at high power.
im not saying not to modify the pre-chambers. i have bored out the expansion holes by around.020" and chamfered the at around 15*. this did noticeably help with output and smoking however i am running significantly more boost and fuel. as such im not sure what effect it might have on a stock engine.
failure,burning or melting of tip. 30.000 miles later, 1-1,600 mi. trip mostly 80-85 m,p.h. 12- 14 hr. days ,have pulled those prechambers,and cleaned and checked
with a eye loop inside and out,no signs of any damage,no discoloration. Lower end of transfer tube stays the same as stock,so there will be no over heating
of tip. Most of material removed at top of the the transfer tube. Hope this helps.
A little better info. from me,Talking about 617 engine,taper inside hole of transfer tube on prechamber. Outside taper I agree,would cause premature
failure,burning or melting of tip. 30.000 miles later, 1-1,600 mi. trip mostly 80-85 m,p.h. 12- 14 hr. days ,have pulled those prechambers,and cleaned and checked
with a eye loop inside and out,no signs of any damage,no discoloration. Lower end of transfer tube stays the same as stock,so there will be no over heating
of tip. Most of material removed at top of the the transfer tube. Hope this helps.
Quality 1/2 pipe reamer,measure where on transfer tube where the inside 8mm ends,about where tip necks down,leave about 1/8 inch of inside tube unchanged.
Now grind off end of reamer,will take a while,very hard,measure up from end of reamer to the area to be untouched,round end of reamer.that is your stop.
Drill press works great,lube reamer well,do not press hard ,no need to,cut a small distance,stop,clean reamer,dump chips from prechamber,relube do again.
Should take 7-8 times doing this to hit bottom. Remember to chamfer top of newly cut hole,but not more than 3/32 ". Learned this the hard way.
Lost a small bit of the just off idle performance by cutting wider. With most reamers should leave about a 10mm hole at top. My reamer was made by bluepoint.
Scribe the pin to prechamber on large end of pin (placement) then with pin punch tap out on small end of pin towards large end.Small bit hard at first.
Quality 1/2 pipe reamer,measure where on transfer tube where the inside 8mm ends,about where tip necks down,leave about 1/8 inch of inside tube unchanged.
Now grind off end of reamer,will take a while,very hard,measure up from end of reamer to the area to be untouched,round end of reamer.that is your stop.
Drill press works great,lube reamer well,do not press hard ,no need to,cut a small distance,stop,clean reamer,dump chips from prechamber,relube do again.
Should take 7-8 times doing this to hit bottom. Remember to chamfer top of newly cut hole,but not more than 3/32 ". Learned this the hard way.
Lost a small bit of the just off idle performance by cutting wider. With most reamers should leave about a 10mm hole at top. My reamer was made by bluepoint.
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
Sorry I'm a bit lost. Can you describe with a drawing? Are you tapering the inside of the 'firing duct" where it meets the chamber proper?
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
advanced,fuel will not be completely ready to burn well,that"s the reason for advancing timing, to give the fuel a head start,a little more time.
There is some performance gains with this method,very good near sea level BUT the higher in elevation starting about 1,500 hundred ft. loss
of performance and heavy smoking. With a taper the timing will not need to be reset,performance gains will be achieved and no more than
normal smoking at altitude. Will most likely see a fuel mileage increase,if you can keep your foot off.
Thank you TK for posting that picture ,always have trouble doing that. If one increases size of transfer tube to 10mm timing will need to be
advanced,fuel will not be completely ready to burn well,that"s the reason for advancing timing, to give the fuel a head start,a little more time.
There is some performance gains with this method,very good near sea level BUT the higher in elevation starting about 1,500 hundred ft. loss
of performance and heavy smoking. With a taper the timing will not need to be reset,performance gains will be achieved and no more than
normal smoking at altitude. Will most likely see a fuel mileage increase,if you can keep your foot off.
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
This?
