Manifold flange thickness

[Mr Spigot]

Having tracked down an elusive carburettor problem (fast unadjustable tickover, stalling at junctions, uneven plug colour etc) to a leaking inlet manifold gasket, I bought an new gasket and installed it. I know from fitting it all originally many years ago that the thickness of the flanges on the inlet manifold (cooled alloy mini metro) was thinner that that of the exhaust manifold flanges (stainless 1.5" LCB). To obtain even tightening, I cut some washers in half and stuck them to whole washers to take up the gap - see photos. Has anyone else come across this and have any better solutions?

[oliver90owner]

I’ve milled down the thicker to the thickness of the thinner. I’ve added extra gasket material under the thinner item. I’ve made stepped washers with the lathe/milling machine. Never relied on glue as a fix, but if it works, why not, I suppose.

[philthehill]

The problem is easily overcome by packing out with an additional manifold gasket cut just to the length of manifold which needs packing out. Cut vertically through the mount holes of the gasket to retain a location ability.
I have used this method many times without encountering any problems. No need to make up any fancy washers or machining manifold flanges.
Smear the faces of the gaskets with GP grease before fitting.

[Mr Spigot]

Thanks for the advice. Additional gasket material seems to be the easy answer.

[myoldjalopy]

Brilliantly simple solution!

[panky]

I've done the same on my traveller and the recently departed Mini and both worked fine with no issues since.

[Nickol]

i have stumbled across this thread because having removed the manifold from my 1098 Traveller in order to gain access to the tappet covers, I wanted to know if when replacing the gasket ( a new one) it should be smeared with grease or not? That seems to be the case.

I noticed when removing the nuts when I removed it that the two innermost ( most inaccessible ones) that they were loose.

Now it is mentioned in the thread that the inlet and outlet flanges are uneven? Is that what I can interpret? I suppose putting a straight edge against the flanges will show any discrepency. Until now, I have not noticed any performance shortfall.

Again, if I interpret correctly. I can use the cut sections of the old gasket ( which is in good condition ) over the inlets to achieve the correct spacing?

[Mr Spigot]

The gaskets should be lightly smeared with grease. If you have the standard manifolds, they should be the same thickness as far as I recall. I had fitted a Metro inlet manifold, and have a stainless LCB exhaust manifold, hence the difference. A straight edge across them should confirm. The inner nuts may have been loose as they can be a bit tight to get a socket on - a box spanner can help.