[Z06] Replacing an already pinned harmonic balancer
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Joined: Dec 2015
Posts: 86
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From: Overland Park Kansas
Replacing an already pinned harmonic balancer
Well folks...
The Vette Gods have frowned on me yet again
I was attending a local test n tune 1/4 mile event last weekend when my harmonic balancer decided to "let go" and wobbled bad enough to lose belt tension and kill the battery, but not so bad that it came loose from the crank.
Anyways.... Fast forward to about 20min ago when i was finally able to pull the balancer off only to realize that it had been previously pinned. (it is the stock balancer)
I have purchased a replacement balancer but how do i go about installing and pinning it to match??
Would it be ill advised to re-pin in a different position thus having 2 "key ways" in the crank shaft snout??
I need the help of the experts whom reside here in this form.
This is on a 2003 Z06 with a D1SC Procharger among other goodies... 575rwhp 511 ftlbs
The Vette Gods have frowned on me yet again
I was attending a local test n tune 1/4 mile event last weekend when my harmonic balancer decided to "let go" and wobbled bad enough to lose belt tension and kill the battery, but not so bad that it came loose from the crank.
Anyways.... Fast forward to about 20min ago when i was finally able to pull the balancer off only to realize that it had been previously pinned. (it is the stock balancer)
I have purchased a replacement balancer but how do i go about installing and pinning it to match??
Would it be ill advised to re-pin in a different position thus having 2 "key ways" in the crank shaft snout??
I need the help of the experts whom reside here in this form.
This is on a 2003 Z06 with a D1SC Procharger among other goodies... 575rwhp 511 ftlbs
Last edited by ezstreet; Jun 7, 2016 at 01:01 PM.
Thread Starter
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Joined: Dec 2015
Posts: 86
Likes: 1
From: Overland Park Kansas
I do not so i would be purchasing a new pinning kit if that is the consensus.
OR
Would it be possible to install the new balancer, then align the guide to the current location and re-drill making sure to only remove material from the new balancer... Seems like that would be hard to pull off just right.
OR
Would it be possible to install the new balancer, then align the guide to the current location and re-drill making sure to only remove material from the new balancer... Seems like that would be hard to pull off just right.
Last edited by ezstreet; Jun 6, 2016 at 11:34 PM.
Instructor
Joined: Dec 2007
Posts: 231
Likes: 10
From: NH
I have installed a new aftermarket balancer after pinning the stock one
Just install as normal use the drill guide again and redrill just drill slow and keep the drill from walking and it will be fine if the hole winds up a bit loose no worries, I back filled with red loctite and it is fine the pin only keeps the balancer from slipping it does not need much force to do this remember these things stock are only press fit and then the bolt holds it on.
I lost the stock balancer on track then replaced and pinned it and then the ring slipped on the new one in just a few races the current balancer has been on the car for 4 years of VERY hard use. NO ISSUES!!!
I know there will be some purest that say you cannot this but I have worked on drag and road race cars for 35 + years and I have NEVER had a crank or snout failure....
Just install as normal use the drill guide again and redrill just drill slow and keep the drill from walking and it will be fine if the hole winds up a bit loose no worries, I back filled with red loctite and it is fine the pin only keeps the balancer from slipping it does not need much force to do this remember these things stock are only press fit and then the bolt holds it on.
I lost the stock balancer on track then replaced and pinned it and then the ring slipped on the new one in just a few races the current balancer has been on the car for 4 years of VERY hard use. NO ISSUES!!!
I know there will be some purest that say you cannot this but I have worked on drag and road race cars for 35 + years and I have NEVER had a crank or snout failure....
Last edited by 555ss; Jun 7, 2016 at 06:49 AM.
Racer
Joined: Jul 2013
Posts: 450
Likes: 65
Does the bolt and washer cover the pin so it can't come out? If so you might be able to redrill the hole in the original location and have it work even if the hole is slightly oversize.
the issue is:
1. Aligning the drill guide over the original hole. Any misalignment will cause the hole to be oversize and/or oval.
2. Drilling a straight hole. The drill bit will walk due to the partial hole. Think interrupted cut, the bit will tend to drift toward the open space and away from the metal to be drilled.
Both of these issues can be addressed with the proper equipment. I would mill a spare pin, removing half of the material, and use that to align the drill guide. The milled end of the pin would fit into the partial hole and the un-milled end would align the guide. Use a shorter "screw length" drill bit to drill the hole. They are stiffer and tend to drill straighter than the standard "jobber length" bits.
Still easier to just drill a new hole opposite the first. It WILL be stronger than trying to re-use the original hole. Do which ever you are comfortable with.
the issue is:
1. Aligning the drill guide over the original hole. Any misalignment will cause the hole to be oversize and/or oval.
2. Drilling a straight hole. The drill bit will walk due to the partial hole. Think interrupted cut, the bit will tend to drift toward the open space and away from the metal to be drilled.
Both of these issues can be addressed with the proper equipment. I would mill a spare pin, removing half of the material, and use that to align the drill guide. The milled end of the pin would fit into the partial hole and the un-milled end would align the guide. Use a shorter "screw length" drill bit to drill the hole. They are stiffer and tend to drill straighter than the standard "jobber length" bits.
Still easier to just drill a new hole opposite the first. It WILL be stronger than trying to re-use the original hole. Do which ever you are comfortable with.
