Engine Stud Bolt question

[Basket Case]

OK, this should be a quick question.

I broke my engine apart, doing the full rebuild of the bike. A friend of mine, who is an exceptional car mechanic, tells me that I'll have to replace the engine stud bolts just because I'm breaking the engine open, due to stretching and weakening.

Now, this may be true on the cars he's worked on, but I see nothing about that in my Clymer's guide. Does anyone know if I really do need to replace the 8 studs, or if I can just use what's there?

[Road_Clam]

Dude,
I think now your talking about splitting hairs. I really wouldn't worry about replacing the studs. You're buddy's claims DO have some truth to them, but I know many of us (myself included) have replaced top ends on GS bikes without any mention of replacing studs, and I have not heard of any negitive issues resulting from using old studs. I can tell you you absolutely need to pay attention when removing the head nuts and washers! On my 1100, Suzuki uses both copper, and steel washers, and the need to be replaced in their correct respective places. Good luck,
Rich

[Basket Case]

Thanks. I was thinking the same thing, but of course, figured I double check with people who know these GS's.

Thanks for the word of warning on the washers. Luckily I saw that and have 'em all marked.

[bwringer]

Somebody better tell all those drag racers that they have to replace the studs every single time they take the head off... they'd probably throw a few at you.

It's not normally necessary to replace the head studs on a GS engine. The studs holding down the head on an air cooled engine are much longer than the bolts on a water cooled car. The extra "free length" allows them to accomodate greater variations in heat expansion without permanently stretching. Properly torqued, they are designed to maintain consistent clamping force through their longitudinal elasticity. You can't really see this stretching -- it's measured in .01mm increments -- but it's why cylinder heads can go thousands of miles without warping when they're hot and leaking when they're cold.

Some car engine head bolts are designed to be re-used, but many are designed to permanently deform or stretch just a bit when installed and cannot be re-used. The latter are becoming pretty common in cars.

There was an excellent Kevin Cameron article a while back that examined head bolts and studs in detail. I love reading his columns on technical minutiae.

[Jackrp]

OK, this should be a quick question.

I broke my engine apart, doing the full rebuild of the bike. A friend of mine, who is an exceptional car mechanic, tells me that I'll have to replace the engine stud bolts just because I'm breaking the engine open, due to stretching and weakening.

Now, this may be true on the cars he's worked on, but I see nothing about that in my Clymer's guide. Does anyone know if I really do need to replace the 8 studs, or if I can just use what's there?

Having gone thru Suzuki school thru the golden GS years, In engine school there was NO mention of stud replacement,Fresh gaskets Yes, maybe if I had an Oh My gosh drag racing, bored out nitrous, turboed GS I might consider it. But normaly, No.