I have a 1988 Chevy C3500 with a 5

COLTEN_SIMONDS

MEMBER
1988 CHEVROLET CHEYENNE
107,000 MILES

I have a 1988 chevy c3500 with a 5.7 tbi 350 and recently I started rebuilding engine due to 2- spun rod bearings.I do not no exactly what to do with crank. I believe it needs to be undersized/resurfaced -0.010" due to minor damage(not bad) caused from spun rod bearings. Do I need to get crank turned -0.010" and just get -0.010" undersize rod bearings. If so would I have to change piston rods if I did that. Also I dont think there was any problems with main crank bearings but would like to get resurfaced also. Do I need to get that part of crank -0.010" undersized and just buy -0.010" undersized main bearings. I am having block bored 0.030" of inch over bored and 30 over pistons/rings im just not sure about connecting rods, crank, and bearings undersize

4 Replies

JACOBANDNICKOLAS

MECHANIC
108,179 POSTS

If the crank needs cut, check into getting a new one. You will have about the same money into it. If you decide to keep the one you have and have it cut, you need to cut it until there is no more damaged surface. I don't know if 10 thousands will do it. The machine shop will know. Then, you have to get bearings to fit to whatever amount was cut.

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Wednesday, January 23rd, 2013 AT 2:38 AM

COLTEN_SIMONDS

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What all will need to be done to the block when sent off to machin shop. I think the crank is ok but do I need to get it ballanced or turned. All I no is that cylinder walls are goin to get bored 30
over.

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Thursday, January 24th, 2013 AT 9:12 PM

JACOBANDNICKOLAS

MECHANIC
108,179 POSTS

Just have them bore the cylinders for you. You will have to get new pistons for the size change, As far as the crank, make sure it is in good condition and doesn't require being cut.

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Friday, January 25th, 2013 AT 11:51 PM

COLTEN_SIMONDS

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The part of crank where the rod bearings spun looks pretty good. But is there suppose to be any kind of stagger on the crank between where the two rods connect. I pulled all pistons and rods out then examined crank for any metal to metal contact or heat marks and all looked pretty good but the journal that connects the 3rd and 4th piston looked staggered a little. Where the 3rd rod connects to the crank looks a little higher on one half than where the 4th one goes, kinda like a little lip half way around that journal. Theres not any signs of heat marks or metal to metal it almost looks normal but as far as I no its suppose to be a flat surface all the way across all journals. Any clues?

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Saturday, January 26th, 2013 AT 4:41 AM