SonexBuilders.net

Hi, so When I removed my heads due to some new replacements, I noticed that there was no head gaskets in my aerovee engine. I do know that the engine was sent to great planes for building with the new crank before my time, but is that normal for an aerovee to not have any head gaskets? Performance has been great except for recent burnt valve which warranted a new head (in my opinion)

Regards,
xy

Yes and no. If it is a stock Aerovee built to the manual then it should have .060 thick copper gaskets between the barrel and the head. When building to the aerovee manual the calculations for how many and what thickness barrel shims you need (between the barrel and the case) to get the correct compression ratio assumes that you area also installing the copper gaskets between the head and the barrel.

With that being said, it is possible and was pretty common to build up aircooled VW motors without the copper gaskets. You can still get to the right compression ratio but needed to use thicker or more barrel shims depending on how deep the head was cut. Personally I would use the copper gaskets. They should provide a better seal between the head and the barrel, are called out in the aerovee build manual, and cost less than $40 for the set of 4. If you don't want to use them I would at least double check your deck height and make sure the compression ratio is correct.

Keith
#554

The barrel-shim/head gasket guide in the assembly manual shows several scenarios where the head gasket is not used on the 8:1 side of the chart. The head gasket is probably used to keep the shim count down, more than being a head gasket.

The aluminum case I'm using doesn't require any cylinder shims due to the taller deck, and only a .040 thick head gasket. That's for a 7ish:1 ratio. The calculations for an 8:1 would only require a .010 cylinder shim with no head gasket.

This is what Sonex told me about the head gaskets:

Regarding the head gaskets, there is no way the heads will seal properly without the copper gasket in place. Do not attempt to run the engine without head gaskets in place.

I'm not sure I completely agree, but I do use the gaskets.

I imagine that without the gaskets, the cylinders will dig into the aluminum a little and might become more prone to leaking especially after removing and reinstalling the heads.