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+--- Thread: Prechamber Mod "Flame" Front (/showthread.php?tid=2169)
RE: Prechamber Mod "Flame" Front - garage - 03-02-2011
(02-24-2011, 01:15 AM)Captain America(02-23-2011, 05:33 PM)winmutt(02-22-2011, 03:50 PM)Captain America Looks like I have all three? styles of pre chamber now... '81, '82, '85 in my hands
Clean them up and lets see some pics for starters!
I still need to get the tools to pull them. The '82 and '85 don't run. Im driving the '81 currently. I will pull all three, compare and come back with pics
Bump Captain!
RE: Prechamber Mod "Flame" Front - Captain America - 03-02-2011
Ha! All I need is time and money baby...
RE: Prechamber Mod "Flame" Front - MacDoe - 06-16-2012
I think Homeostasis is the key here and what I think F.I is trying to get at. He just has'nt come right out and said it or maybe he has and no one was listening......man what a long write up....took nearly a couple hours stretched over two days to read this entire thread and there is really no conclusion or answer to any testing....what a rip off.
Could it be that F.I was right and everyone left cause they did not want to admit it. For someone that has so many credentials and access to so many tools and testing equiptment with the area 51 security I am surprised that there is no conclusion to this thread.
RE: Prechamber Mod "Flame" Front - MacDoe - 06-17-2012
so, anyways, whats up?....do you have any updates in your research or did you give up? I hope not , cause that would be a shame...share more, please....don't let him bother you, this is an awesome thread.
I am working on cleaning the prechambers for my cylinder head that was rebuilt and had some of my own research to do which is how I ended up here. I was simply posting something for reference for a discussion I was having at P.P for post #66 and the information regarding the reaming and chamfering tools that Hercules was using. It would be easier for him to find if a post was made to put it to the top. I have some burrs around the holes in the tips that I was wondering what to do with, but with just a stock engine won't be enlarging the holes but rather just want to clean them up. I put one on a wire wheel and think that I may have pushed the burr into the oriface. Can the holes be chamfered for a stock engine?
RE: Prechamber Mod "Flame" Front - Captain America - 06-19-2012
All I can say is I am thoroughly confused from "thread cleaning"
Mac: I definitely would not want any kind of burr on any orifice in the engine. I would LIGHTLY chamfer the holes. I will play with the 1985 pre chambers, I just always have a lot going on and its on the list.
RE: Prechamber Mod "Flame" Front - ronnie - 06-19-2012
I.ve open the holes(.010) on mine and yes it does help with power. This is assuming you have already turned up the ip, and now making a least a little smoke. I have the results posted somewhere, on the peachparts forum.
RE: Prechamber Mod "Flame" Front - winmutt - 06-19-2012
URL? Cant find your username over there?
RE: Prechamber Mod "Flame" Front - ronnie - 06-20-2012
47dodge is my user name over there
Here copied from peachparts post "eeking out better performance from 240" This was last fall I did this, have since rebuilt the engine and added a turbo.
"I reamed out the holes in the pre chambers(pc's) this week, and this does give a nice improvement. It has been talked about so I took the plunge and did it. Here are the areas of the holes in the pcs,
616 .0528 square inchs '78
616 .0498 square inchs uprated? an '83
617 .0595 square inchs turbo, '83
It is interesting to note that the uprated ones have less area. three holes are bigger(.125), but two are smaller(.090), plus the mini hole(.025) in the bottom. If i where to go .125 on all five holes in the old style pc then it comes to .0613.
I did ream to .125 diameter on all holes, they were .116.
Results, 5 mph faster on the hill climb. Egts just over 1300 at top of hill. Hill has 700ft of elevation change. Not sure of the distance, but it is steep, and starting from a stop.For general driving lower egts, and more responsive, less smoke too. Now a normal start from a light gets no visible smoke.
This is not a stock engine, changes are new manifold, advanced timing, larger exhaust, ip adjustments. So nothing radical, but not stock either."
__________________
RE: Prechamber Mod "Flame" Front - OM616 - 06-22-2012
Here are some pics of the most recent modded PCs for my 616 turbo.
One pic shows a stock up-rated PC, Ronnie's old PC he opened up to .125 and the same PC all 5 holes opened up to .136.
Another pic shows the injector seat has been modified per MB with a little more lowering than MB suggested, (1mm), I lowered it down 2.5mm.
