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DRACO A5OG DRACO A5OG is offline
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Quote:
Originally Posted by bdonally View Post
Not magnetic



Actually 180K kms, so 110K miles, maybe 20K or so of that track time.
When you found the thrust and IMS bearings shot, how were the rods and mains?
And did the IMS and thrust wearing down to the copper damage the crank or IMS?
As posted above, it might be the Aluminum IMS gear wear probably due to the IMS bearings wearing down, causing slop and smashing into the other harder gear ergo the shavings. Won't really know until you split it to confirm.

The other thing could be spun crank bearings, hope not. Probably not.

110K, not bad, but as you know, track time wears things a bit faster than street use. Per Bruce Anderson engine should be rebuilt around 120K miles so you are probably there.

As far as the Crank and IMS shafts, I was lucky and they were still in spec so I used Standard Spec bearing replacements. I did have both checked for cracks and trueness, measured then polished. I did the IMS for extra measure. Gears looked good.

The worn bearings to copper did not harm the shafts as the shafts are considerably harder, The harm comes when metal shaving/dirt gets in between the worn bearings and shafts i.e. scoring or marring or worse gouging.

I am sure other pro builders will chime in but this is just my take on my rebuild experience and observations.

Best wishes Brother,

J
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Old 11-01-2017, 01:04 AM
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