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Discussion Starter · #1 ·
Hi all, during the evaluating of this block to pair with a crank to decide destination of use, performance, normal use, "1000miles and die/discard"... I found this funny things in this block while measurement.
First - "almost weird" solution on position 4:

Automotive tire Wood Rim Gas Bicycle part
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Tire Wheel Automotive tire Light Synthetic rubber
Automotive tire Automotive design Motor vehicle Rim Bumper

Second - "strange" measurement of bores (second is square):
1 - 63,22 - 63,205
2 - 67,00 - 66,99 (if you see well there is a straight mark almonst 10mm under the stud in the direction of the crank axle, it define a bulge in the aluminium)
3 - 63,19 - 63,21
4 - 63,21 - 63,19
5 - 63,20 - 63,215
Workshop manual say main bores are 63,657 - 63,676 mm...
If you do the reverse math you can find an average 1,625 mm bearing thickness...
Double mmmhhh

About crank.
Marked in red was regrounded/polished, ultrasonic cleaned and has (second is square):
1 - 59,95 - same
2 - 59,95 - same
3 - 59,96 - same
4 - 59,95 - same
5 - 59,96 - same
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Automotive tire Tire Wood Rim Bumper

What do you will do with this?
Performance, normal use, "1000miles and die/discard"?


Next step will be the studs evaluation.

929 Posts
Hi, the motor has had a bearing problem or lack of oil at #4 main bearing. The bearing will have been very hot almost to seizing and has been moving inside the tunnel causing damage. Somebody has used another engine make of bearing
to machine the bore larger to clean the damage.
If all bearing fits/tunnels are correct sizing for the bearing and crankshaft, this can be a useful method to re-use a damaged block when replacements are difficult. You need a good engineer machine works to asses this for you.
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