One pic tries to show the injector in the PC after the modded seat.
RE: Prechamber Mod "Flame" Front - Alastair E - 06-23-2012
Anyone noted improvements in fuel consumption with a modded pre-chamber...?
RE: Prechamber Mod "Flame" Front - Hercules - 06-24-2012
(06-22-2012, 04:49 PM)OM616 Here are some pics of the most recent modded PCs for my 616 turbo.OM616,was there improvement with the .136 holes over the .125? Low,mid or top rpm"s ?
One pic shows a stock up-rated PC, Ronnie's old PC he opened up to .125 and the same PC all 5 holes opened up to .136.
Another pic shows the injector seat has been modified per MB with a little more lowering than MB suggested, (1mm), I lowered it down 2.5mm.
One pic tries to show the injector in the PC after the modded seat.
As much or more from the stock to the .125?
Did lowering the injector help? How? (less smoking etc...)
I only tapered (not enlarged),which worked well. Always looking for a little more GO POWER.
(06-23-2012, 10:44 AM)Alastair E Anyone noted improvements in fuel consumption with a modded pre-chamber...?
Mileage improved 2-3 mile per gallon on average.
RE: Prechamber Mod "Flame" Front - sassparilla_kid - 06-26-2012
(06-24-2012, 12:47 AM)Hercules Mileage improved 2-3 mile per gallon on average.
That is awesome, I would do this mod just for the improvement in mileage, the additional power is just an even bigger plus. I think I'll add it to the to-do list lol
RE: Prechamber Mod "Flame" Front - ronnie - 06-27-2012
just a reminder for those who want to do this you will need a carbide reamer, as the pc's are quite hard, and a regular reamer or drill bit will not cut it. It is well worth doing though
RE: Prechamber Mod "Flame" Front - OM616 - 06-27-2012
I installed the moded PCs and a late model cam yesterday and had a set back, I was torquing the last injector and herd a POP and the injector turned easy.
I lowered the seat 2 mm lower than MB specked and that is where the upper half threads start so there was very little material left, and when I torqued the injector, the PC lower half broke away from the upper half.
SO... I cleaned up the ones I pulled out, reamed the burn holes to .136 dia, and only opened up the seat dia, did not lower it, ( the 1.5mm was not worth the time and seeing how the PC is made, I feel better with it thicker).
Reinstalled them this morning. It starts easer, had to lower the idel a touch, torque is better, and it takes the fuel better at the top end (much stronger on the high way). EGTs are on average 75 degrees lower under all conditions compared to stock, but keep in mind that I did change the cam too.
My personal recommendation to anyone who needs to be convinced that this is a good thing to do, is not to do it.
RE: Prechamber Mod "Flame" Front - ronnie - 06-27-2012
not supposed to change two things at once....... Oh well. glad to hear even more improvement
I should figure were your holes are in terms of area compared to the modded 617a ones. I did the three main holes .010 bigger , and left the tiny ones alone. Then add this to my chart.
RE: Prechamber Mod "Flame" Front - OM616 - 06-28-2012
(06-27-2012, 08:57 PM)ronnie not supposed to change two things at once.......
LOL.. I really did not have the time to do this once
(06-27-2012, 08:57 PM)ronnie I should figure were your holes are in terms of area compared to the modded 617a ones. I did the three main holes .010 bigger , and left the tiny ones alone. Then add this to my chart.
The total area for the 5, .136 dia holes = .0726335 sq in, that is just over 20% more area than the 7mm burn tube. I wanted to make as much of the pressure head at the base of the tube as possible to increase the velocity as much as possible.
For some perspective, the 60X engine has about 15.7% less cylinder volume than the 61X, and the stock 60X PC has a total burn hole area of .060836 sq in.
RE: Prechamber Mod "Flame" Front - Freefuel - 07-01-2012
a Silly question maybe, What material is the prechamber made of? and is there a useful benifit of making them out of inconel so they are less likely to melt? other then making your bank account angry....
RE: Prechamber Mod "Flame" Front - ronnie - 07-01-2012
Hardened steel, not sure what grade. I am not aware of any that have melted. I'd be more worried about pistons.
RE: Prechamber Mod "Flame" Front - OM616 - 07-02-2012
(07-01-2012, 08:59 AM)Freefuel a Silly question maybe, What material is the prechamber made of? and is there a useful benifit of making them out of inconel so they are less likely to melt? other then making your bank account angry....