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
altitude, well at sea level there is 1013 mb, at 18.000 ft there is half that , but using a turbo will eliminate that thing and i seriously doubt someone will drive above 5.000 ft were atmosferic pressure is 900mb...
dadadad.
Thanks for posting those conclusions , maybe i will try them, and have success, but be aware that in a 60X engine the neck is 7mm.
FD,
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Nothing to comment against those conclusions, one thing i have learn this far about pre cups... is that with superpumps that concept is completely against what everibody is doing...
altitude, well at sea level there is 1013 mb, at 18.000 ft there is half that , but using a turbo will eliminate that thing and i seriously doubt someone will drive above 5.000 ft were atmosferic pressure is 900mb...
dadadad.
Thanks for posting those conclusions , maybe i will try them, and have success, but be aware that in a 60X engine the neck is 7mm.
FD,
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Yes ,I could see if a later model,larger more efficient turbo was used less smoking would happen.Not every one has that.
I almost always think out side the (box),meaning I ponder what others are saying or doing and not just go alone with the crowd.
For an example:WHY did M.B. drop to a 7mm burn tube??? WAS it for a lower emissions? possible just off idle smoothness?
I can not believe it was for higher performance. Please advise!! With facts.
I lived at 7,200 hundred ft.high dry desert,passing through Yosemite Ca.often.UP and over the pass 9,200 hundred down to near
sea level,not all people live in the flat low lands. Can up with this mod.tried what others had done with out much success.
So far have not noticed any down side to this mod.
Hi Barrote,yes I am aware that the 60x engine has a 7mm neck hole. The 61x has a 8mm,so thought I"d start there.
Yes ,I could see if a later model,larger more efficient turbo was used less smoking would happen.Not every one has that.
I almost always think out side the (box),meaning I ponder what others are saying or doing and not just go alone with the crowd.
For an example:WHY did M.B. drop to a 7mm burn tube??? WAS it for a lower emissions? possible just off idle smoothness?
I can not believe it was for higher performance. Please advise!! With facts.
I lived at 7,200 hundred ft.high dry desert,passing through Yosemite Ca.often.UP and over the pass 9,200 hundred down to near
sea level,not all people live in the flat low lands. Can up with this mod.tried what others had done with out much success.
So far have not noticed any down side to this mod.
Modern diesel are amazing because of the benefit of evolutionary design as well as CFD analysis, which Mercedes didn't have available to them when they designed the OM617. They made changes until a desired result then called it good. I'm a design engineer so I know what the process is like. The reasons for the result could very well be emissions, reduction of NVH, or anything else that may or may not contribute to efficiency or power production.
I think the tapering of the throat is a valid hypothesis to test because fluid flow likes nozzles, which is what is being created. In this patent for Cummins, in section 0039, they talk about the nozzle shape and how it reduces separation of flow.
https://www.google.com/patents/US20140261298
They also talk about the importance of radiusing the apertures to maximize mass flow. If I ever pull my prechambers I'm definitely going to do that!
It is very difficult to have "facts" concerning Mercedes prechamber mods. Too few scientific style experiments have been done, like dyno - make a change - dyno - record result. That's what we need but I don't think anyone has done it.
Modern diesel are amazing because of the benefit of evolutionary design as well as CFD analysis, which Mercedes didn't have available to them when they designed the OM617. They made changes until a desired result then called it good. I'm a design engineer so I know what the process is like. The reasons for the result could very well be emissions, reduction of NVH, or anything else that may or may not contribute to efficiency or power production.
I think the tapering of the throat is a valid hypothesis to test because fluid flow likes nozzles, which is what is being created. In this patent for Cummins, in section 0039, they talk about the nozzle shape and how it reduces separation of flow.
https://www.google.com/patents/US20140261298
They also talk about the importance of radiusing the apertures to maximize mass flow. If I ever pull my prechambers I'm definitely going to do that!
