Blown manifold gasket again!

[glang]

Anyone else had problems with exhaust manifold gaskets blowing? Its a Vit mk1 and Ive had two last less than about 1000miles even though they were installed with sealant and torqued correctly. Cant remember where I bought them now but are there different qualities/materials available?

[Nick Jones]

Head/manifold or manifold/downpipe?

Could be crappy gaskets or a lack of flatness of the mating surfaces.

Nick

[glang]

Definitely manifold to head and they seem to blow in more than one place and each time different places so could be gasket quality. Anyone got any recommendations?

[Andy Flexney]

I would try without sealant if the faces are flat then you don't need sealant. If it does not seal then have the faces skimmed. Also make sure you try to keep them dry once installed. If the get soaked and then hot the water expands and destroys the paper filling.

AndyF

[Pete Lewis]

Check the gasket all aligns with the studs and ports ive had mk1 gaskets which are not cut correctly
and exhaust ports dont line up.
pete

[RobPearce]

Mk1 Vitesses blow that gasket with alarming frequency unless everything's spot on. My recommendations, from experience with Tessa:

- Don't use any sort of goo. The manifold expands as it heats, so sticky stuff with rip the gasket apart
- Don't over-tighten the nuts at the two ends of the manifold (factory manual advice, this one, to allow for the expansion)
- Check whether the inlet and exhaust manifolds are interfering with each other - mine were a very tight fit, they shouldn't be
- Check for consistent thickness - the Mk2 clamps can cope with differences, the Mk1s can't
- and as Andy said, you may need to get the faces skimmed flat

It is possible to have no trouble at all. My first Vitesse was fine.

[glang]

Thanks Rob, what do u mean by consistent thickness? If its the gasket then maybe there are quality problems with some suppliers..... If someone gives a positive recommendation for a gasket I'll try again this time as u say without goo and taking great care with the torquing up.

[RobPearce]

Sorry, no, what I meant was that the flanges on the inlet and exhaust manifolds have to be the same thickness. The clamps try to act on both but are far too narrow to tolerate even the slightest variation. If the inlet flanges are fatter than the exhaust ones, then the exhaust manifold is not being clamped in place.

I had some, small, improvement from fitting two gaskets, but that wasn't a reliable fix

[glang]

ok I see what you mean and its not something Ive looked at previously. Next time I get it apart I'll have a closer look and measure a few bits but thinking about it the design is pretty poor and I can understand why they changed it for the MK2!

[mazfg]

Never had a problem with manifold gaskets. Definitely never used a sealant...could be your problem?  I did my cylinder head a few years ago and didn't realise it was a dry fit. Ended up using Wellseal gasket sealant... after a few 100 miles the head to block was compromised and had to do it all again....DRY though and been good ever since!