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MG Midget and Sprite Technical - Re-torque head gasket

I know there has been many threads on this subject and it seems that there are just as many differnt thoughts on this subject.
I have 200 miles on a new head gasket and thought this is a good time to re-torque (75' 1500).
Some say to lossen each nut (in sequence) 1/8 turn then re-torque right after. Some don't lossen them just re-torque. Some say do it cold then run engine to operating temps then re-torque.
The Hynes manual is not that specific.
Is there a concenses on how this is to be done??

RC Bishop

I have built MANY engines of different types, the system I have always used is to re-torque when the engine is cold and slacken off 1/4 turn before bringing back to the correct torque.

Don't forget to re-set the tappets afterwards too....

Mark.

MG Car Club midget Register Tech Advisor
Midget and Sprite Club Tech Advisor
M T Boldry

Mark, you don't mention after how many miles/kilometers you do this.
(I'm about to take of the head again after a suspected HG failure on a freshly rebuilt engine :(
Alex G Matla

There are several different ways of doing this, and by all reports most of them do the job. I've used Mark's method as successfully as he has, but subsequently adopted a different approach due to the uncertainties of sending a car out with some customers whose enthusiasm might get the better of them on a freshly fitted head.

This is to run the engine at about 2000 RPM for about 10 min after initial start-up so it is at proper working temperature, then retorque while hot.

This method has been equally successful and is really worthwhile when you have a race the next day or have something serious to attend to in the middle of a rally (in my most recent case, 2 broken new valve springs ... on the same valve!) as you can give the engine death straight away (well, after 10 min/retorque/ tappets) without having to run mileage first.

Torque figures assume the fastening is moving already rather than static with the associated higher frictional drag. Almost always the nut moves without having to back it off a bit and goes on to the right torque. however if it doesn't move before triggering the torque wrench I back it off about 1 flat (1/6 turn) and torque from there.
Paul Walbran

After consulting my mate, and he also uses Paul's technique for his customers for 30 years orso, I will go that way. Only he doesn't loose the nuts first as there is no way in knowing if it's the nut or the stud wich is coming loose

And then there is my own suspected HG failure......it didn't.
Shame on me, but from the first exhaust valve the nut came loose (after I checked the rocker for hitting the pushrod) and ended up with a valve clearance of say 500/100's....
Ah well, it happens....
Alex G Matla



I am an advocte for slacking off the nut 1/8 to 1/4 turn before retorquing and to do it in the proper sequence. expermenting with a piece of wood does yeild big differances....as the nut NOT slackened buries deeper in the wood then the one with its pressure relived

because my engines have always been stock, I have waited the 500 miles to do the adjustment Then did them cold and never adjusted the rockers, with no problems

But On a high performance engine I think you have to go the extra differance....Hot, slaken, and rockers adjusted....At least thats how Im going to do my engine.

BTW....God I hope I get my engine back tomarrow..LOL

Prop
Prop

I have sent off for on oil cooler and an allunimum valve cover (have trouble getting everything to seal dealing with the valve cover).
While waiting for these I will adjust valves and wait for the 500 miles to re-troque the head.

I only drive in the summer (NO RAIN) months, hope to put a couple thousand on her this year. I have just too much time spent in restoring her to drive in those wet snowy months.
Here is a quick pic.
RC Bishop

Sorry the picture did not go through.
RC Bishop

Alex, you ask for a time.... I have re-torqued race engines after initial run up (once cooled) or road engines have been left for up to 500 miles.

Mark.
M T Boldry

Same here RC,

I hate to even take it to the car wash....after all the soft stuffed teddy bear toy and a bucket of soapy water does so much better


LOL
Prop

This thread was discussed on 09/06/2009

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