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Bent Crank ??

Old 09-02-2004, 12:52 PM
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Bent Crank ??

Any help or theries would be appreciated.

A small oil leak started and I could tell where it was coming from. Didn't leak while running under 2000 rpm on trailer. After putting back in the waater It got worse quickly. Found it slinging oil from behind harmonic balancer. Removed balancer and found rubber portion of oil seal completly destroyed spring just hanging there. Knowing this doesn't "just happen" and a couple of marks on the balancer where it had rubbed something but not where the seal rides. I set up a dial indicator and checjed the run out on the front of the crank just behind the keyway it is 0.020" it is noticably out of round while cranking the engine which is a well built 454 BBC. My main questions are:

Has it been this way since I got the boat ~15 running hours ago or did it just happen?

What could cause this if it just happened?

Should I replace the seal and hope I can finish the end of the boating season here in the north east. Would really like to take the boat to the races in Cambridge, MD in September.

OR retire it for the year and fix it right.
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Old 09-02-2004, 01:32 PM
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Default Re: Bent Crank ??

That's weird. I can't imagine why that would happen unless it was dropped? I hope your front mains are tight. You have to remve the seal anyway so might as well change oil. Check for metal powder in the oil.

Roby
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Old 09-02-2004, 03:31 PM
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Default Re: Bent Crank ??

What was the crankshaft manufacturers name?
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Old 09-02-2004, 03:52 PM
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Default Re: Bent Crank ??

That motor looks very familiar....Is it in the JAWS?

Give Kurt a call at 732 477 7400 i believe he built the motor.

He might be able to steer you in the right direction.

Hope to see you in Cambridge. Are you gonna race it?
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Old 09-02-2004, 04:53 PM
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Default Re: Bent Crank ??

My guess would be the crank is fractured and hasn't broke all the way yet,ive seen it on small blocks. Ive also seen stock gm 1053 steel cranks that are broke just like they were cast (clean fracture with powdery grain acrossed the break). If it is bent then i would think it was bent before motor was assembled,did it leak from day one? I wouldn't run it(on the chance it would destroy block,rods pistons ,heads etc)if it does come apart completely. If you really wanted to run it(this is going to sound like something a farmer would do to a old tractor) I would whap the crank on the snout with the high side up with a brass hammer,if it changes the runout easily,you can count on it being broken,good luck,smitty
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Old 09-02-2004, 06:33 PM
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Default Re: Bent Crank ??

I had the same symptoms with an oil leak a while back. Changed the seal 3 times with no luck. Changed the timing cover and cured the leak. Dont know if my 2 cents will work but may be worth a try.
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Old 09-02-2004, 07:46 PM
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Default Re: Bent Crank ??

Articfriends, my brother and I were wheeling the desert with his FJ44 and took a rock real hard on a sharp drop. Bent something and he did just that, pounded the hell out of the balancer. Held a piece of charcoal steady while engine cranked to find the high spot then smack the crap out of it. Repeat until straight. Next we attacked the oil pan by draining the oil into a cooler and punching a hole into it. Remove lag bold from bed and screw into hole. Attach piece of chain to bolt an lever pan away from crank. Seal hole with JB weld and pour oil back in. Made it Barstow and back before proper repair made. Glad he does not work on my boat!
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Old 09-02-2004, 08:22 PM
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Default Re: Bent Crank ??

Toss a seal in and run it the season is about over anyway.
Keep your rpm's down and keep and eye on it.
If the crank is bent that much chances are it may be cracked and ready to break.
If it breaks you are in serious trouble.
Go boating with another boat just in case you get into trouble.
Good Luck and keep us posted.
Brian
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Old 09-02-2004, 08:33 PM
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Default Re: Bent Crank ??

Originally Posted by articfriends
My guess would be the crank is fractured and hasn't broke all the way yet,ive seen it on small blocks. Ive also seen stock gm 1053 steel cranks that are broke just like they were cast (clean fracture with powdery grain acrossed the break). If it is bent then i would think it was bent before motor was assembled,did it leak from day one? I wouldn't run it(on the chance it would destroy block,rods pistons ,heads etc)if it does come apart completely. If you really wanted to run it(this is going to sound like something a farmer would do to a old tractor) I would whap the crank on the snout with the high side up with a brass hammer,if it changes the runout easily,you can count on it being broken,good luck,smitty
If this is the case don't bother playing the lottery because your good luck was spent on the fact you have salvagable parts. I wouldn't think of starting the engine. Do your runout test w/ plugs removed on starter only.

Roby
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Old 09-03-2004, 05:20 AM
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Default Re: Bent Crank ??

I do agree with Roby, if you do run it and loose it and the crank fractures, you will take out several parts with it, the safe approach would be to bite the bullett and take the motor out and remove the crank, have it magneflexed and inspected and if it is bad replace it.
While your in there replace the main and rod bearings, and oil pump.
You should also check compression before you tear it down, if it is good you won't have to play with rings, or a valve job.
Best of Luck
Keep us posted.
Brian
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