Valve Lash Cold vs Hot
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=160555
Printed Date: 18 Dec 2024 at 3:51am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: Valve Lash Cold vs Hot
Posted By: Dave(inMA)
Subject: Valve Lash Cold vs Hot
Date Posted: 01 May 2019 at 6:24am
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I'm planning to check the valve lash in my WC/WD45/D14 and re-check the CA. Getting the engines on my tractors into the operating temp range is a challenge - they all seem to want to run below the range on the temp gauges. It'd be easier to set valve lash with the engines cold. Is it okay to do it this way? Or is this approach only to get the setting close for an engine that's just been rebuilt? If setting lash cold is okay, what would be the cold engine spec? The CA manual specifies 0.012" with the engine at operating temp. I recall seeing 0.015" for a cold engine, and Sugarmaker mentioned the same value for his WD45 engine rebuild. So would adding 0.003" to the hot spec get me to a good cold spec for these engines? Thanks much. Dave ------------- WC, CA, D14, WD45 |
Replies:
Posted By: DougS
Date Posted: 01 May 2019 at 6:40am
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I've seen the .003 spec for other valve settings too. I've always wondered about that, since it is slightly more than a human hair. I would think the exhaust valve stem would expand more than the intake too. |
Posted By: Lonn
Date Posted: 01 May 2019 at 7:19am
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.015 is what I usually do. You can check it again after it warms just to make sure none are too tight. Loose is better than tight. ------------- -- --- .... .- -- -- .- -.. / .-- .- ... / .- / -- ..- .-. -.. . .-. .. -. --. / -.-. .... .. .-.. -.. / .-. .- .--. .. ... - Wink I am a Russian Bot |
Posted By: Gerald J.
Date Posted: 01 May 2019 at 9:51am
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The extra clearance when setting cold has to be enough to allow for the expansion of the valves (both intake and exhaust collect heat from the cylinder combustion, exhaust more because the combustion gas goes through the open valve) and the push rods. The expansion of the head and the rocker shaft supports increase the hot clearance. The cam shaft position can affect the valve clearance if it moves up or down in its bearings that have a few thousandths of clearance. A valve with insufficient clearance gets burned and then leaks combustion products into the intake or exhaust manifold. Adjusting with the engine warm is not horribly difficult, adjusting with the engine running (which Ford required in their in line 1954 six cylinder car engine) is a lot more pain but for the overhead valve engine is possible. It would be best if the owner's manual or shop manual specifies cold valve clearance. Gerald J. |
Posted By: plummerscarin
Date Posted: 01 May 2019 at 11:00am
| The service manual for my 7045 states the cold lash is to get you close so you don't wreck something before you get to operating temp. I just did my 7045 and after it cooled off I checked the cold lash for grins and it was in spec for cold lash. |
Posted By: Dick L
Date Posted: 01 May 2019 at 11:18am
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My chart covers up to the WD. I would guess that the thermostat temperatures where higher after the WD and would require a slightly greater gap. My chart calls for .010 H and I have always used .012 C. When I was still setting them at idle I still used .012 H on the B, C and CA. 
