Bearing Tolerances... Advice Needed

[Simon-S14]

got my crank linished and fitted with crank collar and some new ACL mains bearings.. anyway just checking the clearances with plastigauge and they seem to be all over the shop! they measure out to be the following ( i checked 4 times, also swapping bearings around with each other)

1: 0.050 2 thou

2: 0.050 2 thou

3: 0.250 1 thou

4: 0.038 1.5 thou

5: 0.038 1.5 thou

6: 0.050 2 thou

advice needed

[GTR1993]

Measure the crank with a real mic, use a dial bore indicator on the mains, then you will know where the problem is. Worst case you will have to get the crank journals sized correctly then get the block line bored.

[The Dan]

got my crank linished and fitted with crank collar and some new ACL mains bearings.. anyway just checking the clearances with plastigauge and they seem to be all over the shop! they measure out to be the following ( i checked 4 times, also swapping bearings around with each other)

1: 0.050 2 thou

2: 0.050 2 thou

3: 0.250 1 thou

4: 0.038 1.5 thou

5: 0.038 1.5 thou

6: 0.050 2 thou

advice needed

What is the main tunnel size measurement? And did you check the girdle for straigtness or fretting on the parting pace? Is everything clean etc?

[Simon-S14]

getting an inside mic tomorrow to measure the tunnel sizes and then measure the crank mains. i didnt check the girdle.. and yeah everythings clean.

[r33_racer]

If you have an external mic, I recommend a dial bore gauge. Get a longer one if possible so you can get into the centre main, unless you can get one that has a small head on it so it fits between the mains with enough room to rock.

If you dont have an external mic...then I'd recommend that too.