A thought re. inlet manifold water leaks

[Alacrity]

I am in the middle of a total rebuild of the Stag including the engine & today I fitted helicoil inserts to all the inlet manifold threads on the heads. In doing so I noticed that most of the thread holes were not very deep, being full of packed 'rusty' muck.

It made me wonder if some peoples issues with a leaking manifold could be caused by this - the bolts bottoming in the holes before they pull the manifold down tight on the gasket?

If nothing else it is something that should be checked. The threaded holes are now twice the depth they were now they are clean.

[jbuckl]

This joint is often troublesome, sometimes for the reason you found, but also others too.
The 3 bolts per leg are barely adequate.
The sequence of assembly is critical.
First time success is elusive because of those issues.
Opening out the manifold holes to 9.5mm can help.
Using tiger-seal (p-u) sealer can help. (Avoid most silicone types)
Having 2or3 spare sets of gaskets in readiness seems to have a magical influence too! (I only have a problem when I have run out of spares it seems....aka Murphy’s law applies)

[NickA]

This joint is often troublesome, sometimes for the reason you found, but also others too.
The 3 bolts per leg are barely adequate.
The sequence of assembly is critical.
First time success is elusive because of those issues.
Opening out the manifold holes to 9.5mm can help.
Using tiger-seal (p-u) sealer can help. (Avoid most silicone types)
Having 2or3 spare sets of gaskets in readiness seems to have a magical influence too! (I only have a problem when I have run out of spares it seems....aka Murphy’s law applies)

Using the OEM manaifold gaskets helps as well as the pattern ones are much thinner. They still do come up for sale every now and then

[richardthestag]

if the engine was assembled with OE gaskets then all well and good, but if thin gaskets were used then the OE gaskets will be too tight.

I always run a tap down the threads before fitting up, gloop in the bottom of the thread hole will compress and give a false tightness reading when you are fitting up. In the past I have also had the thread strip in the head, why is it always the last long bolt? I found that the carb elbow bolts are a few mm longer and can be substituted. Makes mental note to helicoil it next time it is apart.

Anyway I generally drop the manifold in with no gaskets, check clearances all around to make sure that the head and inlet manifold faces are parallel, if not then you are wasting your time - get the inlet manifold faces skimmed to fit. then measure up what gasket is needed. Stag wellseal for me every time. I have also used tigerseal which is superb but once opened it goes off so I end up lobbing the cartridge the next time I find I need it months down the line