Has anyone crank-walked a built 7 bolt???

[my98gsx]

I know 7 bolts are known to crank walk, and i knew this but now im well...
I did a rebuild last year block .040 over, eagle crank acl bearings, arp everything, all the parts were balanced and i thought i had a bullet-proof engine.

This year i wanted my built engine and transmission to have a turbo that would better power my car. I spent some serious cash bought a jmf intake manifold, a punishment t3 exhaust manifold and a forced performance hta35-86. I started the car up this year hopeing to have one fast car, but to my disapointment i think i crank walked my new engine already.

I took the car out for a ride tore through 2,3,4 gear and the car pulled ( 18lbs break in for the turbo, afrs 11.6-11.8 ) after the pull i felt a vibration, i pulled over checked the car out, found nothing and drove home.

After the ride home the car wouldnt start, i changed the plugs, iac, power cont mod, and the car did not want to idle. After some playing i did manage to get the car running but now when i put the clutch down the sar stalls or drops rpm into the 300 range eventully killing the idle. After looking on the forums this "clutch kill" seems to be linked to crank-walk. ( im also getting a vibration on my crank pulley under idle )

The sad thing is that when the block has 120k on it, the rebuild last year only has 2k on the engine. Has ANYONe ran into this problem with all of these aftermarket parts within the short block? ... i didnt in a million years think this would be possible.

 

[TOONAH]

Crankwalk is a silly term form 'premature thrust bearing failure'. Thrust bearings are designed to control the crankshaft end play, which should not be more than 4-6 thousandths in the 4g63. Seven bolt blocks have the one piece main bearing girdle, whereas the six bolt block has individual main bearing caps.
So what causes "crankwalk"? Nobody seems to know for sure, though myself and some others believe it has a lot to do with softer steel that was used in post 1993 engines. The thrust wall on the crankshaft would wear as fast as the thrust bearing itself. Also statistics
show that the manual transmission 7 bolts failed more per ratio that the automatics. So clutch technique, such as "launching" or letting the ctuch out at 2500 rpm's is a no no with the seven bolt crankshaft. It does not seem that you have proven that your engine has crankwalk. You must measure the end play using the proper tools, though a simple feeler gauge will get you in the ball park. Let us know how it goes. PS. The last 4g63 I tore down
had 25 thousandths end play, crankwalk for sure but it ran good until the balance shaft broke and broke the timing belt. Even with 0.025' endplay the clutch worked ok. I believe
your clutch may not be fully disengaging.