internally balanced 360 crank (BIG PROBLEM) need input

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victoriabc67dart

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this is my first post but i have used this website a ton over the last year and a bit while working on my 1967 dodge dart and doing a full swap. I had my motor bored and everything done to it as well as the heads done, during the process i was asked by my machine shop guy if i wanted to have my crankshaft balanced and change it from an externally balanced motor to an internally balanced motor. I asked about the difference between the two and decided it was a good thing to do at the time. i got my engine back and was pumped i spent alot of time and with some help pulled off swapping everything and getting the motor in and up in running with myself and a few friends. after breaking in the cam and taking it out on the highway a few times i put my insurance on it and was thinking i was ready to rock for this summer starting up. i just started taking it for some spins earlier this week and had my carb tweaked up and it was running great, then yesterday i pick my friend up to go for a ride. we had got to a stop sign and i have it in first (it's a 3 speed 727) and start to drive i get it up to about 2500 and go to shift into 2nd and hopefully get a little chirp but instead around the same time as shifting i hear the worst noise ever, sounded like a metal spoon being banged around inside a steel pot. i immediately pull over and shut it off my friend an i notice a nice stream of oil running out from the rear of the pan i look underneath the car and it is pissing oil out of a big hole and a little hole that has been bunched through the pan by something i automatically think i threw a rod. i got the oil pan off this morning and to my surprise there is no rod inside it but there is instead a pile of shrapnel pieces of the oil pump and what was left of the pick up along with a socket shaped piece of metal. i called a friend of mine with much more experience then myself and he instantly looked in the oil pan and pulled out that socket shaped piece of metal. after telling him i have had my crank internally balanced we go under to inspect the damage that had been done and we see the spot on the crank where that piece of metal which was what was the weight for balancing the crank had broken off and hit the oil pump breaking it, sending the pump and pick up then into the crank and being smashed and twisted into a million pieces and also damaging two of the pistons. i know am pretty pissed and also upset that i have spent so much time in getting all of this going and finally i can drive it and this happen has anyone had this happen before and what should i say to the guy who balanced the crank? any input would be appreciated , sorry for the long post but i gotta vent lol
 

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Looks like something the machine shop might be liable for.
 
Bummer. On the bright side, it is under warranty. Looks like you'll be out of commission for a while. Good luck @ the machine shop. Is the crank now ruined also? Maybe stick with an externally balanced crank next time around.
 
bighammer said:
Bummer. On the bright side, it is under warranty. Looks like you'll be out of commission for a while. Good luck @ the machine shop. Is the crank now ruined also? Maybe stick with an externally balanced crank next time around.
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i bet from the cam down is toast... the block even looks cracked...
 
just to note the machine shop had the crank sent to a different place to get balanced. the underside of both the rear pistons are for sure damaged and its unknown at this point how much of the shrapnel spread through the motor... where do you see a crack in the block? (which pic)
 
Did the balance guy try to weld a slug in the original balance hole in the counter weight? Or did it come out the side of the counter weight? In the pic the counter weight balance hole is still welded up. Is the front counter weight balance hole missing the slug?
 
I hope you have a good lawyer. or a good machineshop sorry for your dowm time, good luck.
 
To internally balance an externally balanced cast crank they have to add weight to the counterweights. Second picture, there is a bolt and nut, top just let of center nex to the counterweight. There appears to be a crack and a piece of block(?) about to break off.
 
If I had to guess that slug came out of the front hole of the crank, went through the pan to the back, and got caught up and broke the pump. The #5 cap has a chip breaking off it but that's the the pump aligning and IMO the cap's still good. This is purely the shop's fault. Some shops will drill sideways into the counterweight to press in the Mallory - some will drill vertically into it but it's still a mild press fit and welded in place. That looks like the front peice was not properly welded at minimum , and probably was in too large ofa hole to begin with. Marks on the pistons are not a big deal - and I'd wager you shut it off before too much crap went into the oil system.
THIS SHOULD BE ALL ON THE SHOP'S DIME.
 
victoriabc67dart said:
just to note the machine shop had the crank sent to a different place to get balanced. the underside of both the rear pistons are for sure damaged and its unknown at this point how much of the shrapnel spread through the motor... where do you see a crack in the block? (which pic)
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If they balanced it, or had it balanced, THEY are the ones that YOU paid correct? If they recieved the money, then they can argue with the shop they chose to do the work. Hopefully they stand behind their work, other wise you'll be in court going after your money.
 
MTmopars said:
To internally balance an externally balanced cast crank they have to add weight to the counterweights. Second picture, there is a bolt and nut, top just let of center nex to the counterweight. There appears to be a crack and a piece of block(?) about to break off.
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That's the oil pump drive(your bolt & nut) and the rear main cap that's cracked. Not the block.
 
Save ALL The pieces. Including the shrapnel you found in the pan & pump & take it back to the machine shop & leave as much of it together as you can. Don't do any more exploritory diassembly on it. Leave that up to them. If they are reputable then they will stand behind it & make it right. It's a mistake that happened & can be corrected. It may take a new short block, but it all can be rectified. As long as they are honest.
 
The worst thing is if they try to re-use any of the parts that may slightly damaged or banged up, like pistons or main caps. You paid for a fresh motor, not a re-done, slightly grenaded one. Yeah, I hope they are cool and trustworthy.

I've already dealt with a flaky machine shop that built a bad motor and of course the first thing out of their mouth was "well, what the heck were you doing with this motor that made it grenade like that?" Good luck man.....
 
The spot on the crank that is in the picture still show the mallory metal in the crank and welded to ensure it stays. The piece that came out must be from a different spot in the crank. One question. Did you make sure that you used an internally balanced dampner and torque converter, not the original 360 stuff?
 
Damn that is not good. Seems between you and your friends, you guys have knowledge enough to pull off the rebuild on your own. If it were me I would try to work out a cash settlement and find a different machine shop and build the engine yourself. I know time plays into this but at least you will know what you got when it is all said and done. Plus with the $$ Saved you can buy better parts like rods etc.
 
..........and dont let them run the shot by you that you were abusing it either. If that was the case, every thing in the bottom end would be piled up in the oil pan. It's very obvious this happened at low RPM under no stress whatsoever.
 
RustyRatRod said:
..........and dont let them run the shot by you that you were abusing it either. If that was the case, every thing in the bottom end would be piled up in the oil pan. It's very obvious this happened at low RPM under no stress whatsoever.
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x2
 
I went and saw the engine,.. the piece that he's holding came off, it was butt welded to the end of the counter-balance,, no hole.. It appears to be a piece of steel tube with a chunk of, I'm guessing, tungsten inside it, with the outer end pounded over to hold the weight, other end welded to crank..

In the #2 and #5 picture,, that shiny ring of spot welds is what held that slug onto the crank.. It doesnt appear the spot welds penetrated the counter weight.. - ( Can someone please post a pic of how a weight should be professionally attached, this could be helpful in his discussions.. )

It was welded on the rear counter weight, and musta been whizzing past the oil pump body by very close distance.. I figure it started to pull off, hit the pump, you can see the impact point on one of the larger pump body pieces.. what a mess, 2 piston skirts damaged for sure, no sign of water, so he may be lucky..
 
That's just totally the WRONG way to balance a crank. I'll be damned if I wouldn't demand a total refund and find another machine shop.
 
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