Here's a VW document that proves they should not be used on Type 1 engines.
The story is that back in the 80's, Johnny's Speed and Chrome started to market Type 3 lower tins as "Super Cool Tins" and many drank the Kool-Aid and believed it with no proof.
So here's proof that VW said not to use them.
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Glenn - I always question how effective this quarter sized piece is on '71 dual port engine head.
I have no data on it's effectiveness, I always take the view that the VW engineers were pretty smart. And if it wasn't needed, they would of left it out.
This goes for all the tin and even the 4th engine bolt by the clutch lever that so many people leave off.
Bigger, higher horse power engines do not run hotter than a stock engine if driven the same. But leave off tin, use aftermarket fan shrouds with no fins, have gaps in the body to engine seal, run with carbs and timing incorrectly sent and you could have a hot engine.
My 2180 runs cool as stock and it doesn't need a secondary oil cooler.
Thanks for the info Glenn. This is 1 instance where I believed the VW engineers. The type1 engine sheetmetal was designed as a unit and must be installed as such, and the type 3 air deflector was designed for a completely different application (the fan is mounted at the back of the engine instead of on top). Intermixing parts without proper testing doesn't make sense.
Greg- Filling that hole with that little, seemingly innocuous piece of sheetmetal forces the cooling air through the fin area where it belongs instead of a significant amont of it escaping without absorbing much heat. I've always looked at it from the standpoint that if it wasn't needed VW could have saved money by not installing it. It probably only makes a difference of a few degrees, but it's all in the details, and a few degrees here and a few degrees there and some people wonder why their engines run hotter than others...Al
