The Cal-look Lounge

Cal-look/High Performance => Pure racing => Topic started by: Jon on January 04, 2011, 23:08:22 pm



Title: Saving a crankshaft
Post by: Jon on January 04, 2011, 23:08:22 pm
I have this eighties crank marked BCB, its in perfect shape (78.4). But it had a severe case of loose flywheel fever some years ago, this have made the dowel holes rough and also the mating surface for the flywheel is pitted. I have a friend that have the skills to weld it back up and re grind it, but he asked me to find out what kind of welding rods to use. Can anyone help with this?


Title: Re: Saving a crankshaft
Post by: DKK Ted on January 05, 2011, 00:17:56 am
There is high end crank shop here in the states. It's in La Mirada, Ca. Phone number is 714-523-0321. Being your in Norway, they should be able to answer your question, you not takeing customers away. They have done work for me and a repair, came out like new, never knew what happen. Good luck!

Ted


Title: Re: Saving a crankshaft
Post by: ugly duckling on January 05, 2011, 04:43:31 am
let see some close up,s of the damedge. maybe not totally necessary to weld. maybe a basic butt grind will do . .UD.


Title: Re: Saving a crankshaft
Post by: Neil Davies on January 05, 2011, 10:01:10 am
I've got a damaged crank too, 82mm CB if I remember correctly, spat the Berg Equaliser pulley off and damaged the woodruff key slot. Also damaged the end of the case. I'm thinking that a machine fit sand seal will probably sort the case out, but I'd be interested to know more about the repair on the crank if you find out JHU!


Title: Re: Saving a crankshaft
Post by: Fastbrit on January 05, 2011, 10:04:05 am
Neil, go to the Autosports show next week at the NEC (Friday to Sunday) and you'll find several companies in the trade/engineering section who can repair cranks...


Title: Re: Saving a crankshaft
Post by: Torben Alstrup on January 05, 2011, 11:46:34 am
Iīm with Jeff. A butt grind and 11/32" dowels may do the trick, if the damage is not too severe.

The repair of a wodruff key slot is another story. I have sometimes used chemical steel to fix some minor damage. But donīt know if it would hold on the pull side of a woodruff key.
T


Title: Re: Saving a crankshaft
Post by: Jon on January 05, 2011, 12:58:57 pm
Thanks Racecraf, I will give them a call.

I think it would clean up the flywheel end with 1mm of grinding. But since I at the time used a Berg overachiever it completely busted the small end too... and THAT needs weld, looks more like a potato now :-[

Thanks guys!


Title: Re: Saving a crankshaft
Post by: RMS Boxer Service on January 05, 2011, 21:33:00 pm
Send Udo Becker an email with a picture of the damage. He repaired a stroker WBX
crank for me last year that looked pretty awfull after the flywheel bolts snaped.


/Rolf


Title: Re: Saving a crankshaft
Post by: Jon on January 06, 2011, 10:57:20 am
There is high end crank shop here in the states. It's in La Mirada, Ca. Phone number is 714-523-0321. B

I called these guys last night, and they were very helpful, they guessed the material to be 4340 and told me to ask a welding supplier here in Norway.
So I'm at least some of the way closer to solving this.

Can anyone shed some light how these cranks are hardened and so on... I suspect it to be only surface hardened, so I would have to get it re hardened?
Will it get brittle from the welding?


Title: Re: Saving a crankshaft
Post by: flatfire on January 06, 2011, 11:45:01 am
I've got a damaged crank too, 82mm CB if I remember correctly, spat the Berg Equaliser pulley off and damaged the woodruff key slot. Also damaged the end of the case. I'm thinking that a machine fit sand seal will probably sort the case out, but I'd be interested to know more about the repair on the crank if you find out JHU!

How bad is the keyway on the crank? If you have lost your tolerance on the sides get the keyway cut slightly larger and use a stepped key. Your local engine recon guy should be able to fix this. If you have the skills buy a bit of keysteel and file a new key.


Title: Re: Saving a crankshaft
Post by: Udo on January 06, 2011, 12:50:12 pm
There is high end crank shop here in the states. It's in La Mirada, Ca. Phone number is 714-523-0321. B

I called these guys last night, and they were very helpful, they guessed the material to be 4340 and told me to ask a welding supplier here in Norway.
So I'm at least some of the way closer to solving this.

Can anyone shed some light how these cranks are hardened and so on... I suspect it to be only surface hardened, so I would have to get it re hardened?
Will it get brittle from the welding?

Tell the welded that you can bore the material after the welding.. I would not harden the crank only because of the flywheel surface

Udo


Title: Re: Saving a crankshaft
Post by: nicolas on January 06, 2011, 14:15:28 pm
make sure it is sandblasted and CLEAN, all impurities will make it weaker.