I was told by another member that they are made out of 80A, Valves are made out of the same material.
I have been toying with making a set of PCs based on what I have learned and was planning on using Inconel. After splitting one, I think I may do a phase 1 by just making a new upper half, with the injector lowered and angled. If I can find the time that is, lol.
I have been tuning after the swap and ran out of slot on the IP to advance the timing any further. You can run a good amount more timing with larger holes, it runs like a gasser now.
I also installed the EMP gauge and was very pleased to see that it is reasonable with the current vain setting, depending on how I drive it, the EMP is +3-5psi over boost, 1 to 1, or in third I can see more boost than EMP.
Cruising at 70mph (3500 RPM) EGT steadies out at 600*, with 4lbs of boost, EMP @7lbs. I am very interested to see how the larger elements effect it.
Ronnie, I will be ordering a sample of the new element I am considering using next month to be sure it what I want.
RE: Prechamber Mod "Flame" Front - ConnClark - 07-02-2012
Any before and after dyno charts on these mods?
RE: Prechamber Mod "Flame" Front - OM616 - 07-02-2012
(07-02-2012, 01:45 PM)ConnClark Any before and after dyno charts on these mods?
If you are asking me?..... Nope....I post information really for those who have done it to compare against...Like I said, if one needs proof beyond someone’s word, then it is best not to touch it. And I mean that respectfully.
I mean...yes, it would be interesting to see some numbers for sake of discussion, but I see no need to spend time and money to ream the piss out of an engine with 230,000 miles on it, to advance a theoretical discussion. I normally send this type of information underground to eliminate the arguing, but I got the impression that some were genuinely interested to see if our engines were going to blow up when we started them, lol. We are all just fine, so far that is lol.
RE: Prechamber Mod "Flame" Front - ronnie - 07-03-2012
I kind of agree, just do not want to take the time or money, and beat my engine just to have proof. Perhaps someone with more of both could do it. For me it climbs the hills much better and I did get numbers on that so at least we have some referance.
RE: Prechamber Mod "Flame" Front - Alastair E - 07-03-2012
Well, Got meself a 3.5mm Carbide drill-bit, Now all I need is a set of spare pre-chambers......!
RE: Prechamber Mod "Flame" Front - barrote - 07-04-2012
hello fine people,
OM 606, have u ever considered to look at a OM605 or 606 engines and compare the pre chambers , especially the turbo versions?
to say that i have one of this engines and i assume Mercedes would have done some mods to gain power and reduce smoke (emissions), keeping in mind that this engines has a all lot more power by cylinder not to say the double.
could someone en light me the reason why u guys haven´t drop on of this engines inside your reliques
. i´m so sorry i´m being honest, will have to remove my PC and when i´ve done it certainly i will drop inside some with mods like u are talking about.
regards to u all.
RE: Prechamber Mod "Flame" Front - OM616 - 07-04-2012
(07-04-2012, 07:03 AM)barrote hello fine people,
OM 606, have u ever considered to look at a OM605 or 606 engines and compare the pre chambers , especially the turbo versions?
to say that i have one of this engines and i assume Mercedes would have done some mods to gain power and reduce smoke (emissions), keeping in mind that this engines has a all lot more power by cylinder not to say the double.
could someone en light me the reason why u guys haven´t drop on of this engines inside your reliques
i´m so sorry i´m being honest, will have to remove my PC and when i´ve done it certainly i will drop inside some with mods like u are talking about.
regards to u all.
I have looked at many different prechambers including non MB ones when I was researching, even talked with a couple of guys over seas if you know what I mean.
The 60X PC burn hole area to displaced cylinder volume ratio, compared to the 61X ratio is what caught my interest right away. Then when you figure out the ratio after they are opened up, it really gets interesting.
From what I have found, the larger holes allows the PC pressure to raise faster, so the temp is at ignition temp sooner, which will support a more advanced injection timing that results in more torque. If one reads back, that was my original theory.
I was advanced as far as I wanted to go on this engine prior to modding the PCs, I had a bit of idle smoke, and I had to let it warm up for a min to keep it from nailing. After the mod, the torque was up, EGTs down, no smoke, and it was easer to start. So I advanced the injection timing gradually until I ran out of adjustment, I now have a little idle smoke, still starts easer but you can tell it is advanced, and I heard only a faint nailing once when I started and immediately drove off but the nailing was not harsh.
