GarrettT/A

Got a NA 402ci lq4. Tore it down for new bearings and rings as it has roughly 400 passes on it(bracket car). No symptoms, simply preventive maintenance.

7/8 rod journal is clearly cracked, I cannot imagine that it would have lasted too many more passes.

Looks like i got very lucky, could have been far worse. All rod bearings were in excellent shape except for number 7. Mains are in worse shape.


Question is, what would cause this? do I have a block/main alignment issue? Never blew a trans or rear end, never got hot, all motor. shift at 6800. Assembled short block was built by a reputable shop/sponsor. Was a new unused lq4 block when built.

thoughts?

4.005 bore
4" stroke Callies 4340
callies 6.125 compstar rods h beams
wiseco pistons
11.5 cr

th400 w/transbrake

Jontall

It could have been a crack that was undiscovered when the motor was built. Did they Magnaflux the crankshaft before installing it? Did you contact Callies??? If not I would.

cookseyb

Casting flaw, High stress caused it to show up.

Karlw

iTrader: (5)

Wow. Amazing it's still one piece!

JakeFusion

iTrader: (7)

How does that rod look?

RockinWs6

It happens, nothing is perfect. I've seen cranks cracked all the way through and the engine still ran ok, Odd but true.

GarrettT/A

Rod is fine, No signs or of heat or any damage luckily. One half of the bearing was down to the brass. Number 8 bearing was mint.

The block is on its way to the machine shop for a line hone to be sure.

A.R. Shale Targa

iTrader: (2)

When the upper shell is copper but the lower is fine, usually points to detonation trying to back the crank up. Aftermarket forged cranks are harder/denser than cast but less malleable. A hardening flaw or lack of proper depth combined with higher order balance harmonics (think tuning fork) can cause it as well

GarrettT/A

heard back from the machine shop, Everything checks out with the block.

99 Black Bird T/A

iTrader: (4)

What balancer or under drive pulley was on the crank?

Monzsta

I'd contact Callies. They may replace it for you if it's an obvious product defect.

GarrettT/A

I called Callies, they said they would look at it if i shipped it to them but they have no way of surmising if its a defect. So, basically **** up a rope they said. Im in Canada, im not shipping cranks all over the continent for no reason.

Called the engine builder(LME), I was looking for clarification on the crank part number. Build sheet says it is a 2.0 rod journal and the crank is clearly a 2.100.
He said he'd call back, haven't heard a word. Plus the balance sheet was never filled out. Some balanced and blueprinted short block I got here.

The local race engine builder will be getting all my work from now on.


it is a Powerbond keyed balancer.