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MG Midget and Sprite Technical - head gasket question

1971 midget 1275. I rebuilt last year. Two head bolts are now dripping coolant very slowly when engine is at operating temp. See pic attahced.. it is those two middle bolts in the picture. As far as I can tell nothing is leaking under the valve cover (I hope). Well I was going to retorque the head bolts and I was wondering if I should do it with cold or hot engine.

I was going to back off each head bolt in order a quarter turn then retorque it (one at a time).

Thanks for any comments


Ken Bargeron

Hey Ken,

I cant really tell from the pic. but is the coolent coming from betweenthe head and the block or the head and valve cover?

to retorque, back off the nuts in the # order as stated by haynes then re-torque in the proper sequnce BUT DONT torque the whole setting at one time, devide the setting into 3

exp. setting is 70ftlbs...1st round torque at 25, 2cd round torque to 50, then the 3rd round to 70

As to your problem, is the coolent is leaking between the head and block..go ahead and retourque, you have nothing to loose, then look at the oil for slime and coolent for loss, and watch gauges for over heating...if these are problems then its a head off and new gasket and check for crackes between the valves seats and put a staight edge across the head and block face for straightness and level planks

prop

prop
Prop***The End in 2012

well it is leaking from the nut? so for example when the eng is at normal temp I look at the eng I see a little coolent on the top of the head nuts (the two shown in the pic). If I whipe it off it comes back in a small drip again. Not enough to run down the block. You have to look at it closely just to see it.

Have you ever heard a recomendation for doing this on a cold or warm engine?

Thanks
Ken Bargeron

Ken
IIRC the offending studs extend into the water jacket and the coolant will be coming up past the threads. Glycol coolant will make this worse. That stuff is so slippery it will leak past a good head gasket.
Mike Allen

Hhhhmmmm Ken,

On the surface, it appears there is a leak in the water jacket like mike pointed out, but unless this area was mechined recently, I have a gut feel the problem is deeper, a cracked head

I always do these cold.


Like I said, it dosnt cost anything to re-torque, if it fixes it Great!!, if not, then its head off

prop
Prop***The End in 2012

yes do it cold
Prop***The End in 2012

Prop,
You do it in 3 turns, I do mine in 5 lb increments. Takes much longer, but less chance of a problem.
I am with Prop, retorque then if no luck, a new head gasket. While the head is off it is worth getting it checked for cracks, warpage, get seats and seals done.
I have just gone through this and there are some fiddly bits, but pretty easy.
Let us know what happens.
Allan
Allan Jacks

There also an article by minispares in which you are warned not to overtight the head studs, as by doing this you will split the fire-ring in your gasket which causes the compression to blow trough the gasket into the cooling system.

I know I've had mysterious water in cyl. nr. 3 when I took of my head to replace it with a flowed one.
Alex G Matla

Ken,

If it is like Mike said regarding the studs in the water jacket, then it doesn't seem like the head gasket is the problem since the coolant can climb up the stud without having to breach the gasket.

If it were mine, I wouldn't pull the head. I would drain the coolant, pull the leaking studs, run a long handled round wire brush (like used for gun cleaning) through the threads in the block, put some sealant on the block end of the stud threads, and put it back together. I would complete one before starting the other.

Also, if that is a fresh rebuild, it might stop leaking on its own after a while. Perhaps consider running it a while unpressurized.

Charley
C R Huff

On retorquing the head, you don't need to loosen the nuts all the way, just an eighth of a turn is all you need. What you are trying to do is to make sure that the nut is turning as you come up to torque. If you don't loosen the nut bit, yo can wind up with the torque wrench trying to overcome the starting friction, which is greater than the actual torque than what the nut was torqued to originally, when the stretch of the bolt as actually resulted in less tension than full torque. Cheers - Dave
David DuBois

I had this on the Sprite. There's nothing to get excited about. I'm sure the head is just fine - at the most do what Charley advises or just put in some Bars Leaks and that fixes it.
f pollock

Wow a lot of good input from everyone. I will post up the result. I am going to try to retorque tomorrow and see what happens. Next I will pull the head and take a look..

Again thanks for all the great responses everyone

Ken
Ken Bargeron

The factory put a shot of Bars Leaks into every new system. That's quick and easy so worth doing after you re-torque.
Mike Allen

Do these studs go into the water jacket on all engines? Or to be more specific, do they go there on my 1275 CE? If so, I guess it's normal to put some gasket compound around them when they're fitted.

I don't like "bars leaks" and the like. It sets on contact with air, so a bubble ending up in your thermostat and next thing it's clogged with gunk.
Ant Allen


< I am going to try to retorque tomorrow and see what happens. Next I will pull the head and take a look..>


Ken,

I would suggest doing the diagnosis before removing the head.

Charley
C R Huff

Ken
I have always and will continue to retension A&B series head nuts with the engine at normal running temperature.Simply warm up to temp take the rocker cover off and attack. Start in the middle in the normal sequence, Back the first one off(Not using your tension wrench) about 1/4 of a turn as suggested by others here and pull it up to full tension (B series-50 A series unsure but you can look that up ) The rest of the studs are already at full tension or very close to it so you can go full tension straight off -no problem then progress through them in order one at a time but move briskly while the temp is up. then reset valve clearances and put the lid on. A little bit of stopleak isn't a bad idea. Just a clean liquid one like Wynns. Less than half a bottle will do the trick. Works for me. Cheers Willy
WilliamRevit

well I retorqued the head and problem solved! turns out there are two torque settings 42lbs and 50lbs. I had set mine to 42 which is wrong it should have been 50. So I retorqued to 50 and all it good.

Thanks for all the input everyone :-)

Ken
Ken Bargeron

Well, that's nice.

Charley
C R Huff

Congrats. Ken,

glad to hear it, be sure to purchase a lotto ticket, you dont want to let that bit of good luck go to waste.

prop
Prop***The End in 2012

This thread was discussed between 11/03/2009 and 15/03/2009

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