19 replies to this topic

[mk=john]

Hello all
On my early Mk1 mini, which has an 850cc unit, the front cylinder head studs are screwed into the block, using `Hermitite Red' on the bottom threads. This is because the threaded holes in the block go into the water jacket (early flaw in the design of this engine). The Hermitite Red is used to seal the thread at the bottom of the cylinder head stud, into the block.

Anyway, my question is, the front middle nut on the cylinder head is now seeping coolant, just a little bit which means that I need to remove the stud and reseal the bottom thread.

I don't really want to go through the hassle of removing the entire cylinder head just to do this. Can I just remove the single stud, and after applying the sealant to the bottom thread, replace it and torque it up? I know its not ideal, but its just one stud, and the engine is an 850cc unit so isnt put under great compression.

Thanks

John

[KernowCooper]

Its always a chance John even on 1 stud you could do the job and a short while after like others here who have fitted roller rockers and driven off only to find the gasket fails 2 weeks later.

If you have a water leak already are you sure the gaskets not damaged? Being the front centre nut as well is the one stud which could cause you trouble between cylinder 2/3

2 choices

Remove the stud and do the job as you described and see how it turns out or head off and do the head and studs all together.

[mk=john]

I think then I will try removing one stud as I descibed, take the car for a short drive and see how it goes. If it doesnt fix it, then I will take the head off and fix it that way with a new Gasket.

[Ipod]

i'd do it the right way the 1st time.
if you got that ickle doubt in ya head, hence asking on here

[Ethel]

The killer will be retightening the nut: the gasket has been compressed so torquing it again would compress it a bit more, that'd cause it to fail if anything does.

I'd scratch a line across the nut & stud to use for realignment and count the turns as you undo it. Since you'll also be pulling the stud (could be tricky in itself with the head on), I'd slacken the nut then retighten measuring the torque required to realign your marks, and use that figure for the final refit.

[Cooperman]

You can normally get away with taking one out, but more than that can be a bit 'iffy'. As both block & head are cast iron the material is very stiff, in engineering terms, and the distortion is so much less than it would be with an aluminium alloy head.
It's worth a try as there is nothing to lose and it could well save a lot of work.
For re-sealing Loctite Bearing Seal might be better than red Hermetite.

[mk=john]

That's what I'm thinking. I wouldn't try in an alloy head, so I think I will try the one stud approach. I have to take it out tomorrow to a local classic car show, so it's a good opportunity to try it and see if it has worked once I'm home.

[mk=john]

Ok. I've just done what I intended by removing one stud, and red hermitite was all I had so I used that, then retorqued it. Started engine to warm idle. Its much better, just a trace of water but I guess that's residual water at the bottom of the hole in the cylinder head, just around the threaded hole in the block. I wiped that away and it didn't return. Anyway tomorrow I will go or a drive so will know more then.

John

[KernowCooper]

Keep your fingers crossed its done the trick, nothing to loose as per my first post if it needed attention

[Vipernoir]

I've alway believed that removing nuts/studs was okay as long as it was only one or two, and the head had no chance of shuffling sideways. Vertical movement in exactly the same place should be alright, it's when the two mating faces compress a different part of the gasket that problems arise.

I've certainly been using my Sykes engine cradle for many years with no troubles at all, and that requires the removal of the outer two front nuts.

[mk=john]

Agreed. Ive also used my sykes engine bracket, and you have to remove the two outer cylinder head nuts in front of the rocker cover. Done that multiple times on another engine with no trouble.

Edited by mk=john, 31 March 2013 - 08:05 AM.

[tiger99]

I would suggest loosening each nut, one at a time, and retorquing, with the engine cold, and then again after it has been run for a bit, just as if you have actually changed the gasket. That will help to ensure that each stud is exerting equal pressure on the head, otherwise due to the gasket creeping under load the one which you have removed is likely to be actually exerting more pressure than the others, which may not be good.

The only snag is that you have to take the rocker cover off, and the valve clearances will need to be checked afterwards, but if all goes well they will not have changed by very much.

Or, you can do nothing and just run it until it fails, or not. It may be ok for 50k miles, or fail next week, but it is only a head gasket, no big deal compared to the other problems which Minis have from time to time.

It is just impossible to know in advance what course of action is best.

[mk=john]

Hi
I tok the mini for a drive today, around 50 miles (went to a classic car show which was cancelled when I got there!). The car was faultless, the cylinder head stud is not leaking, dry as a bone. So good news so far.

Only time will tell, but it looks promising.

[MRA]

The original engine lifting equipment required 2 nuts to be removed to fit it, it was NOT always the case that the unit was being removed for an engine rebuild, as it may be used to strip off the transmission, change the diff etc.

The front centre stud is actually the "dowel" stud and is possibly the worse one to do, however as the OP has stated it is currently working ok, it would be good if you could report back on here in say 3 to 6 months or if it fails ?

[Dan]

Out of interest how did you manage to avoid smearing any Hermitite inside the head stud bore? Especially given that it is the one with minimal clearance!