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I think my machine shop screwed me up. They put mallory metal in my *BALANCER*!!

10K views 15 replies 10 participants last post by  RPM  
#1 ·
(Also posted on the corral)

Has anyone *ever* heard of this? They added about 10 grams of metal to my damper when they balanced my engine. I noticed that my balancer was looking kind of bad a few weeks ago so I ordered a new SFI model. When I got the other one off I noticed that there was metal in it from the balance job.

I took both of the dampers back to the shop that did it to get him to make them the same but he said that he'd need to rebalance the whole thing. He can't just make the two balancers alike.

Anyone know how to get this new balancer to match what he did so I don't have to tear down my whole engine? That would be a significant emotional event for me! Much pulling of hair and gnashing of teeth!
 
#2 ·
Here's a couple of photos of what they did.

http://www.keydatatech.com/damperfront.JPG

http://www.keydatatech.com/damperback.JPG

As you can see the weight isn't on the big end of the damper and it's spread out in two locations. If it was all the way to the outside edge and at the center of the weight it would be a very large amount. As it is, because of it's location, I don't think it wouldn't equate to the same amount of weight if it was on a crank throw.

Any machinists (or anyone else for that matter) here that can tell me I'm still within factory tolerances (5-8 gramsw I think?). Can I just put on an aftermarket damper and be okay as far as crank life goes? I have that SFI damper too so I could just throw it on if it would help...

At this point I don't plan on turning any high RPMs.

<font size=-1>[ This Message was edited by: tateg on 9/27/03 7:07am ]</font>
 
#3 ·
It should work just fine, it's just not proper form to weight the harmonic dampner during the balancing process... as it makes the dampner impossible to replace at a later date, and keep the balance in check.

They just got lazy and installed weight in the dampner's 'pre-drilled' holes instead of drilling new ones in the crank. They probably got it within spec by adding that weight... but it sounds like you've got some lazy, and/or sloppy machinists.

Good Luck!
 
#6 ·
The rubber's looking kind of sorry. It's starting to stick out. It's from an '82 mustang so it's 21 years old.

I was hoping to replace it with a new one. I was thinking that if I removed the weight from the predrilled holes and replaced into the same holes in the replacement damper I'd come close to being right. Closer than just slapping a new one on there.
 
#7 ·
If your car is not a full time drag racer, save your money and return the SFI balancer. Send your old balancer to the damper doctor at http://members.aol.com/damperdoc/dampers.html.

First, give him a call and tell him about the heavy metal and he may be able to refurbish it for you. He uses a polyurethane instead of rubber for the damper. He does heat the damper to stress relieve it so there may be an issue there.
 
#8 ·
I can't say I've ever heard of anyone putting metal onto a balancer?
Image
In fact if it's an SFI balancer it would void it's SFI rating and would be illegal for NHRA and thusly most if not all forms of organized racing.

<font size=-1>[ This Message was edited by: 1 Bad 88 GT on 9/28/03 2:06pm ]</font>
 
#9 ·
I think that's right. They voided the SFI approval by adding weight to it. I would return it to the shop that added the weight and make sure they make it right with you. If they don't...well you can deal with that one however you'd like...but I know how I'd do it.
 
#10 ·
They didn't add any weight to an SFI balancer, they added it to an OEM that I was replacing with an SFI. Now I have an SFI damper I can't use because my engine will be out of balance.

I'm going to take the advice to have it rebuile by the Damper Doc. I'm just waiting on him to respond to my emailed questions.
 
#12 ·
As much as I first thought the Machinist was lazy....I deleted that reply...for on an EXTERNALLY balanced engine, this is the typical area along with the flywheel/flexplate, you add or subtract weight to balance the assembly.
 
#13 ·
On 2003-09-29 09:19, Just Strokin wrote:
As much as I first thought the Machinist was lazy....I deleted that reply...for on an EXTERNALLY balanced engine, this is the typical area along with the flywheel/flexplate, you add or subtract weight to balance the assembly.
HUH?? This is normal? So he didn't screw up? I just got unlucky?

The guy that did the job commented that he hated to balance this way because every time he externally balanced an engine it was a gamble.
 
#14 ·
Will not say unlucky or anything, but an externally balanced engine means just that.....the weight used to balance it is outside the engine, i.e., the harmonic balancer and the flywheel/flexplate. The problem I see with an exteranally balance engine is if the balancer gernades or the outer ring slips, the balance is gone and will have to rebalanced as a unit (crank with bob weights, balancer and flexplate/flywheel) in most all cases.
 
#15 ·
When I had my motor built by DSS they did the same thing-they added weight to the damper, as it's almost impossible to add weight to a flexplate. I had to send the damper I planned on using to DSS so they could balance the rotating assembly as a complete unit.

You'll end up having to have the rotating assembly on your motor rebalanced if you wish to use the SFI Damper.