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MG MGB Technical - Payen head gasket issue

I found with a new Payen AK660 head gasket (from Moss US) that the holes for head studs 10 & 11 were too small. Hole diameter was 10 mm (0.393") whereas head studs are 7/16" (0.438"). The other 9 head stud holes were approx. 1/2" giving good clearance around the studs. (I resolved the problem by enlarging the holes using a small grinding wheel on the Dremel).

Has anyone else had this problem? I assume 11 head studs on all 1800 B series engines are all 7/16" dia.? This head gasket is marked Made in South Africa rather than England.
Mike
Mike Ellsmore

Hi, I have just fitted a Payen gasket and had no problems. It was marked "Made in England". This probably hasn't helped you.... Sorry.

Mike

PS: The car is refusing to start now...
Mike Standring

Mike the head studs on the B series engine are 3/8"??

Denis
Denis4

Denis are sure? Mine are all 7/16" but is a modified engine with Derrington HRG head, Titan rocker gear - stud holes 1-9 in the gasket had plenty of clearance for 7/16" dia studs so something odd here!
Mike
Mike Ellsmore

Definitely 3/8", and those end holes are made to be a snug fit so they locate the gasket properly
Paul Walbran

Thanks Paul, that solves the problem. Appears original engine builder increased stud dia. Inspecting old head gasket I see that these holes had been enlarged also.
Does anyone know whether Titan roller rocker pedestals are made for 7/16" head studs (or have mine been modified also)?
Mike
Mike Ellsmore

I would hazard a guess that your Titan roller rocker assembly has been modified to fit the larger head studs. It would make sense since you have a Derrington head to match. RAY
rjm RAY

This thread was discussed between 10/09/2013 and 12/09/2013

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