Solex mechanical fuel pump issues

[1QuickS]

I am working a project that has a warped mounting flange on the Pierburg fuel pump used for engines using Solex 40PI carburetors. I have a recommendation to mill the flange flat, the offending ear looks to be bent down around 0.09". I do not want to experiment with heating and straightening as I don't have a replacement flange. Suggestions?

Also, I need the thickness of the phenolic spacer between the cam box cover and the pump flange...or I need to buy a used one.

By the way, Ed Fall did the fuel pump work and I am VERY pleased with the result and his attention to details.

[304065]

Paul,

I can measure the paper gasket, but don't have the "intermediate piece."

I can measure the gasket as soon as I get near one of my mics or calipers. Now where did I put them?

This pump will be posted in the Classifieds shortly for sale BTW, only to a Solex car owner who is restoring to OWN, not flip.

[Flat Six, inc.]

Paul, I can measure the spacer tomorrow for you.

Aaron

[chris_seven]

3.5mm.

I wouldn't heat this type of alloy and try to bend it back. many die casting alloys are just not suitable for 'hot work' as they don't form single phases at intermediate temoertaures and tend to remain brittle almost up to their melting points.

[1QuickS]

Hi Chris,

Thanks for the info. Funny that they can be bent unintentionally without fracture (hairy armed mechanic technique) but trying to return them to original shape (thoughtfully performed with heat and fixturing) will result in fracture. This phenomena is why I'm hesitant to attempt without a replacement.

[chris_seven]

Paul,

The ductility of these alloys is very poor and is only 3-4% which is easily used up.

When you try to bend them back there is no ductility remaining.

Metals regain their ductility by processes broadly known as recovery and recrystallisation and eventually grain growth.

Steel is very benign in this respect. It starts to recover at relatively low temperatures and the soubility of carbon increases and helps ductility until recrystalisation occurs. It is very difficult to induce grain growth.


Aluminium die casing and zinc based die casting alloys are quite different.

They will recover very slightly, it is difficult to make them recrystallise and they tend to jump staight to grain growth which makes them very brittle.

It is quite common for this type of part to be heated and then gently 'crumble' as you try to straighten even when warm.

It may be possible but you would need good details of the alloy and very close temperature control.

I wouldn't be brave enough to try and would machine it flat.

[1QuickS]

Sage advise and technical explanation; machining will be my path forward.

Thanks again Chris.