Mercury crankshaft

[elwood]

Wow, I wonder what happened to this crankshaft ..
Ive had this Mercury crankshaft for a few years, and Id like to use it, but not sure if it would hold up, It is somehow cut close the rod journal, never seen this before.
Casting flaw ?

[texas webb]

looks intentional.

[40 Deluxe]

It's probably already ran many thousands of miles without any problems. No reason it can't go many more miles without problems!

[JWL]

It is in the area where excess weight often needs removed for balancing. I would suggest that is the most likely explanation.

Whether or not I would use it would depend on the level of performance the engine was being built for. But, if it is ok in all other respects I doubt it would be a problem in the average street performer.

[WABOOM]

Its been machined for balance.

[flatheadmurre]

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Ive seen some pretty rough machining on them...if it´s to remove casting inlets or balance...but looks like they used a blunt axe sometimes...just check for sharp deep cuts that can be the start of cracking...otherwise i wouldn´t worry to much.

[19Fordy]

The only way to know for sure is to check it for balance. Looks like a friction saw attacked it.
I would NOT use it. Your entire engine would literally "revolve" around that cut. Hard to believe it was that much "out". Not worth taking the gamble.

[Tim Ayers]

Originally Posted by 19Fordy

The only way to know for sure is to check it for balance. Looks like a friction saw attacked it.
I would hesitate to use it. Hard to believe it was that much "out".

I was going to say the same. Seems like an awful lot to take off to get it to balance. I guess the shop's drill bits were lost when they balanced this crank. LOL!

[rotorwrench]

These crankshafts were cast in a gang. The sprue ports interconnected in the mold so that cast iron would reach all the areas of the mold. When they broke the cranks apart, it sometimes leaves some jagged areas so areas like that were generally machines smooth just like removing flashing. It was rudimentary machining so it wasn't always purty.

[tubman]

I've seen a lot of flathead crankshafts, but never one that looked like that. I would not use it without a LOT of checking (balance, magnaflux etc.). It might be easier/cheaper to find another crank.

[flatford39]

You need to get that thing balanced at a machine shop. I sincerely doubt it can be. That's probably why it's not in an engine. I wouldn't use it.

[40 Deluxe]

Originally Posted by flatford39

You need to get that thing balanced at a machine shop. I sincerely doubt it can be. That's probably why it's not in an engine. I wouldn't use it.

It passed inspection at the factory and doubtless ran for many years and miles without any problems. A lot of unwarranted assumption going on here.

[JSeery]

I was going to post similar to what 40 Deluxe posted above. My guess would be it came from the factory like that, balanced within spec at the time and most likely has at least 100,000 miles on it!

[Ggmac]

Agree cmpletely with the last 2 posts . I'd use it , I've used ones similar maybe worse but have personally removed them from running engines .

[elwood]

Thanks for the replies guys, Im gonna keep it, ll be building a engine for my 30 pickup soon, Ill put it in there,
Cheers ….

[supereal]

At our shop we MagnaFlux all cranks before grinding, and check for any distortion that would affect use. It isn't unusual to detect problems, as many cranks were salvaged from engines that had been junked.

[Pete]

...

[34 GAZ]

Originally Posted by supereal

At our shop we MagnaFlux all cranks before grinding,

So what does a balanced crank look like ? Would you actually see tell tale grinding marks on the counterweights or are they polished and smooth with all casting blems removed ?

[rotorwrench]

They generally just drill into the counterweights to remove weight or add weight depending on the imbalance characteristics. We had a discussion on here before about cranks that had more metal loss than expected when the gang of shafts were separated at the foundry after casting. There have also been some discussions about balancing.

Prepping one for racing applications is a lot more involved than just balancing one.

Ford would grind off lumps and smooth out flashing before machining the shafts for front & rear shafting & flange, oil flow ports, and bearing journals. I don't know what there inspection procedures were but they likely performed some NDT inspection to weed out any that were obviously not going to pass QC. The clean out plugs would likely have been the last thing installed. Balancing would have been performed prior to sending them on to the assembly line. Sometimes the funky looking stuff lasts longer than the nice looking stuff.

[ford38v8]

Rotor wrench, myself not being an engine builder, please forgive this dumb question regarding engine balancing: Is the weight of oil in the crank's oil gallies taken into consideration when balancing a crank?