Crankshaft bearing sizing

[laseron]

I've been rebuilding my 89 FJ with 100,000 miles on the clock. I'm about to replace the crank main bearings, and have a question. I've done the procedure described in the shop manual, subtracting the journal numbers stamped on the crank webbing from the numbers scribed onto the rear of the crankcase. The results seem straightforward, but there seems no way to account for crank journal wear, which would increase clearance values. So the new bearings I installed and torqued to 17 foot pounds are showing clearances of around .076 mm on the Plastigauge scale. Much too loose, as specs call for .020 to .044 mm. Any help or suggestions would be really appreciated.

I measured the clearances with both crank journals and bearings dry, as it seems lube on their surfaces would give a false reading.

Thanks,
Ron

[Old Rider]

Hi did you take a measure with the old bearingshells ?
What plastigage are you using?
I'm asking about the plastigage because i found that when i did my engine i found that the green plastigage i used was more difficult to read
the scale than the red british made i tried later.
You can read about it here page 7 and 8 :http://www.fjowners.com/index.php?topic=18143.105
I guess you got the numbers on the back of the enginecase right the last number is journal 1 and the first number stamped on the crank is
corresponding to that

[laseron]

I measured the clearances with the old bearings in place, and got roughly the same readings as with the new ones. I'll try the british red plastigauge and see what I get. And yes, I saw from the manual that the journal numbers on the case are marked in reverse sequence.
Thanks for the thread- it's quite a read!

Ron

[Old Rider]

I measured the clearances with the old bearings in place, and got roughly the same readings as with the new ones. I'll try the british red plastigauge and see what I get. And yes, I saw from the manual that the journal numbers on the case are marked in reverse sequence.
Thanks for the thread- it's quite a read!

Ron

okay i also found that when  taking the measurements in a freezing cold environment the clearance was larger.Later when re measured in room temperature the clearance was smaller. I tip is to use a toothpick to add a tiny tiny dab of grease at the outer sides of the journals to make the plastigage strip stay in place and a little silicone spray on the bearingshell where the strip is going to get crushed.

Rolf