Why does Oldsmobile use shim steel intake gaskets? I'm sure there is a reason but no one I've ever known knows why.

 

If you're talking about the 'bathtub' type - to keep the hot oil off the stock intake manifolds - less heat transfer.

 

Is that REALLY the reason?

I mean, with all due respect, with an open exhaust heat riser channel and a heat riser valve from the factory that was restrictive even when open, and all of the heat generally inherent inside an engine anyway, would the additional oil splash really make a difference, or is that just an urban myth of some sort?

- Eric

 

Good question, I´curious to.

Stanley

 

Keeping hot oil off the intake could be it but I doubt that's why Olds did it. I know back in my SB Chevy days they did build a baffle for under the manifold that was there to stop hot oil from getting on the bottom of the manifold when using a cold air intake with no heat cross over.

 

Could be more about protecting the oil from the hot crossover area.

 

Supposedly that is what it is for, so that oil doesn't bake to a hard sludge and end up falling into the valley. My Chevy 305 had a pan rivited to the underside of the intake manifold over the crossover.