As were talking about old tech. another mod.could poss. help some. Years ago 60s poss.70s the impingement pin was not flat on bottom,
but instead had a concave drilled spot.Said to increase turbulence in air flow. Done away with for many years than reintroduced after 85 models.
Does it help??? Poss. with smoke. Did this also and rotated about 10% Do not think M.B. would go to that trouble if it did not help.
Very well said TK . Merceds did not have all the answers back then,or even now,always new and better ways being introduced.
As were talking about old tech. another mod.could poss. help some. Years ago 60s poss.70s the impingement pin was not flat on bottom,
but instead had a concave drilled spot.Said to increase turbulence in air flow. Done away with for many years than reintroduced after 85 models.
Does it help??? Poss. with smoke. Did this also and rotated about 10% Do not think M.B. would go to that trouble if it did not help.
DI engines were not aceptable for MB due mainly to noise and vibes, even when they had to go DI(europe 1999) they choose CDI with the pre injection and some interesting figures like piston bowl and some fancy noise counter devices... but that has all to be done inside emissions regulations.
U my Forum Friends never be tempted to compare a MB automobile(engine) to anything else, and besides Diesel industry lives in germany not elsewhere, just to name a few , MAN , MB, MTU, DEUTZ, LIEBERR , and some other automotive manufactrers .
not this days , but still are some intersting features.
If u want to controll your IDI engine smoke, use premium diesel , maintain compression numbers , run it as lean as u can above 22/1 ratio.
ad a catalitic converter, and particle filter trap oxidizer, those with AD blue .
as of me , collums of dark grey smoke behind the tail....
FD,
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Hy , again .... the IDI is just what it is .... it smokes and none smoke less than a MB... yes prechambers and injector mods in MB IDI had to separate concerns , when the diesel engine was introduced in automobiles, MB was the only brand that succeded with the noise and vibrations, and this was due to high internal mass and injection type.
DI engines were not aceptable for MB due mainly to noise and vibes, even when they had to go DI(europe 1999) they choose CDI with the pre injection and some interesting figures like piston bowl and some fancy noise counter devices... but that has all to be done inside emissions regulations.
U my Forum Friends never be tempted to compare a MB automobile(engine) to anything else, and besides Diesel industry lives in germany not elsewhere, just to name a few , MAN , MB, MTU, DEUTZ, LIEBERR , and some other automotive manufactrers .
not this days , but still are some intersting features.
If u want to controll your IDI engine smoke, use premium diesel , maintain compression numbers , run it as lean as u can above 22/1 ratio.
ad a catalitic converter, and particle filter trap oxidizer, those with AD blue .
as of me , collums of dark grey smoke behind the tail....
FD,
Powered by tractor fuel
(01-04-2017, 12:21 AM)Hercules Scribe the pin to prechamber on large end of pin (placement) then with pin punch tap out on small end of pin towards large end.Small bit hard at first.
Quality 1/2 pipe reamer,measure where on transfer tube where the inside 8mm ends,about where tip necks down,leave about 1/8 inch of inside tube unchanged.
Now grind off end of reamer,will take a while,very hard,measure up from end of reamer to the area to be untouched,round end of reamer.that is your stop.
Drill press works great,lube reamer well,do not press hard ,no need to,cut a small distance,stop,clean reamer,dump chips from prechamber,relube do again.
Should take 7-8 times doing this to hit bottom. Remember to chamfer top of newly cut hole,but not more than 3/32 ". Learned this the hard way.
Lost a small bit of the just off idle performance by cutting wider. With most reamers should leave about a 10mm hole at top. My reamer was made by bluepoint.
I am considering doing this as well but the dimensions of a 1/2 inch NPT reamer do not correlate with your specks.
The diameter of the small end of a 1/2 NPT reamer is .665 inches (16.89MM) and 8MM = .3149 inches
A 1/8 NPT reamer small end is .316 inches (8.02MM) and has a big end diameter of .362 inches (9.19MM)
The angle of a NPT thread is 1.78 degrees (give or take).
Have I misunderstood what you did and used?
