Comp gaskets which way up

paulsv8manta · Post by **paulsv8manta** » Mon Feb 10, 2014 8:06 pm

Hi guys, this may be a stupid question but which way up do these head gaskets go there are no indicators on them.
So metal up

or down

Cheers

crayefish · Post by **crayefish** » Thu Feb 13, 2014 12:17 pm

Would have thought it wouldn't make any difference given both sides of the gasket will be up against a flat ally surface; not really any difference between heads and block in that respect.

stevieturbo · Post by **stevieturbo** » Thu Feb 13, 2014 2:03 pm

Wouldnt be bothered either way really.

Post by **scudderfish** » Thu Feb 13, 2014 5:33 pm

Fit one each way on each head and then let us know which one gives you trouble in the future

mgbv8 · Post by **mgbv8** » Thu Feb 13, 2014 8:54 pm

Fit the metal side down so its on the block. This will give you best resistance to gasses leaking between cylinders if it gets worked hard. And if you want a really good seal use some copper gasket adhesive.

For a car that only gets normal road use it wont matter which way up they go.

paulsv8manta · Post by **paulsv8manta** » Fri Feb 14, 2014 7:40 am

Thanks guys, I'm going to try scudderfish idea and see what happens, if anything.

Post by **scudderfish** » Fri Feb 14, 2014 9:56 am

I was joking! Don't blame me for anything that happens

DEVONMAN · Post by **DEVONMAN** » Fri Feb 14, 2014 3:46 pm

A bit OCD I know but if the fire ring on the gasket is wider on one side then I usually put that side against the block.
Reason? The fire ring sometimes overhangs the chamfer on the top of RV8 cylinder liners and a wider fire ring help to compensate for this.

I have examined a few sound used gaskets and the marks indicate that part of the underside of the fire ring had been exposed to combustion gasses.

Any comments Sidecar ??

badger · Post by **badger** » Thu Feb 20, 2014 7:56 pm

I agree with Devonman. Wider side of the fire ring to the block, every time.

sidecar · Post by **sidecar** » Thu Feb 20, 2014 9:07 pm

DEVONMAN wrote:A bit OCD I know but if the fire ring on the gasket is wider on one side then I usually put that side against the block.
Reason? The fire ring sometimes overhangs the chamfer on the top of RV8 cylinder liners and a wider fire ring help to compensate for this.

I have examined a few sound used gaskets and the marks indicate that part of the underside of the fire ring had been exposed to combustion gasses.

Any comments Sidecar ??

Er yep, I think that there is a mis-match in the design of most comp gaskets and the RV8 bores, the bores have a huge taper at the top and at least half of the fire ring is just left uncompressed floating about doing nothing. This setup appears to be OK on a standard engine but when you start pushing up the peak cylinder pressure via the usual tuning methods a point is reach where the gaskets 'let go' with the result that your engine starts to make strange 'farty' noises!

You can get MLS gaskets that are 2mm over size with regards to the bores, I'll use them next time my heads come off. At the moment I'm using comp gaskets with copper spray, they have held up so far but I think that MLS ones would be better.

mgbv8 · Post by **mgbv8** » Thu Feb 20, 2014 9:13 pm

The MLS gaskets I bought ages ago have been re used a few times now and are holding up just fine in Jasons Escort now.

I'm still using stock comp gaskets on my new engine with O ringed heads.