[cv70chall]

Managed to get the pistons in, upgraded cam and timing chain/ gears, so we're on our way! Heads have been restored and will be mated to it next week.
We're getting close!!

[fbernard]

At this exact point in the rebuild, I have a question :
Did you check whether the two #3 bearing halves (the bearings with the thrust surface) were *exactly* aligned?
The #3 mains should be torqued last, and with the crank pushed forward to ensure the bearing halves are aligned.
You should have less than 0.010" of crankshaft end play (between .004 and .007 is normal)

If the bearings are not exactly aligned, the oil film can be wiped off by one bearing half, which end up with the destruction of the crank (a friend of mine has .65" of end play, on an engine with less than 5000 miles).

So, if you haven't done it already, loosen the #3 mains, push the crank forward with a prybar or big screwdriver, and torque the #3 mains while pushing the crank.

Here are the pics :

[cv70chall]

I'll double check all of that! Thanks!

[fbernard]

I'll double check all of that! Thanks!

Next month I'll be yanking my engine/trans out of the car for a transmission change, I'll check the engine too...

The bearings on my friend's engine all looked like they had 150K miles on them, the oil pump had seen better days, all the crank journals were scored, and we found filings in the oil pan.
This we couldn't explain until we saw the #3 bearing half, which had been ground by the crank thrust flange.

[dave-r]

I had the same thing but it was due to the torque converter ballooning.

[fbernard]

I had the same thing but it was due to the torque converter ballooning.

My friend bought a set of trans pressure gauges so that we can check if that may have been the culprit.
Do you have any pics of your ballooned converter?

[dave-r]

There was nothing much to see from the outside of the torque converter but the fluid that came out was chrome/silver rather than red.

The bearing fails due to pressure pushing the crank forward. I have heard this overlap theory scraping the oil off the surface but I don't completely believe it because if one face was further forward to the other it would soon wear down to the point where they were both equal. Then their wouldn't be a problem.

My bearing was worn down almost completely through the backing plate and the thrust surface of the crank was equally worn. If an initial slight step in the bearing did that then I have trouble understanding why.