Pinning the Crank
Thread Starter
Burning Brakes
Joined: Oct 2002
Posts: 833
Likes: 2
From: Pembroke, GA
Pinning the Crank
been seeing this reference in some posts..did a search found little info on it other then suggestions to do it, but no info on why its done or how to do it. Is this a must on FI cars or is it a highly suggested mod? can someone explain...thanks
Former Vendor
Joined: May 2006
Posts: 718
Likes: 1
From: Riviera Beach FL
It is for supercharged engines. The crankshaft pulley is a slip fit with no key way. The additional force required to operate the supercharger (centrifugal or roots type ) will cause the pulley to slip on the crankshaft snout.
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
I have done this on all the cars I have worked on. The damper is an interference fit, the pin won't allow the damper to move relative to the crank snout and back off as a result. The ATI kit works well, but you must have a damper with a 3/16" keyway milled into it. The ATI and Powerbond both have this keyway, not sure on others.
Safety Car
Joined: Apr 2004
Posts: 3,932
Likes: 8
From: Hayward California
Contact ECS or A&A and they can sell you a pinning kit for non-keyway or whatever you have..
Or... if you're feelin lucky, post to borrow one one on the FI section and just pick up 1/4" hardened pins.
Arnel
Or... if you're feelin lucky, post to borrow one one on the FI section and just pick up 1/4" hardened pins.
Arnel
Safety Car
Joined: Jul 2004
Posts: 3,904
Likes: 29
From: Vancouver Washington
HOW? (Thread Infringement)
I have done this on all the cars I have worked on. The damper is an interference fit, the pin won't allow the damper to move relative to the crank snout and back off as a result. The ATI kit works well, but you must have a damper with a 3/16" keyway milled into it. The ATI and Powerbond both have this keyway, not sure on others.
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
There are two types. The ATI kit drills the crank crosswise and then it is precision reamed. Once done, a 3/16 pin (or optionally two pins) are then put in the hole and the pulley re-installed. This requires the pulley to have a 3/16" keyway milled in it. The other type that AVB was discussing removes the bolt from the pulley and a fixture is installed such that the drilled hole is half in the crank and half in the pulley hub. This is done end wise.
The ATI kit (I used this one) is shown below and the 2nd photo is the kit installed on the crank for drilling (ignore the aluminum foil, that was to keep the chips out). There is one additional advantage to the ATI kit. I use the drill hub to align the timing cover when I do a cam. It slides on and is used to center the front seal. Once the cover it tight, you can slide it off and take your time putting on the damper.
The ATI kit (I used this one) is shown below and the 2nd photo is the kit installed on the crank for drilling (ignore the aluminum foil, that was to keep the chips out). There is one additional advantage to the ATI kit. I use the drill hub to align the timing cover when I do a cam. It slides on and is used to center the front seal. Once the cover it tight, you can slide it off and take your time putting on the damper.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Race Director
Joined: Sep 2003
Posts: 13,550
Likes: 6
From: Now in God's Country, the Big Sky, Montana!
Cruise-In 7-8-9-10 Veteran
St. Jude Donor '06-'07-'08-'09-'10-'11-'12
If you are using a stock balancer you will need to pin with the ECS or A&A pin kit. You will not be able to pin with the ATI kit if using the stock balancer. I always include the crank pinning when I do a cam job just in case the customer goes FI later.
Race Director
Joined: Sep 2003
Posts: 13,550
Likes: 6
From: Now in God's Country, the Big Sky, Montana!
Cruise-In 7-8-9-10 Veteran
St. Jude Donor '06-'07-'08-'09-'10-'11-'12
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
Correct, unless you want to have a machine shop mill the keyway into the hub. I know someone who has done this. The only disadvantage to the end on kit is re-alignment of the pins should you remove later and then re-install or use a new pulley that is not drilled.
Team Owner
Joined: May 2007
Posts: 48,589
Likes: 245
From: In the woods so F%^$ O&&
St. Jude Donor '17-'18-'19
Pin it while you are on the stock shortblock and when you want to replace that then get the crank milled for a keyway that is what I am doing now with my crank.
