Engine Crank Broke?!

robertmee

Member
Joined
Oct 11, 2009
Long story short, I got my car back after a long period from a well respected member here that had done some top end work on the car...Nothing in the lower end. I only mention it just to give a bit of history on the car...I don't suspect any of his work contributing to my issue.

After getting the car back, I've taken it on exactly three mild drives to local car shows/cruise ins. No hopping on it (I had it detuned actually for better driveability). While on business last week, my wife wanted to surprise me and drove the car to have it professionally detailed. While 3 miles from the house, driving at low speed, she noticed smoke coming from the cowl area. She's extremely paranoid about driving my car, so she immediately pulled over and noted transmission fluid leaking. She contacted me and I called Haggerty to flatbed it to a tranny shop, thinking I dropped a cooler line. They called today and said upon inspection that the flywheel is wobbling and that means my Crank Shaft has broken in two. WTF? I've never heard of that before unless a manuf defect. But for that to happen under mild conditions, oil in the engine, car running perfectly...what?!?!

I don't know if I should trust this transmission shop, but that seems awfully suspect to me. The member that worked on it is 3 hours away, so I'll probably have it shipped back to him for a better opinion, but until then, anyone have any insight on what could have happened? And if it is truly broken, is the engine toast? What are my options for rebuild?
 
Most machine shops will not warrantee these builds as its a racing application. No matter what you tell them. Was your wife with the car the entire time at the detail place. Only takes a minute to do a burn out and boom. If your using a used crank it might have been done before you brought it in to them.


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Never made it to the detail shop....She was driving there 3 miles from the house. I'm not after any warranty...I'm wanting to know what could have caused it, what the potential damage is, and what can be done to fix it.

Again, bottom end is stock...no work has been done to the bottom end ever. Stock block, crank, pistons, etc. The only thing changed in the engine were the valve springs. The previous work didn't result in this damage, as it was all bolt on, tuning and top end stuff.
 
Well if it was never touched and you didn't hear any tapping after you got the car back. Then you must of hit the gas pedal at some point to get the RPM up and with a bad tune something went pop. Well in your case Boom.
Was the timing chain replaced too?

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Go to this trans shop and inspect the damage for yourself. I have only seen a broken crank once in a passenger car and it was still running! If it is trans fluid leaking there are plenty of reasons why other than a broken crank. Ask them to show you why they think it's broken. I don't see how it could wooble causing a trans leak without engine oil pouring out.
Jeremy
Sent from my A110
 
If you snapped a stock crank with the mods you have listed, that I am sorry to say is not uncommon. With that big of a turbo, alky and good heads you can make 600 hp pretty easily. Look up pictures of carnage and the Drove Over Thye Crankshaft club and you will see what is going on.

The fix is a forged rotating assembly and that will cost you a little.
 
Nope, timing wasn't replaced....I'd driven it three times, and other than the waste gate actuator falling off once, the car drove fine. I have both SM and Powerlogger and everything on the three drives was perfect. I have A/F and EGT and nothing was wrong. New Alky Kit although never got on it to burn meth (was waiting to get to track), new TT chip, new valve springs, new fuel pump, and some other small stuff. I really don't think that work contributed to BOOM. And it was cruising at 35Mph when wife noticed smoke. Now, she drove it at least 1/4 mile further to safely pull into a parking lot. If the crank snapped, I don't see how it could drive 5 feet much less 1/4 mile.
 
I just can Fantom driving one of these cars and not hitting the gas pedal once. I wouldn't even buy a car off of someone if I couldn't air it out. That's just me.


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They called today and said upon inspection that the flywheel is wobbling and that means my Crank Shaft has broken in two.

That diagnosis is horseshit.

It is possible that a crank can break and keep running. for the flexplate (not a flywheel) to wobble it would have had to break at the back or the rear journal. If it breaks there, the engine can't move the car. Plus the torque converter pretty well keeps the flexplate running fairly true.


When you get it home grab the bolt on the crank snout and move it back and forth. If you can't make the two ends move independatly of each other, it's still one piece.

Also, cranks don't smoke and leak ATF on the ground when they break. It does sound like a tranny might be in your near future though.
 
get the car away from that trans shop

when you get it looked at and if its a broken crank then post up the pics

until then you are just going on a transmission shops idea of why the flywheel could wobble without any real inspection

if someone just bolted a flywheel up to an eagle crank and didnt chamfer the back edge of the flywheeel to clear the radius on the crank its highly possible the flywheel bolts into the crank are loose
if its a stock flywheel they break ..not uncommon even with stock hp
these are issues that arise with turbo buicks that a run of the mill shop would never be aware of ,
 
Lemme get this straight.

A transmission shop diagnosed an engine problem..........a broken crank to be more specific.......

I'd like a second opinion, please and thank you.

Sorry for your luck.
 
X2 on the broken flex plate. I have one hanging on the wall with a crack between each bolt hole. It made a heck of a screaching but ran fine.
Second getting another opinion. Those yahoos at the trans shop would probably have a hard time with the 2004r , I doubt seriously they have any knowledge of an LC2.
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if its a stock flywheel they break ..not uncommon even with stock hp

I've seen this happen before, and the result was the flywheel which in turn took out the front pump on the trans which caused the fluid loss.

I see a flexplate and trans rebuild in your near future if I was clairvoyant.

Oh! and don't let that shop repair anything including the trans.
 
I have personally experienced a couple broken cranks, and seen a few others as well, and the engine would still run?

A turbo Buick will usually break the crank at a rod journal, and if it is at nos. 5&6 it could certainly cause tranny damage to the pump/converter which would leak fluid?

A local GN broke his crank on a 13 sec. run and took out his block and tranny, needless to say, this one did not run. :eek:

This one did not run either and the crank and trans were trashed, but the block was repaired:

DSC00335.JPG
 
Hopefully the crank isn't broken but it does happen. Truth be told if you haven't owned the car since it was new you have no idea what is in the motor and what condition it was in prior to the damage. Most of these cars have had a half dozen owners in the last 25 years which would make most people question what was done to the car / motor prior to you owning it.

Neal
 
I have personally experienced a couple broken cranks, and seen a few others as well, and the engine would still run?

A turbo Buick will usually break the crank at a rod journal, and if it is at nos. 5&6 it could certainly cause tranny damage to the pump/converter which would leak fluid?

A local GN broke his crank on a 13 sec. run and took out his block and tranny, needless to say, this one did not run. :eek:

This one did not run either and the crank and trans were trashed, but the block was repaired:

View attachment 204241


Whats the story on the TA block with the hole in it?

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