broken crark shaft

[towtruckdave]

What shape is your harmonic balancer in??? Can you pull some mains or rod bearings and see if this was a 10,20 or 30 ground undersize crank... Sometimes the grinders don't chamfer the edges correctly and it causes stress cracks....

Good point! I would like to know.

 

[THECACKLER]

All IDI cranks have the same casting number.
do avoid the oem turbo motor crank just in case though.
you're the fourth person in a one year period to have reported this problem.
does the motor look like it has been rebuilt in the past?

O.K So what's the deal with the OEM Turbo Crank???? I'm a couple days away from laying mine and there's still time to mike out another Crank...
It's a 94 IDIT crank and it mikes out round and to the plus side of spec and it shows virtually no wear. I thought I was in High Cotton... What Gives?

 

[Alex S]

Geez a GM 6.2 is looking prety reliable these days. Hahaha

 

[icanfixall]

The turbo idi crank is balanced for a heavier rod set because the pins are larger. So that makes for a heavier rotating mass. If you install a turbo idi crank in a non turbo idi motor make sure you have it balanced for the non turbo rods.... Otherwise any 6.9 or 7.3 idi crank will fit any idi motor. They are all the same casting and demensions.... Isn't that great news.... We can still find parts but.... Nobody is making new 6.9 heads nor a 6.9 or 7.3 block.... But we can buy new 7.3 heads.....

 

[THECACKLER]

Yeah, I'm going back with the same (new) Pistons, Rods, Crank & Balancer but the engine already had a SM Flywheel on it, so no Turbo Flywheel. One thing I am changing is the Serpentine Belt system back to "V"-Belts. When I tore it down I found all the bearings were in good shape with the exception of the bottom side of the center main and, more disturbingly, the P/S Pump side of the #1 Mains. I had the A-Bore checked and it's good.
All I can think is that the Serpentine Belt pulled the Crank Snout to the left.
Is there any way to Identify a Turbo Crank from a N/A one? Are they all "Steel" cranks?

 

[fobrnno]

got it apart it still have std. bearing so it wasn't rebuild. the forth main bearing spun, going to take the block and see if it is repairable later this week.
the balancer is in good shape, the rubber insert is still in one peice and not cracked or squeezing out.
I have a crank lined up for $175.cnd.
ther was no warning signs oil pressure was good always on the high side of the gauge. the week before i did a oil change and no signs of metal on the magnetic drain plug.

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[fobrnno]

different question on the head bolts?
are they reusable or are they a torque to yield (one time use) bolt?

 

[THECACKLER]

Man that's sick. That Block took some heat. What the hell's the deal with a Factory STD Crank that it Broke the Crank & Spun a Main. Are you running a Single Mass Flywheel? StD or Turbo Rods? You're up for at least an Align Bore and all New Bearings & Gaskets and of course that Crank. I'd disassemble the cooler and flush it out as well.
The Head Bolts are reusable.

 

[towtruckdave]

Yes, you will need the mains line bored but that will leave your pistons sticking out of the deck further-not good. Believe me, it will be cheaper, easier and more reliable to start with a known good, never grenaded block. My 2 cents.

I have a few known good 7.3 blocks and cranks sitting here in the 44109. What is your zip?

 

[fobrnno]

its just your standard flex plate for a auto trans.
"I have a few known good 7.3 blocks and cranks sitting here in the 44109. What is your zip?"
i'm at toronto ontario a little north of you but thank for the offer

 

[towtruckdave]

its just your standard flex plate for a auto trans.
"I have a few known good 7.3 blocks and cranks sitting here in the 44109. What is your zip?"
i'm at toronto ontario a little north of you but thank for the offer

You are only 300 miles away.

 

[typ4]

that main bore will be shrunk as well as the cap. It may not line hone. The cap fit to the block must be tight, if it is loose junk that block.

 

[icanfixall]

Sorry but the block is no longer fit to hold a bearing in the spun journel. Line boring the block may help but... Thats a long shot at best. The process will cause the pistons to be up more than usuall out of the block but that wont hurt you at all. The factory setting is 31 thous max. I ran a set of turbo pistons as much as 54 thous out of the block. I don't recommend this at all. If the block is saveable you can run some low comp pistons. They have the pins bored 10 thous lower in the pistons so they sit that much lower in the cylinders.

 

[fobrnno]

just talk to the machine shop he said they can line hone and talk about the piston height. but also saying it will raise the crank and the lash will be too tight on the timing gear and over time will chew up the gears.
so it looks like i have a boat anchor for sale lol.
now off to the wreaker for a good used motor.

 

[icanfixall]

The shop spoke the truth. It "can" be machined true but the crank will climb up into the block by the machined off amount. I really dought the gears would fail but not knowing how much they feel needs to be machined off is the deciding factor. So the best idea is looking for another crank and block like you posted. Remember how the oil is pushed thru the crank. All bearings down stream from the number three main will be hurt... Even the cam bearings and lifters down stream will have metal in them....