Power is way up, and EGTs are down after the timing adjustment. I think the hole ratio in the 60X allows them to be run more advanced than the 61X engines, and with better air flow from a different head design they really can come to life.
If you open up the burn holes, be sure to advance the timing a little at a time to take advantage of the new PCs.
RE: Prechamber Mod "Flame" Front - barrote - 07-05-2012
OM606, as i understood even for a stock engine would help to enlarge the holes.
We must never forget that this engines are line production , and are not blue printed. that´s what we want to do.
Do u have any idea of which increase should one do for 60X PC, i will do it and post the results , just want to start from where u guys arrived . i want to save time and money.
by the way have u or know of anyone which has a repair manual for 60X engines? or web site to go to?
regards
FD
RE: Prechamber Mod "Flame" Front - OM616 - 07-05-2012
(07-03-2012, 05:56 PM)Alastair E Well, Got meself a 3.5mm Carbide drill-bit, Now all I need is a set of spare pre-chambers......!
Unfortunetly the drill bit will only destroy the hole, you have to use a reamer to open them up.
RE: Prechamber Mod "Flame" Front - Austincarnut - 07-05-2012
(06-22-2012, 04:49 PM)OM616 Here are some pics of the most recent modded PCs for my 616 turbo.
One pic shows a stock up-rated PC, Ronnie's old PC he opened up to .125 and the same PC all 5 holes opened up to .136.
Another pic shows the injector seat has been modified per MB with a little more lowering than MB suggested, (1mm), I lowered it down 2.5mm.
One pic tries to show the injector in the PC after the modded seat.
What is the difference between the round PC and the angled ones? The ones in my 123 are round tipped, I know they were changed later in life, are these an example of the change? MY on mine is '83 617.
RE: Prechamber Mod "Flame" Front - ronnie - 07-05-2012
the uprated engines starting around 1980 or so have the round ones, and differant pistons. Must keep matching pistons to pc's, as the flame pattern is differant. Also the cylinder bore is slightly smaller on the uprated engines.
RE: Prechamber Mod "Flame" Front - OM616 - 07-06-2012
(07-05-2012, 12:28 AM)barrote OM606, as i understood even for a stock engine would help to enlarge the holes.
We must never forget that this engines are line production , and are not blue printed. that´s what we want to do.
Do u have any idea of which increase should one do for 60X PC, i will do it and post the results , just want to start from where u guys arrived . i want to save time and money.
by the way have u or know of anyone which has a repair manual for 60X engines? or web site to go to?
regards
FD
Yes, a stock engine will benefit, the biggest bonus being you can advance the injection timing.
The 60X PC has more holes than the 61X PC so the additional area adds up quick, it doesn’t take much per hole. My notes say that the 60X PC has 8, 2.5mm holes and a 8mm burn tube.
IMOP increasing all the burn holes to 2.75mm or 3.00mm would be with in reason. I would recommend that you try and contact jeemu (I apologize if I spelled it wrong), he has a project car in that section, and he has built 500+HP 60X engines.
Definitely get a service manual as you will need the torque specks for the PCs and Injectors, you can find them on e-bay some times, not sure if there is a link to a manual on this sight.
Don’t forget to pull the glow plugs out first, BEFORE you remove the PCs.
RE: Prechamber Mod "Flame" Front - Austincarnut - 07-06-2012
(07-06-2012, 05:34 PM)OM616(07-05-2012, 12:28 AM)barrote OM606, as i understood even for a stock engine would help to enlarge the holes.
We must never forget that this engines are line production , and are not blue printed. that´s what we want to do.
Do u have any idea of which increase should one do for 60X PC, i will do it and post the results , just want to start from where u guys arrived . i want to save time and money.
by the way have u or know of anyone which has a repair manual for 60X engines? or web site to go to?
regards
FD
Yes, a stock engine will benefit, the biggest bonus being you can advance the injection timing.
The 60X PC has more holes than the 61X PC so the additional area adds up quick, it doesn’t take much per hole. My notes say that the 60X PC has 8, 2.5mm holes and a 8mm burn tube.
