Looking for ATI harmonic balancer users

[Jeff G 78]

I thought the same thing about the red Loctite, but the experts say it comes apart without heat.  It only takes a few drops to keep everything tight.  I would have gone with blue had I not read that the red comes apart well.

[Patcon]

A serpentine belt damper is interesting too and opens up a lot of other options

[Zed Head]

There's a ton of opinions out there.  Sometimes the  methods used are really just making up for failings in other areas.  Proper fitment is the key for dampers, which the various instructions out there go in to detail about.

Even if thread locker is used, it too has to be used properly.  Loctite on oily threads isn't worth much.  So, it's not just a more is better scenario.  It's the details.  Red Loctite on a sloppy fit will probably fail also.  Some of these guys go "full red" Loctite, some don't even use it.  Why not just tack it on with a MIG?

One surface that's not mentioned much is the flat mating surfaces, where the clamping actually happens.  Not the bore.  Those surfaces need to be clean and flat and parallel so that no distortions are induced by the bolt.  It's a simple looking part with lots of complexity.

https://sdparts.com/attachment/306380-Installation Instructions

http://harmonicdampers.com/downloads/pdf/tech/BHJ_DamperSteelInstallPress.pdf

http://www.atiracing.com/instructions/Super-Damper.pdf

https://en.wikipedia.org/wiki/Thread-locking_fluid

 

[madkaw]

I’d locktite the next stock bolt on the next rebuilt stock damper and call it good. Your not running forged pistons and running 9k rpms are you? If the problem was a bolt coming loose, lesson learned . 

I do plan on running some kind of fancy damper on my Rebello- if I ever see it- but I think I transplant my L24 damper( rebuilt) on to my L28 build. And make sure I locktite it! 

 

[Jeff G 78]

Not running super high RPM, but it does run 5000-7000 for hours at a time. Races range from 7 hours to 25 hours. Once a race starts, there is no time to check over the car. That’s why most failures are pretty ugly. Had this been a street car, I would have felt a vibration or a slight miss and looked into it. In an endurance race, if it’s turning laps, all is good. Once it stops turning laps, there is a mad scramble to diagnose and hopefully get back on track. An average race costs $3000 to $4000 for prep, entry fees, tow rig fuel, and consumables. Luckily that is split between 3-4 teammates but when something breaks and you go home early, most of the weekend costs are sunk and you are left with nothing but a parts bill and a lot of future garage time. 

I appreciate all the help. 

[madkaw]

So was the damper a rebuilt one? It’s hard to tell from the pic. Could a out of balance damper help work a bolt loose? 

I know the Damper Doc bragged about how his rebuilds were good for 10k rpm and 400 ft lbs of torque. Never tested that , but a fresh bond on the damper makes me feel good about revving it out. 

This does make me research more about loose crank pulley bolts. 

[Jeff G 78]

I feel better about the situation. Today, I filed and polished the galling and metal transfer off the snout enough that the gears will go on and off properly. It actually looks fairly decent other than one depression left from the rocking damper. 

Now to have the machine shop magnaflux the crank and fit a new damper. 

Still looking for bolt recommendations. 

[madkaw]

RUN IT!

[Jeff G 78]

I thought about not even tearing the bottom end apart, but I’d hate to get this far only to have micro cracks in the crank. ?

[Patcon]

12 minutes ago, Jeff G 78 said:

I thought about not even tearing the bottom end apart, but I’d hate to get this far only to have micro cracks in the crank. ?

On the bolt, what is the size and thread? I might match it that way. Order what you know you need in an 8.8 or stronger...

[gundee]

3 hours ago, Jeff G 78 said:

I thought about not even tearing the bottom end apart, but I’d hate to get this far only to have micro cracks in the crank. ?

If this were a street car I would run it as is. Being a race engine I would replace the crank completely if it were mine.

I would not risk a expensive damper on that crank. IMO.

[jonathanrussell]

Here is an alternate approach. Not saying it is the best.

Don't discount the fact that you have run hundreds or maybe thousands of hours on the track and haven't had a bolt come loose. Maybe you have your damper rebuilt, install it with a new factory bolt, torque it to spec, and re-torque after every race or so.

Just another perspective.

Wish you the best. Always enjoy reading your posts.