3.2 Head sealing

Discseven · Discseven's Garage

There's no gasket on 3.2 head and I find it hard to wrap my head around that.

Does anyone use ANY kind of sealant between the cylinders and heads here?

Heads were machined. (By a Porsche specialist, shop that does Singer's heads so they should know what they're doing.)

Cylinder tops are not.

Want to be at peace matting these surfaces with nothing between... or adding a sealant if that's a proven "upgrade."

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Flat6pac · 02-10-2023, 11:17 AM

Just follow the torque specs and they seal
Bruce

gled49 · 02-10-2023, 11:19 AM

I believe there is a slight angle machined into the cylinder top sealing surface that creates the sealing pressure.

Zuffenwerker · 02-10-2023, 12:38 PM

No sealant. There are a few options for sealing rings that require machining. Back when the 3.2 first came out there was a problem with leaking between the cylinders and heads. The dealer was installing new pistons and cylinders to fix the issue. Not sure what was different about the cylinders but pretty sure there was still no gasket

Neil Harvey · 02-10-2023, 02:30 PM

Something like this. Have done this for many over the years. Second photo Turbo engine with years of running.

mikedsilva · 02-11-2023, 12:40 AM

stownsen914 · 02-11-2023, 05:04 AM

So if cylinder top surface is machined to true, does it get machined flat, or with .0016-.0032" of taper?

Zuffenwerker · 02-11-2023, 05:39 AM

Does anyone know if LN Nickies have this same sort of raised edge for sealing? I’m asking because their cylinders do not have any provision for a CE ring like the 3.2 we’re discussing. However they machine their cylinder tops (probably just followed Porsche) they seal great.

Discseven · Discseven's Garage

Quote:

Originally Posted by mikedsilva

Am going to check the .04 - .08 mm spec on every cylinder. Post what I find next week.

Appreciate the input all. Mike, thanks for positing image. What document is that page from? I'd like to get that whatever doc it is.

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mikedsilva · 02-11-2023, 11:24 PM

Quote:

Originally Posted by Discseven

Am going to check the .04 - .08 mm spec on every cylinder. Post what I find next week.

Appreciate the input all. Mike, thanks for positing image. What document is that page from? I'd like to get that whatever doc it is.

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I took a photo from a friends Bentley Manual for the 3.2 Carrera. We were discussing it just the other day. He puts his cylinders in his lathe and makes sure they are all exactly the same.

Neil Harvey · 02-17-2023, 06:53 AM

Our latest sealing system for the larger bore 2V engines uses a gas filled ring. Under temperature it increases its internal pressure and seals. We have been using these rings for many years on the water cooled Turbo engines.

They do require a back up ring to support them.

Discseven · Discseven's Garage

Quote:

Originally Posted by mikedsilva

I took a photo from a friends Bentley Manual for the 3.2 Carrera. We were discussing it just the other day. He puts his cylinders in his lathe and makes sure they are all exactly the same.

Thanks for Bently note Mike. I just put a straight edge on my cylinders. Didn't measure it but the angle is there.

Quote:

Originally Posted by Neil Harvey

Our latest sealing system for the larger bore 2V engines uses a gas filled ring. Under temperature it increases its internal pressure and seals. We have been using these rings for many years on the water cooled Turbo engines.

They do require a back up ring to support them.

Gas filled heat expanding rings. That's some technical thinking Neil!

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