11 replies to this topic

[germini30]

On my 1275cc the thermostat housing is held up by three bolts. The threads aren't the best and I'm looking to replace them.
Online most mini sites seem to list studs and nuts/washers.
The head is a 12g940b unleaded from a mini spi. Thank you.

[Midas Mk1]

Studs and nuts all day every day, i’ve had to helicoil my ‘stat threads thanks to bolts.

Edited by Midas Mk1, 04 August 2024 - 09:21 PM.

[germini30]

OK. The head threads are good,the bolts are corroded away so I'll order some studs and nuts

[nicklouse]

Never a fan of tightening a unc thread when you can be tightening a UNF thread.

[weef]

I think there are arguements for and against either fixing method.

If using studs and nuts, corrosion can form between these steel studs and the alluminium thermostat housing making the removal of said housing difficult but this method negates damage to the threads in the cylinder head, but in practice I find that if this corrosion has occured then the steel studs have to be removed anyway for replacement, so they are unscrewed from the head.

By using bolts to secure the housing them the action of unscrewing the bolts can "break" any corrosion between them and the housing and permit the removal of the housing undamaged.

The use of stainless steel fixings and a ceramic grease may help the situation regarding the corrosion between them and the housing and by torqueing these fixings, either bolts or studs should result in no damage to the threads.

Others may have strong arguements for their preference but this is my take on things, the choice is yours.

[Steve220]

I've always used stainless bolts with duralac on the threads and shafts. They're a low torque, so i'm not fussed about the UNC thread.

[Spider]

I prefer bolts here.

If there's corrosion, I've always found there's a better chance of getting the bolt out than with studs.

I'll add that every single time I fit or re-fit the bolts here, I grease them along the shank so there is reduced corrosion.

[Steam]

Given the 4 hours I wasted last time trying to remove a tstat housing with studs I go bolts every time.

[DeadSquare]

Studs.  .............. And carefully wrap a little PTFE tape, clockwise round the shanks, after fitting the gasket.

 

The nuts come undone easily and any aluminium corrosion doesn't get to the steel studs.

[Stevie W]

As Deadsquare above suggests, or a very light smear of copper ease.

 

Cheers, Steve.

[Ethel]

Tape or RTV is a good idea on the threads if the hole goes through to the water jacket. 

 

Haven't tried it, but I expect plastic washers, for insulation, would work fine too.

[germini30]

About 50/50 studs and nuts or bolts