Rebuild Testing

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cannondale27 · #41 Post by **cannondale27** » Fri Jun 04, 2004 12:24 pm

The bearing has a race and seperate pin retaining rings on outside.Those retaining rings are beat up bad like needles tried to pke through.Race looks like new.

cannondale27 · #42 Post by **cannondale27** » Fri Jun 04, 2004 12:26 pm

Small galling

cannondale27 · #43 Post by **cannondale27** » Fri Jun 04, 2004 12:28 pm

Major Pitting

cannondale27 · #44 Post by **cannondale27** » Fri Jun 04, 2004 12:31 pm

Major grooves from those retaining rings on side of rod bearing.

Jammer72 · #45 Post by **Jammer72** » Fri Jun 04, 2004 12:53 pm

Looking at your pics I would lean towards number 3. Looks like tightening up the side clearance is causing a whole different issue.

NRath · #46 Post by **NRath** » Fri Jun 04, 2004 4:30 pm

I don't see how increasing the side clearance is going to help prevent the rod from twisting. I would expect the opposite. The tighter the side clearance, the less room there is for the rod to twist. The twist would be restrained by the washers, right? Which would, of course, start wearing the washers.
Unfortunately, I don't have much to offer on what the problem really is. I'd have to be looking at #4, but it seems unlikely it was a BAD bearing. Especially considering this is apparently a recurring problem. My first thought is that it flat out isn't a strong enough bearing, not capable of carrying the load it's seeing. This is reinforced by the fact that many of the 450's are what are dying. The 440's are lasting a lot longer.

I like your observations that it may not be an oiling problem, too. You can only tell that be looking at the parts, which I can't.

wistech · #47 Post by **wistech** » Fri Jun 04, 2004 7:30 pm

Hopefully your rod is still in good enough shape to check for distortion in the big end. Bearings like that should have a even wear pattern across the journal to.

cdrookie · #48 Post by **cdrookie** » Fri Jun 04, 2004 9:10 pm

does it say the bearing manufacturer on the race?

i think i remember winky saying something like they regrind the crank pin when they balance them to within .0004". that is a HUGE tolenance for a needle bearing. if you could mic the crank pin and get the bearing # maybe a bearing store could give you the bearing ID.

i think Nrath is right about the side clearance. more would make it worse. and lack of oil would create heat, and from the pics it doesn't look like it got hot.

could it maybe be a piston/wristpin issue? something could be slightly out of line thus putting undo stress and binding on the big end bearing? i don't know how far back these failurers date to but it seems like just recently(last few months) all the 450's are dropping dead. is everyone using the same pistons? bad production run? is anyone running a 450 without a winky crank?

cannondale27 · #49 Post by **cannondale27** » Fri Jun 04, 2004 10:00 pm

Okay there was no wear at all on wristpin.I think the tighter sideclearance could be a issue since with a tighter clearance if the piston is slightly cocked in bore AND the crank walks back and forth which we know it does this would either **** the rod or put alot of pressure onto thrust washers which arent designed for that much.With a bigger clearance the rod could just slide over.All really just theories but very possible.Combine that with the fact Cannondale made ALL the cranks with big clearance and the fact that my clearance grew to almost same as stock crank and it isnt so easy to dissmiss.

cannondale27 · #50 Post by **cannondale27** » Fri Jun 04, 2004 10:04 pm

Wistech the journal is pretty shot but the race of bearing is like new.So we should be able to get good measurements off that.