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What Thread Insert Do I need?
Posted: Mon Jun 30, 2014 12:39 pm
by Tomshayes
Hi All
Can anybody tell me what thread insert kit I need for repairing the rocker box stud threads in the cylinder head on my 1991 350.. I think it's 1/4" BCy... But not sure!
What Thread Insert Do I need?
Posted: Mon Jun 30, 2014 1:52 pm
by PeteF
More likely to be BSF on the engine.
Same TPI (26) unfortunately so that doesn't help to identify it. The thread form is different so you should use the correct one really.
If you have the facility to measure the existing stud thread,
All the information is here.
What Thread Insert Do I need?
Posted: Mon Jun 30, 2014 2:16 pm
by Tomshayes
Hi Pete
thanks but that's the problem, I have no way of measuring the thread other than by eye at the moment.
What Thread Insert Do I need?
Posted: Tue Jul 01, 2014 8:01 am
by simon
1/4 cycle mos def. 26 tpi at 60 degrees thread angle. Which differs from 1/4 BSF which is also 26 tpi but 55 degrees thread angle.
What Thread Insert Do I need?
Posted: Tue Jul 01, 2014 6:10 pm
by Tomshayes
Cheers Simon..
I just happen to have that very Helicoil Kit.. Much appreciated!
Tom