IMOP increasing all the burn holes to 2.75mm or 3.00mm would be with in reason. I would recommend that you try and contact jeemu (I apologize if I spelled it wrong), he has a project car in that section, and he has built 500+HP 60X engines.
Definitely get a service manual as you will need the torque specks for the PCs and Injectors, you can find them on e-bay some times, not sure if there is a link to a manual on this sight.
Don’t forget to pull the glow plugs out first, BEFORE you remove the PCs.
I get it now, I looked up the changed in the MB parts fisch today. The angled ones you show in your pictures are non-turbo pc's and the round ones are turbo. I have all the original manuals and show all the dimensions but don't see any references to the mod of lowering the injector seat. Where did you find this? I haven't read through the entire set of fisch.
RE: Prechamber Mod "Flame" Front - OM616 - 07-06-2012
quote='Austincarnut' pid='42847' dateline='1341620637']
I get it now, I looked up the changed in the MB parts fisch today. The angled ones you show in your pictures are non-turbo pc's and the round ones are turbo. I have all the original manuals and show all the dimensions but don't see any references to the mod of lowering the injector seat. Where did you find this? I haven't read through the entire set of fisch.
[/quote]
From my thread in the othe forum, Tomnik posted this;
--------------------------------------------------------------------------------
Hi,
I found an MB internal article that suggests PC mods in case of idle and partial load smoke.
See the pic below.
Increase the bore from 8 to 14 mm (616 and 617 engines) or from 12 to 14 mm for 615 engine.
As a result use the 617 017 03 60 plate (heat shield) with 10 mm inner diameter.
Further they lowered the position of the nozzle (closer to the ball) by 1 mm from 16.5 to 17.5 mm.
The second part of the page talks about shaking and poor idling quality.
The suggestion here is to change the tolerance of individual fuel quantity from (Bosch) 1 mm3/stroke to < 0.5 mm3/stroke (MB), IP bench setting.
Tom
Attached Thumbnails
RE: Prechamber Mod "Flame" Front - Austincarnut - 07-07-2012
(07-06-2012, 11:46 PM)OM616 quote='Austincarnut' pid='42847' dateline='1341620637']
I get it now, I looked up the changed in the MB parts fisch today. The angled ones you show in your pictures are non-turbo pc's and the round ones are turbo. I have all the original manuals and show all the dimensions but don't see any references to the mod of lowering the injector seat. Where did you find this? I haven't read through the entire set of fisch.
From my thread in the othe forum, Tomnik posted this;
--------------------------------------------------------------------------------
Hi,
I found an MB internal article that suggests PC mods in case of idle and partial load smoke.
See the pic below.
Increase the bore from 8 to 14 mm (616 and 617 engines) or from 12 to 14 mm for 615 engine.
As a result use the 617 017 03 60 plate (heat shield) with 10 mm inner diameter.
Further they lowered the position of the nozzle (closer to the ball) by 1 mm from 16.5 to 17.5 mm.
The second part of the page talks about shaking and poor idling quality.
The suggestion here is to change the tolerance of individual fuel quantity from (Bosch) 1 mm3/stroke to < 0.5 mm3/stroke (MB), IP bench setting.
Tom
Attached Thumbnails
[/quote]
can you email me that picture?
RE: Prechamber Mod "Flame" Front - Captain America - 07-10-2012
I am always genuinely interested in any thread OM616 is posting in
RE: Prechamber Mod "Flame" Front - sassparilla_kid - 07-10-2012
(07-10-2012, 03:08 AM)Captain America I am always genuinely interested in any thread OM616 is posting in
I second that!
RE: Prechamber Mod "Flame" Front - Simpler=Better - 12-06-2012
What do you all think of using a corner-rounding endmill on the holes to add even-sized fillets?
Mcmaster has a variety, here are two:
p/n 8505A41 has a .125" tip, .1875" shank, and .03125" radius
p/n 8508A45 has a tip of .090" and, .25" shank, and a .075" radius.
![[Image: 8508a47c1l.png?ver=28551532]](http://images1.mcmaster.com/Contents/gfx/large/8508a47c1l.png?ver=28551532)
RE: Prechamber Mod "Flame" Front - OM616 - 12-06-2012
(12-06-2012, 10:54 AM)Simpler=Better What do you all think of using a corner-rounding endmill on the holes to add even-sized fillets?
