'Quick' Main Bearing Replacement

Posted by InfiniteGSX, Jan 30, 2013
Cylinder Head & Short Block - 4G63 cams, valvetrain, pistons, rods, stroker kits, 6-bolt swaps, hybrids, etc. Read this Forum's Strict Guidelines.

  1. InfiniteGSX

    InfiniteGSX Proven Member

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    Tijeras, New_Mexico
    I have a quick question for a friend. He just rebuilt most of his bottom end after frying some rings and he did a good job with the motor in the car. Replaced the rod bearings with ACL's. New Pistons, New Rings, Honed the cylinder walls, MLS Head Gasket, New Valve Stem Seals. But he did it without pulling the motor or trans. So the Crank bearings weren't replaced.

    Car started up today and is running good. He has an idle issue we think is the FIAV but I setup his Butterfly set screw and BISS. and he went for a long drive for his first part of breaking it in. So far in my mind the motor is running great, Until he text me asking me why when everytime he presses the clutch, the motor dies........:sosad::banghead: My only explanation is when he fried the rings, he also damaged the thrust bearing.... Or the thrust bearing is just normal wear and tear but his motor is not strong enough yet. IDK.

    He still has the ACL Mains that came with his engine kit. So were wondering how easy will it be to do with the engine in the car. I was thinking it possible to pull the transmission, flywheel, and dropping the crank down not unbolting the rods and just pulling the mains and thrust bearing and cleaning the surfaces and replacing them that way. What are your thoughts? This motor right now is halfway in on a break in and the only thing that wasn't replaced was the mains. So he's about ready to tear it down so he can save his break in oil he just poured in.
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  2. abaum565

    abaum565 Proven Member

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    At that point with all the work arounds to keep the motor in, why not just pull it and do it right. Probably not going to loose much time and effort.

    To answer your question, I don't see why you couldn't do that.
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  3. InfiniteGSX

    InfiniteGSX Proven Member

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    Pulling a motor is much harder. I just wanted to know if people have done it, or is it too hard to get the block side bearings in with the crank hanging by the rods. Would like to just pull the trans since thats easy enough being FWD, and just drop oil pan, crank, pull bearings, clean surfaces and replace bearings and reassemble. I just feel bad for this guy, going through all this work to get his only car back running, to have the only thing he didn't replace end up failing also.
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  4. donniekak

    donniekak DSM Wiseman

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    It's impossible to get all of the honing grit out of the engine without washing the block. I bet all of the bearings have honing grit in them.
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  5. T is for TURBO

    T is for TURBO Proven Member

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    Yup

    Also, how is all of that stuff easier that pulling the engine. With two people, you should be able to pull the engine out in under an hour. I guarantee more time than that was spend dicking around trying to do all of that stuff with the engine in the car.
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  6. iugrad92turbo

    iugrad92turbo Proven Member

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    Been there pull engine get it cleaned out or other wise you'll have other issues down the road. for it once the right way.
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  7. gieri002

    gieri002 Proven Member

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  8. YZFR1

    YZFR1 Proven Member

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    Pull the main caps one at a time and replace the bearings also one at a time. If not, than you will also be replacing your front and rear seals. Use a nail to carefully guide new bearings in.
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  9. JacksonAuto

    JacksonAuto Supporting Vendor

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    The entire engine is contaminated with debris from honing the block. The oiling system is contaminated with this debris plus material from the damaged bearing. There is no way to clean it out short of removing the engine from the car, stripping it to a bare block, cleaning all of the parts and reassembling it once all the clearances are checked. Not to mention that after "frying rings" combined with mileage and wear, the cylinders aren't round. Installing new pistons and rings into worn, out-of-round cylinders kinda defeats the purpose of a rebuild.
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  10. InfiniteGSX

    InfiniteGSX Proven Member

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    I'm at a loss for words. So I'll just throw it out there, Engine is re assembled and running amazing and now have a few hundred miles on it going on first oil change now. Thx for the help. Guy did it all faster than I could type this up there.
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  11. lowell

    lowell Supporting Member

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    Keep an eye on the thrust measurement, and cut your oil filters open to check for debris. Glad to hear it worked out for you.
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