Hot, cold or running?

[Bob Riding]

I am doing an engine swap between my '56 with the Power Pack option (230cu in with 2bbl carb, 132hp) and my current powerplant in the wagon, a 218 with 2-1bbls and split exhaust. The 230 is running and still in the car. I want to do a valve adjust before I pull it.  Keith's videos show him doing the adjust while the engine is running.

Flat Head Chrysler Valve Clearance Check

The Tech Tips suggest bringing it up to operating temp and then shut it off and do it hot. Others say cold with different tolerances. Thoughts?

[Merle Coggins]

I've done the valves on my truck with the engine running and warmed up. It's actually fairly easy. You'll need long tappet wrenches to keep your knuckles away from the exhaust manifold. And even then you'll need some good gloves to protect your hands from the heat. 

[DJK]

When I rebuilt my engine I set the valves while on the engine stand at .012 in and ex., after installing and running to operating temp., I rechecked with engine running, two needed to be loosened up slightly for proper clearance of .010".

[keithb7]

I did check them while hot and running. You can feel the right tug of the feeler gauge. I'd shut off the engine and to make an adjustment. Then fire it up again and test the gap while running. It was an interesting experiment. However, I also have achieved great results when setting them cold and adding .002" to the spec.

 

If you do want to set them hot keep in mind hot coolant temp does not mean the oil and block are hot. It takes quite a while to get the oil hot, the block fully warmed up. Take off the inner fender access panels and go for a drive. If you can drive up some hills it will heat up quicker. Flat driving, it'd estimate 20 mins of run time to get everything up to temp.

Edited August 10, 2022 by keithb7

[Adam H P15 D30]

I set mine cold mostly because of the headers I have.  .002 added to the intake, .003 added to the exhaust spec.  Checked one cylinder hot once and the intake was right on spec and exhaust was slightly loose.  Remember, slappy valves are happy valves...