Modified crank

[Dwaz45]

Hello all. When I had my 440 built a couple years ago, the shop called me to come look at the crank.... I do not have any info on the motor prior to me inheriting the whole project from my father.....it appeared someone had ground down parts of it. The builder guessed maybe someone did it to lighten it or balance it. My father had another crank so that's what was used in the build. My question is..does anybody know why someone might have done this and was it a thing back in the day?

 

[gkent]

I don't see anything unusual

 

[pnora]

I don't see anything unusual

Top picture shows a lot of meat cut off.

 

[gkent]

So what !

 

[1967coronet]

I see it, you guys did make the right call ,
Rod journals look like they needed turned anyway. These old engines you never know what you going to see or find.

 

[gkent]

Quite often those rod throws have a big hole bored through to remove weight. This one was done by grinding. My guess is it didn't need as much taken off as the hole would have removed. And whoever did it knew enough not to cut into the sides of the journals. AND it rteally doesn't look like they ground off much more than the rough surface.

 

[pnora]

So what !

It obviously triggered a concern from the crank grinder. It does not look like any of the other throws that I can see. It might be ok but I would question it.

 

[HawkRod]

My guess would be for balancing. Mostly, you take weight off the counterweights. But adding weight to the counterweights can be difficult. So I suspect that rather than adding weight to the counterweights someone instead removed it from the rod journal side. A few grams won't hurt anything, but I can't comment on the crank you have pictured. Probably it would be OK and not much strength has been removed.

 

[pnora]

My guess would be for balancing. Mostly, you take weight off the counterweights. But adding weight to the counterweights can be difficult. So I suspect that rather than adding weight to the counterweights someone instead removed it from the rod journal side. A few grams won't hurt anything, but I can't comment on the crank you have pictured. Probably it would be OK and not much strength has been removed.

Could be. But you would think the other throws would also have some removed. I still question it but if a competent crank grinder checked it out and said it was good to go I would run it.

 

[493 Mike]

That would scare me. I learned to grind crankshafts in college. In fact I spent a full year in Auto Machine at Ferris State in 1971.
Mike

 

[HawkRod]

Could be. But you would think the other throws would also have some removed. I still question it but if a component crank grinder checked it out and said it was good to go I would run it.

Yeah, and I would have thought the weight would be mostly removed from the rod journal side opposite the counter weight. The counter weights on each side of the crank are where most balancing is done.

The second picture the OP posted shows that the counter weight has been drilled for balancing. My guess is that during a rebuild, they needed to add weight back in. Instead of doing that, weight was removed from the rod journal.

This is, of course, just a guess by me. However, I had the same situation with needing to add weight to my buddy's 440 when I balanced it. Adding weight back in is a pain in the arse vs. removing it. You have to stuff heavy steel wool stuff into the hole, pack it in, and then weld a cap over it. And this then just gets you close. Then you have to remove weight again to fine tune it!

 

[gkent]

I learned to grind crankshafts in college.

But did you learn how to balance them ?!?!

 

[gkent]

There really wasn't much taken off !!

 

[toolmanmike]

I would junk that crank if it were me. You take material off the counterweights not the throws!

 

[493 Mike]

But did you learn how to balance them ?!?!

The school purchased a balancer shortly after I graduated.
Mike

 

[33 IMP]

I don't think that would worry me at all for a stock/mild build.
Most times these days, if a substantial amount of weight has to be added to a crank, mallory metal is used. But mallory is expensive.
I have a top alcohol crank that is cracked, but I keep it because it has ten slugs of mallory in it, that I might need.
I've also got a hard chromed crank that I took out of my max, that has a couple slabs of steel welded to the counterweights.

 

[Dwaz45]

I appreciate all the info guys. I know nothing cept the basics with all this motor stuff. My engine builder said he wasn't comfortable using this crank and I had another one that looked brand new. I was just looking for some insight. And I'm thinking maybe my father knew all this and that's why he had another one to use. As I've said in other posts, he had all the parts for this engine build (and the car for that matter) he just never got around to getting the motor built before he passed.

 

[Bird 426]

Well, we all see things everyday, that we have never seen before. I have never heard of using steel wool for balancing before. Having said that, never heard of lead being used for the same purpose, but just had a ton (7) slugs of it taken out of my Hemi crankshaft, along with this being removed from the crankshaft flange. Was being rebalanced after replacing the heavy NASCAR rods with H- beams. 7-8 ounces per rod. I have one throw that looks similar to yours, after dressing up the forging. I can not offer a definite answer, if you choose to use it in a street engine, probably fine. It will still need to be balanced for the new assy.

 

[Dwaz45]

Well, we all see things everyday, that we have never seen before. I have never heard of using steel wool for balancing before. Having said that, never heard of lead being used for the same purpose, but just had a ton (7) slugs of it taken out of my Hemi crankshaft, along with this being removed from the crankshaft flange. Was being rebalanced after replacing the heavy NASCAR rods with H- beams. 7-8 ounces per rod. I have one throw that looks similar to yours, after dressing up the forging. I can not offer a definite answer, if you choose to use it in a street engine, probably fine. It will still need to be balanced for the new assy.

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I had another crank avaliable to use. I know very little about the internals of engines. I was more curious when my builder seemed a little stumped. I finally got around to digging out the photos and asking the experts here. It sounds like it probably would have been ok to use if I had to but like I said I had another. Also sounds like there's many ways to skin this cat lol. Thanks again for everyone's input. I love this forum. I've learned alot since inheriting my dad's cars.

 

[DPeltz]

I’d say the 1-2 rod journal has had material removed on the #2 main side. Too much to compromise strength is beyond my pay grade. Rest of what I can see looks like general clean up - deburring. Someone refresh my aging brain, which cranks had holes through the rod journal, and which didn’t?