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Diameter of Normal Thru Stud?

avrojockey

Well Known Member
Patron
Anyone know the diameter of a normal sized Lycoming 76220 thru stud or have one around they can mic?

There seems to be a previous attempt to repair my thru stud leak and I want to know if I have an oversized (76220 P01) stud installed. Theres no stamp on cylinder pad but there's also no record of a leak repair attempt in logbook.

Thru bolt bore was measured at .5007, and my thru bolt is .5013 which seems like a normal thru bolt diameter considering the need for the .500x20 threaded end to pass through easily.

Just wondering what oversized stud to buy to do SI 1290.

Thanks!
 
As I recall the ECI oversized studs I used on a OH had the oversize stamped on the ends of the studs. P1, P3, P5 etc.
 
As I recall the ECI oversized studs I used on a OH had the oversize stamped on the ends of the studs. P1, P3, P5 etc.

Thanks Bob...no stamp on bolt. The measurements I took pointed to a normal interference fit so it makes sense it's a normal thru bolt. Just wanted to check.

FYI...cam and tappets still looking good. Just concerned about the fretting of that middle main...though there has been no loss of torque on the thru bolts.
 
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