Anyone have one of those fancy stem height checking tools they could loan me?? Or know of another way to check valve stem height?? I guess i could measure it with a caliper....does anyone know the correct height from the seat?

 

Tim,
I have one of the actual GM factory tools. I have a drawing I made of the dimensions but don't have it on my computer here at home. A word of warning, some of the aftermarket tools are not correct. I had a customer bring me one along with a set of heads to do a few years back. Something did not make any sense with the tool compared to the valve stem height listed in my engine builders software. So I managed to get hold of the GM tool from a friend. The aftermarket tool was quite a bit off.

The valve stem height listed in my engine rebuilders software is 2.016" to 2.046" I have found that is pretty close but the spring seat machining leaves something to be desired.

If you can wait till Monday I will get the dimensions of the tool. Joe P might have to drawing too, I think I had e-mailed it to him.

 

Ok, Found the pictures. It give you the basic idea but it would be hard to make one because of the angle of the valve.

 

Hi Bill,

Can you clarify your valve stem height specs "listed in my engine rebuilders software is 2.016" to 2.046"versus the height from the webpage below which mentions 2 heights based on the retainers/rotators "1966 and up 400 and all 455’s without rotators; 1.880" and 2.035” for 455’s with rotators."

http://www.supercarsunlimited.com/in.../stem/stem.htm


best regards,

John

 

John,
I just looked again and on certain years there is a note saying that the non rotator heads are 1.8760-1.9060 Those heads must have a shallower spring pocket. On Olds heads though what is mainly important is the height of the stem compared to the valve cover rail because of the non adjustable valve train. I have found that factory spring pockets are very inconsistant

 

Bill,

So would that also mean that there would be 2 valve stem measuring tools? One for rotators and one for non-rotators?

cheers,

John

 

The CSM shows you how to use a feeler gauge between the tool and the valve tip. The tool is configured for the tallest possible valve. The use of feeler gauges lets you check valves at a lower dimension.

By the way, here's a clever way to make your own version of the Olds tool.

 

John,
No because the difference is that the head is machined deeper to allow for the thickness of the rotators. The height above the valve cover rails / rocker mount has to be the same or you would need different length pushrods. I dont have an Olds rotator here to measure but Chevy ones are around .200 thick.

 

OK, I get it now....

The different measurements are from the base to the top of stem which differ from rotator and a non-rotator
The tool uses the head rail but should be similar to both in depth to the top of the stem.
correct?

cheers,
John

 

Back in the day, when Joe Mondello was alive, I bought one of these checkers from him. I'll try to get pic of mine and post it here.