Construction and other equipment - Allis Chalmers HD5 Governor

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Allis Chalmers HD5 Governor

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=153159
Printed Date: 21 Aug 2025 at 6:47am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com

Topic: Allis Chalmers HD5 Governor

Posted By: Bcuhanson
Subject: Allis Chalmers HD5 Governor
Date Posted: 18 Aug 2018 at 11:30pm

Good afternoon,

I have a 1954 AC HD5 Dozer that i have been working on for several years to restore. I have recently updated my starting system to a 42mt per Coke's recommendation and i couldnt be happier. Get rid of the old push rod and embrace solenoid technology :)

I really appreciate all the information and knowledge that is shared on this forum.

Now to my question, i recently had an issue with a bad valve seat that caused a teardown of the head and rebuild of the top end. I reassembled and started the motor with an easy couple cranks. It runs strong with full power again.

The problem i have is that the motor will run WOT if i quickly decelerate to idle. If i slowly idle the motor down all is good and i can just turn off the machine without issue. However a rapid deceleration causes the motor to run WOT. This also happens repeatedly if the process is repeated. I have not changed anything in the governor and the injectors have recently been cleaned and reassembled. I have been all over the internet looking for the answer. I am hoping that one of you may have a suggestion.

If i did not have Vice grips on the rack this initial startup would have given me a heart attack...

Replies:

Posted By: SteveM C/IL
Date Posted: 20 Aug 2018 at 2:16pm

Been a long time since I fiddled with DDA's. Sounds like you didn't get something back together right with the gov linkage. The fuel shut off should be positive push on rack.You do have the injectors indexed into the rack,right? Easy to miss one. Did this work right before you worked on it? If you don't know,you may have trouble in the gov itself. Good luck!

Posted By: Bcuhanson
Date Posted: 21 Aug 2018 at 11:19am

HI Steve,

Yes, everything did work correctly before i removed and replaced the head.

I am curious, does the injector have a point at which the fuel would would run full wide open on the opposite end of it's adjustment. When the WOT scenario happens, i have to grab the vise grips and push them just slight in the direction that should increase fuel to the motor to find the "Sweet Spot" where the fuel is off.

I know that the full fuel on position is with the injector control arm all the way in, but i am starting to wonder if the injector goes back to full fuel if adjusted too far out as well.

I thought i would be ok with reassembly if i left everything as it was, however, maybe now that i have full compression and the motor is running strong that the governor settings are off from compensations made by the previous owner due to lack off compression.

I would love to find a DD tech in this area who is knowledgeable in making rack adjustments.

Posted By: DMiller
Date Posted: 21 Aug 2018 at 5:32pm

You need to have someone that has run a rack look it over, you have one of the injector racks hanging, cannot tear down and just reassemble reverse order on these.

Posted By: SteveM C/IL
Date Posted: 23 Aug 2018 at 6:54pm

I'm not around my book and been 22yrs since I had my 8V92 but don't you have to have the gov set WOT to adjust rack levers? Also the rack tube has to rotate freely before anything is connected. They can bind at pivots.Have you got a book explaining proceedure?Setting injector height/timing is not for a beginner either. Full in is WOT full out is no fuel.You are turning a helix to increase fuel.Reversing direction only shuts off delivery.

Posted By: PaulB
Date Posted: 30 Aug 2018 at 5:01pm

I have a Detroit Diesel service manual for the highway vehicle inline 2 cycle engines available. I also have a Korody-Colyer (K-C) parts book for the Detroit Diesel engines. I will sell them both for $75 including the shipping within the lower 48.

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If it was fun to pull in LOW gear, I could have a John Deere.
Real pullers don't have speed limits.
If you can't make it GO... make it SHINY

Posted By: Bcuhanson
Date Posted: 31 Aug 2018 at 3:24pm

Hello Guys,

First off, thank you for your help and time reviewing my post.

I found the issue...(I am an idiot) I made a drastic mistake while cleaning my injectors.

Once cleaned, they do spray a nice 7 orifice pattern from the spray tips.. but while cleaning on one of the injectors, i did have the small pinion gear fall out of the plunger portion of the injector. I did, at the time, notice a small identifying dimple point on the pinion gear. However, without the injector's small control rack removed, i did not realize that this small dimple point on the pinion gear must align between two similar dimple points on the injector's control arm/rack.

So, this whole issue was all my fault from the beginning. Once I aligned the Injector's control arm/rack and the pinion gear inside the injector using the alignment dimples the motor and governor responds as expected and no more near heart attack situations.

Posted By: Coke-in-MN
Date Posted: 31 Aug 2018 at 8:03pm

Hmm must be why I had the injectors cleaned and adjusted through a truck dealership account that i plowed snow for . Cost me at the time $27 each to have them do the HV7 injectors at a Detroit Diesel repair center .
The guys there also gave me a timing gauge to set them properly when installing them back into head .

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Life lesson: If you’re being chased by a lion, you’re on a horse, to the left of you is a giraffe and on the right is a unicorn, what do you do? You stop drinking and get off the carousel.

Posted By: SteveM C/IL
Date Posted: 01 Sep 2018 at 2:48pm

the school of hard knocks strkes again....in the original post,you didnt mention that the injectors were worked on by YOU.im sure most overlooked that remark thinking it was done by someone who knew what they were doing.No suprise that what was wrong didn't stand out...just saying

Posted By: Bcuhanson
Date Posted: 02 Sep 2018 at 10:23am

Yeah, I thought about that. I should have mentioned it in the initial post. I wanted to follow up though and come clean on the issue so someone could learn from my mistake.