(01-04-2017, 12:21 AM)Hercules Scribe the pin to prechamber on large end of pin (placement) then with pin punch tap out on small end of pin towards large end.Small bit hard at first.
Quality 1/2 pipe reamer,measure where on transfer tube where the inside 8mm ends,about where tip necks down,leave about 1/8 inch of inside tube unchanged.
Now grind off end of reamer,will take a while,very hard,measure up from end of reamer to the area to be untouched,round end of reamer.that is your stop.
Drill press works great,lube reamer well,do not press hard ,no need to,cut a small distance,stop,clean reamer,dump chips from prechamber,relube do again.
Should take 7-8 times doing this to hit bottom. Remember to chamfer top of newly cut hole,but not more than 3/32 ". Learned this the hard way.
Lost a small bit of the just off idle performance by cutting wider. With most reamers should leave about a 10mm hole at top. My reamer was made by bluepoint.
I am considering doing this as well but the dimensions of a 1/2 inch NPT reamer do not correlate with your specks.
The diameter of the small end of a 1/2 NPT reamer is .665 inches (16.89MM) and 8MM = .3149 inches
A 1/8 NPT reamer small end is .316 inches (8.02MM) and has a big end diameter of .362 inches (9.19MM)
The angle of a NPT thread is 1.78 degrees (give or take).
Have I misunderstood what you did and used?
(flame tube).
Nice clean looking job on that prechamber, I taper opened my outlets,had to advance timing 3 degrees, my guess was taking
longer for the flame travel, (spreading ) out more. Please post your results.
Yes you are correct , should be a 1/8 to 1/2 taper pipe reamer.Grind off end until 8mm size just above end of transfer tube,
(flame tube).
Nice clean looking job on that prechamber, I taper opened my outlets,had to advance timing 3 degrees, my guess was taking
longer for the flame travel, (spreading ) out more. Please post your results.
like a Di engine. Too much of the heat energy being used up as piston is near the top of stroke.
Slot may work,but I do know that speed of flame is very important. A wide fan on outlet of prechamber produces slower travel
speeds,which means slower temperature rise.Advanced timing would be needed,to give more time.
Just thinking out loud,If slot could work,I think maximum out let area would be no more than total front hole area.
I would think there must be enough restriction to have enough pressure to still have flame travel out the other holes.
Good luck,keep us posted of results.
Pondering the slot idea on prechamber,there must be a restriction to slow flame or top end will be effected,becoming to much
like a Di engine. Too much of the heat energy being used up as piston is near the top of stroke.
Slot may work,but I do know that speed of flame is very important. A wide fan on outlet of prechamber produces slower travel
speeds,which means slower temperature rise.Advanced timing would be needed,to give more time.
Just thinking out loud,If slot could work,I think maximum out let area would be no more than total front hole area.
I would think there must be enough restriction to have enough pressure to still have flame travel out the other holes.
Good luck,keep us posted of results.
(03-05-2017, 01:14 AM)OM616 I decided to take some me time and finally do something fun. My 300D needs injectors and I have been holding off putting in new ones until I modded the perchambers I had so I can swap out both in one shot.
http://www.superturbodiesel.com/std/atta...p?aid=8997
What are the advantages with this mod?
(03-05-2017, 01:14 AM)OM616 I decided to take some me time and finally do something fun. My 300D needs injectors and I have been holding off putting in new ones until I modded the perchambers I had so I can swap out both in one shot.
http://www.superturbodiesel.com/std/atta...p?aid=8997
What are the advantages with this mod?
(03-06-2017, 04:25 AM)erx(03-05-2017, 01:14 AM)OM616 I decided to take some me time and finally do something fun. My 300D needs injectors and I have been holding off putting in new ones until I modded the perchambers I had so I can swap out both in one shot.
http://www.superturbodiesel.com/std/atta...p?aid=8997
What are the advantages with this mod?
