New to AC with a WC, rocker shaft / oil pressure
Printed From: Unofficial Allis
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=207184
Printed Date: 19 Jul 2025 at 9:17am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: New to AC with a WC, rocker shaft / oil pressure
Posted By: Blown331
Subject: New to AC with a WC, rocker shaft / oil pressure
Date Posted: 21 Jun 2025 at 5:38pm
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I bought my first ever Allis Chalmers which is a 1936 WC. It appears to have a 1947 electric start engine in it. I got a great deal on it and it's in nice condition and runs great. When it gets warm the oil pressure gets a little lower than I would like. I'm running a Fram filter with straight 30 weight oil. I tried switching back to the Carquest filter that was on it with no change. The filter standpipe is in place. I added one washer under the oil pressure relief valve cap and did pick up some pressure. I think a switch to 20w50 oil may be what I need. But I also recently learned that the rocker arm shaft is somewhat pressurized and sealed on the ends with cork. I'm guessing I may need those corks replaced. Would this be responsible for the lower oil pressure? I have a parts book and have the part number for the corks but nothing really comes up online. Are people just making these? It seems like driving in a freeze plug would be a better idea. Anyone do this? What size? Any other comments or suggestions are welcome. Thanks. |
Replies:
Posted By: steve(ill)
Date Posted: 21 Jun 2025 at 6:07pm
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what is the pressure ? These engines dont need or have a LOT of pressure.. ------------- Like them all, but love the "B"s. |
Posted By: evan austin
Date Posted: 21 Jun 2025 at 6:51pm
| When I had my WD45 engine apart last year, I think I used tapered rubber plugs in the ends of the rocker shaft instead of corks. I think I had to trim some off of the smaller end because they were long, but I oiled them up and they pressed right in. Still use the cotter pin behind them to keep them from blowing out. Not sure what the real manual calls for, but the I&T manual says that normal oil pressure is 11psi. Or, like my operators manual says, somewhere between the "O" and the "M" of "NORMAL" on the gauge |
Posted By: AaronSEIA
Date Posted: 23 Jun 2025 at 5:52am
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Whats the oil pressure? They are a bypass system and only ran 15 psi at best when new. AaronSEIA
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Posted By: Blown331
Date Posted: 23 Jun 2025 at 9:09am
| Oil pressure is on the M when cold. Adding the washer took me up to the A. But when warm it drops to the line at the bottom of the normal range. Slightly below at idle. |
Posted By: steve(ill)
Date Posted: 23 Jun 2025 at 9:23am
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normal pump wear on an 90 year old engine can cause loss of pressure at low idle.. Remember its a BYPASS SYSTEM.. The PRESSURE is not what is going to the bearings, it is just BACKPRESSURE on the system caused by the filter.... You might still have plenty of oil going to the bearings/ cam / rods in FLOW... just not much pressure.. I have seen these engines run with less than 5 psi at idle.. Pickup to 12- 15 psi at 1600 RPM is good... You idea of trying a 20w 50 oil would be a good test..
if your going to take the valve cover off... run the engine at idle and SEE what you have for oil flow at the top end.. ------------- Like them all, but love the "B"s. |
Posted By: AaronSEIA
Date Posted: 23 Jun 2025 at 4:05pm
Sounds like it's doing fine. What it probably needs is an overhaul. Cam bearings are a major issue on these engines. The camshaft is actually the main oil galley and worn bushings cause low pressure issues. AaronSEIA
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Blown331 wrote:Posted By: Blown331
Date Posted: 23 Jun 2025 at 4:35pm
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It starts and runs really good with plenty of compression and no smoke. I would say pistons and cylinders seem to be in good shape. Perhaps that part of the engine was overhauled but the cam bearings were not addressed. I plan on pulling the valve cover, adjusting the valves and replacing the corks in the rocker arms. I feel like if the rocker arm shaft is carrying pressurized oil but it's just pouring out of the end, that would decrease oil pressure throughout the entire oiling system. I guess I'll switch to 20w50 as well. I feel like that has to make a difference. |
Posted By: Allis dave
Date Posted: 23 Jun 2025 at 4:55pm
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If you're corks are bad you'll know it. When running, you'll be able to either see oil running our the end of the shafts past the corks or no oil will come out there becasue the corks are doing their job. Do you mean when it's hot it runs at or below the "N" on the gauge? |
Posted By: Blown331
Date Posted: 28 Jun 2025 at 8:22pm
| Yes it's below the N on the gauge when hot. It's at the L when cold. |
Posted By: 55allis
Date Posted: 29 Jun 2025 at 12:14am
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My 49 WD would take like 3-4 minutes before it would get oil pressure, come to find out the pump screen was plugged with sludge. So I’m in the process of cleaning all sludge out and replacing the crank seals and all the gaskets on the engine. So take that into consideration of possible problems…. ------------- 1955 AC WD45 diesel with D262 repower, 1949 AC WD45 |
Posted By: IBWD MIke
Date Posted: 29 Jun 2025 at 6:56am
| Adding a quart of Lucas oil conditioner would probably help some. |