Manifold Studs (1934 engine)

[Hugh Sammons]

One of the manifold studs has pulled out from the engine block. What is the best way of replacing the stud?
Is it possible to tap the hole 5/6" and use a stepped stud?
If this is possible does anyone supply these or do I make one?

Your observations and suggestions would be most welcome.

Many thanks.
Hugh

[Chris KC]

When you say 'pulled out' Hugh, is the thread in the block stripped? (if in doubt, try gently screwing in a 1/4 BSF bolt and see if it holds).

If yes you have 2 basic options, helicoil the hole or drill & tap oversize. The latter is probably more robust. I wouldn't attempt it in the car though. I'm sure one of our suppliers can sort you out a stepped stud.

If there is a bit of thread left you can probably run around for a while without major consequences but you will need to address water leaks into the manifold most likely.

[John Mason]

Hi Hugh, most of the cherished suppliers do stepped studs. I myself use helicoils and the same size thread stud. Some forum uses prefer stepped studs as the length of thread in the block is not very long. Whatever you use I recommend you use some thread sealant on the threads to prevent water escaping from the water jacket.

john Mason

[Ruairidh Dunford]

Which stud has come out?

[Hugh Sammons]

Which stud has come out?

The third one from the front.
Having looked at all the others three out of the six look as though they are on their last legs, (or threads).

[Andy Bennett]

I have helicoiled in situ with success but definitely add loctite stud sealant to secure in place.

Andy B

[Ruairidh Dunford]

3rd stud is easily accessible whilst in car. Use the manifold as a guide to drill it out for tapping to helicoil or stepped stud (both require same size tap), then remove manifold and tap, fit helicoil and stud or stepped stud
with preferred sealant.

Jobs a good-un.

[Hugh Sammons]

Many thanks for all the help.

[mk1-mark]

Helicoils are certainly a better way to go that stepped studs. Sticking with "Standard" parts is always a good bet, with a helicoil fitted you can utilise a standard stud & have made a perfect repair.

A correctly fitted helicoil will always be stronger than the original fitment.

[Chris KC]

What you say is generally true Mark. I have slight reservations here as if the helicoils are less than perfectly inserted they tend to disappear off into the cooling jacket when the studs are tightened, also harder to get watertight.