Head Gasket O-rings? Required?
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Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=150365
Printed Date: 09 Jun 2025 at 7:32am
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Topic: Head Gasket O-rings? Required?
Posted By: bobforapples
Subject: Head Gasket O-rings? Required?
Date Posted: 11 May 2018 at 5:48pm
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OYE! Well, working on my Allis C rebuild. I pressure tested the cooling system today after installing new sleeves and gaskets. To my delight I found a substantial leak bewteen the block and head on the rear of the engine. The headgasket is new and the head and block are flat. Here's just a wild shot in the dark please help if you can!!! The engine gasket kit came with 4 o-rings that I never found a use for. At one time I thought I should install them in the water passages between the head and block... I didn't remember the old head gasket having o-rings so I thought I must have been wrong and never found a use for em. So, Am I supposed to install these 4 o-rings between the head and block? |
Replies:
Posted By: DrAllis
Date Posted: 11 May 2018 at 6:29pm
| Perfectly dry head gaskets on 70 year old blocks and heads aren't a good idea. That head gasket needed to be coated/painted with something on both sides. I'm assuming the four O-rings you have are for the valve cover nuts/washers. |
Posted By: bobforapples
Date Posted: 11 May 2018 at 6:36pm
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Good call on the O-rings for the valve cover. I cant believe the dry gasket is the culprit, but maybe I learned something today. |
Posted By: Dick L
Date Posted: 11 May 2018 at 8:29pm
| Did you warm up the tractor and re torque it to spec afterward? I have never used any thing on a fiber gasket and never had a leak on these little engines. I would guess that dirty holes in the block could be the problem or something along that line. Most all of those blocks I have cleaned had crap in the threaded holes that came up when I run a tap in when it came out. |
Posted By: HoughMade
Date Posted: 11 May 2018 at 8:54pm
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I used copper gasket sealer spray on both sides of the head gasket on my B. That and torquing the head in 5 increments, then retorquing after it had warmed up and cooled- no leaks...but it could be luck of the draw, ------------- 1951 B |
Posted By: DrAllis
Date Posted: 11 May 2018 at 10:38pm
| When I was in business, I had three things I would fire an employee for. Never had to do it because they always complied. Always run a thread tap down thru each head bolt hole and blow them out and then bench wire brush off the head bolt threads clean and use light grease on the threads for lube. Clean, clean, clean. You can't do a good job of torqueing a head bolt if the threads are dirty, dry and rusty. We never worked on B's and C's but I can assure you the head gasket would have been painted with something on BOTH sides. |
Posted By: bobforapples
Date Posted: 12 May 2018 at 8:53am
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Thanks for the advice everyone. I'm going to remove the head and run a tap through the holes, wire wheel the bolts, coat a new head gasket on both sides and try again. |
Posted By: Gatz in NE
Date Posted: 12 May 2018 at 8:58am
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Might try Permatex Hi-Tack spray. Give it time to get tacky before assembly. We used it alot on car & tractor engines and found it very suitable for Oliver Diesels when nothing else would hold. |
Posted By: bigal121892
Date Posted: 12 May 2018 at 9:16am
| On a gas engine, I would always spray paint both sides of the head gasket with aluminum paint, never had a head gasket leak. |
Posted By: john(MI)
Date Posted: 12 May 2018 at 9:33am
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Did you have the manifold on the engine? One or more of the studs may go thru to the water jacket. ------------- D14, D17, 5020, 612H, CASE 446 |
Posted By: Fred in Pa
Date Posted: 12 May 2018 at 11:09am
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When u say head and block are flat .Where they machined and sleeve height set . ------------- He who dies with the most toys is, nonetheless ,still dead. If all else fails ,Read all that is PRINTED. |
Posted By: bobforapples
Date Posted: 12 May 2018 at 2:32pm
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head and case checked for flatness, and also checked once the sleeves were it. -Good point about the exhaust studs. I don't know if they are blind holes to the jacket, bet the pressure leak was form the head gasket. Autopsy tomorrow. |
Posted By: B26240
Date Posted: 12 May 2018 at 3:31pm
| Like bigal I also use aluminium paint on both sides. I once worked on a tractor that someone had prior to me worked on and used some sticky stuff on the gasket, I had tractor lifted off the ground with the shop hoist and useing wedges on the corners finally got the head off. |
Posted By: DiyDave
Date Posted: 12 May 2018 at 5:57pm
shellac also works good as a sealer, too...
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Posted By: LeonR2013
Date Posted: 12 May 2018 at 6:50pm
| A product called Flo-ex is the best stuff to use if you are having a problem getting a head gasket to hold. Bar none. |
Posted By: bobforapples
Date Posted: 13 May 2018 at 7:59am
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I hope this post will help someone in the future! The head gasket included in my gasket kit was not labeled for Top/Bottom/Front/Back etc. I initially picked the orientation that matched the holes as close as possible. The water pump was not on the block at the time. Later when I installed the water pump I noticed that some of the headgasket was overlapping the block and was crushed by the water pump. I chalked that to poor quality and standards by the gasket company. (clearly this was not the case). I installed the head gasket backwards. Don't be like me! When you install a new gasket make sure the front of the gasket is flush with the engine block and not sticking out. The water passage on the rear of the head will not seal if the gasket is backwards!!!! Time to order a replacement gasket and try again. |
Posted By: WF owner
Date Posted: 13 May 2018 at 9:01am
| We've all done something similar. At least you didn't put a clutch plate in backwards and have to split the tractor again. Don't ask who would do something that dumb!!! |
Posted By: Dick L
Date Posted: 13 May 2018 at 9:07am
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There ya go! I now remember doing the same years ago. When I went to put the water pump on I removed the head and turned the gasket around. When I was pulling I used the same head gasket several times when trying out different grinds, valves, and porting. I reused the head gaskets until some of it picked up on the block or head. I never painted them with any thing. The idea back in the 1940's to paint the gaskets with aluminum paint was an anti seize idea to reuse the head gaskets at the time. I ground the valves on my 1952 Chevy and reused the head gasket that had been painted with aluminum paint. Back when people didn't have a government safety net people had to think about a possible slim financial future year. That is why your ancestors didn't throw many things away. |
Posted By: Sugarmaker
Date Posted: 13 May 2018 at 9:10am
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Bob, Thanks for your post! May save one of us some time money and frustration too! Will be doing a pressure test on my WD45 today. Looking for leaks in all the right places! Regards, Chris ------------- D17 1958 (NFE), WD45 1954 (NFE), WD 1952 (NFE), WD 1950 (WFE), Allis F-40 forklift, Allis CA, Allis D14, Ford Jubilee, Many IH Cub Cadets, 32 Ford Dump, 65 Comet. |