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HD10 Engine Question

Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Construction and other equipment
Forum Description: everything else with orange (or yellow) paint
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=33908
Printed Date: 26 Jun 2025 at 6:17am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com

Topic: HD10 Engine Question

Posted By: Rufus
Subject: HD10 Engine Question
Date Posted: 15 Jul 2011 at 4:58am

Hi,

the GM4-71 is blowing a lot of oil fumes from the breather pipe. If I open the filler cap or remove the dipstick very little (if any) fumes come from those two places.

After removing the head I found a crack under a valve insert and the valve guides were quite worn.

To me the oil fumes sounds like a head problem, but I am wondering if I should be looking at blower seal's and/or replace the liners/pistons now that the head is off.

Any help is appreciated

Cheers

Replies:

Posted By: Tad Wicks
Date Posted: 15 Jul 2011 at 3:30pm

It sounds as though it is tired, how much white smoke in the exhaust?? since the head is off, you might as well keep going. That is the low block 4-71, it should have a two valve head, trunk pistons, and small port liners, have you checked availability of the head gasket set? everything else should be the same,more or less. These engines will build up oil residue in the airbox if the drains are not maintained. Tad

Posted By: Coke-in-MN
Date Posted: 15 Jul 2011 at 3:42pm

the crack in the head are almost a normal thing and if they do not leak or the valve seat is not burnt to the point in needs replacing it is a question of IF. valves are not expensive but the head work can be. Diesel Cast Welding in Mpls Mn did my head for 2-71 and exchange for a loaded head it was not real bad price. A crack running to the injector copper tube from the hole to the valve seat area is almost common.

Pistons and liners are not that bad either compaired to some engines and I found Det Diesle dealer prices on gaskets were cheaper than buying from my truck supplier.

-------------
Faith isn't a jump in the dark. It is a walk in the light. Faith is not guessing; it is knowing something.
"Challenges are what make life interesting; overcoming them is what makes life meaningful."

Posted By: Rufus
Date Posted: 16 Jul 2011 at 1:28am

The motor doesn't seem to blow white smoke from the exhaust. But it pours out the breather pipe from the governor.

I have made a few inquirys about availabilty of parts and it seems that I can get the gaskets/rocker arms and every else to do the head. I was quoted a ridiculous price to have the head repaired (I almost fainted)

Because the budget is tight, I am still deciding if the pistons should be done. My limited knowledge says the head is possibly the problem but I don't want to be wrong!

Posted By: DMiller
Date Posted: 16 Jul 2011 at 4:30am

Vapors from a crankcase vent can only realistically come from rings. Detroit engines use oil control rings to seal blower pressure out at the bottom of the piston, it is more likely these are worn out which also means the upper compression rings are done. There are also seals on the wrist pin ends, there is a specialized installer for them if you go into a overhaul plus they must hold vacuum as a test after install. I had one gentleman try to convince me it was possible blower seals but they are in the low pressure region on the blower and if fail pull vapors from the crankcase.