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MG MGB Technical - head on....mgb

To continue the job i started ealier i got the head off and ground.
i got the gaskets but not sure if the cooper side of the gasket should face up does not have the any ref. mark except a number stamped on the cooper side.
suppose its up then refit the head...what is the force to apply on the rachet? and where to start from to tight the bolts?
them should i redo the valves clearences?(i have never done it..)
thanks
Alf
alfredo

alf- use a Payean gasket, black, torgue 3 x after start, after 500, and after 1000. V
vem myers

What is a Payean gasket? What is special about it?
werner haussmann

Hello Alfredo

As per Bentley Shop Manual for the 75-80 MGB torque is 45 to 50 lbs. For the tightening order, it's not easy to explain here but it's important to respect that order and tight each nut progressively. I would redo the valve clearance. It takes no time and certainly won't hurt. Maybe you should get that Bentley Shop Manual there's a lot of priceless infos in there.
M Gaudreault

The Payen gasket is considered to be a much better gasket than standard types. It conforms more to imperfections in the block or head which I believe is due to its resin core, and has an extra bead of material along the spark plug side of the gasket which provides a better seal in that area. This is to deal with a known problem of head gaskets leaking on that side of the block. I believe John Twist recommends using a strand of copper wire laid along the spark plug edge of the gasket to seal regular gaskets. The Payen does this for you.
The Payen is sometimes also known as Fel-pro - I believe the names are used interchangeably. As Vem says above, make sure it is torqued properly and at mileage intervals.

Erick
Erick Vesterback

Head bolt tightening sequence and torque specifications are in Section A of the Bentley manual.
The Bentley manual also has information for setting the valve clearances. If you don't have the manual, it is available from a wide variety of sources; bookstores, MG parts suppliers, ebay, amazon, etc.
Kimberly

Werner,

the Payen head gasket is an epoxy prepeg gasked that is 'baked' to the surfaces, once the engine comes to temperature. The resin is considered to fill all the smallest scratchs that remaind from milling the surfaces. At critical spots as the water passages and the oil feed to the rockers, it is fitted with a small layer of self vulcanisating rubber to eluminate any leakes that might occure within years to come.
I tried it some years ago and there is nothing that i can say against it.
When retorgueing the engine should be warm, as the resin would not be compressed if cold and the polymers would be destroyed.

Ralph
Ralph

If you can't find the printed word on head tightening, it's not difficult. You start in the middle and work to the either end alternately ! Torque again at 500 miles. Valve clearances should be done with a warm engine.
Allan Reeling

Thanks Erick, Ralph,

I have had the 'infamous' coolant leak. I will try the Payen gasket next chance I get. I have wondered what size copper wire John Twist recommends when he suggests a fix for coolant leak.
werner haussmann

As no one addressed this, for Alfredo: there will be "large" coolant passages (or openings) on one end of the gasket as compared to the other. The larger openings should be located at the rear of the engine - and this will determine whether the copper side is up or down. If you don't get this right, the engine will overheat.

For John Twist's discussion on weeping head gaskets, go to http://www.british-cars.org.uk/kimber/namgbr/techtips.htm#engine .

Wayne
Wayne Pearson

Thanks for the tips,as result of them i think the cooper side should face up,now i slide the head on and just slightly tight the nuts until i get a torque wrench.( by the way i drain the oil to clean the oil cooler and pipes and fit new oil filter)
i will come back when ready to do the valves.
Alfredo
alfredo

This thread was discussed between 17/09/2007 and 19/09/2007

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