Hi guys as the title say i know there is a difference between the head gaskets my question is why would some stockist have the cometic head gaskets as the same from 1990 - 1997 being as the same.. Also my car is a Rev1 if any one knows the correct part number for the cometic head gasket for REv1/Rev2s
This would be a big help at the stage of building my engine
No it does not need to be modified. It is a multilayer steel gasket. Toyota also addressed a problem with the earlier engine by adding an oil restrictor in the gasket that is located at the feed to the head. this reduces the tendancy for the engines to fill the head full of oil at constant high rpm.
Cometic improved the rev2 gasket but did not put the restrictor in.
if you run the rev3 belt on a rev2 by swapping to the smaller oil pump pulley thus improving oil pressure then definatley go rev3 gasket (or you could fit a restrictor in the head if you run the cometic in any of the engines,)
Find the oil feed to the head then look at the gaskets.it should be obvious.
Ok i am going to backtrack a little:
I dont know what oil clearances you are building the bottom end to or your intended use (ie high rpm) so really just pointing out something for you to take into consideration. As bob likes to say it is more than just bolting a box of parts together.