Have blown a head gasket on my 86 four runner. It has a 22-re and this will be the 2nd h-gasket I have replaced on this particular runner. The last time I replaced it, everything was factory and the motor had not been taken a- part before. This time I took the head to a different machine shop (old one out of business) to have the head cleaned and checked. The new shop told me the head is milled past spec by a 5000th??? They recommend a shim to go with the h-gasket thus putting the head thickness back within spec. This to me seems like another place for the gasket to fail...anyone with any experience in this area? Also I am fairly sure that the h-gasket blew this time because of a faulty thermostat. I have been running with this head for 2 years now with no problems until a few recent overheats. They say the head doesn't need to be milled this time. Should I forgo the shim? Sorry for the long post. Any info would be appreciated. Thanks,
Eric

 

take it to another machine shop and get a second opinion.

 

Did they say it was off by 5 thousanths (0.005"), or by a five thousanth (0.0002)? Either way, the valve to piston clearance is not so tight on an otherwise stock engine that it should matter. If the head is straight and not cracked, put an OEM Toyota gasket in it, fix the cause of the overheat, and reassemble.

 

I've never ran a shim but I do no people that have and still do. A good friend has a dirt track Celica with 20/22r hybrid. He runs a copper gasket that's a one piece gasket. It makes up the gap difference. However he still has to change it every so often do to so much compression.

 

OK, thanks all, going to continue w-out shim.
Eric