Jimmy P

iTrader: (177)

My Eagle crank was pinned a while ago. Car seemed to run fine. The balancer hub wasn't spinning on the crank this time, but it did manage to snap the pin, and damage the crank as well. What do you guys think I should do?
Can I take it to a machine shop,and have it keyed? Or will they just tell me to buy a new crank?
Thanks

kp

iTrader: (34)

You can cut a real 3/16 keyway in a different place but the crank snout looks pretty torn up. If you dont have enough interference fit the new key wont hold up long so that needs to be checked, they may be able to repair it. I assume you are using an ATI damper.

Jimmy P

iTrader: (177)

I am using a ATI damper and their hub. So you think that I can have the shop machine a 3/16 key way and I should be good to go?

ls1290

iTrader: (20)

Ummmm....... I do not know. As KP said, the snout looks pretty torn up. A machine shop might be a able to clean it up, but I would be tempted to get a new crank.

A keyed crank will always be better and stronger than a pinned one. If you have the crank out for any any reason, there is not reason not to have it keyed. It is simple and inexpensive to do so.

Keith

kp

iTrader: (34)

They can measure the snout and see if its OK, also make sure the inside of the hub doesnt isnt chewed up as well. Usually the hub will take most of the abuse (softer then the crank). If the crank measures OK and the hub looks worn just buy a new hub and have the crank keyed and be done with it. ATI hubs are a little on the tight side so its best to bring the hub with the crank and let them measure it, the instructions say what the interference fit should be, I forget.

I am using a full length 3/16 key, ATI damper and an ARP bolt torqued to 175ft lbs and have never had it loosen up or move. But that single pin should have held, either it loosened up or the hub is too loose, the pins going in from the front of the crank are the weakest.

BIG BAD BLACKSS

iTrader: (4)

I always thought a pin going in from the front would be stronger as the pin would have to be sliced in half lengthwise to fail. Just seems sheering a pin liek the one above owuld be easier to do. After seeing this i am probably gonna use both pins that came with my ATI pin kit!

kp

iTrader: (34)

It depends on how deep you drill the one in the front, most use the pin on the front for a stock balancer and a lot of times the balancer will crack above the pin if it moves around. It is pretty strong, think of a pebble stopping a shopping cart wheel, but if its drilled a little off or the balancer starts moving it will crack, sen it a couple times.

I think ATI meant to use the two pins, but no matter what you use if the balancer loosens up it will beat anything out after a while.

stevieturbo

Surely a pin mounted like that will be pretty feeble ?

The Kit I used, gave me 2 pins, ranning axially along the cranks length.

So I effectively have 2 x 1/4" round keyways on my crank/damper.

kp

iTrader: (34)

Any pin or keyway is pretty feeble when its the only thing keeping the damper from moving trying to drive 100hp worth of accesories

If you have a good press fit, the bolt stays tight and you have no weird harmonics going on I would think that single radial pin would be enough for a street sized blower, but it takes only a few minutes to put another pin in so better safe then sorry.

As far as axial vs radial, I dont really know which would be stronger, if the damper already has a keyway a pair of 3/16 pins should hold I would think. If you have no keyway in the damper I'm sure a pair of 1/4" pins 1/2" or more deep from the front would hold just about anything also. The only failures I have seen myself have been wih stock dampers with the front drilled pins. But you just dont know how long it was driven with a loose bolt beating it up.

Either was a square full length key is the strongest, just the least convenient to install since the crank needs to be out.