The Stovebolt Site Forums The Shop Area Engine Shop 216 valve lash question

Hello folks,

Since I've had the 41 I've always adjusted the valve clearances hot ( take the truck for a wee run and then let it idle for 30 minutes ). Someone ages ago mentioned about setting the clearances cold ( Tab i think ) which raised a bit of discussion. I noticed in my manual that although they recommend setting the lash hot and mention the changes in clearances as the engine heats up, they illustrated this by setting clearances cold ( .006 inlet and .013 exhaust )After 30 minutes idling with clearances checked every 5 minutes, at the end of 30 minutes idling the clearances were at the starting clearance ie .006 inlet and .013 exhaust. Question then I suppose is does it matter whether they are set hot or cold?

Cheerrs

Bob

Setting them hot is the preferred method, it's also more accurate as the parts will already be at their maximum expansion.

Thanks Bill. I was interested as all other inline six engines that I've had ( mainly old Rovers )give a hot and cold setting.

Cheers mate

Bob

I'm not totally clear on the question. If you set them at .006 and .013 cold, they would be tighter when hot, obviously.

If you don't want to deal with a hot engine, or are assembling a engine after a total rebuild, you can set the lash cold if you add .001-.002 to your measurement.

So the answer to your question is yes, it does make a difference.

Stuart

Thanks Stuart. I raised the question because the manual shows that the clearances do vary and tighten up as you would expect as the engine warms up but once it reaches operating temp and the engine temp is normalised the clearances are back where you started. The manual shows the variations in section 6-29.

Bob

mozzie,

Very interesting. I have never actually thought of it like that before, but it sort of makes sense.

Maybe they are implying that the valve train 'grows' first, then, as things equalize, the 'block grows' and cancels out the valve train growth...it's all one hunk of cast iron!

Wow, I think I've given myself a migraine!

Stuart

As I recall, I think the shop manual says to allow about .005" additional to the hot setting if the engine is cold.

Mozzie -look in the Teck Tips section for help on setting your valves without the engine running. Yes the best way to get an accurate lash is with the engine at operating temperature or you will get the valves too tight and possibly cause a burnt valve. I use to set my valves with the engine running but have found out that I could bend the push rods that way..it is more difficult to get an accurate setting that way also. I set my valves at .008 intake and .015 exhaust (Hot) on my 62 1/2 ton truck with a 235 six. If you can't hear the valves "clicking" they are too tight! Hope this helps. Sorry to hear about Irwin's death..

Thanks for the input guys.

All the best

Bob