BSA B31 Restoration Part 3 Crank - Big End & Main Bearings

In this video I show how I rebuilt the crank for the BSA including replacing big end and main bearings. I also had to make a special tool to hold the crank. Checked and adjusting run out.
As always this how I did it, not a how to... always refer to your own workshop manual.

[@thomaswykes3647]

I took my crankshaft to Richard at Coltec Racing in Suffolk. He did an excellent job and reasonably priced. I highly recommend him.

[@sugengdiablo6925]

Nice work..i just wanna said why you didn't use hidraulic press for the crankshaft bearing till you write it on the video 😅.thanks for sharing sir.

[@nickbarber2080]

Also put the mains on before putting the crankshaft back together so that the act of pressing the main bearings on doesn't knock the run-out out of true....setting the run-out becomes the last task on the crankshaft before fitting.

[@vintageenthusiast9615]

Thanks for filming this job, very interesting. Where did you buy the big end pin please?

[@InTheShedUK]

As far as I can remember I got it off eBay, a Hepolite one. I do know Feked.com also sell them.

[@patrickluthi5273]

Hello
I have a problem with my b31 crank. I replaced the big end pin and the outer race in the conecting rod.
Now my problem is that i can't put the conecting rod on my new roller bearings because it seems that the tollerances are to small. Have you ever had that problem?
Kind regards
Patrick

[@InTheShedUK]

Yes the tolerance is very small and is difficult to fit, you could try putting the con rod in the freezer for 24-48 hours. Failing that you may need to take the crank & con rod to an engineering firm to have the outer race ground to fit. The I/D of the outer race gets compressed when installed in the con rod.

[@johncrowley5612]

@@InTheShedUK Surely you would warm the conrod?- holes get bigger when heated, smaller when cooled.

[@InTheShedUK]

@@johncrowley5612 True, like fitting bearing into a casing, heat the casing, freeze the bearing... weird as heat causes expansion in all directions, so why does this work?
I've just read a Timken tech tips that said 'For a press fit, cool OR heat tapered roller bearings to aid in assembly or removal'
Physics master required to explain!

[@Cobra427Veight]

Wouldn't recommend grease as it doesn't dissolve, better to use Vaseline to hold your big end bearing rollers In place .

[@InTheShedUK]

Sort of depends on the grease, not all grease is equal... engine assembly grease is still a grease.
It's the thickener that doesn't dissolve (just melts with heat), grease can be anything from 70-97% oil & 3-30% thickener.. Vaseline is pure hydrocarbon so it should dissolve in theory, might try mixing some with oil to see what happens.
I did manage to do it without anything in the end, just took a while.