At 10:50 PM 4/6/2008 -0500, Robert J. Guinness wrote:
>In reinstalling the head on my 1963 MGB engine I am using a new
>Payen Head gasket. When I torqued the #9 head bolt it broke at 40
>ft/lbs (I used new studs). I have 2 question:s 1. Can I reuse the
>new head gasket after it had been torqued to 40 ft/lbs? 2. The
>manual says the torque is 50 ft/lbs. Is that correct, or should it
>be lower? ....
1.) I will be bold enough to to say yes, you can R&R the head and
use the same gaket, as it was not pulled up to full torque and the
engine was run. The Payen head gaskets are very good quality and
should have no problem with this.
2.) 50 lb-ft torque is correct for the iron head. Some aluminum
haed manufactures specify 40. Head studs of original quality will
tolerate 50-60 with some safety margin. Any stud that breaks at 40
is definitely sub-standard. If you have just installed a complete
new set of studs, one breaking at 40 makes the entire set
suspect. If you have no way of testing every individual stud, I
would be inclined to return the entire set to the supplier and demand
a refund, then buy the next set somewhere else.
3.) You didn't ask this, but there is no reason to buy special high
strength head studs for a street engine. It is important for
standard (normal strength) studs to be "strong enough" for the
application, as in similar quality and strength compared to the
original studs. Most people have no way of testing the individual
studs, so must rely on the suppliers to get it right. IMHO, any
supplier who would allow even one sub-standard stud into a customer's
hands is negligent. Customers should demand suitable quality control
on fasteners, and suppliers should be responsible enough to do
it. If you accept a broken fastener without returning the whole set,
the supplier has very little incentive to improve the situation.
1958 MGA with an attitude (and lots of original head studs)
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