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Posted By: Dave(inMA)
Date Posted: 01 May 2019 at 5:25pm
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Thanks, everyone. Looks like a 0.002" addition for the cold spec sounds right. I'm a little puzzled why AC has published one spec (0.012" hot) in the Operating Instructions and Repair Parts Illustrations for the CA vs the Service Manual chart (0.010" hot). I'll go with the Service Manual and see how the engines like it! I appreciate the help. Dave ------------- WC, CA, D14, WD45 |
Posted By: DiyDave
Date Posted: 01 May 2019 at 6:16pm
You could just put a piece of cardboard, in front of the radiator, works fer me! ------------- Source: Babylon Bee. Sponsored by BRAWNDO, its got what you need! |
Posted By: Dave(inMA)
Date Posted: 01 May 2019 at 8:12pm
Dave, I tried the cardboard trick. It helped some, but still didn't get temp into the operating range. I'm wondering if there's actually a thermostat inside the housing! At the risk of messing with something that mostly works, maybe I should pull the housing and see if there's anyone home in there.  ------------- WC, CA, D14, WD45 |
Posted By: Lonn
Date Posted: 02 May 2019 at 6:52am
------------- -- --- .... .- -- -- .- -.. / .-- .- ... / .- / -- ..- .-. -.. . .-. .. -. --. / -.-. .... .. .-.. -.. / .-. .- .--. .. ... - Wink I am a Russian Bot |
Gerald J. wrote:Posted By: DougS
Date Posted: 02 May 2019 at 6:57am
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I think the .012 hot setting already allows for a hot engine. If the engine overheats you don't want to compound the problem by burning a valve. |
Posted By: Sugarmaker
Date Posted: 02 May 2019 at 8:26am
Dave, Each one of my machines that did not come up to temp, which was several, did not have a thermostat in them. Seems that was a common adjustment to these machines. Not sure exactly why? I like to have the thermostats in place and see the engine get up to run temps. Just seems like the right thing to do? Maybe some experts will remind us of the pluses and minuses of the thermostat being in or out? Yea its kind of a pain to open the cooling system to check for the stat. If you do you might as well plan on putting one in if missing or replacing a defective one. I have a off color tracked loader, a IH unit. It never came up to operating temp. Its another of my big toys that I got after retirement. My neighbor who runs this type of newer equipment advised me to just leave it alone. Of course I didn't, and had a nice adventure finding the correct thermostat, cleaning up the old housings, making new gaskets, new hoses, clamps, new coolant. I am happy to say it now comes up to temp. Worth it? Maybe? Just made me feel better! Was good to drain flush the cooling system anyway. 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. |
Posted By: Gerald J.
Date Posted: 02 May 2019 at 9:23am
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I have had old thermostats open at less than 100 degrees. The chamber containing the expansion fluid had leaked and they had water in there. When the thermostat opens or isn't present the engine power is significantly reduced because the cool head and block prevents the combustion getting warm and so it doesn't expand and have the pressure on the piston of proper combustion temperature. I mistrust thermostats to the point of testing old and new in a pot of hot water in the kitchen before installing, while monitoring the water temperature with an instant read cooking thermometer. Gerald J. |
Posted By: Sugarmaker
Date Posted: 02 May 2019 at 11:39am
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Gerald, Great suggestion for testing them in water for function at temp. 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. |
Posted By: DrAllis
Date Posted: 02 May 2019 at 12:24pm
| .015" COLD was the way I was taught. When doing them cold, you are consistent in your settings because the temp stays the same. Good luck doing an engine hot and having it be the same from beginning to end. |
Posted By: SteveM C/IL
Date Posted: 02 May 2019 at 12:42pm
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Yeah,my hot engines aren't as hot when I'm done as they were when I started. .... My Detroit manuals said cold .002 more than hot. Always seemed right when checking hot. Cat gives you cold settings only with + or - .002. Range of 5 |
Posted By: Dave(inMA)
Date Posted: 02 May 2019 at 7:28pm
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Thanks for all the advice! I bet that Chris is right about missing thermostats. Checking all the tractors for that and the valve lash will take a while - I'll start with the CA since it's sitting in the shop. Will let you know what I find. Dave ------------- WC, CA, D14, WD45 |
Posted By: ACinSC
Date Posted: 02 May 2019 at 7:58pm
| My old D 15 runs 180 degrees with or without a thermostat . Kinda strange . |
Posted By: Allis dave
Date Posted: 03 May 2019 at 7:29am
| Better to be a little large on the gap than a little tight. I little loose and you'll be fine, a little tight and you'll burn a valve. I said a little loose, not a lot. |
Posted By: Dave(inMA)
Date Posted: 03 May 2019 at 2:52pm
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Sounds like 0.015" cold s/b okay! Please stay tuned....... ------------- WC, CA, D14, WD45 |
Posted By: SteveM C/IL
Date Posted: 03 May 2019 at 6:23pm
| the cold clacking goes away as soon as it gets a little heat in it. |