• Steel Soldiers now has a few new forums, read more about it at: New Munitions Forums!

  • Microsoft MSN, Live, Hotmail, Outlook email users may not be receiving emails. We are working to resolve this issue. Please add support@steelsoldiers.com to your trusted contacts.

Intake/exhaust port CFM flow? Porting the heads? Tech babble.

m16ty

Moderator
Moderator
Steel Soldiers Supporter
9,580
218
63
Location
Dickson,TN
You can lower the compression ratio by adding a thicker head gasket. I don't know how much you could do before your pushrods are too short though. If you lower the compression, you'll likely have to also do other mods to get it to run right.

Trying to get high HP out of a multifuel is kind of like polishing a turd. Not that the multifuel is a turd but it is what it is.
 

gimpyrobb

dumpsterlandingfromorbit!
27,786
757
113
Location
Cincy Ohio
Maybe I'll just buy a used LDS for $2500. I mean where else can you free up 80hp from a LDT and still keep it multifuel. Just buy an LDS and throw it in. Done :mrgreen:
You would be better off finding an LDS IP and putting it on your LDT. The pump is 90%(maybe 99%) of the difference.

Turn up the fuel on an LDT; same thing and you can save $2500. It is only 40 or so HP difference.
I agree with this the most. I have a deuce with an LDS motor. A buddy has an LDT in his. He has tweeked it so that it puts out similar power as my truck. I only know this cause he asked me about my motor after driving it for a day. He said I had more power, but not by much. Installing a good flowing air filter, a pyro to monitor the EGTs, turning up the pump, keeping your valves adjusted right, and making sure your injectors are in "spec" is the best thing you can do to get the most out of your motor. Until you do those things, everything else is a waste of time and effort.
 

welldigger

Active member
2,602
16
38
Location
Benton LA
I'm not sure how the lds injector pump makes such a difference. Maybe the timing on the fuel rates is a bit different? It can't be the max fuel rate alone. The ldt pump can be cranked up to the point it will melt pistons.
 

gringeltaube

Staff Member
Super Moderator
Moderator
Steel Soldiers Supporter
6,994
2,561
113
Location
Montevideo/Uruguay
....... The cam is also different between the engines.
That is really THE question...
If you go by that diagram you posted- then YES. But if you look up the different parts books (TM 9-2815-204-34P; TM 9-2815-210-34P, May'74 & TM 9-2815-210-34P, June'98 ), the camshaft is #11610283, for ALL model Multifuel engines.


G.
 

rustystud

Well-known member
9,298
3,074
113
Location
Woodinville, Washington
That is really THE question...
If you go by that diagram you posted- then YES. But if you look up the different parts books (TM 9-2815-204-34P; TM 9-2815-210-34P, May'74 & TM 9-2815-210-34P, June'98 ), the camshaft is #11610283, for ALL model Multifuel engines.


G.
That is really interesting. Why would the manual give two different specs ? Maybe there where two different cams, but after time they decided to use just one that fit generically all engines.
 
Last edited:

patracy

Administrator
Staff member
Administrator
14,653
4,848
113
Location
Buchanan, GA
Ok so if we wanted to lower the compression would the easiest way be to swap the pistons with the tractor version or de-stroke the engine a little.
Easiest trick in the diesel world is a thicker head gasket. But that's fractional CR reductions at best. Destroking would require custom pistons. Tractor pistons wouldn't have the proper bowl for the mutifuel heads/injectors. Probably fly cutting the piston faces or increasing the bowl diameters (risky) is the best option.

I've been through this over and over in my head. It's just not cost effective to build up a LDT or LDS in my opinion due to their inherent design. But if anyone wanted to build up one and keep the key trait of multifuel ability, I would do the following.

1. Balance the rotating assembly, this simply isn't done in the military.
2. Rod bolts, speculation at best, but once you've been in one of these engines you'll understand how much weight you're slinging around.
3. Main bolts and a girdle.
4. 2 port oil squriters if you only have singles.
5. Make sure you have a TD block to start with!
6. Custom head studs
7. Develop a fire ring solution on the head gaskets.
8. Have the cam custom ground.
9. Clean up the intake and exhaust ports on the head, nothing major though.
10. Build a custom intake manifold to remove the coolant passages or re-work the
11. Heavier valve springs.
12. Different turbo (would have to do the math on the map).
13. FASS or airdog lift pump.
14. Therm fan clutch/fan.
15. LDS pump that has been tweaked.
16. Increase pop pressures on the injectors.
17. And likely you'd need a better clutch and transmission.

But with all that I think you could have a 300hp daily driver multifuel. Problem is, that engine probably would cost what several complete deuces cost.
 

patracy

Administrator
Staff member
Administrator
14,653
4,848
113
Location
Buchanan, GA
Very small image, but you'll notice in the tractor engine, there's no swirl notch in the piston bowl that is in the multifuel.

oliver piston.gif

So it stands to reason, and likewise with your link. The multifuel piston could go into the tractor engine. But I'd suspect issues in fitting the tractor pistons in the multifuel.

http://www.steelsoldiers.com/attachment.php?attachmentid=184116&d=1275169069


I didn't measure the injector placement in the holes while I had my engine apart. But I do recall the injector nozzle ports being angled to one side. I *believe* the injector ports angle outwards from that bowl cut, as the multifuel design mentions the swirl of fuel pattern.
 

