Practically Classics Forum

Can anyone recommend a product for sealing the face of a cast iron manifold to the gasket face on my 1725cc Rootes motor.I have fitted a new gasket but it still leaks very slightly.The manifold is very,very slightly warped,this can be seem by shining a torch from behind a true straight edge,light is hardly discernible but enough to cause a gas leak. I know the perfect solution is to have the manifold machined but as I cannot get that done a sealant would be the only option.
Johnc

johnc wrote:I cannot get that done

Surely any garage or small engine rebuilding place would run the manifold over their surface grinder for the price of a small contribution to the canteen fund? I use a place down by Morpeth for this sort of work, their routine work is building, repairing and testing steam engines, boilers and similarly large scale stuff but they're up for anything.
There are also around half a dozen garages who'll use their tables for this sort of thing and that's without getting to within forty miles of a town.

Hi John,thanks for the ultra quick reply.
My problem is that I live in a rural area France and the only mechanical expertise locally seems to that of welding lumps of scrap onto agricultural vehicles to give them another 50 years of life.I'm looking for a product that I can buy on line.
Johnc

The newer silicon based exhaust paste in a tube should work. Easier to use than gungum and far less messy to apply.

Fit two gaskets.

Being the butcher I am at times, I would use a belt sander to get it flattish, then finish off by lapping it on a ground glass sheet covered with valve grinding paste.

I did a couple for a V8 that way a while ago, works a treat. Good for blisters to...they come up a treat!

Thanks for the input guys.
I'll have to use the silicone option as I don't have access to a belt sander and the Rootes manifold has two gaskets as standard which doesn't resolve the problem.
John

Tube I have is Walker Exhaust Jointing Paste ... http://www.walker-eu.com/en-uk/walker-p ... ste-putty/

Not sure if you can get that 'En France'

PS that is about the extent of my French ...

Using a flat surface such as float glass.

Smear engineers blue. ( or lipstick or shoe polish etc etc) on the manifold faces then rub the manifold over the flat surfaces this will show up the high spots. Using a feeler gauge will show how big the gaps are.

Then file off the high spots. This takes time and patience. However even if you only decrease the gaps it may be enough to stop the blow.

If the gap is small then place a sheet of emery cloth on the flat surface and rub the manifold on it. For absolute perfection use lapping paste on the flat surface.

Manifold gaskets are made of various stuff. If these are LIKE cardboard then soaking the gasket in water helps it deform and seal better. Also warm engine up and give the manifold to head nuts a tweak. Don't keep going in an effort to stop the blow because something might break.

Bob

Sharpie marker is a good substitute for engineers blue as I learnt on youtube watching an excellent machinist building a model steam engine boiler