Hi All

I was asked this the other day.

Is there a specific reason why Citroen used studs on the exhaust ports and bolts on the inlet ports.

Peter

Apart from the fact that it would be impossible to remove the manifold if studs were fitted to both inlet and exhaust ports?
This didn't apply to the older 'flat manifold' engines, of course.

Also, aren't studs more resistant to the higher temperatures experienced on the exhaust ports, as long as the correct grade of steel is used.

ken

No such thing as a stupid question, is there?

Unless your me

I believe that the stud is not torqued heavily in the threads of the engine for easy removing.

Hi Guys
Thanks for the answers.
Maybe it is the heat aspect of being more tolerant on expansion and contraction.

And James stop downing yourself it is not you, just your phone cannot spell sometimes

Peter

with 8 studs the manifold never can get into place (2cv6) because they are under different angles

So why not 8 bolts?

because the 4 studs hold it in place while the 4 bolts are placed

the screw fastener on the exhaust will corrode and sieze, by using studs you dont have to dis assemble them when taking the manifold off, and so there is no damage done to the expensive aluminium casting. The nut can be treated as a use once item and nobody is going to moan that they had to replace 4 nuts doing a decoke - different matter if you had to bin the heads every time you took the manifold off.

Thumbs up.