The V8 Owners Forum -

Im getting really p-ssed off with having to change exhaust manifold gaskets, primarly because they seem to leak after a few months, my engine is a fairly tight install and its about a 4 hour job per side, are there any alternatives to the composite sandwich things, Mine ate probably failing because I have to remove loads from them so they do not restrict the exhaust ports, I have seen some on Fleabay, they look a bit dubious in construction, but they may work????
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... &rd=1&rd=1
anyone tried these????

Thats Bizzare Ian
I just popped into Real Steel today for a set of the ususal silver ones. And they offered me a heavy duty set like the ones in you picture. I got both sets just in case. The twin heavy duty ones look like card, but they do have a steel mesh inside. And they have much bigger holes. They were 10 quid for the set of 4.

POOH ------Guess where I was today, Looks like another trip round the M25 Carpark

I read somewhere (probably an American site) and they recommended using silicon sealer to seal the headers. I tried it in conjunction with the gaskets and it certainly helps and doesn't seem to burn off. My headers are pretty tight too, and it's a major job to get them off or on (have to remove rocker cover on 1 side).

Pete

As ornage says, you can get a special high temp silicone. Its copper based, and isnt too bad at all.

That said, the head/flange interface will only really get as hot as the head itself, so normal silicone might be worth a try.


But more importantly. Make sure your flanges are 100% flat, and true.


Then just bolt it up with no gaskets. That way they wont blow out again...and no, Im not joking.


Thats the way I ended up running my TT, as no gaskets ever lasted more than a few weeks without blow outs.
Yes there were some minor leaks when cold, but once warmed up, it was fine.

n/a manifolds wount be subject to the same warpage as turbo manifolds though, so it should work much better.

i use normal silicone sealer on my exhaust joints and manifold gaskets for the past 3 yrs,
i was told about this by a fitter at the local exhaust center, makes taking system apart easier too,

Just got the bigger gaskets from RS, much better than the Steel composite, I have allways had to enlarge the ports on the composite ones, and have used ones from Pop Browns at £35 a set, I have assumed the gaskets have failed due to the reason being that the only way to trim the gaskets was with a wad punch and very sharp Chisel, and risk de-laminating the gaskets,
These new ones still will need a bit of porting but not much at all. and all for £10.71, Bargain
a thought just whizzed thru the brain, As RS never used to do these gaskets, I wonder if they are for their new Merlin Heads???

Yes, I like those gaskets from Real Steel, soft enough to be able to enlarge with a dremel and a burr + everything lines up far easier than the juggle with single ones, and I am trying Silicon as a sealer rather than that horrible ceramic exhaust paste,

I just found that they foul the head studs on a 14 bolt head so I had to trim them down a bit. I must say, they seem to be quite a sturdy gasket.
I'll have mine back in the bay tomorrow so I can see how the fit.
But they look pretty good at the moment.

done and running, no leaks, just a smear of silicon, and only 5 hours to get one set of 8 bolts done up, who said they will never distort but they are done up now, untill next time-------------------------------------------------

ian.stewart wrote:done and running, no leaks, just a smear of silicon, and only 5 hours to get one set of 8 bolts done up, who said they will never distort but they are done up now, untill next time-------------------------------------------------

Blimey, and i thought i had it bad with my setup!

stevieturbo wrote:As ornage says, you can get a special high temp silicone. Its copper based, and isnt too bad at all.

All silicone is virtually indestructible heat-wise. We use normal gasket silicon sealant on Caterpiller turbo manifolds, and they glow red sometimes.

I've even used it INSIDE exhaust header pipes on a motorcycle, to try and stop the chrome blueing where the pipe meets the cylinder head. A fingerfull was smeared as far inside the headers as you can reach. (not far with my pudgy fingers )

It didn't work, but the silicone was still stuck in there next time I took the pipes off.

I fitted mine yesterday with no sealant, and they seem fine so far with only an hour or so of running.

Have I got this right? Just use silicon sealer and no gaskets? What sort of silicone sealer, the bathroom type?

Fil

If you are using fabricated manifolds, I would say use gaskets, I am fairly certain the fastory cast iron manifolds never had gaskets, but sealed OK,
From experience, I use a sealant, Bathroom sealer will work, But I would use a RTV hi temp silicon which you should be able to get from any decent spares shop, I have also used with some success Blue Hylomar,
The one thing I do not like is the white exhaust assy paste, not only is it messy, its corrosive as well,
Ian