Blowing Exhaust manifold.

tetlow · Post by **tetlow** » Tue Jun 26, 2007 5:38 pm

I have had problems with my exhaust manifolds blowing ever since I fitted them.
They are SS Block Hugger, Ceramic coated and are not too old.
I have tried different gaskets with little sucess.
I have just removed the engine today and checked the surface of the manifolds. Of course they are not flat, up to 1mm out of true.

Has any one had their manifolds skimmed?
Any help would be appreciated as they cost a packet.

Regards
Dave

Alley Kat · Post by **Alley Kat** » Tue Jun 26, 2007 6:39 pm

I had mine refaced, 'properly' done as opposed to someone trying to linish them flat. Cost £120 if I recall right. Part of the cost was in shipping to/fro though. The thing is finding someone who can machine something of the size/shape of a header

tetlow · Post by **tetlow** » Tue Jun 26, 2007 7:44 pm

Is there any way of sealing the pipes without having them flat?
I have tried composite gaskets with paste but no luck.

Alley Kat · Post by **Alley Kat** » Tue Jun 26, 2007 7:54 pm

Mine were a bit rough and there was a small nick in one part. Prv owners had just put up with it, changing exh gaskets very regularly. I did it once, they never lasted long, so refaced them and prob sorted once and for all.
Suppose there may be some substance that may do it, depending on the particular situation, but flat faces have got to be the best way i'd have thought.

tetlow · Post by **tetlow** » Tue Jun 26, 2007 8:21 pm

Yep. Me too.
Ta

tetlow · Post by **tetlow** » Thu Jun 28, 2007 8:17 am

Mr Alley Kat Sir.

Can you tell me where you got your manifolds levelled as so far my local chaps can't do it.

Regards
Dave

Alley Kat · Post by **Alley Kat** » Thu Jun 28, 2007 8:25 am

For some reason that escapes me, I took the car to a workshop and actually parted with some money

Didn't have a garage then. Anyway, it was a place called Motorvation in Sarratt, Herts; but they would have farmed it out an engineering shop and I don't know who that was...
Another possibility, adrenaline-race.com, and the shops like Andy Robinson, Hausers, plus local general engineering shops

tetlow · Post by **tetlow** » Thu Jun 28, 2007 3:32 pm

Thanks.
I have tried my local guy, he said he could do them but would have to make a jig so it would be £200+. He's good but I would prefer to get someone who has done it before.

Dave

Alley Kat · Post by **Alley Kat** » Thu Jun 28, 2007 4:43 pm

No worries. £200

I did have trouble finding somewhere, think thats why I went to Motorvation. The local engineers shops were either unable cos of size/shape or more interested in tea & biscuits than work

tetlow · Post by **tetlow** » Fri Jul 20, 2007 9:21 am

MGOC have given me a name of a engineer to linish the manifolds.
All by hand but the guy knows what he is doing.

Will report back when manifolds are flat or scrap.

Dave

Paul B · Post by **Paul B** » Fri Jul 20, 2007 4:55 pm

tetlow wrote:MGOC have given me a name of a engineer to linish the manifolds.
All by hand but the guy knows what he is doing.
Will report back when manifolds are flat or scrap.
Dave

A flat surface (to check against) and a 4" grinder with a flap disc in and you can flatten them yourself near enough to seal. They don't have to be perfect to 0.005", just close enough that a gasket and a squeeze of silicon will seal them.

tetlow · Post by **tetlow** » Fri Jul 20, 2007 9:16 pm

Paul.
What Silicon would that be?
I have tried exhaust paste and it was crap.
Dave

mgbv8 · Post by **mgbv8** » Fri Jul 20, 2007 9:28 pm

My manis are not perfect. So I used the RS comp gaskets with no sealant and they seal up fine.

tetlow · Post by **tetlow** » Fri Jul 20, 2007 9:34 pm

So far I have tried the single silver type and the composite twin sport type from Rimmer, both with and without paste, and they still blow.

mgbv8 · Post by **mgbv8** » Fri Jul 20, 2007 9:48 pm

You must have some badly out of line flanges Dave.

Are you running RV8 style or Block huggers?

Mild steel or stainless?