JasonS

Well-known member
1,656
167
63
Location
Eastern SD
Very small image, but you'll notice in the tractor engine, there's no swirl notch in the piston bowl that is in the multifuel.

View attachment 484162

So it stands to reason, and likewise with your link. The multifuel piston could go into the tractor engine. But I'd suspect issues in fitting the tractor pistons in the multifuel.

http://www.steelsoldiers.com/attachment.php?attachmentid=184116&d=1275169069


I didn't measure the injector placement in the holes while I had my engine apart. But I do recall the injector nozzle ports being angled to one side. I *believe* the injector ports angle outwards from that bowl cut, as the multifuel design mentions the swirl of fuel pattern.
Why could it go one way but not the other? They are virtually the same engine.
 

patracy

Administrator
Staff member
Administrator
14,653
4,848
113
Location
Buchanan, GA
I mentioned earlier, the injector placement I believe is in that notch area of the piston with the ports of the injector only aimed on one side. Since the tractor doesn't have this "swirl" design, it could get the multifuel pistons. But I'd suspect a piston/injector nozzle interference in the multifuel engine if you tried the tractor pistons. Would be nice if some of the tractor guys could give us a nozzle placement measurement on the head and we do the same to a multifuel head to see where things line up between the two.

I am again speculating. But I know from every other DI diesel I've owned. The injector nozzles are arranged in a circular pattern and injected into the bowl. The multifuel has a unique piston bowl to anything I've worked on before. That notch and the nozzles seem like they would be arranged differently.
 

JasonS

Well-known member
1,656
167
63
Location
Eastern SD
I mentioned earlier, the injector placement I believe is in that notch area of the piston with the ports of the injector only aimed on one side. Since the tractor doesn't have this "swirl" design, it could get the multifuel pistons. But I'd suspect a piston/injector nozzle interference in the multifuel engine if you tried the tractor pistons. Would be nice if some of the tractor guys could give us a nozzle placement measurement on the head and we do the same to a multifuel head to see where things line up between the two.

I am again speculating. But I know from every other DI diesel I've owned. The injector nozzles are arranged in a circular pattern and injected into the bowl. The multifuel has a unique piston bowl to anything I've worked on before. That notch and the nozzles seem like they would be arranged differently.
Look at the last post in this thread http://forums.yesterdaystractors.com/viewtopic.php?t=436351 " The nozzle in the 585 MM has 1 large hole to shoot into the deep piston bowl, while the Hercules has 1 large hole and a small one." Isn't this the same as the multifuel?

http://forums.yesterdaystractors.com/viewtopic.php?t=423411 "The Herks have a M.A.N. combustion chamber."

http://www.smokstak.com/forum/showthread.php?t=115579 "it used the MAN system, the same type of piston combustion chamber that was used the in army 2.5 and 5 ton trucks and the White 2-135 and 2-155 tractors, the Hercules 478 cubic inch engine, which was developed earlier in the early 60's."
 
Last edited:

gringeltaube

Staff Member
Super Moderator
Moderator
Steel Soldiers Supporter
6,994
2,561
113
Location
Montevideo/Uruguay
That is really interesting. Why would the manual give two different specs ? Maybe there were two different cams, but after time they decided to use just one that fit generically all engines.
I have cams here, from every model engine (except the LDS465-2), starting with the early 427's... and I have yet to find a part number stamped or written anywhere - on any of them. So the only effective way to confirm if there are- or were- any differences would be by measuring. But who would take the time for just that...?

What year is that -35 TM you have?
I know one thing for sure: humans wrote these books...


G.
 

patracy

Administrator
Staff member
Administrator
14,653
4,848
113
Location
Buchanan, GA
Here are some pics, first of a 24v cummins piston. Next, a multi. Next a pic of the multi nozzle. Then me holding where the objectors where it belongs in a cummins to the piston. Next a close up pf deposits in the multi piston bowl. Then a guess of the injector alignment in the multi based on the hold down clocking and angle.

I don't have the oliver engine piston, so I'm only basing this off the typical diesel concept of a bowl that is injected into. A 12V cummins has a similar setup. Although the 24v has a 90* relationship to the piston where as the 12V has an angle in the bowl. However they all have a circular pattern in spray from the injector instead of the narrow path a multifuel does.
 

Attachments

rustystud

Well-known member
9,298
3,074
113
Location
Woodinville, Washington
  1. View attachment Scan0001.pdfView attachment Scan0004.pdf
    I have cams here, from every model engine (except the LDS465-2), starting with the early 427's... and I have yet to find a part number stamped or written anywhere - on any of them. So the only effective way to confirm if there are- or were- any differences would be by measuring. But who would take the time for just that...?
What year is that -35 TM you have?
I know one thing for sure: humans wrote these books...


G.
The year is 1964. Some more pictures to look at.
 
Last edited by a moderator:
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website like our supporting vendors. Their ads help keep Steel Soldiers going. Please consider disabling your ad blockers for the site. Thanks!

I've Disabled AdBlock
No Thanks