Crank death

[DaveL485]

Good mate of mine has a small problem. His crank, which is a four figure custom steel jobbie, is fooked. It's picked up the mains and big ends after an unfortunate combination of bad luck and circumstance. It is bad enough to not be repairable with a simple regrind-oversize bearings.

I had a bit of a google but I can't find what I was looking for....I know there are places out there that repair/rebuild custom or obsolete stuff by layering weld on the damaged area's and machining it back to spec.

Can anyone recommend anywhere that does this please?

Cheers!

[stevieturbo]

Might also help if you gave people a clue as to what engine. Im sure it wouldnt be difficult to get a new crank made with enough money.

Although I'd have thought most decent machine shops would be able to sort it, or surely know of somewhere that could.

Edited by stevieturbo on Sunday 27th September 12:22

[Boosted LS1]

Could it be offset ground or ground down to a smaller diameter and then use different rods? You can metal spray them to build them up but I don't know who does it. Welding would change the composition of the forging so I don't like that idea. You may be able to find 'thicker' shells from the US and grind the crank to suit.

As Stevie says, what crank what engine?

[DaveL485]

Renault J-Series from a 21Turbo, Steel crank retailing £1500. Would rather fix than buy a new one!!

[Boosted LS1]

I once had a plasma sprayed crank, I didn't do it but it seemed ok. Look here for info:

http://www.google.co.uk/search?hl=en&q=plasma+...

Maybe this would be the answer.

[DaveL485]

Thanks, that's definitely an option!

[Pumaracing]

Damaged crank journals can be built up using a process called submerged arc welding. Hillthornes in Hayes used to do it. No idea if they still do.

[eff eff]

There is a process that used to be called fescalising that I have used to build up worn bearing journals with hard chrome. If you google "hard chrome deposition" there are companies still doing it, as far as I know it's a low heat process that wont alter the substrate properties.

[Pumaracing]

Here you go.

http://www.coventryboringandmetalling.co.uk/serv04...

Sub arc welding and regrinding of damaged cranks.

Google is your friend.

Submerged arc welding is a process whereby the journal being welded is rotated and continuously submerged under a flood of granules of summat or other which keep the air away from the job and stop weld spatter. This enables a perfect defect free weld to be produced so the component, crankshaft in this case, can be rebuilt to its original specifications. I watched a crank being done once at Hillthornes. It's very dull because you can't actually see any sparks or bright lights because the welding process is completely hidden by the granules pouring out of a hopper above the crank. It just looks like a crank rotating under a grain hopper. Once it's built back up though you can regrind back to original size.

Your crank will almost certainly be EN40B nitrided and I'm sure they'll know what welding wire specification to use to restore it properly.

[DaveL485]

Pumaracing said:

Here you go.

http://www.coventryboringandmetalling.co.uk/serv04...

Sub arc welding and regrinding of damaged cranks.

Google is your friend.

Submerged arc welding is a process whereby the journal being welded is rotated and continuously submerged under a flood of granules of summat or other which keep the air away from the job and stop weld spatter. This enables a perfect defect free weld to be produced so the component, crankshaft in this case, can be rebuilt to its original specifications. I watched a crank being done once at Hillthornes. It's very dull because you can't actually see any sparks or bright lights because the welding process is completely hidden by the granules pouring out of a hopper above the crank. It just looks like a crank rotating under a grain hopper. Once it's built back up though you can regrind back to original size.

Your crank will almost certainly be EN40B nitrided and I'm sure they'll know what welding wire specification to use to restore it properly.

Ah! Exactly what I was after....and I live in Coventry as well. Thanks very much! Will post some pics of the damage soon when he sends them to me. Looks like the metallic bits in the engine have done some extensive damage....Mains, big ends, liners and more. Where they came from...well...thats still under investigation. Will report back!

[Pumaracing]

Before you decide you really need sub arc welding have a very carefull measure of the journal sizes and look to see what undersizes you can actually get bearings in. Different bearing suppliers offer different ranges. If it's the crank I think it is I can get big ends down to 1.25mm undersize and I doubt the damage is worse than that.

Post your exact engine spec, original journal sizes and what you now measure them at and I'll see what I can do.