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Turn or Weld??

Posted By: marvo451

Turn or Weld?? - 10/27/11 04:23 PM

It appears that I have a crank that needs some work. 451 Low deck made from a stock 440 steel crank. It messed up #5 rod journal. Journal is .020 under now, would it be better to turn the crank again or have the journal welded and repaired? I've looked and bearings are available up to 0.050 under.
Posted By: JohnRR

Re: Turn or Weld?? - 10/27/11 05:14 PM

Have you had it checked for cracks ?
Posted By: Cab_Burge

Re: Turn or Weld?? - 10/27/11 05:20 PM

Have it magnaflux for cracks first and then decide. The crankshaft company should be able to guesstimate how much turning down it will take to fixed that throw versus welding it and the mains , they usually warp when you weld a throw and then the crank has to be straightened and turn the mains to get them concentric with the center of the crank again Any chance of having the one throw turned downed and hard chromed that fixes the bad throw and usually the crank doesn't need any work on the mains Look around, it is expensive, most people have all four rod throw journals done at the same time :think, you can bring it(the size) back to stock also :
Posted By: marvo451

Re: Turn or Weld?? - 10/27/11 07:10 PM

I haven't checked it for cracks yet....nothing turned colors, the bearing just failed.
Maybe from when I smashed the oil pan.......but it sure took a while. The Oberg filter saved the motor.
Posted By: gregsdart

Re: Turn or Weld?? - 10/27/11 07:28 PM

How about a new crank? New metal, standard bearings, peace of mind.
Posted By: tubtar

Re: Turn or Weld?? - 10/27/11 07:42 PM

Quote:

How about a new crank? New metal, standard bearings, peace of mind.




That's kind of where I'd be looking.
Sink a chunk of dough into a marginal piece or a larger chunk into one that should be worry free ?
The math does itself.
Posted By: dogdays

Re: Turn or Weld?? - 10/27/11 08:20 PM

Nothing wrong with grinding it down to the next undersize. It's done every day. Remember that there are many stock forged cranks with rod journals offset ground to 2.200". So taking the 2.375 down to 2.335 isn't as radical. As a matter of fact, there is at least one board member who I remember is running a stroker made from a stock crank with a bad rod journal. I believe they couldn't quite get a 3.9" stroke, but it came out to 3.88 or something.

R.
Posted By: marvo451

Re: Turn or Weld?? - 10/27/11 08:52 PM

New crank seems like an unnecessary cash outlay. The problem wasn't with the crank but the bearing, or the lack of oil to it. New crank plus all the incidentals will end up nearly a thousand dollars.
Posted By: rickraw

Re: Turn or Weld?? - 10/27/11 09:34 PM

why take the risk.
Posted By: bumps440

Re: Turn or Weld?? - 10/27/11 09:37 PM

what risk is it? A newly ground bearing surface is as good as a new crank. Go ahead and have it cut, get new bearings and dont sweat it. A new crank will need to be balanced also.
Posted By: marvo451

Re: Turn or Weld?? - 10/27/11 10:39 PM

Balancing was part of the "incidentals" I was referring to.
Posted By: Oyvind Mopar

Re: Turn or Weld?? - 10/29/11 09:32 AM

You should also check the rods. I have a job for a customer now grinding the 5-6 journal from 020 to 040 (it could not clean up at 030), no more problem with this crank (which is lightened due to lighter pistons). However, his corresponding H-beam rod is .010 out of round, and the neighbour rod is .002 out of round (stretched). It may end up with a new set of rods, if they are all stretched. (Or I can recondition them, but it will also cost some...) So, getting a new set of rods might need another balance of the crank. Normally rods are sorted to get a weight matched set. By coincidence you could have another set with same weight distribution, but most unlikely. Will this difference matter? Depends on your application. If you can accept 10g too light or too heavy, maybe it is no issue. And if you did not know, I bet you could not feel it when driving.. Depends on you.
With this in mind, another good crank could have been another way to go....
That said, if you are on a budget it can all be repaired at less expense than newer parts. Next time something happens it needs not necessarily be linked to the use of repaired or new parts. I have seen much wasted money on super parts being destroyed due to simple issues, so putting money into it is not a guarantee for the outcome.
My
Posted By: gregsdart

Re: Turn or Weld?? - 10/29/11 03:27 PM

What is the history of the crank? Both before you got it and after. If It has been beat on a lot, no way would I just fix and go. They do crack and break at some point.
From friends experiences, at 550 hp the average life of a good unabused stock crank with stock bearing sizes and lighter than stock pistons was about 1,000 to 1100 runs. If you think you are over half way there, might be worth the $$ to upgrade. Only you can make the call.
Posted By: marvo451

Re: Turn or Weld?? - 10/29/11 03:36 PM

Started life in a 1970's New Yorker. Motor had 83K. Was made into low deck crank years ago, but it sat unused a long time. It now has about 80 mostly 1/8 th mile passes on it. That's why I'm planning on repairing it. Motor is probably 650 horsepower.
Posted By: robnbird

Re: Turn or Weld?? - 10/29/11 06:23 PM

just find a new crank or a good used one. yexas should be full of 440 cranks.
Posted By: marvo451

Re: Turn or Weld?? - 10/29/11 06:52 PM

I've got 5 more, but why use vthem if this one is repairable? The wounded one has the counterweights turned to 7.25" and is turned to 400 main size and is balanced to my assembly.
Posted By: 10sec440

Re: Turn or Weld?? - 10/29/11 07:53 PM

wow if you're actually putting out 650HP thats pushing it for a stock crank, especially one that has these problems AND hasn't been crack checked. Almost guaranteed its cracked. You wouldn't catch me with a crank like that under my feet. Good luck.
Posted By: marvo451

Re: Turn or Weld?? - 10/29/11 08:39 PM

It was checked when it was put together. Horsepower is an estimate. 10.0's @ 133 is what it runs in the quarter mile. 6.30's in the 1/8th.
It has Victor heads and intake with a roller cam.
Posted By: 10sec440

Re: Turn or Weld?? - 10/29/11 09:13 PM

Quote:

I haven't checked it for cracks yet....nothing turned colors, the bearing just failed.
Maybe from when I smashed the oil pan.......but it sure took a while. The Oberg filter saved the motor.




The stock cranks are known for cracking around the fillet at lower HP levels than that. I'd have it check first off and go from there.
Posted By: marvo451

Re: Turn or Weld?? - 10/31/11 01:02 PM

I dropped it off at the machine shop Friday. I'll make the final decision after hearing back from them.
Posted By: moparacer

Re: Turn or Weld?? - 10/31/11 03:01 PM

Quote:

How about a new crank? New metal, standard bearings, peace of mind.





I think I would go this route if it were mine.
Posted By: smokinwoody

Re: Turn or Weld?? - 10/31/11 03:54 PM

get a new Callies crank and have peace of mind...








Posted By: CompWedgeEngines

Re: Turn or Weld?? - 10/31/11 04:38 PM

At that level, its really time to go aftertmarket.
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