Hey everyone, I have been researching this but cant seem to find a solid answer...
Im replacing the head gaskets on my 3.9 V8, there was coolant leaking from cyl 2, 5 and 8
I know they were done once before for 2 reasons
1 - They only had 10 bolts instead of the 14 ( its a 91)
2 - When I pulled the heads off they had composite gaskets
Using dial calipers I wanted to see if the heads were machined before. My conclusion is they weren't, they measured the same size as pre sufffix B heads. They also were put in with torque to yield bolts, so my theory is that the original tin gaskets went, someone pulled the heads off and put composites in, reused the bolts and only put 10 in and threw away the other 4...
Anyway, I have read that the heads should be brought down .020"-.030" in order to maintain the correct compression ratio. I was thinking if I had them machined to suffix B cylinder head dimensions that would bring the motor to the correct compression ratio when fitted with the composite gaskets but I only have one shot at it so I want to make sure my thought is correct.
Or does it not make that much of a difference and I should just have the heads skimmed and put it back together...
Im replacing the head gaskets on my 3.9 V8, there was coolant leaking from cyl 2, 5 and 8
I know they were done once before for 2 reasons
1 - They only had 10 bolts instead of the 14 ( its a 91)
2 - When I pulled the heads off they had composite gaskets
Using dial calipers I wanted to see if the heads were machined before. My conclusion is they weren't, they measured the same size as pre sufffix B heads. They also were put in with torque to yield bolts, so my theory is that the original tin gaskets went, someone pulled the heads off and put composites in, reused the bolts and only put 10 in and threw away the other 4...
Anyway, I have read that the heads should be brought down .020"-.030" in order to maintain the correct compression ratio. I was thinking if I had them machined to suffix B cylinder head dimensions that would bring the motor to the correct compression ratio when fitted with the composite gaskets but I only have one shot at it so I want to make sure my thought is correct.
Or does it not make that much of a difference and I should just have the heads skimmed and put it back together...