Reuse head bolts after swapping heads?

[tocino]

Hello all,
I ordered a set of the aluminum FlatHead Power heads for my 37 UH. Should I just reuse the head bolts / washers, or should these be replaced? Checked somehow?
thanks
Steve

[sirhrmechanic]

Unless they are torque to yield (which most flatty bolts are not) you will be fine.

The best way to check them is to measure them for any waisting. In other words, measure at 3 or four positions along the shank. If they are hour-glassed, that means they are stretched. Get new ones.

Make sure the threads are good both on the bolts and in the jugs. If necessary, lap in so that you get a TRUE torque reading, not a torque reading that is affected by friction caused by a tight fit. You should be able to turn bolts in by hand... no wrench until they hit the shoulder. Clean lapping compound out well and lubricate the threads.

Hope this helps.

Cheers,

Sirhr

[Chris Haynes]

Head bolts for alloy heads are different than bolts for iron heads.

[Rubone]

Head bolts for alloy heads are different than bolts for iron heads.

True on 45s not for BT. They use the same bolt, just different washers.

[Tom Lovejoy]

Also good to make sure the bolts go all the way down and don't bottom out. Should be able to tighten without the washers and pull the head tight. Then you know that their not bottoming out, if they do. You can pull the threads while trying to reach your tourqe amount. Something I learned from not checking and stripping my threads,or other damage to the cylinder, sometimes the bolts are longer than needed. Check the threads too, it's a drag to pull them right as your looking forward to a ride. I have done that too, when retourqing the heads. Good luck.

[Steve Slocombe]

Just to repeat Chris' comment that you need to change the washers for the ally heads to those big thick 15-39 instead of the 0232 ones. And of course the torque is different. I use about 50 pounds feet instead of 65 on the iron heads.

[tocino]

Thanks all - especially for the warning re: the washers. Where would I get the proper ones?
I like the trick of checking for bottoming out and will do that.

[Steve Slocombe]

I know Colony do those 15-39 head bolt washers, which means most old bike dealers should stock them.