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In other words, with a diameter of 49.00mm cr-journal, the bearing clearance of the connecting rods will be 0.05mm.

According to Volvo's book, the diameter of the 0.25mm undersized main bearing journal is 63.197-63.210mm, so at least with NPR/NE bearings the clearance would be 0.07-0.08mm.

The end result is that with a 63.22mm journal the clearance would be 0.05-0.06mm in my own block. That is, when the crank goes for grinding, the wish is a 49.00mm rod journal, which is well within Volvo's tolerance, and a 63.22mm main bearing journal, which is 0.01mm larger than the upper limit of Volvo's tolerance of 0.25mm undersize journal.

Copy paste with google translator so there may be some odd things.

As long as you mike the crank and the inside bearing diameter with the same mike you are OK.
But don´t go under .05. .07 is just fine. .05-.07.

Erland

Erland Cox skrev: ↑tis dec 20, 2022 12:49 pm As long as you mike the crank and the inside bearing diameter with the same mike you are OK.
But don´t go under .05. .07 is just fine. .05-.07.

Erland

Yes if the company wich is grinding the crank can grind it to dimensions what i asked for the clearances should be between 0.05-0.06mm.
Need to verify that and measure again just in case when get vrank back from grinding.

Thanks Erland for your answers.

Erland Cox skrev: ↑lör okt 15, 2022 10:42 am If you grind a crank to 85mm you must relieve the 4 sharp cut outs in the number 1 and 4 rod throw.
Make sure that the bottom corner is rounded instead of sharp.
Take the same amount of metal from number 2 and 3 beföre balancing.

Erland

Now i understand this,misumderstood before

Should i just make corners rounded or blend whole cutout and take same amount off 2&3 before balancing?

E: And should i cut some oil escaping grooves to rod big ends? Rods are with wide big end and using B2xx bearings so rod is steered from crank.

You can just round the corners, that should be enough.
I do not think that you need groves in the rods as long as you have some side play. 0,25mm should be enough.

Erland

Erland Cox skrev: ↑tor apr 06, 2023 9:38 pm You can just round the corners, that should be enough.
I do not think that you need groves in the rods as long as you have some side play. 0,25mm should be enough.

Erland

Okay and thanks again