question on the design of the inlet manifold

[cassiewoofer]

I'm having trouble sealing the inlet manifold of the UMB engine I'm working on.
    My question is- why does the cooling water flow through the gasket so as to contact the centre inlet manifold? The other two inlet manifolds do not have this arrangement and so have simpler gaskets with air/petrol contact only.
    The only thing i can think of is that it's something to do with the thermostatially controlled central carb? :-?
    I'm using graphite based 1.5mm gasket meterial and having filled up the radiator The centre inlet gasket leaked.... I immediately dismantled and removed the inlet manifold. Everything's now been dried and I will re fit the inlet manifold next wekend.
    Any help would be greatly appreciated.
   Oh and what's the normal running temperature of the gaskets on the inlet side? (I thought graphite gaskets were for high temps)
    Thanks.

[cassiewoofer]

Well I've solved the problem, the (probably very common) one of the gasket mating surface not being perfectly flat. Looks like this middle one is seriously exposed to leaks and hence corrosion. Now machined (1/2mm removed)and will (probably) red gasket compound on both sides of the gasket.... I originally just expected the gasket to seal and using this compound might have meant it not necessary to re-machine a flat surface but then again.... I'm a bit of a perfectionist.
    Still would like to know exactly why this water contact is necessary, as I would have thought the studs would transmit the heat fairly well.
    Will report on progress.....

[keithjecks]

i just had exactly the same problem. I think the water feed was to enable water heating of the manifold, but on my 1937 car, it certainly serves no purpose. I used a new gasket set from Brian Eacott, which are (I think) paper based.
   
   You shouldn't use the red gasket stuff on these. A small amount of silicone around the water feed is all that is needed - the rest should be installed dry

[cassiewoofer]

Thanks Keith,
   Well I have installed the outer ones dry, but before reading this I used the red stuff on the centre one, Now I don't know whether to dismantle and use silicone based or continue and see if the red stuff works.
    I mean it says on the packet that it seems to be ideal for this job, well you learn by your mistakes so unless there's a clear (chemical or physical) reason not to use the red 'stuff' then I'll continue with assembly.
    Will obviously let you know how it goes!
   Keith Penny.

[keithjecks]

I would take it off. I learned the hard way that the red goo soon breaks down and you start to lose water...

[cassiewoofer]

Thanks Keith,......will do!