Adjusting valve tappets hot vs cold

chas036 · May 6, 2018

The service manual for my Massey 85 gas tractor with a Continental engine says to adjust the valve tappets when hot, 0.016 for intake, and 0.018 exhaust. I don't want to deal with the problems of rigging up a gas line and some temporary tank, and trying to start the tractor without the main gas tank installed.

I assume that those adjustment specs are set for when the metal block and head have fully expanded with heat. My question is, if I want to adjust the valves cold, what should compensate those settings too for a cold engine?

If I just use those same hot values when I adjust it cold, would this cause any problems?

Janicholson · May 6, 2018

.003 looser than spec should do it. It might be a little noisy but that is OK.. Jim

BushogPapa · May 6, 2018

Best to add .002" when set Cold..

covers expansion of parts when at operating temp..

Russ from MN · May 6, 2018

I think you should set it a little loose and run it awhile and then re-torque the head and set the valves again.

Steve@Advance · May 6, 2018

Is this an adjustment following a disassembly, or a routine adjustment?

If it's been apart, I would rig up a fuel supply and run it up to temp, retorque the head bolts, and set the lifters hot.

If routine, as others said, add .002" to .003" to the recommended hot setting.

Moonlite37 · May 7, 2018

I assume the valve gets hotter than the head

chas036 · May 7, 2018

(quoted from post at 04:29:07 05/07/18) Is this an adjustment following a disassembly, or a routine adjustment?

If it's been apart, I would rig up a fuel supply and run it up to temp, retorque the head bolts, and set the lifters hot.

If routine, as others said, add .002" to .003" to the recommended hot setting.

This is a complete reassembly. The valve in number one was completely stuck open. When I took the valve cover off, I saw a lot of condensation and rust , so I assume the valve was rusty and got stuck. I am taking the head to a machine shop to be cleaned up.

Dieseltech · May 7, 2018

As been said, add .002 and you will be fine. Perkins says best set hot at .010 for example, but the book also says .012 cold..

Adjusting valve tappets hot vs cold

chas036

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Janicholson

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BushogPapa

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Russ from MN

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Steve@Advance

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Moonlite37

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chas036

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Dieseltech

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