LOL... That remains to be seen
For the story on how things progressed to this point see http://www.superturbodiesel.com/std/show...p?tid=2169
(03-06-2017, 04:25 AM)erx(03-05-2017, 01:14 AM)OM616 I decided to take some me time and finally do something fun. My 300D needs injectors and I have been holding off putting in new ones until I modded the perchambers I had so I can swap out both in one shot.
http://www.superturbodiesel.com/std/atta...p?aid=8997
What are the advantages with this mod?
LOL... That remains to be seen
For the story on how things progressed to this point see http://www.superturbodiesel.com/std/show...p?tid=2169
(03-05-2017, 06:00 PM)Hercules Yes you are correct , should be a 1/8 to 1/2 taper pipe reamer.Grind off end until 8mm size just above end of transfer tube,
(flame tube).
Nice clean looking job on that prechamber, I taper opened my outlets,had to advance timing 3 degrees, my guess was taking
longer for the flame travel, (spreading ) out more. Please post your results.
Can you take a pic of the reamer you used? I have a 1/8 NPT reamer here and it is consistent with the specks I posted. The very end is just over 8mm in diameter and will create a step in the wall of the burn tube.
At 10mm the wall thickness will be about .100" which I am ok with, but the largest diameter of the reamer is just over 9mm. Before I have a reamer made that will do what I want, I want to make sure that I am not misunderstanding something.
(03-05-2017, 06:00 PM)Hercules Yes you are correct , should be a 1/8 to 1/2 taper pipe reamer.Grind off end until 8mm size just above end of transfer tube,
(flame tube).
Nice clean looking job on that prechamber, I taper opened my outlets,had to advance timing 3 degrees, my guess was taking
longer for the flame travel, (spreading ) out more. Please post your results.
Can you take a pic of the reamer you used? I have a 1/8 NPT reamer here and it is consistent with the specks I posted. The very end is just over 8mm in diameter and will create a step in the wall of the burn tube.
At 10mm the wall thickness will be about .100" which I am ok with, but the largest diameter of the reamer is just over 9mm. Before I have a reamer made that will do what I want, I want to make sure that I am not misunderstanding something.
(03-06-2017, 11:10 PM)Hercules Did a web search for the tool used. Look up repairman"s reamer. very common tool,and not very costly. $8.00-$15.00
goes from 1/8"-1/2"in size. Who knew that would be the name??
Agh! that makes more sense..
I back cut bellow the seat to help keep the nozzle tip cleared out and reamed the burn tube. I am also going to angle the ball flat a little more than stock.
These prechambers have really been worked over lol..
(03-06-2017, 11:10 PM)Hercules Did a web search for the tool used. Look up repairman"s reamer. very common tool,and not very costly. $8.00-$15.00
goes from 1/8"-1/2"in size. Who knew that would be the name??
Agh! that makes more sense..
I back cut bellow the seat to help keep the nozzle tip cleared out and reamed the burn tube. I am also going to angle the ball flat a little more than stock.
These prechambers have really been worked over lol..
Newbie-read this: Cheap Tricks
617.952-220k-Getting built up
larsalan I guess I need to look at this stupid ass drip shit. What you have to like mess with those elements on the pump? What a fucking hassle. then use some wire to hold the throttle open or some shit?
Simpler=Better
03-20-2017, 10:39 AM #27You're doing the lord's work sun.
Newbie-read this: Cheap Tricks
617.952-220k-Getting built up
larsalan I guess I need to look at this stupid ass drip shit. What you have to like mess with those elements on the pump? What a fucking hassle. then use some wire to hold the throttle open or some shit?
Newbie-read this: Cheap Tricks
617.952-220k-Getting built up
larsalan I guess I need to look at this stupid ass drip shit. What you have to like mess with those elements on the pump? What a fucking hassle. then use some wire to hold the throttle open or some shit?
