alternative to firegum?

[eastlmark]

Anyone recomend an alternative to firegum for sealing an exhaust manifold-head joint? Firegum does the job but is so messy and unsighlty. Use high temp silicon on other parts of the exhaust but assume this joint is above the temp limit.

[HustleRussell]

Why do you need a sealant there? Wouldn't a new manifold gasket do the job?
When I had this problem I had my header flanges linished flat and it solved it.

[eastlmark]

HustleRussell said:

Why do you need a sealant there? Wouldn't a new manifold gasket do the job?
When I had this problem I had my header flanges linished flat and it solved it.

just always have used it, was told today I was probably using way too much, hence the mess.
thanks.

[Nick1point9]

If you need an additional sealant then something isn't right; clean, smooth mating faces will seal with the correct gasket

[Mr2Mike]

eastlmark said:

Anyone recomend an alternative to firegum for sealing an exhaust manifold-head joint? Firegum does the job but is so messy and unsighlty. Use high temp silicon on other parts of the exhaust but assume this joint is above the temp limit.

No sealants whatsoever should be needed provided the manifold and cylinder head gasket surfaces are clean and flat. Silicon sealer is a very bad idea here since it pollutes oxygen sensors and stops them working.

Firegum etc. should be reserved for sealing leaky slip joints and the flanged joints that are held together with a clamp around the outside.

[rev-erend]

High temp silicon sealant .. I use it on my stainless steel headers with no problems.

[Mr2Mike]

rev-erend said:

High temp silicon sealant .. I use it on my stainless steel headers with no problems.

You simply should not need any sealant on your MANIFOLD (we are in the UK) unless it's knackered. The high temperature silicon sealants only go to 300-350C, and manifold temperatures can easily exceed this.

Edited by Mr2Mike on Wednesday 7th November 12:14

[one eyed mick]

As said flat faces and proper gaskets are the way there is no other correct way unless you like continually taking the the bloody thing off do it right and you only do it once

[Bennachie]

High temp silicon (the good stuff) is too runny but goes to 1200 degrees C.

[ridds]

Loctite 5910 or 20 is a high temp silicone perfect for manifold to head flanges.

Used on my racing engines so save the agro of poorly sealing gaskets.

Silicone is fine as long as you leave at least 24 hours for the sealant to cure over. No danger of poisoning sensors then.

The flange to head joint doesn't see anything like the heat of the exhaust due ot the fact that the heat transfers back into the head.

[Mr2Mike]

ridds said:

Loctite 5910 or 20 is a high temp silicone perfect for manifold to head flanges.

200 Celsius maximum service temperature. You must have an unusual engine if the manifold get's no hotter than that.

[ridds]

Well take a look at any AJP TVR engine and many other race engines and they are all sealed this way and tbh I've never heard of anyone complain of leaks.

Mine has been sealed like this for 6 odd years.

The flange joint doesn't get as hot as you'd think.

[one eyed mick]

I wouldn't put my ---k on one!!!!!!

[NOTAFINGA]

As said already no reason whatsoever for using sealers on manifold to head joints, and if you do fix the defect.