Head studs

Post by **iddy** » Sat Nov 29, 2008 5:40 pm

My blooming head gasket needs changing. Can I take the studs out with a molegrips so I can clean the block face, and when replacing is there a problem with torque or do I just tighten them until they don't move?
Can I just clean the head and block faces with fine emery paper?

I notice the new gasket is wider between the piston bores than the old one - they are both the copper type, though from different suppliers.
cheers,
iddy

Trying to upload photo:

<a href="http://s28.photobucket.com/albums/c236/ ... otif_2.jpg" target="_blank"><img src="http://i28.photobucket.com/albums/c236/ ... otif_2.jpg" border="0" alt="Old and new gasket"></a>

Post by **iddy** » Sat Nov 29, 2008 5:42 pm

Mmmm,

Will have to adjust size next time

And the names are in particular order

iddy

Post by **iddy** » Sat Nov 29, 2008 5:43 pm

Doh,
I meant NO particular order

iddy

Post by **bmcecosse** » Sat Nov 29, 2008 5:47 pm

DO NOT use Mole Grips! But Do take the studs out - use double nuts on the studs and then wind them out. Clean the block and head very carefully - and if possible - run a small countersink in each of the stud holes to remove any pulled up lip. Then re-fit the studs - double nuts again - just tighten them as seems sensible - or use the torque wrench at say 40 ft lbf. The new gasket looks a bit weird - the 'rims' round the bores don't look as good as the old gasket - but it should be ok. Smear both sides with a very little grease - and tighten the head nuts in order of course - going round and round until finally 44 ft lbf. Set the valve gaps and then run the engine up till hot - and allow to cool. Then retighten to 44 again - and reset the valve gaps. However - while the head is off anyway - you should really take the chance to grind in the valves before re-fitting!

Post by **iddy** » Sat Nov 29, 2008 8:21 pm

Will do bmc - except for the valves bit, not quite sure what to do there. Will have to read up on it for next time! And get a spring compressor.
Can I use one of those small conical grinding stones that fit on a drill for the countersinking?

What does the grease do btw?

Much obliged,
iddy

Post by **bmcecosse** » Sat Nov 29, 2008 8:24 pm

NO - don't get grit from stones in there! Just a touch with a larger drill bit would do. Otherwise - leave as is. If you don't have a workshop manual - pm me and i will give you the link for the free download. The grease btw - just helps the gasket to settle in and helps get a decent seal. Some don't agree with it - but i have always done it - and on some very high power A series at that!

linearaudio · Post by **linearaudio** » Sat Nov 29, 2008 8:34 pm

Agreed! Just finished writing he same!!

Post by **iddy** » Sat Nov 29, 2008 8:34 pm

Thanks again bmc.
I've got two manuals - one in the garage covered in oil and grease, and one clean one in the house for pre maintenance reading!

iddy

Post by **bmcecosse** » Sun Nov 30, 2008 10:52 am

Oh well - you can soon read up how to adjust the valve gaps!

Post by **iddy** » Sun Dec 07, 2008 9:28 pm

Well, she's up and running and all is OK.

Have rechecked nuts and reset valve gaps.

I happened to be talking to a retired mechanic yesteday, he worked in a Morris garage years ago and told me they used to set the valves at 12 thou for intakes and 15 thou for exhausts. He said the engines ran quieter when doing this. Any thoughts?

iddy

Post by **bmcecosse** » Mon Dec 08, 2008 8:35 am

Exactly - I've been saying that on here for ages. Many prefer to stick to the 'official' settings of 12thou all round. But they didn't have unleaded fuel in thos days! The little extra gap on the exhausts gives that bit of extra space for the exhaust valve to expand without closing the gap. If the gap ever closes - then the seat will burn !
I do suggest you run the car for a few hundred miles - then torque it down again - and again re-set those gaps.

Post by **rayofleamington** » Mon Dec 08, 2008 3:01 pm

What does the grease do btw?

What it does is expand and melt when the engine gets hot - it then leaks out of any gaps, potentially leaving pockets of low compression in the gasket. If you did use grease you REALLY need to retorque the bolts after a few hours running, but you should do that anyway.
It is common to use grease on a head gasket as this was useful on soft gaskets (e.g. coolant system) and has been carried over to head gaskets by word of mouth. It's not a significant problem as it is very unlikely to lead to problems but those who know their engineering principles (including those people who develop headgaskets for a living, and those who build tuned a-series engines for a living) would say never to use grease.
I used to do it when I was inexperienced but learnt not to - none of my heagaskets failed with grease or without.

More important that the grease is to re-torque after the engine has had some use. If the mating surfaces are not distorted and the nuts are tight, then it's pretty darn unlikely you will get any more problems. The risk is of course that the head or block was not flat before which led to your failure or that the burnt gasket had allowed some damage to the surfaces.

Post by **les** » Mon Dec 08, 2008 9:51 pm

He said the engines ran quieter when doing this.

Wonder why this is, normally they are quieter when adjusted right!
The mg metro, I believe, has .015'' on the exhausts.

Post by **rayofleamington** » Mon Dec 08, 2008 10:48 pm

The mg metro, I believe, has .015'' on the exhausts.

probably because it runs hotter (due to turbo) and also has different valves due to the heat...

Post by **bmcecosse** » Tue Dec 09, 2008 11:33 am

I wouldn't say it runs any quieter with 15 thou exhaust gaps - but certainly less chance of burning a valve. ALL the later A series engines were speced to 15 thou.
The smear (and only a smear - not great dollops!) of grease just helps the gasket to settle and form a good seal - i've always used it on A series engines - even on an 8 port alloy head, and some very high performance 5 port engines (> genuine 110 bhp) - and it IS the way to go!

Post by **simmitc** » Tue Dec 09, 2008 4:05 pm

We could also re-open the debate on whether to torque with the engine hot or cold......

"Leaves by the drain"

Post by **les** » Tue Dec 09, 2008 4:55 pm

but those who know their engineering principles (including those people who develop headgaskets for a living, and those who build tuned a-series engines for a living) would say never to use grease

Accepting the above to be true, it takes a hell of a lot of confidence to go against headgasket developers and engineering practice to say grease IS the way to go! I personally would do a bit more wondering!

Post by **bmcecosse** » Tue Dec 09, 2008 7:28 pm

Use it or not - it's up to individuals - I always have and always will use it!