Simpler=Better
04-03-2017, 01:31 PM #28Bumpity bump bump
Newbie-read this: Cheap Tricks
617.952-220k-Getting built up
larsalan I guess I need to look at this stupid ass drip shit. What you have to like mess with those elements on the pump? What a fucking hassle. then use some wire to hold the throttle open or some shit?
(04-03-2017, 01:31 PM)Simpler=Better Bumpity bump bump
The machining is done, need to clean them up and reinstall the balls, then put them in along with "special" injectors.. definitely an "Oh Shit Change" lol
I had to take my mom to the hospital a week ago and I have been here ever sense so this is on hold until she is better.
I can't think of anything else to do them while they are apart. I really don't have time to play with this car, so I am hoping it likes the new PCs lol...
(04-03-2017, 01:31 PM)Simpler=Better Bumpity bump bump
The machining is done, need to clean them up and reinstall the balls, then put them in along with "special" injectors.. definitely an "Oh Shit Change" lol
I had to take my mom to the hospital a week ago and I have been here ever sense so this is on hold until she is better.
I can't think of anything else to do them while they are apart. I really don't have time to play with this car, so I am hoping it likes the new PCs lol...
I have neglected performing maintenance for some time and it caught up with me... The Glow Plugs were going south and one morning most of them gave up.. So I thought I would swap out the prechambers and replace the glow plugs and injectors... I tried some Chinese nozzles that I have been working on and although they ran fine, I was not pleased with the sound and smoke, so I put the old ones back in. It ran smoother and did not smoke quite as much when cold, but is still noisy..
I thought that these prechambers were going to be radical and I was right.. There is definitely a trade off between high end and cold Idle warm up / quiet idle as the flow rate of the Prechamber goes up..
It starts real nice and smooth when cold, but as soon as the glow plugs cool down, its starts to lope and miss now and then, bluish gray smoke, and is rattely..
Driveability is not really affected, and once it warms up the smoke at idle goes away. It really likes high speed running and I can really tell when the advance comes in because it starts to pull stronger and builds more boost faster than before. ( I have the waste gate actuator unplugged). I now really have to watch the boost gauge because it builds more boost at what feels like the same petal input. ( This is my daily driver so I instinctively drive it and can tell the difference in how it runs)..
It really likes the highway, and revs well.. Definitely can handle more advance and fuel.. I cant make it smoke under load like it did before..
I dont have an EGT gauge so I cant report on temps..
The idle is rattley like a truck.. I would not call it nailing, but it is a strong diesel rattle that goes away when you take off.
I am going to advance the cam 8* and see if that cleans up the idle at all.. and I need some good nozzles... If that does not clean up the cold warm up, I will drill out the original prechambers to the same specks that I did my turbo 616 and put those in. If I end up doing that, the ones I am running will be available if someone wants them..
They would be great for a track car or someone who doesn't mind trading off a nosier idle, and maybe a little smoke at idle, for as much power as their fuel setting can make with out smoke..
I have not touched the pump at all on this car, but I would bet that a HX30 and a 10mm pump would really run well.
I think it is safe to say that this is as close to a direct injection mod as can be done on a om617 engine. At this point in my life, I think I prefer a half way mod lol.. That being said, when I take off from a light now, I hate the tought of going backwards lol..
Up date...
I have neglected performing maintenance for some time and it caught up with me... The Glow Plugs were going south and one morning most of them gave up.. So I thought I would swap out the prechambers and replace the glow plugs and injectors... I tried some Chinese nozzles that I have been working on and although they ran fine, I was not pleased with the sound and smoke, so I put the old ones back in. It ran smoother and did not smoke quite as much when cold, but is still noisy..
I thought that these prechambers were going to be radical and I was right.. There is definitely a trade off between high end and cold Idle warm up / quiet idle as the flow rate of the Prechamber goes up..
It starts real nice and smooth when cold, but as soon as the glow plugs cool down, its starts to lope and miss now and then, bluish gray smoke, and is rattely..
