From: Dave Baker
Newsgroups: rec.autos.tech
Date: 25 May 2002 11:52:50 GMT
Subject: Re: Stupid question, but I gotta know...
Message-ID: <20020525075250.05334.00000421@mb-mm.aol.com>

>From: "Edgar Montrose" edgarmontrose@techie.com_nospam
>
>Yep, they're trash now. Once the fire ring has been crushed, it can't be used
>again.

Nonsense - If the engine hasn't been run and the gasket isn't damaged in an way
then torqueing it back up again puts it into exactly the same state as it is
now. The fact that the fire ring has been crushed is neither here nor there. It
isn't being crushed any further second time round. The only reason not to
resuse a head gasket after running the engine is because they are usually
coated with lacquer that melts to seal imperfections and then comes away as it
sticks to the head or block when you strip the engine. However there are plenty
of non coated gasket types that are quite happy being reused even after the
engine has been run.

The high performance metal layer gaskets you can buy for VW Golf engines for
example - I think they were std on the G60 supercharged engine. We used to
reuse those time and time again on race engines.


Dave Baker
Puma Race Engines (www.pumaracing.co.uk)

From: Dave Baker
Newsgroups: rec.autos.tech
Date: 25 May 2002 13:13:40 GMT
Subject: Re: Stupid question, but I gotta know...
Message-ID: <20020525091340.03037.00000707@mb-da.aol.com>

>From: Dean Dardwin dd@dxd.com
>
>Dave,
>
>Nonsense yourself. I can see you don't install many Fel-Pro gaskets!
>They come with a set of installation tips. For this type gasket, reuse
>is forbidden.


1) You can be damn sure any manufacturer is going to cover their arse about
installation procedures, especially somewhere as litigation prone as America.
It also helps gasket sales no doubt ! It's a bit like Peugeot specifying that
you cannot skim their cylinder heads by more than a few thou and they even list
a slightly thicker gasket for skimmed heads. But the heads can be skimmed by 60
thou without the slightest hint of a problem and for race engines that's
exactly what you do to get the compression ratio right. In fact if everything a
manufacturer said was gospel then no one would modify any engine in any way
because supposedly the manufacturer would have got it perfect to start with.

On many modern engines you aren't even supposed to recut the valve seats if you
believe the official word. You're meant to throw the cylinder head away and buy
a new one. Yeah right.

2) Reuse after the engine has been run is not the same as reuse just because
the head has been clamped down once. Composite type gaskets like OE stuff and
Felpro quite often leave half of themselves stuck to the head and block when
you take an old one off and of course you can't reuse them if they are in
multiple pieces.

I repeat - if the gasket hasn't yet been exposed to temperature and is not
damaged in any way then clamping it back down to the original torque puts it
into exactly the same state as it was to start with. That's just engineering
common sense. Sadly common sense isn't a common commodity I find these days.

If you think you can tell me how applying the same torque twice changes
anything then I'll be fascinated to hear your reasoning.


Dave Baker
Puma Race Engines (www.pumaracing.co.uk)