The V8 Owners Forum -

Ive read on here a few people are using silicone instead of a gasket on their exhaust manifolds. Im interested to know did they blow or are they still holding up?
What silicone did you go for in the end?

thanks

Hi temp silicone sealant on mine. I forget the actual make.

The manifolds blow a little when the car is first started now, but it stops in around 30 seconds so I don't worry. They've been fitted that way for 2 years now, and it's the longest term solution I have yet found.

Just make sure the head and the manifold mating surfaces are in perfect condition, or it won't work too well.

Why would you not use gaskets?

Chris.

I know a stockcar racer who uses high temp liquid rubber gasket for his manifolds, in fact, for everything other than the head gaskets themselves, given the number of times a race engine needs pulling apart during the season, proper gaskets add up in cost.

his trick is to prep the surfaces by rubbing them in a small circular motion with 60 grit sandpaper to swirl/hatch the surfaces to grip the rubber better.


edit: this is on a Holden 243, an old small block Chev clone from aussie.

Thanks chaps
It looks like im going to have to go down this route as i cant find any gaskets to fit my ports? 300mm x 400mm. Tried V8D and John Eales today but no joy.

Wow 300x400mm are flippin big ports!

Can't see how V8D's gaskets couldn't be trimmed to size they must cover more than the available metal that might be ground away?

I think he means 30mm x 40mm. That is quite large, but you could get the decent paper gaskets and cut them down, that's what i did, with a bit of sealant on top.

oops

I managed to get a set from racetech that only needed a little trimming and used some high temp silicone as a precaution.

Thanks chaps