Quote:
Originally Posted by slowbird
Haven't read all the post so not sure if it's been said, Ford runs 4 head bolts and they hold up good. 5 is better but 4 will do fine.
The number of head bolts isn't what causes Langer to replace head gaskets every 25-35 passes it's heat from the paired exhaust ports. The end cylinders are happy and could go a A LOT longer but the center cylinders just can't deal with that heat in that area
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Have to agree, Brian, totally with that observation.
The center cylinders head material sees twice the heat cycles of combustion from the paired exhaust runners.
With most engines, ideally, you would have have each runner see one heat cycle in 8 firings. In the case of the Pontiac,
4 cylinders are seeing that double heat cycle. 3 and 5 on the drivers side and 4 and 6 on the passenger side.
50% more heat per engine combustion engine cycle than necessary vs using the Ford or RA-V exhaust design.
AND the Pontiac Engineers knew of the issue in 1967 and earlier, when they were doing the initial engine work on the RA-V engine.
Tom V.