Mcmaster has a variety, here are two:
p/n 8505A41 has a .125" tip, .1875" shank, and .03125" radius
p/n 8508A45 has a tip of .090" and, .25" shank, and a .075" radius.
That would work if the holes were on a flat surface, but they are on a radius so the cutter would really have to hog in deep to get all the way around.
Just looking at an uprated PC....it might get you 90% there, and then blend in the lower portions by hand, or it might just do it on its own. You will want a carbide one, or at least cobalt, cutting fluid and slow speed. Some times you just have to try something to know for sure.
Personally, I have not tried to taper or radius the inlet yet, so I will add that to the next set I do.
For reference, I am currently running .136 dia burn holes in my 616 turbo and will be going to .145 with a tapered inlet when I put in the Bosio nozzles.
RE: Prechamber Mod "Flame" Front - Graminal95 - 12-06-2012
I was talking with some people doing research for Bosch, and it seems that for common rail applications they want the rough surface finish that EDM leaves on the holes in the nozzle in order to get better atomization. The only trouble is that they need to smooth out the entrance to the hole for better flow while leaving the rough EDM surface intact.
I wonder if having a rough (within reason) surface on the PC outlet holes would be of any benefited to the older prechambers.
RE: Prechamber Mod "Flame" Front - Simpler=Better - 12-06-2012
(12-06-2012, 11:51 AM)OM616(12-06-2012, 10:54 AM)Simpler=Better What do you all think of using a corner-rounding endmill on the holes to add even-sized fillets?
Mcmaster has a variety, here are two:
p/n 8505A41 has a .125" tip, .1875" shank, and .03125" radius
p/n 8508A45 has a tip of .090" and, .25" shank, and a .075" radius.
That would work if the holes were on a flat surface, but they are on a radius so the cutter would really have to hog in deep to get all the way around.
Just looking at an uprated PC....it might get you 90% there, and then blend in the lower portions by hand, or it might just do it on its own. You will want a carbide one, or at least cobalt, cutting fluid and slow speed. Some times you just have to try something to know for sure.
Personally, I have not tried to taper or radius the inlet yet, so I will add that to the next set I do.
For reference, I am currently running .136 dia burn holes in my 616 turbo and will be going to .145 with a tapered inlet when I put in the Bosio nozzles.
I have a set of 85 PCs, I just need to pull them and play with them (probably won't have time for at least 2 months)
RE: Prechamber Mod "Flame" Front - Tmadia - 12-06-2012
It looks like rounding the edges will give about 30% more flow.
http://www.mcnallyinstitute.com/13-html/13-12.htm
I wonder if it may be better to shape the flow rather than increase it. Instead of 4 round jets of burning diesel, maybe a fan shaped flow would mix better with the oxygen in the cylinder? One could just cut a horizontal slit on each side of the holes to make it fan out. Just a thought.
Great topic by the way!
RE: Prechamber Mod "Flame" Front - sassparilla_kid - 12-07-2012
I may have already asked this, or it might be somewhere earlier in the thread, but how difficult is it to pull pre-chambers?
RE: Prechamber Mod "Flame" Front - Captain America - 12-07-2012
(12-06-2012, 03:53 PM)Simpler=Better I have a set of 85 PCs, I just need to pull them and play with them (probably won't have time for at least 2 months)
Same here.
(12-07-2012, 01:50 AM)sassparilla_kid I may have already asked this, or it might be somewhere earlier in the thread, but how difficult is it to pull pre-chambers?
Need special tools.
http://www.mercedessource.com/node/8479
And
http://www.mercedessource.com/node/8478
RE: Prechamber Mod "Flame" Front - sassparilla_kid - 12-07-2012
$160 worth of tools seems a little ridiculous to me
RE: Prechamber Mod "Flame" Front - Tmadia - 12-07-2012
Good read.
http://www.vwdiesel.net/forum/index.php?topic=2329.0;wap2
RE: Prechamber Mod "Flame" Front - MFSuper90 - 12-24-2012
I've got most of my stuff made for my prechamber puller, now just waiting on the shimano crank puller.
om616,
so you are Increasing the holes to .125 or .136 and opening up the tube to 14mm?
What effect does opening up the tube have, and what tool did you use since the PC are so hard?
