Injector nozzles, 1 vs 2-hole which do i want?

[Mike944]

Hey everybody,

1971 M35A2, LDT-465-1C engine rebuilt in '85. Currently has the 2-hole injectors (nozzle ADB-35S-124-7). They're not opening cleanly (some are dribbling at 2600, opening at 3000) and the spray pattern doesn't look too great.

Thinking about replacing injectors/nozzles. Seems like the 1-hole nozzles are widely available, and fairly cheap. The 2-hole nozzles are much harder to find and more expensive. Which one do i want, and why? (the WHY is really the question i'm trying to answer here)

So far, my only choices (in the 2-hole) are chinese ones at $100/set (last-resort option, IMO), or some mil surplus ones that i found from a seller in Germany at 68 euro each!!! Before i continue scouring the globe, i'd like to understand when the 2 different nozzles were used, and the advantages (and disadvantages) of each. I can't seem to find a thread on this exact subject.

Doesn't the multi-fuel engine NEED the 2-hole injectors to make the whole multi-fuel thing work? I run a mix of pump diesel, and 1-micron filtered WMO. Perhaps the 2-stream is really only needed to run on gasoline?

 

[Elijah95]

Go 2 hole if you can find them, I can’t locate the picture but by design the 2 hole injectors make a more “complete” combustion and in theory of operation help increase economy and decrease emissions.

2 holes do help when running alternate fuels

 

[porkysplace]

Read through this.
[h=1]1 or 2 hole injectors[/h]This thread has info on injector line fittings.
[h=1]Injector installation (nozzle direction)[/h]

 

[Mike944]

Ok, so I want the 2-hole ones. Just like I thought. Why do lots of vendors say their single-hole ones are for an M35a2 multifuel?

 

[Floridianson]

I might try and run some strong cleaner in your injector tester then let the whole injectors tips sit in a can of the same stuff for a day or two. Then run them through the injector tester with cleaner again then switch to Diesel. You most probably have the newer injector that you just use a Allen wrench to loosen or tighten the plug in the center where the return fitting goes. Clock wise increases pressure and set them for 3500psi. You don't have to put a plug in the return fitting when you are testing them just remove the return fitting, loosen the top cap, use the Allen wrench and adjust. When correct pressure is found then hold injector in vise, hold Allen screw and tighten top cap.

 

[Mike944]

I should have mentioned, I'm opening them up, and putting the nozzles into an ultrasonic cleaner. Doesn't seem to be making much difference.

 

[frank8003]

Yes and Yes
post 15 + 16 in here
https://www.steelsoldiers.com/showthread.php?5411-1-or-2-hole-injectors/page2

I measured it all for me and find that one should have the two hole injectors as per M.A.N. design.
Pictures for the General.




I worked many ultrasonic machines, sometimes they don't clean like one thought they would clean. Soot particles, rocks of carbon, won't shake off.

 

[frank8003]

Ok, so I want the 2-hole ones. Just like I thought. Why do lots of vendors say their single-hole ones are for an M35a2 multifuel?

Single hole will run the engine but many are stuck with hundreds of single hole
injectors, you want the two hole injectors.
One hole at .0157"
One hole at .0177"

I see one is now $91.60 on that auction site.
One may also get a quote on them from... https://www.wbparts.com/rfq/2910-00-861-1408.html

2910-00-861-1408 A spring loaded nozzle designed to meter and inject fuel at specific pressure(s) to engine fuel combustion chambers.20229100042Engine Fuel System Components, Nonaircraft29150064Engine Fuel System Components, Aircraft and Missile Prime Movers

Part Alternates: AKF130S5677A, AKF130S6614A, KT7827, KT-7827, 10-328427-4, 380331C, 7748863, 2910-00-861-1408, 00-861-1408, 2910008611408 , 103284274, 008611408

Engine Accessories | Engine Fuel System Components, Nonaircraft

Supply Group (FSG) NSN Assign. NIIN Item Name Code (INC)
29 01 JAN 1962 00-861-1408 60779 ( NOZZLE, FUEL INJECTION )

Cross Reference | NSN 2910-00-861-1408
Part Number Cage Code Manufacturer
10-328427-4 77820 AMPHENOL CORPORATION DBA AMPHENOL AEROSPACE INDUSTRIAL
2910008611408 SCY13 E.C.A ETABLISSEMENT CENTRALD'APPROVISIONNEMENT DES
380331C 1ML14 D.W. HERCULES, LLC DBA HERCULES ENGINE COMPONENTS
380331C 28265 HERCULES ENGINE CO INC
7748863 19207 U S ARMY TANK AUTOMOTIVE COMMAND AMSTA-IM-MM
AKF130S5677A 01843 AMBAC INTERNATIONAL CORPORATION
AKF130S6614A 01843 AMBAC INTERNATIONAL CORPORATION
KT-7827 01843 AMBAC INTERNATIONAL CORPORATION

 

[rustystud]

Ok, so I want the 2-hole ones. Just like I thought. Why do lots of vendors say their single-hole ones are for an M35a2 multifuel?

Well they do fit. Are they the best for the engine ? No.

 

[cattlerepairman]

A few comments.

