Quote:
Originally Posted by undy
The rule-of-thumb for thread contact is, 1.5 x diameter of bolt/stud. This is a generality, variables like hardness, materials, threaded hole depth etc impact on it. Bottom line, if you follow this you'll never come up "short". 
That was one of the first concepts I learned in the Navy's Machinist Mate "A" school back in 1970.. |
Undy, if you had read this thread from the beginning (at least from the point where Tom Kirkham brought up the concern with the bolts), you would realize that you are repeating what has already been stated...and that this is exactly the concern.
As previously discussed in this thread, with the ARP fasteners you very well may NOT have this thread depth. (Actually, ARP said 1.5 X dia. MINIMUM, and RECOMMENDED 2 X dia. when threading into aluminum.)
ARP has stated their pressure plate bolt sets are intended ONLY for OEM replacement and could very well NOT have adequate shoulder or thread length for aftermarket aluminum flywheels.
You guys jumping in at the end of this discussion need to read this thread from the beginning to get the whole story.
As far as Rick's statement: "Jim go with a longer bolt if you want, just make 100% sure that the other end doesn't hit the block, or block plate in a full 360 degree rotation." This too has already been discussed. Go back and read the entire thread. I did this and ARP explained in detail why that was the WRONG thing to do...unless you do some careful measurement concerning the shoulder length (and no, ARP says you should NOT use a shoulderless bolt....read their reason in my posts in this thread.)
I retired from a career as an engineer in the maintenance department of a major chemical production facilty where I learned the devil is hidden in the details. You may not realize the weakness of a component (or worst case, the failure thereof) until you look at it in the smallest detail. I've also been a gearhead/semi-pro racer all of my adult life. My hobby and my career complimented each other and each helped me to be better at the other.
OK....I'm off the soapbox.
Maybe we have taken this to a greater level of detail and concern than necessary. Maybe just using a suitable bolt (obviously Grade 8 minimum) of a length to obtain adequate thread engagement is all that's really important. Maybe the shoulder isn't even necessary. Maybe the advice from ARP is more detailed than we need to be concerned about.
Rodger