Allis Chalmers HD16

[BigC]

OK somebody out there knows the answer to this. I have bee fighting with this repower of an old hd16. I put in a 25000MKII motor and it smokes like you wouldn't believe. I know what your thinking...but have
1. New pistons ad rings
2. new valves
3. been through two injection pumps.
4. new injectors
I have this theory. On some of the 16000 through 25000 series motors they used what was called a long-sac injector and short-sac. Apparently there is an insert that the long-sac used and since it was discontiued you were supposed to remove the insert and use the more recent injector tips. Does anyone know wht these inserts look like and can I remove them without taking the head off. Any info you can give wouold be helpful. My theory is the injector is sitting too high i the head and is dribbling in fuel instead of misting.

 

[ACHD21A]

I have 2 HD21As with the Mark 11 engines. In looking at my AC books, the long sac and standard sac injectors will not interchange. The standard sac injector has a longer length than the long sac. There is an insert on the long sac and the heads have a smaller diameter bore for the injectors than the head for the standard sac.
The long sac injector does sit high in the head where as the standard sac injector tip is 1/16 below the bottom fo the head. The insert is pressed in the bottom of the head and is not part of any cup type insert. To go the the standard cup means reworking the head because of the smaller bore diameter of the long sac. Have to go but will check back in the morning. Bob Chillicothe, Ohio

 

[BigC]

I knew you would know Bob. I have a question does this extra insert reside below the injection sleeve. I am thinking I could pull it up through.

 

[ACHD21A]

This insert is below the injector sleeve and is inserted fron the top side of the head. It has a bevel near the top of it and the head has a bevel machined in it to keep the insert in place when the injector sleeve is pressed in and held tight as the injector is tightened down. Thus the bottom part of the insert has a smaller diameter than the top side. This is why the head has to be remachined for the standard sac injector sleeve. I dont know which injectors my 21s have. I have not done any reading on the pumps yet but to confuse the problem more I see that there is a high pressure system(American Bosh) and a low pressure system(Robert Bosch). The low pressure is not used on crawler tractors. Are you the person from the Cincinnati area that was having injector pump troubles with an open port injector pump. If you are getting black smoke and no white smoke you must have good atomization at the nozzle. My first thoughts were , it is overfueled, turbo not working correctly, or airflow restricted. I think they took the Mark 11 series and turned them to 350 to 400 hp and used them in graders and big stuff and ended up tearing up blocks and cranks because they couldnt take the extra HP. In one of my books they talk about setting the plunger rack linkage to the governor linkage to get the correct fuel flow. A local has a 16 which has a standard 855 engine it and he turboed it but I dont think he turned it up to 300 hp. He can probably help us out on the problem. Bob

 

[BigC]

Yep its me from Cincinnati. I have been through this thing six ways to Sunday. I am getting a ton of white smoke that smells like unburn"t fuel. I measure how far the injector goes down and it on goes about 1/4 inch into the head and sits up high. I don"t think the bottom of the injector is even making contact with the sealing washer. On top of it all the oil seems to have alot of diesel in it. I think the injector is sitting up so high it is spraying against the inside of the head and not letting it atomize the fuel resulting in the white smoke. I have elimanted any othe fule leaks. I"ll bet that nozzle tip isn"t even sticking down into the cylinder. They made it sound like all you have to do is pull the insert but if it is under the injector sleeve that means the heads have to come off. Not something I am looking forward too.

 

[ACHD21A]

Send me your e-mail address and I will send you some pictures. [email protected]

 

[BigC]

Yeeee Haw. It's alive. Not without some issues but what a difference. So I worked all day on it but here is how it went. I got your pictures and it confirmed what I thought it had the inserts. Now how to get them out?? Well I got some literature from Illini Construction parts and low and behold they made those inserts with internall threads (12-24 machine bolts). According to the literature you should be able to remove them with a slide hammer. Well thats not something you buy off the shelf. So after 3 trips to the hardware and many failed attempts. I took apart my slide hammer and used the weight. The got a piece of 5/8 ready rod and drilled the end, tapped with a 12-24 tap and threaded in a 2 inch piece of 12-24 bolt. It fits perfect into the injection tube...Then it screwed it into the inser. About 5 hits up and out they popped!!! Then I rebuilt three of the injectors since I had the new nozzles..set my pop off pressure with my homemade pressure tester ad put her all back together. Primed the fuel and a few shots of either later (which by the way it knocked like crazy since it sat a week and the oil runs into the cylinders through the injector holes). It fired up. Sounded alot like my IH 7.3L in my truck with that diesel rattle. BUT not a bit of smoke out the exhaust. Now it smoked like crazy out the breather...but I am assuming it is from all the diesel in the oil and my valve covers are now leaking but hey I'll take it. Hopefully changing the oil will stop the smoking out the breather (It reaks of raw diesel). Some new gaskets and might be able to use it this year. I'll keep you posted.

 

[BigC]

Well out of the frying pan and into the fire. Now that it is firing like it should I have a ton of alot of smoke come out the breather. Not sure what its doing now. Runs like a top...no smoke out the exhaust. Man I am getting tired of working on this motor. I may have bit off more than I wanted to chew on this one. I knew I should gone through this motor when it was out....but figured the guy had just rebuilt it why bother...obviously he cobbled it together.

 

[steve n carol]

Big C.... Don't know a thng about you AC. But I think they are cool monsters.

Anyway, Glad you got some of the smoke cleared up. got some good help here to!

I was thinking ablut the smoke from the breather....

my thoughts, 1) That the new rings haven't sealed. Is causing some blowby. The valve cover gaskets are leaking, I believe that is what you said. tends to verify this. But this should pass.
2) Also, perhaps the crankcase oil is some what diluted with diesel fuel at this time, because of your injector issues. As well as maybe an increased oil level. This can also cause increased crankcase pressure. Now [u:f9a2971ae9]maybe[/u:f9a2971ae9] all of these things are contributing to the smoke that you are seeing in the breather. Maybe not. I don't know what crankcase ventilatingn is on this machine, if any. But you can look into that.

3) perhaps some intake valves that are too tight. allowing exhaust transfer on the valve overlap 'overlap'.

4) does the intake seimiese with the exhaust manifold on this machine?

Just a few thoughts....sl

 

[BigC]

I had the same thoughts...I was just about ready to start tearing her apart when I thought...wonder if pressure is blowing by the injectors? Took the valve covers off and started it.....sure enough... looked like little volcanoes going off. Torqued down the injectors and all the blowby is gone! Today I put the air filter unit back on. A few more things to take care and I might get to use it. Has way too much power for the unit but I can just run it at half throttle.

 

[steve n carol]

WOW, how easy was that!!!

Roll on...sl