Classic cars forum & vehicle restoration.

[Bayliss Thomas]

One problem fixed and another follows it seems. Having splashed out on an stainless steel exhaust system I now find that the manifold is still leaking, despite the best efforts of the exhaust fitting company. They did their best but say do not have the equipment to deal with the leakage. They fitted new manifold gaskets but the leak seems to be underneath the pipework of the manifold, its an inlet and exhaust on one side of block on my 1928 Vauxhall 20/60. The Company suggest taking it to an engineering workshop so that they can 'plane down' the surfaces. Its all cast iron of course. Is this an job which is ultra rare or an more common job on vintage cars? I have never heard of the plane down myself?

[victor 101]

I reckon there talking about a skim, much like you would have done on a warped cylinder head. I think your going to have to remove the manifolds to get to the bottom of the problem.

[michael1703]

take the manifold off and place it on a flat surface and try sliding a feeler gauge under it to see if its warped

[Salopian]

I know someone who had a manifold "planed" or skimmed. It was not a success as I recall it weakened the flanges in that case and they just warped away.
I've used a liberal dob of exhaust assembly paste (not Gun Gum) on a similar problem then a gentle warm up. That worked and in fact on the MG TD I have no manifold gaskets just assembly paste - its been on and leakproof for years. Some people use high temperature silicon sealer for this as well.
If the leak is due to manifold distortion (is it all in one piece?) I would try these workarounds.
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Jonathan Butler
Alvis SD 12/50 1928 MG TD 1950

[Bayliss Thomas]

Thanks for replies, its almost certainly the area of manifold where the six branches lead into two collector box area. Its going into car hospital on Monday.

[Special K]

I ve had the same problem on my 28hp bedford. Apparaently its a common fault on vauxhall 6 cyl engines. And to skim the head and manifold is the correct repair. But I didnt want to get that involved jst yet and have found that holts fire gum has done the trick so far. And my faces are quite warped. ste

[Bayliss Thomas]

O.K. thanks Special K. I will post up and let you know how we get on with the problem.

[Bayliss Thomas]

My car has just been returned to me from my trusted engineering company. They had found the source of the problem and put right earlier botches, they hoped that the problem is now resolved but did mention that 'we may have to skim the manifolds etc. Indeed after just an few miles the problem returned, nothing like as bad but still leaking. Its going back to the engineers for doubtless 'skimming', this sounds like an expensive job - comments welcomed.

[Roger-hatchy]

I had a problem with loose manifold.
My induction manifold would work loose after a few miles, with the inevitable over heating due to too lean a mix.

There are just four bolts to hold the manifolds on, E93a engine
My problem was a steel exhaust and ally induction, Aquaplane for twin carbs.
After it happened on the journey to Blackpool it was noticed that there was no washers under the nuts, proper washers for the job, thick high tensile, were fitted 1200 miles later still no problem.

I presume it was because of mixed metal the nuts bottomed out on the steel and with difference of expansion etc. etc.

Just thought I'd mention in case your manifold are different metals.

[47p2]

If it's the manifold that is causing the problem it can be rectified on a linisher, most small garages have them and it wouldn't be an expensive job
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ROVER
One of Britain's Fine Cars