Welding on a crank?

[matrox02]

Hi guys, I have an 1990 RMX250 L that is near on impossible to find a replacement crank for does anyone here know if its possible for an engineer to weld on said crank to fill in a flat spot on a crank shaft flywheel shaft and then have them turn it back down to suit the rest of the shafts shape? or would anyone say to leave it as is??

I would post a picture but the picture i have of it at the moment isnt too great and doesnt really show the issue

anyone know otherwise? anyone know of a decent guy who can do the work in auckland too??

[unstuck]

Would a speedy sleeve not work?

[skippa1]

Hi guys, I have an 1990 RMX250 L that is near on impossible to find a replacement crank for does anyone here know if its possible for an engineer to weld on said crank to fill in a flat spot on a crank shaft flywheel shaft and then have them turn it back down to suit the rest of the shafts shape? or would anyone say to leave it as is??

I would post a picture but the picture i have of it at the moment isnt too great and doesnt really show the issue

anyone know otherwise? anyone know of a decent guy who can do the work in auckland too??

Welding on a crank is possible, but not advisable due to heat distortion/alteration of the hardness/brittleness of the metal. It can be successfully done though. Machining likewise. Cost is a whole different ball game. You need engineers that know what they are doing, not think they know what they are doing.

[Akzle]

that sounds entirely possible

[matrox02]

Would a speedy sleeve not work?

From what iv seen of the speedy sleeves no, if you look at the link, the flywheel goes on after part 14, the flywheel is on a tapered shaft

http://www.partzilla.com/parts/searc...%29/parts.html

From what i know the speedy sleeve only works on non tapered shafts, though, that may be an idea to make a sleeve to fit? only problem is i would need the woodruf key to be in the right place and the only other problem is that it would weaken the shaft itself

[matrox02]

Welding on a crank is possible, but not advisable due to heat distortion/alteration of the hardness/brittleness of the metal. It can be successfully done though. Machining likewise. Cost is a whole different ball game. You need engineers that know what they are doing, not think they know what they are doing.

yeah.. thats my problem so far, No one ( engineers ) has been able to give me a definite answer, Im thinking maybe I should glob on high temp solder and then just smooth it out just to get the shape and balance back somewhat?? its going to be held in by a flywheel anyways, so i dont think it will just "fall out" or anything?

[skippa1]

yeah.. thats my problem so far, No one ( engineers ) has been able to give me a definite answer, Im thinking maybe I should glob on high temp solder and then just smooth it out just to get the shape and balance back somewhat?? its going to be held in by a flywheel anyways, so i dont think it will just "fall out" or anything?

Whack a good pic up, hard to imagine the extent. There are engineering companies that have the expertise on staff up your way. I may be able to point you in the right direction. Pics first

[Haggis2]

Engine reconditioner?

[matrox02]

Whack a good pic up, hard to imagine the extent. There are engineering companies that have the expertise on staff up your way. I may be able to point you in the right direction. Pics first

cheers, i will do, sadly.. Im at work till 3pm so ill have to try to remember to upload a pic, I though also thought that maybe i should just JB weld the prick and just reshape the jbweld Hmm, I also needa m12 x1.25 die to chase the threads

[AllanB]

Bloke in CHCH welds all types of engine parts old and new. Highly likely he has welded numerous cranks.

[unstuck]

I used knead it steel on a crankshaft on a v6 maxima about a year ago, still going strong. The key way for the crankshaft pulley had broken away on one side, and this seemed like the simplest solution at the time to get the car back to gore. It does some big kms too and no dramas yet.

[jonbuoy]

Don't see why not, cranks get built up with weld for increasing the stroke all the time. Maybe find a performance/ classic car engine reconditioner.

[matrox02]

I used knead it steel on a crankshaft on a v6 maxima about a year ago, still going strong. The key way for the crankshaft pulley had broken away on one side, and this seemed like the simplest solution at the time to get the car back to gore. It does some big kms too and no dramas yet.

That right there i think is my ticket to Success, Ill buy a tube of that and order my seals and bearings and gaskets sooner than i thought!

[DrunkenMistake]

get it metal sprayed and turned back to whatever it needs to be?

[Grumph]

metal spraying gets the shaft too hot - distortion is what you want to avoid.

From the sound of things it's on the taper - broken out the keyway ?

The crank will have to be split as once it's built up it needs machining between centers. Personally, I'd use bronze. Once the taper is lapped, the key is only to ensure correct assembly and doesn't actually hold anything.