rpoz20

iTrader: (1)

I just purchased a new GM LS7 clutch assembly from a fellow board member and one of the three locating dowel pins on the perimeter of the steel flywheel broke in transit. I called a reputable local machine shop I've used and they told me that I should be fine to run without it since there are still two other pins to align the pressure plate, but I'd like to get some opinions to either confirm or deny that.

My main concern is whether the pin which sheared off even with the flywheel would be enough to throw off the balance of the clutch assembly. The assembly is being used with an LS3 mated to an LS T56. The piece of the pin that broke off weighs 2.5 grams (approx 1/8 oz) on my kitchen scale.

If I do have to replace the pin, I've read that the best approach is to drill a 1/16" hole through the back side of the flywheel and then use a punch to knock out the pin. Agree? I assume the hole itself wouldn't weaken the flywheel?

BTW, this falls under the category of sh** happens. Everything had been packaged very well and FedEx hadn't abused the box so I think there was just enough shifting inside the box to hit the pin just right to break it.

lizeec

iTrader: (57)

If you drill a hole on the backside, you are back to your concern of material being removed from drilling causing a weight imbalance. I would try to drill the front to the exact size of the original hole and install a new dowel pin. With that said my Monster clutch had no dowel pins installed for the pressure plate. I called Monster and they said some flywheels have them some don't?

rpoz20

iTrader: (1)

Thanks lizeec. I had considered that drilling from the back would remove some metal, so it's really a Catch-22. The potential problem with drilling from the front with the same size bit is that I read on one of the forums that there is a taper on the pin (and I would assume the pin hole as well). I need to order a pin and take a look. I was hoping that a 1/16 hole would only remove a negligible amount of metal.

lizeec

iTrader: (57)

If drilling from the front it would be very hard to keep the bit centered as well, maybe drill a small hole in the dowel and try an EZ out at the same time heat up around the dowel hole to expand the metal? Or possibly drill a small hole in the dowel and stick a screw in there and weld it to the broken dowel and use a slide hammer to pull it out, also while trying the heat around the hole at the same time? Just a few thoughts, good luck and just use patience.

SNLPerformance

iTrader: (15)

All our flywheels are shipped w/o dowel pins installed, it is your choice to install them as they are only for assisting in installation as the bolts actually hold the
pressure plate to the flywheel. I personally don't have any dowel pins in my Monster if that helps the OP. IIRC GM balance spec is 12 grams, so you should be fine, but could always take it to a machine shop to have it checked for balance.

rpoz20

iTrader: (1)

I appreciate the responses. The balance spec was the piece of info I think I needed to make a decision. Since the broken part of the pin weighed in at 2.5 grams, I'm well within the margin of error for the balance spec, so it sounds like I'll be ok without that third pin. Having a machine shop check it for balance sounds like cheap insurance, so that's what I'll do.

Thanks again!

Maxx_Z06

iTrader: (1)

Glad you got it figured out.
Thanks a again.

BALLSS

OP

if you are going to take the FW in for balance to a machine shop they could remove the sheared pin and replace. I would think the cost to replace the pin is same as balance. I would think if the missing dowel did effect balance replacing it would resolve.

FWIW I sent in a "new" billet FW from my McLeod twin kit, floater plate & PP to confirm "zero" (my motor is internal balance 383) to a machine shop (The Balance Shop) as the install instructions advised. The FW was 26 grms off. The 4 holes drilled in the FW for the screw on counter weight that would be used for a external balance motor amounted to that much weight. weighed 26 grms of screws/washers to put in the holes (3) and all was then zero including floater & PP as they were added to FW as each was confirmed for neutral balance.

just goes to show how such a small amount of metal could weigh so much.

SNL says their LS FW does not "need" dowels to be used so you could pull the other 2...

rpoz20

iTrader: (1)

Thanks ******. On the day I received the assembly I ordered a couple replacement pins, so once I get them I'll take it over to the machine shop to have them take a look. My LS3 came without a flywheel, so there are no reference marks to line up to put everything back together as originally assembled. Just another reason to have a machine shop go over it.