Movement in the crank????

[WHYBYNU]

Had my truck in the shop today for same old starter problem (3 starters 3 monthes). The starters grinding the flywheel,we put on a new starter and still grinding the flywheel tried shims samething might start 15 times and then it starts ginding again, mech checked the flywheel no real sign of wear so he said it could be play in the crank. Anyone heard of this,I was going back next week to let him check it out. Have any of you guys ever had this problem, what causes play in the crank???? How do you fix it???

[True Blue '72]

Ask your mechanic to check the bearing clearance and thrust clearance of the crankshaft with a dial indicator.
Should be within spec

You say starter is grinding the flywheel with no signs of wear?

Starter motor may start to turn before starter teeth are engaged with flywheel teeth

[69 longhorn]

Movement in the crank......do you have really low oil pressure?

[Desert Rat]

I had a old Stepside that would do the same thing after a while would grind,but then i knew i had to crawl under and tighten the bolts,the holes in the block were worn,and i didnt have that starteer brace on-one time i thought ill get buy a little longer,wrong!!!!! i busted both bolts on the block,i was miles from home in a bad area,no money I felt screwed.
From all that i always use correct starter bolts,and always remember to put the strap brace to the starter to the motor.And i never use a used starter anymore,i go buy a new one,and keep the warranty in the glovebox,so when my starter goes out,im probably somewhere near a Kragen,Checker,or Shmucks!!!Now i burn them up frequently,maybe the headers?but i got smart i made the wires longer and put quick disconnects on them so starter swap is now a 5min no big deal job,no more searching for the little posts,and dropping that odd sized nut-somewhere????then getting a wrench on them-i do all that before it goes in now.

[WHYBYNU]

Thanks for the replys. He is going to check the clearances Mon.I have great oil pressure. The movement in the crank is something new to me,not sure exactly what causes it or how he will fix it. Truck runs strong its a 71 super swb, org. 350/350 118000 mi. on the motor with a Eldel. intake and 600 carb. Dynomax headers and Flow Master 50s dummped above the rear.just can't get the Damn thing to start.

[Fast68Chevy]

if its side to side movement, thne you have problems, if its fore and aft movement, then you have bad thrust bearing(#5 main cap)
commonly damaged by people beating on balancer onto crankshaft with a BFH, or if engine was in a vehicle that was in a bad enough head on crash or something to exert enough force on the thrust bearing



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Randy- Lincoln, IL
r68c30@hotmail.com

71 C-10, trying to assemble....sigh..
parting out 5.0LTPI '81 cutlass supreme brougham
*Paint is overrated
© RSS Enterprises 2000

[71GMCstreet]

I'll bet you need to (and I know this sounds outta here) add spacers between the block and the starter. I say this because I had an 84 Z-28, with the HO305 and bought a "small-block" starter from the Auto Zone. I ran into the same symptoms, I threw spacers in the thing and worked great.

[GMCPaul]

Early V-8 block castings are notorious for being slightly off in the starter mounting area requiring shimming for correct functioning of starter. However Fast & your mechanic are correct that a damaged thrust bearing can cause this also and most common reason a thrust bearing is damaged is a heavy force hitting the front of the crankshaft most commonly done by novice mechanics beating harmonic balancers on. If left unattended a damaged thrust bearing besides creating greater internal wear to motor will lead to starter damage, and if pulling or hauling heavy loads eventually you can even break the front half of your automatic transmission housing off from the forward and aft movement of crankshaft.
GMCPaul

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[loenuf]

oh man, i bought a used 350 out of a wrecked truck last year and i think it damaged the crank. it had lots of play, pull the belts off and you should feel it. mine was so bad it wouldnt keep time due to the cam walking inn and out. it was coming out so far that it almost wore a hole in the timing chain cover. if this is the case, the motor will not last very much longer! the bearings will decentegrate over time and there was nothin left if the thrust bearing in the crank when i tore it apart.hope this helps..