Driveability is not really affected, and once it warms up the smoke at idle goes away. It really likes high speed running and I can really tell when the advance comes in because it starts to pull stronger and builds more boost faster than before. ( I have the waste gate actuator unplugged). I now really have to watch the boost gauge because it builds more boost at what feels like the same petal input. ( This is my daily driver so I instinctively drive it and can tell the difference in how it runs)..
It really likes the highway, and revs well.. Definitely can handle more advance and fuel.. I cant make it smoke under load like it did before..
I dont have an EGT gauge so I cant report on temps..
The idle is rattley like a truck.. I would not call it nailing, but it is a strong diesel rattle that goes away when you take off.
I am going to advance the cam 8* and see if that cleans up the idle at all.. and I need some good nozzles... If that does not clean up the cold warm up, I will drill out the original prechambers to the same specks that I did my turbo 616 and put those in. If I end up doing that, the ones I am running will be available if someone wants them..
They would be great for a track car or someone who doesn't mind trading off a nosier idle, and maybe a little smoke at idle, for as much power as their fuel setting can make with out smoke..
I have not touched the pump at all on this car, but I would bet that a HX30 and a 10mm pump would really run well.
I think it is safe to say that this is as close to a direct injection mod as can be done on a om617 engine. At this point in my life, I think I prefer a half way mod lol.. That being said, when I take off from a light now, I hate the tought of going backwards lol..
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
Really interesting. Thanks for posting these updates
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
I should have waited until I tuned the engine for the big mouth prechambers. After my last post, I advanced the injection timing a degree (that is what was left of adjustment) and that cleaned up the idle and cold warm up.. Even quieted it down a little. I ran a tank of fuel through it and found that I am getting the same mileage with winter fuel that I was with summer fuel, 26/27 mpg.. Now I know only one tank is not enough, but normally winter fuel drops the mileage down to 24/25 mpg.
I then advanced the camshaft 10* and ran it for a couple days. Then today I removed the pump, turned the fuel up all the way, turned the torque control in 5 turns, and replaced the high speed governor spring with a solid link, (eliminating the high speed fueling reduction). I then put the pump back in and set the start of injection at 28*.
It has been a while sense I have adjusted a governor and I did not turn the idle governor up like I normally do for some reason.. I and I should have.. I had to pull the cover plate and turn the idle governor up
.. Now that I have driven it a bit, I am going to turn it up a little more to get it right where I want it.It really came to life. I defiantly need to make a boost controller, and I am going to put the ALDA back on, but shimmed up so it just keeps the low boost smoke away on take off. I may advance it to 30* but I want to see how it starts in the cold first. I would like to keep the total advance below 40*.
I infidelity have changed my opinion about these prechambers.. I am very happy.
Up date on the big mouth prechambers..
I should have waited until I tuned the engine for the big mouth prechambers. After my last post, I advanced the injection timing a degree (that is what was left of adjustment) and that cleaned up the idle and cold warm up.. Even quieted it down a little. I ran a tank of fuel through it and found that I am getting the same mileage with winter fuel that I was with summer fuel, 26/27 mpg.. Now I know only one tank is not enough, but normally winter fuel drops the mileage down to 24/25 mpg.
I then advanced the camshaft 10* and ran it for a couple days. Then today I removed the pump, turned the fuel up all the way, turned the torque control in 5 turns, and replaced the high speed governor spring with a solid link, (eliminating the high speed fueling reduction). I then put the pump back in and set the start of injection at 28*.
It has been a while sense I have adjusted a governor and I did not turn the idle governor up like I normally do for some reason.. I and I should have.. I had to pull the cover plate and turn the idle governor up .. Now that I have driven it a bit, I am going to turn it up a little more to get it right where I want it.
It really came to life. I defiantly need to make a boost controller, and I am going to put the ALDA back on, but shimmed up so it just keeps the low boost smoke away on take off. I may advance it to 30* but I want to see how it starts in the cold first. I would like to keep the total advance below 40*.
I infidelity have changed my opinion about these prechambers.. I am very happy.
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