Gipsy manifold material

According to my plans the inlet manifold should be made of mild steel.

looking at a couple of completed engines on the internet I notice one has used brass and another has used a mixture of brass and steel as the one pictured below.

Is there any reason for using brass , as in the bottom plate on this one,

It looks pretty.

And it does not show the silver solder joint

WOW. Very nice.

Stainless it is then.

I think if I were doing it I would machine some stock down to 0.475" and then mill out the recess from below to 0.425" deep and then recess the bottom plate into the 3/8" wide passage so no joints are visible unless you are looking from underneath.

Depends on which engine, but on the Gipsy Major the inlet manifold was steel. It has two half pressings with a welded seam and individual steel plates welded on that bolted to the cylinder heads.

Andrew

Brass has an expansion coefficient very close to that for Al alloys. The value for Steel is rather less. I suspect this might have been one factor in the mind of the bloke what made it.

Cheers, Tim

Not sure I follow your thinking there? Steel top, brass bottom, sounds like a recipe for a banana to me? As it's the inlet manifold would it actually get hot enough over its length to make any appreciable difference? If it were the exhaust a different story maybe. If you are suggesting coef of ex to match the aluminium crankcase then that only holds good if the whole thing is brass?

Paul.

The lower tapered part down to the carb is aluminium but at such a small size I doubt expansion would be an issue and the suggested Araldite to join it would have enough flex to compensate.