Crank / Balancer interface worn - anybody else seen this? Fix?

[yellowltd]

The radial elongated hole in the vibration damper is normal though does appear light damage in the hole tangential direction from the movement (dowel is a locator only), the gear can be replaced for about $100 or through surface grinding (cheaper) or you may be able to lap it yourself on a surface plate a fine sandpaper after you remove the dowel pin but there may need to be too much material removal to clean it up adequately its hard to tell from pic. You would want to address the surface on the vibration damper as well so you have a good uniform surface for the friction surface as that's how the load is transferred. I would take it to a machine shop and have them fix it as new ones are very expensive like $1,000

I do recall noticing the elongated shape of the hole on an undamaged balancer, but yeah this hole is definitely a little damaged. I'm very hesitant to attempt to recondition that surface on my own, on either part, unfortunately. The surface looks scored but it's smooth to the touch. I think the marks might actually be from heat. I do have a bunch of parts at a local machine shop for cleaning and measuring but they don't have a mill so they can't chuck it up and take a quarter thou off the top. I need to find a new shop.

[yellowltd]

Dang, I had to check you on this and you're right. Wow.
https://www.ecstuning.com/b-genuine-...waAsXtEALw_wcB

It's crazy. They used to be $750~ish for quite a while. Right now the VAC damper is technically cheaper, which hurts my soul. Ross (in Australia) also makes a damper for about $675 shipped.

[digger]

I do recall noticing the elongated shape of the hole on an undamaged balancer, but yeah this hole is definitely a little damaged. I'm very hesitant to attempt to recondition that surface on my own, on either part, unfortunately. The surface looks scored but it's smooth to the touch. I think the marks might actually be from heat. I do have a bunch of parts at a local machine shop for cleaning and measuring but they don't have a mill so they can't chuck it up and take a quarter thou off the top. I need to find a new shop.

would be a fretting type action (relative movement back and forth), there is probably a bit of stick slip going on due the angular torque pulses the damper is trying to absorb. Is the damper in good condition from a rubber perspective if its worn out the torque being transferred across the interface can get extremely high (i.e. enough to snap cranks due to fatigue)

[cobra]

If you find a shop with a lathe they could carefully center it and then take a skim cut like you're suggesting just to clean up the surface. It will probably take 30 minutes to properly indicate and 20 seconds of cutting!

I wonder if it's worth the effort?

[sapote]

It looks like it was run without the dowel pin for a period of time. I'm not 100% certain but I don't think you'd get those long scoring arcs with only a little bit of play in the dowel pin hole.

It was held by 4 long bolts, and so it could not spin around even without the dowel pin. The massive damper just oscillated back and forth with a loose dowel and causing the marred surfaces.

[heinzboehmer]

Curious - do you have a single mass flywheel?



Me too! This fixes half of my problem. :-D

Nope, stock flywheel and clutch for the entire life of the car (125k mi).

[jbfrancis3]

It was held by 4 long bolts, and so it could not spin around even without the dowel pin. The massive damper just oscillated back and forth with a loose dowel and causing the marred surfaces.

Duh, good point…🙄