IP installment with a mystery

[Floridianson]

Don't know if that is his problem but I said it before the O ring that everyone says is correct I believe is to big. When we tighten the control shaft down I believe it put the shaft in a bind. I wish I have one of the O rings Ambac had in with the heads I got from GL.

 

[Bloodmike]

I would agree that the orings were at least 1/2 the issue, however the 2nd part of that is, it would even start without a healthy dose of starter fluid.

I had the same issue and this is what fixed it. Also make sure you have the correct o-ring in there to seal the shut off shaft. some reason the best one I could get to fit was the OEM military one. Anyway, of those two screws are too tight it will make it hunt.

Honestly, I think its my deuce just telling me it wants a 4-71 Detroit under the hood.

 

[rustystud]

OK guys, there is no way that 'O'-ring can cause any binding on the shaft or effect the control rod in any way !!!
That unit is hardened steel and ground to fit that shaft. It is a precision unit, but that little 'O'-ring is NOT going to distort it in anyway !!! What can happen, and most likely did happen to those who keep "claiming" it cured their problem is that there was some gunk on the shaft causing it to gum up and not turn freely. After they messed with it by loosening the two screws it came free and now they think the screws had something to do with it. It would be the same thing as saying the crankshaft was binding in an engine so lets "loosen" up the main bearing caps !!! Now if your not using the correct size 'O'-ring then you can have leaks, and I suppose it is possible if somehow you got a 1/4" thick 'O'-ring in there it could cause some distortion. But the small screws would pull out of the housing first !!! They are not large bolts here people, but extremely small screws. I accidently damaged one by just tightening to much with the screwdriver !
So I say to all who are keeping this "myth" alive to stop and think what your saying and actually "look" at this unit. If you truly look at it you will see there is no way the 'O'-ring can ever cause binding !

 

[orren]

If she runs OK once you get it started but is hard to start, I found the HH pressure to the
injectors is too low because its single piston is no longer able to get pressure up high enough at the
low starting RPMs. This is caused by a slow wearing away over time when fuel is not very, very
clean.

If you are running without the FDC and fuel line now goes directly to HH I found that when
motor was not running fuel was back flowing. So, I installed a 3/8" check valve immediately
after final fuel filter and now she starts like a rocket every time.

Good luck.

 

[Bloodmike]

I would consider all these suggestions, as to what might be the issue, However a fresh rebuilt pump for the factory shouldn't have the issues of a well worn pump....

If she runs OK once you get it started but is hard to start, I found the HH pressure to the
injectors is too low because its single piston is no longer able to get pressure up high enough at the
low starting RPMs. This is caused by a slow wearing away over time when fuel is not very, very
clean.

If you are running without the FDC and fuel line now goes directly to HH I found that when
motor was not running fuel was back flowing. So, I installed a 3/8" check valve immediately
after final fuel filter and now she starts like a rocket every time.

Good luck.

 

[gringeltaube]

...... a fresh rebuilt pump for the factory shouldn't have the issues of a well worn pump....

Agree on that!
Also, one would tend to think that pump rebuilders all have a test stand and do test-run their products before putting their tag on it...?

 

[gimpyrobb]

Agree on that!
Also, one would tend to think that pump rebuilders all have a test stand and do test-run their products before putting their tag on it...?

Mil surplus from a dealer.

 

[rustystud]

Mil surplus from a dealer.

If it was military rebuilt then the "spyder" should be properly adjusted. There is one other thing to look at. On the side of the Hydraulic Head is that 12 point bolt. Under that is the "Fuel Delivery Valve" . if some crud got in there it could cause problems. Also check the "overflow valve" on the Hydraulic Head. It too can be sticking causing fuel pulses, which would end up with a "hunting" problem same as the delivery valve.

 

[orren]

I would consider all these suggestions, as to what might be the issue, However a fresh rebuilt pump for the factory shouldn't have the issues of a well worn pump....

Yes, you would think a rebuilt pump would be tested, etc. but HH piston is not rebuildable, yet.
To see what I mean take all injector feed tubes off of HH and turn motor over. If fuel is not shooting
over a foot high out of holes in HH, start up speed fuel pressure is too low to get fuel to open injectors.
TM's explain necessary fuel pressure to open injectors.

Also, you might see if you are getting a back-flow of fuel from HH when you turn motor off. I changed
my fuel lines to a clear nylon type so I could watch for this and look for air leaks, too.

If you still have doubts about HH pressure maybe you can find someone who has the equipment
to give a good pressure reading at startup speed.

Good luck.

 

[Floridianson]

If it was military rebuilt then the "spyder" should be properly adjusted. There is one other thing to look at. On the side of the Hydraulic Head is that 12 point bolt. Under that is the "Fuel Delivery Valve" . if some crud got in there it could cause problems. Also check the "overflow valve" on the Hydraulic Head. It too can be sticking causing fuel pulses, which would end up with a "hunting" problem same as the delivery valve.

Yep if you remember someone even had a broken delivery valve spring.

Gimpy in OP's pic the head mark is not one tooth to the rear it looks to me when all the others are on the money?

 

[rustystud]

Yes, you would think a rebuilt pump would be tested, etc. but HH piston is not rebuildable, yet.
To see what I mean take all injector feed tubes off of HH and turn motor over. If fuel is not shooting
over a foot high out of holes in HH, start up speed fuel pressure is too low to get fuel to open injectors.
TM's explain necessary fuel pressure to open injectors.

Also, you might see if you are getting a back-flow of fuel from HH when you turn motor off. I changed
my fuel lines to a clear nylon type so I could watch for this and look for air leaks, too.

If you still have doubts about HH pressure maybe you can find someone who has the equipment
to give a good pressure reading at startup speed.

Good luck.

The Hydraulic Head can be totally fine and still not spray the fuel like you described if the fuel pressure and flow are totally screwed up. So you cannot just condemn the Hydraulic Head right out of the gate before you properly diagnose the problem. Really, the Hydraulic Head is a very simple thing. Only thing that wears out is the bore and that's after years of service.

 

[Bloodmike]

A little update, C&C equipment has got me in contact with American Bousch, and they are going to diagnose the pump issue via phone conversation. If they can't walk me thru some standard remedies, I am to pull the pump and send it back to them for testing. Don't know what that turn around time is but, at least this is progress.

The Hydraulic Head can be totally fine and still not spray the fuel like you described if the fuel pressure and flow are totally screwed up. So you cannot just condemn the Hydraulic Head right out of the gate before you properly diagnose the problem. Really, the Hydraulic Head is a very simple thing. Only thing that wears out is the bore and that's after years of service.