gojoe said:
A buddy of mine just got an 86 gn and it has a chip in it and methanol injection in it and he ran it out of alcohol and the motor only has compression in 3 cylinders and smokes alot. I was thinking just a head gasket but some mechanic said 3 pistons were blown. So he took it to the mechanic and he said he was pulling the whole motor out. Do you think the mechanic is screwing him and it is only a gasket? or 3 pistons are out?
Missing compression is due to head gasket, valve, or piston. Typically these motors blow the HG and not pistons, but depends how long he kept his foot into the gas..
There has to be a warning system in place in the vehicle for him to know that the methanol injection is low, car is knocking, etc.. so he can get out of the gas pedal. If not.. this will occur again.
As to what to fix and how to fix before pulling the heads.. that is a judgement call. I dont pull an engine to do head gaskets.. as this sometimes leads to other things.. in other words fix whats broken, and not create a mountain out of a mole hill. Cuase once the engine is out, they are going to find tons of things not rite that will push for a rebuild.
As stated above, have him inspect the damages once apart.. and THEN make the appropriate decision. If the mechanic is not Buick friendly, in other words doesnt work on Buicks.. especially these motors, may want to take extra precautions. If you can fond someone local that owns/works on thses cars.. it would be better.
Blown 3 pistons.. doubt it. If a piston needs replacement.. then cylinder walls, rings, etc need to be addressed as well.