Replace Bent Crankshaft

Discussion in 'Engine Topic' started by reinhardt79, Dec 17, 2018.

  1. reinhardt79

    reinhardt79 Veteran Member

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    I *MAY* have bent the crankshaft in my Camaro. It has a 350 of unknown history in it, PO of engine said it was rebuilt w/ 50k miles or so on it. That was 15 years ago and probably 10k miles ago. I've owned the car the last 17 years. Anyways, about 6 months ago I jacked the front end up for some reason (don't remember now) and the jack slipped off and hit the crank pulley. Wheels off the ground, weight on the crank. Started the car and can see the crank pulley wobble. That was 6 months ago. I closed the hood and walked away for a while.

    Now I am ready to sort this issue. I plan to pull the crank pulley and damper and check run out on the shaft. Maybe I get lucky and the issue is just the pulley or damper.

    If I am not lucky can I pull a crank out of a junker, refurb it and swap it in? I have not been into the bottom end of an engine but I have been shade tree wrenching for many years. If so, what am I looking for in a junkyard crankshaft? Type? Condition? What kind of refurb work needs to be done? What are the bare bones required components to be replaced with the crank?

    I don't have the budget to rebuild the engine. I have a 3 year old and another on the way. Hard to justify big money on a weekend toy. Not looking to get 100k reliable miles out of it. Another 5k miles should get me another 5 years at this rate. :lol
     
  2. Chevyforever

    Chevyforever Veteran Member

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    Hoping you bent pulleys rather than the crankshaft. It takes a heck of a lot of force to bend a Chevy crank. Only the most skilled machine shops can straighten a mildly bent crank. IIRC it takes something like a 50 ton press to do so.
    If you were not so lucky, then at minimum you will require an oil pan gskt, timing cover gskt, water pump gskts, another crank with bearings at the least. If you are careful you can reuse piston rings.
    Super tight budget junkyard crank and bearings from donor engine.
     
  3. biker

    biker Veteran Member

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    Well I can tell you from personal experience that you very likely bent the balancer at worst. I did that same thing, and I checked runout at the balancer. Way out. I was convinced that I bent the crank. Spoke to an experienced machinist, he said check the crank itself with balancer off. I did, and the crank was perfect. Replaced balancer and pulley and motored on.
     
  4. reinhardt79

    reinhardt79 Veteran Member

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    I hope you are right. I really don't feel like pulling that engine apart. I was looking around the inter webs last night and found that a 383 crankshaft costs about the same as a 350 crankshaft. What else would I have to fiddle with to drop a 383 crankshaft in there?
     
  5. Dave Nelson

    Dave Nelson Veteran Member

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    I agree with the others, I doubt that you could bend a crank that way.
     
  6. 70lt1z28

    70lt1z28 Veteran Member Gold Member

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    Pistons. Different compression height on a 383 piston unless you use a 400 rod length of 5.565 inches (bad idea). As other have said, very unlikely you bent the cank. It is a very short distance to the the first main bearing so the crank is very strong there. You most likely bent the pulley. Even the balancer is cast iron and pretty strong.
     
  7. biker

    biker Veteran Member

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    Ye
    Yes the body of the balancer is strong, but what caused the runout on mine was the fact that the inside of the balancer that slides onto the end of the crank seems to be a softer alloy of some sort which basically "dented" from the hit. Very noticeable with the balancer off.

    Bang a new balancer on and go!
     
  8. C4Racer

    C4Racer Veteran Member

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    Or better yet use a balancer install tool! Just saying.
     
    Last edited: Dec 19, 2018
  9. biker

    biker Veteran Member

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    Yes... I actually DO use one!
     
  10. C4Racer

    C4Racer Veteran Member

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    Cheap and simple to use - I don't like hammering on things if I can avoid it.

    Balancer btw - probably sent from my phone that assumed I must have meant to type Balanced since Balancer isn't a word in Siri's world :crazy:
     

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