So I got done doing a head gasket job on a 3.0 Toyota, truck ran fine coming in. When I was cleaning the heads I had a couple of shims / lifter cups fall out. I thought I got them back in there normal spot but it appears I did not. So I did a compression test, all Cyl. came back great except for Cyl. 3. So I checked all valve clearances and everything was in spec except for cyl. 3.

I ordered the smallest shim I could get the 2200, put it in and I now have around 95 PSI of compression in Cyl. 3. My question is this should of fixed it. Also, are the round cups that the shims fit into different sizes? What else could be causing low compression?

Thank you

 

Was the valve in spec after the new shim? U may have to grind a little of the valve stem if the thinnest shim did not leave enough clearance

 

No. I can't even fit a 0.02 feeler gauge in there.

 

Looks like you are going to have to grind a little off the valve stem end. Get it within spec before testing the compression

 

Not liking that idea. Why would it be 100% fine when it came in for a new headgasket, but now all of a sudden its not?

 

Was any valve work performed? If so did they replace the seats? Use the right ones? Anyways the head shop I use adjusts the valve clearances by grinding a little off the valve ends. A lot easier and cheaper. Should have no issues

 

Came in? As in your shop? You did this for money?

Did you test compression prior to head gasket job? You are a proffesional mechanic?

 

Should of checked the clearances w heads off.....

 

No valve work was done. Just checked for warped, and cracks.

 

No valve work was done. Just checked for warped, and cracks.

 

I did some more testing, I checked valve clearances and exhaust side is way too tight on Cyl. 3. So I got some new shims but its still too tight even with the smallest shim in there. One thing I did notice is when the cam lobe is all the way up, that lifter cup sits way higher than the others that are also pointing up. It seems like carbon build up or something is keeping that valve open not allowing it to close. What do you guys think?

 

Is it possible the old shim is still in there?

 

100% not.

 

On the contrary, if the valve was not closed all the way, the lifter would sit lower than the others and would have a lot of clearance between the cam and lifter. sounds like there is something going on with the valve seat/seat surface.. Time to pull the head

 

Yeah that's what I'm thinking.

 

Let us know your findings....

 

Will do