A pin is inserted through the case and stud, it does two things. First the stud can't turn and loosen, secondly it acts like an anchor and spreads the load out more through the case. We never had to do this yet on Harley's. But have used it in other applications over the years. Hope this helps.
John

 

I agree and understand that's the intent of the pin. That being said, I'm not sure I agree with it completely. First, to my knowledge, people aren't experiencing problems with either the inserts or the studs "rotating" and "unscrewing" - meaning that this particular reason for pinning makes no sense to me. Rather, the "studs pulling" is actually that the studs are pulling the actual threads. In this case, I'm not totally sure about "spreading the load" as the pins would have to be pretty darned small diameter. The reason for this is that the inserts are only 1". So, you either have to reduce the engagements of the studs into the insert or you only have a pretty small area "below" the screwed in stud where you can drill through the insert. Now, then you need the OD of the drilled hole, and the interference fit of the pin, and it's pretty darned small. Then, you could make the argument that you've weakened it in that area where the pin could in fact crack the aluminum. Not saying it would happen, but let's face it. The reason this is happening to begin with is for two basic reasons. First, the overall design of sandwiching the base gaskets, cylinder, head gaskets and heads between the block and head nut using a steel stud screwed in to relatively thin cast aluminum with 3/8-16 threads is just plain dumb. That's a Harley mistake. Second, that the composition of these cases is simply of poor quality. So, it's not hard to also conclude that the pins could add as much risk as they remove. Who knows? That being said, I'm in no way saying pinning doesn't work or is a bad idea. Right now, for this particular application, it just doesn't seem to make sense to em.

JMHO.

An aside - keep seeing your sig line about the 82nd. Assuming you were there. Me too.

 

Was looking at some big bored s&s cases today and can now understand why they don't want tieserts as theres just not enough meat.

 

Hopefully that's not the case here with a 4" bore. Frankly, there's a 1/2" (actually slightly less) bore increase over stock, and then consider that only half of that (actually less than half) would be in question as there is no reason that the outside 75% could not have been reinforced by S&S. There are only mechanical constraints on the 25" of the stud area facing the bore(s). So, from a design perspective there is no reason whatsoever that there could not be a design enhancement to remediate this. I can think of a bunch of them right off the bat. Knowing this is an issue, perhaps steel inserts should be in the case from manufacturing. After all, if you're buying a 4"+ bore case, you're not building a stock evo, right?

FWIW, S&S also has apparently different answers depending on who you talk to. The last guy at S&S I talked to said they use and recommend Timeserts. He made no mention of pinning.

Here's a different but related question. Let's say somebody is going to build a motor. What advice would we give them with respect to this off the bat? At this point I'm hearing WAY too many reports of this problem, and the first recommended solution was - put a new block in it - which is exactly where this started. There ought to be a way to build a motor and effectively eliminate the potential of this happening. I build car motors, and would never tolerate this design issue in those cases. This seems too much like rolling the dice for my taste. R&R seems to have a solution, but it's kind of proprietary. They build custom billet motors with base studs and head studs (imagine that?). If my rotating assembly, cylinders and heads would work, that's what I'd move to. But lacking that, what are we to do? I can tell you that I'm very unlikely to build another S&S/Harley Evo or twinkie until I figure this out for the future.

 

Well I'm going to say after using the timeserts on my own cases and although no where near the torque your getting they go in with out a flaw and they would probably do the job for you, you just have to decide which opinion to go by as there sure seems to be some controversial ones available.

 

Make no mistake, my intention is to use them in this case. I was asking more about if somebody were building a "new" motor. Hard for me to justify rolling the dice if these blocks are so prone to stud pulling. What advice if somebody were building a 100-140hp motor?