- the "Chinese" 2 hole injector nozzles were looked at and tested by someone very knowledgeable on this site and given a clean bill of health. The quality was there. These are injector nozzles. They need precise machining and tight tolerances for the holes but they are not a rocket ship part. I have two sets of them and had a diesel injection shop test them, with the same results - good quality, ready to go. They sit on the shelf as spares.

- the multifuel injector spray pattern is unlike "regular" injector nozzles where atomising all the fuel is key. Instead, they produce a "stream" of fuel that allows the engine to run on otherwise volatile fuels such as gasoline. The large droplet stream prevents premature ignition because the fuel first has to evaporate from the cylinder walls. That works in both single and two hole injectors. There are arguments that, especially in overfuelling conditions, the two hole injectors are safer for the pistons, preventing localized heat damage.

- I am running the original single hole injectors in my LDS (because there was nothing wrong with them). It is smoky, like most LDS. Two hole injectors would likely help. Otherwise, the engine seems to care very little about one hole or two holes.

 

[Floridianson]

Oops computer double posted.

 

[Floridianson]

No stream both holes atomize while one directs to the bowl of the piston the other to the side to help start the burn process. Maybe the TM should have said shoots a stream of atomized fuel into the bowl. The key to preventing diesel knock with fuels that have a lower flash point is the hyper cycle piston. The atomized fuel coats the sides of the piston bowl and a slower more controlled burn is the result. Plus the vortex caused by the intake.https://www.bing.com/videos/search?...9E8197B8174C3AE1D2AF9E8197B8174C3AE&FORM=VIRE

 

[frank8003]

No stream both holes atomize while one directs to the bowl of the piston the other to the side to help start the burn process. Maybe the TM should have said shoots a stream of atomized fuel into the bowl. The key to preventing diesel knock with fuels that have a lower flash point is the hyper cycle piston. The atomized fuel coats the sides of the piston bowl and a slower more controlled burn is the result. Plus the vortex caused by the intake.https://www.bing.com/videos/search?...9E8197B8174C3AE1D2AF9E8197B8174C3AE&FORM=VIRE

Video brought to you by Brian Patterson, courtesy of Floridian.
Mr. Patterson also made available that one elusive 1964 TM 9-2815-210-35

The MANN patent shows the two hole injector, so now there is no conjecture.

 

[Floridianson]

Ok, so I want the 2-hole ones. Just like I thought. Why do lots of vendors say their single-hole ones are for an M35a2 multifuel?

Looks like they switch with a work order to get a better burn and they do. The old style you needed shims to adjust the pressure so more of a pain to adjust. I saw a lot of one hundred injectors on GL and was going to bid and glad I did not as they were single hole. I did win a lot of odds and ends that had 18 new style Allen head pressure adjust injectors two hole tips and I sold most of them to a friend for 25 bucks a piece. Sometimes it's better to help a friend than make a couple of extra dollars.

 

[frank8003]

Must find Floridianson's friend that got the screw type injectors, maybe is an SS member and would sell some?
"I did win a lot of odds and ends that had 18 new style Allen head pressure adjust injectors two hole tips and I sold them to a friend for 25 bucks a piece."


Took a couple of whiles, but did find it, the land of crystal clarity.

The M.A.N. invention of the piston and the two hole injectors together results in what they named Spherical Turbulation.
Pictures for the General.

 

[Floridianson]

Sorry Frank I only kept one full set for my Deuce. Here is a pic of the Allen head adjust. The TM's also show a third type that has a lock nut that locks down the adjuster but it shows what looks like a flat head screw driver slot. Never seen one of those type so I can not confirm.

 

[rustystud]

Must find Floridianson's friend that got the screw type injectors, maybe is an SS member and would sell some?
"I did win a lot of odds and ends that had 18 new style Allen head pressure adjust injectors two hole tips and I sold them to a friend for 25 bucks a piece."


Took a couple of whiles, but did find it, the land of crystal clarity.

The M.A.N. invention of the piston and the two hole injectors together results in what they named Spherical Turbulation.
Pictures for the General.
View attachment 754184

View attachment 754179View attachment 754180View attachment 754181View attachment 754182View attachment 754183

I remember reading that the smaller jet is the first to ignite and the larger jet's purpose is to fill the bowl with fuel which will slowly burn as the piston travels down. This allows the burning of more "unrefined" fuels and oils.
Cannot find the article right now.

 

[frank8003]

The answers are in the patent. See 2,907,308 10061959
View attachment MANN US2907308 full patent too.pdf

 

[rustystud]

The answers are in the patent. See 2,907,308 10061959
View attachment 754280

That reminds me of a TV show, though I cannot remember which one. "The answers are here" . I think it was a Sci-Fi show.

 

[Floridianson]

I remember reading that the smaller jet is the first to ignite and the larger jet's purpose is to fill the bowl with fuel which will slowly burn as the piston travels down. This allows the burning of more "unrefined" fuels and oils.
Cannot find the article right now.

From what I read the hypercycle piston allows more refined fuel to be use and not cause diesel knock. Would seem like any oil at 22.1compression would just about light off even if it was not a multifuel. Seems like as said running jet fuel or gasoline that has a lower cracking point needs a more controlled burn and to get the correct air to fuel mixture.
If one hole tips produce more smoke then would seem to make sense to switch so your not wasting fuel and get better atomization.
One of our members was going to try a four hole on just diesel to see how that ran with even better atomization. Seems like it would as better atomization turned to vapor is what we are looking for.