Many thanks,
Eric
RE: Prechamber Mod "Flame" Front - OM616 - 12-24-2012
(12-24-2012, 11:08 AM)MFSuper90 I've got most of my stuff made for my prechamber puller, now just waiting on the shimano crank puller.
om616,
so you are Increasing the holes to .125 or .136 and opening up the tube to 14mm?
What effect does opening up the tube have, and what tool did you use since the PC are so hard?
Many thanks,
Eric
I am not at home so I do not have access to my notes to refresh my memory, so I will not quote any specks, but explain what the thinking was behind them.
Well, I can say that I am currently running .136 dia burn holes on my 616 turbo that uses the old style, (flat bottom) PCs.
Now it is important to note that the 616 and 617 NA PC have a smaller burn tube ID, (the tube that connects the burn holes to the injection chamber), than the 617a. ( I do not remember exactly what the Burn tube IDs are between the two right now).
My goal was to put as much of the pressure head at the Burn tube, as to achieve a higher velocity during compression, (better Swirl).
The .136 Dia burn hole total area, is X% greater than the 616 burn tube ID area. Now the 617a burn tube ID is larger, so to achieve the same % difference, the holes will need to be larger, or an additional hole added, (this would allow all the holes to be smaller while increasing total area).
When I change the injectors out, on my 616 turbo, I am going to increase the burn hole dia again, but again, I do not remember what that will be. Getting old sucks!
Now that I remember, Some one did PM me about opening up the holes and I for got about getting back with them! Sorry to who ever that was.
Anyway, you want to use a carbide reamer and some cutting fluid for steel to open up the burn holes. You will need to go in steps to open up the two little ones on the other side of the three main holes, (leave the bottom drain hole alone). The holes are on angles so be sure to match them when you open them up.
With a reamer, you can only increase a hole so much, it is not a drill, so if you go to, say, Production Tool Supply, or another machine tool supply, bring the PC and they will be able to tell you what reamers you need to open all the holes up, and they will have the cutting fluid as well.
I did not open up the Burn Tube it's self, I only increased the ID of the injector seat as per the MB doc that is in this thread. I tried lowering the seat on the first batch and got a little too frisky by going deeper (quite a bit deeper) than MB called out, and one PC broke when I torque the Injector up. The second batch I only opened up the seat ID, I did not see that it was worth the time to lower the seat .040", when I wanted it a lot lower.
With the PC being able to fill (breath) easer, the air will reach ignition temp sooner, which allows for the injection timing to be advanced more, which increases torque and power. I am at the limits of my pump slots. It will also be able to be filled more completely so you can run more fuel which will increase power. This mod is just like increasing boost, as far a fueling is concerned.
EGTs will be lower and less / no smoke, more power, easer starting, and my engine is quieter as well. Now I ran the engine with the turbo and stock PCs for about 4000 miles so I could tell the difference with the modded PCs, that is why I am going to try larger holes, I am curious to see if there is more to be had!
RE: Prechamber Mod "Flame" Front - MFSuper90 - 12-24-2012
How did you go about enlarging the injector seat? And what is the purpose of doing this?
I have an extra head laying around so I think I will try out some modded PC's also. Sounds like a cheap and worthwhile mod
RE: Prechamber Mod "Flame" Front - OM616 - 12-26-2012
(12-24-2012, 05:42 PM)MFSuper90 How did you go about enlarging the injector seat? And what is the purpose of doing this?
I have an extra head laying around so I think I will try out some modded PC's also. Sounds like a cheap and worthwhile mod
I used my lathe and a boring bar. You do not want to use a drill!!! You will hit the ball!!!
I imagine the larger area helps clear out the injector tip with fresh air. MB says to do this to help reduce smoke, and it is standard on 85 models I think.
RE: Prechamber Mod "Flame" Front - Turbo - 12-26-2012
OM616
Do you know if Jeemu posted some numbers of the bigger injectors and the change of the nozzle hole for the prechamber?
RE: Prechamber Mod "Flame" Front - OM616 - 12-26-2012
(12-26-2012, 07:30 PM)Turbo OM616
Do you know if Jeemu posted some numbers of the bigger injectors and the change of the nozzle hole for the prechamber?
As far as posting actual hole sizes, not that I know of. I have spoken with him privately though. He is a very nice fellow. I do not feel at liberty to share specifically what we talked about though, as he has not posted it for a reason I suppose.
They are very competitive with these engines over there so any technical advantage is a benefit, so very little will ever be posted for all to see.