Is this normal rotor bearing wear? And, rear counterweight question...
 

1) I'm looking at my front rotor. On the gear side, under all three faces, the bearing is worn through to the copper. Is this normal wear? The rear rotor bearing appears to be fine.

2) The rear stationary gear has wear on the side nearest the bottom of the motor. Is that normal? The front stationary gear looks ok.

Car is an '88 10AE, with 70,000 miles, stock Series V turbo (7.5psi), K&N, TB mod, and full exhaust. Dyno'ed 192rwhp. Motor is apart for water seals (and some minor upgrades;). All housings are good. I'm replacing both stationary gears (bearings too, obviously), and both rotor bearings.

3) Last, does anyone know if the '88 and '89 rear counterweights are identical? I assume they are not, but I can't objectively verify it. When I installed an aluminum flywheel in '99, I switched to the rear counterweight from an auto-trans car. I'd like to verify that I have a counterweight from the correct year, without paying through the nose to have the whole assembly balanced.

TIA, and happy rotoring.

Steve C.
- happy to be working on his little project again:)

The counterwieghts are different...and picture would be nice for the bearings. CJ

Bearings will usually show some coppery parts, but not like the whole thing...

Ya if you can see a pretty good sized area of wear where it is worn down into the copper then it is time for a new bearing. I would replace it if you can see any more than just say a 1/4 inch wide "spot".
Hey pp13bnos: I have a question on counterweights also. I am using a front counter wight that is the 180 degree spread one. I am not sure what the counter weight is realy out of, probably out of a REPU or something, This is in a 12a motor, So i got a light steel fly wheel, and i got a rear auto tranny counter weight out of what i am asuming is a 1st gen car. The motor seems to be slightly out of balance or something so this is the first question to pop into my mind. I realy dont feel like pulling the motor out to change the front weight, so which rear will work with the front 180? And also was their any variations in the 1st gens as far as counter wight set ups?

CJG

There where tons of differnt counter weights. I think that 79-80 where the same, then changed from 81-83, then again for the "N" rotors of 84-85. I don't however know the different front vs rear CW that are compatiable with the 13Bs. Probably have to shoot Rob@Pineapple an e-mail.

Long before i knew anything, i put a 1st gen auto counter wieght into one of my old n/a 90s. Make a long story short, the motor had a small vibration. The motor finally ended up in Robs shop about 25k miles later. It was still running fine, but needed it for a good core engine in my current 90. Anyways, the wear pattern was not good at all. If i remeber correctly, the entire outside edge (facing the rear of the motor) was copper..inside was fine. Rob said it was probably out of balance or something.... CJ

ya i guess i will, cus it seemed when i ran the motor last it just wasent as smooth as it should have been. And ya i am using a set of the "N" 12a rotors. so i guess i will e mail him. does he check his e mail often?

CJG

Sorry, no pics, the rotors are in boxes on their way to Mandeville AutoTech. I guess my "boiled-down" question is, would the wrong rear counterweight cause an odd bearing wear pattern of the type I described, or is that a normal wear pattern for a TII w/ 70k miles?

Aside from the water seal problem, the motor made a noise like heat sheilding rattling, under light load going from on-throttle to off-throttle. FWIW, my oil pump drive chain was out of spec too, so that could have been the noise. Anyway, thanks for the input. Anyone with knowledge of "normal" bearing wear, please feel free to add more.

All best,
Steve C.

Some additional info: A local builder suggests that the odd wear pattern matches ones he has seen on cars with out-of-spec e-shafts. I'll be measuring....
s

It is normal to see a copper line on the bearings but it I don't know if yours are bad or not without seeing them. The line is even there on new bearings. The bearings were made from a flat piece of steel and then pressed into their round shape. The copper line you see is where both ends of the bearings are chamferred together and ground smooth during the manufacturing process.

The counterweights are different between '88 and '89. You can't tell the difference by looking at them. The weight differs so little that it takes a postal scale to see the difference in weight. Don't try to interchange them though. That small difference in weight is distributed in a way that your engine will violently shake if the wrong one is used.