Exhaust manifold gaskets and sealing

[James Fishwick]

I have struggled throughout my build to get a satisfactory seal between my cylinder heads and exhaust manifolds. I have a rover 3.5 and Pilgrim Motorsports exhaust manifolds. When removing the previous gaskets some had the inner material missing in places:

20220512_134955.jpg

20220512_135009.jpg

I am now about to remount the manifolds and hopefully for the last time as the car is nearing completion. I have purchased similar gaskets from Rimmer and I have also sourced some alternative ones:

20220512_140417.jpg

I would really appreciate views on both and which would provide a better seal? Also, I am wondering if I should use a very thin coat of exhaust assembly paste on the cylinder head and manifold prior to mating.

Thank you

[aaronjb]

I don't have experience on the RV8, but on another car of mine the gaskets like your first (that sort of metallised sandwich) failed often, but a stamped steel gasket like your last picture worked much better and was indestructible.

I know some folks here recommend just a smear of Copper RTV and no gasket, though.

[Russ-Notts]

I'm not familiar with the Pilgrim manifold. Does the internal shape of the ports on the manifold match that of the gaskets? If not, the exposed part of the gasket will just burn away. I think I just used exhaust sealant paste with my tubular manifolds. I had the same experience with the composite material type.

Russ.

[Chris1]

I have struggled throughout my build to get a satisfactory seal between my cylinder heads and exhaust manifolds. I have a rover 3.5 and Pilgrim Motorsports exhaust manifolds. When removing the previous gaskets some had the inner material missing in places:

20220512_134955.jpg

20220512_135009.jpg

I am now about to remount the manifolds and hopefully for the last time as the car is nearing completion. I have purchased similar gaskets from Rimmer and I have also sourced some alternative ones:

20220512_140417.jpg

I would really appreciate views on both and which would provide a better seal? Also, I am wondering if I should use a very thin coat of exhaust assembly paste on the cylinder head and manifold prior to mating.

Thank you

The gaskets that you show me in the first two pictures are the same as what I have on my SRV8,
the manifolds are different due to them being individual tubes, these are bolted to the correct torque
and have lock tabs on all eight pipes .
I have had these for some years now with no leakages but I do have a nice set of stainless bolts that I
keep meaning to fit .
Obviously this involves disturbing things so when I do, will allow a few more hours just in case of problems
(opportunities).
With these type of things it's just time and patience ,
good luck.
Chris.

[Ian C]

James,

Good to see you're still making progress!!

I would agree with others recommending the steel gaskets (second option) and (personally) would apply the exhaust sealant. It may not be necessary, and may not even seal any badly fitting joint, but it is unlikely to do any harm and may prevent an exhaust blow. The only down side might be making the headers more difficult to remove - but hopefully you will not need to!

Good luck and keep on keeping on.


Take care
Ian

[James Fishwick]

Thanks all for your help and advice, much appreciated.

[James Fishwick]

Good to hear from you Ian,

I am booked in for paint at the end of the month and then hoping to do final assembly before IVA. Hoping all sorted this year!!!!!
I had an issue with my exhausts but thankfully Custom Chrome very kindly sorted them for me (3 years after purchase).

[TINKA]

I had exactly the same issue as you with the same looking gaskets as you show in your picture, also the bolts were always coming loose and on a couple of occasions I lost a bolt or two. In the end I gave up and rather skeptically on the advice of others I just did away with the gaskets completely and used high temperature silicone. That was about 15 years ago now and apart from an engine swap I have never had to touch the exhaust manifold. Never had any of the bolts come loose or had them blow, covered now just short of 50,000 miles.