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Onex 0036, fourth owner. I took my intake elbows off and saw they had thin metal gaskets under them. The aerovee assembly manual says use RTV. Paper gaskets seem common for Type 1 engines on cars. And then there is talk of spacers. No idea what would be best and it's time to reassemble so any comments will be appreciated.

John

The thin metal ones are (were) soft compression gaskets- not very unlike the ones used on the exhaust flanges on the turbine housing of a turbo. A fitandforget solution, but you need new ones every time the headers come off. There is nothing really wrong with RTV, but it could become messy. And take care nothing squezees out over the port edges obstructing flow when you torque things up. Besides, you have some cleaning work cut out for you every time the headers need to come off. Double sided paper is fine, but make absolutely sure the fit is better than best- no edges obstructing flow! Spacers made of high temp composite are really intended as a heat insulation in those (automotive?) situations when a carb is sitting directly on top of the head- fine, I´m sure, but I´m not really convinced they are really neccessary for an aviation application.

My two bits.

My original paper assembly manual, Rev Y dated 9/11/14, specifies Permatex Aviation form-a-gasket #3. I've been using that and it seems fine. I do have the spacers.

The best solvent to remove unwanted RTV is gasoline. Not a particularly friendly goop to use on an intake.

It's my opinion the stamped metal gaskets are the best because they allow heat to transfer to the intake manifolds. Any dissipation is good dissipation.

As pointed out, you will need a weeks production run of the things if you remove the intakes regularly.

Perfect. Thanks to all!