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Engine is really tight!


Wes Flippen

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Just did an in engine overhaul. Valves, guides, pistons and rings. Used standard size pistons and rings. Torqued rod caps to 50 ft lbs per manual. Engine seems really tight now. Even with the head still off, I had to use a 3 ft breaker bar on the crank shaft to get it to spin. Used assembly lube for new valves and wrist pins and dipped pistons in oil before installing. Any thoughts?

Wes

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Checked gaps, They were actually about .002 over spec, so I didn't gap any more. Pistons went into cylinders fairly easy, just light taps with hammer handle. Crank got more difficult to turn as each piston was installed. After the second piston, I could no longer turn it with the fan. I guess my next course of action is to remove the rod caps and check that the bearings are all properly in place. May just try bumping it with the starter to see if it'll turn over.

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Did you check the rod bearing clearances?

 

Years ago, when I was a pup and still peed on the floor, I was putting new bearings in a 400, was worry about spun bearings.  So I put a touch of locktite on the back of the main bearing shells.  I could not turn that engine over at all, even with no pistons installed.  I didn't think it would make a difference, I was wrong.  Doesn't take much to bind it up.

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Once while rebuilding another brand of V-8 motor, I could not turn over as said. When checked bearing clearances with plastic gage one bearing shell was mis-markedon the box and oversize for the cranks size !

 

Worth checking and cheap!

 

DJ

Edited by DJ194950
add box info
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My question is "Did you mike the pistons to see the exact size,and did you run a mike through the bore to size it,also. You said it seemed to get tighter with every piston you installed,so that would be the first place *I* would check.

It is not unheard of for machine shops to bore the blocks to a different overbore than the customer wanted. Or for piston manufacturers to send the wrong size pistons.

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Doesn;t take much.  I learned long ago to spin the crank around at least once after each rod was installed and torqued, when go back and retorque each rod once all were installed.

 

Glad you found it and glad you let us know the issue.  Thanks.

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some ill informed people may regard that big lump of cast iron as being pretty crude

but it is actually a precision fit machine..... as you have recently learned.

 

with the care you have exercised, your overhaul should be a long lasting success. Best of luck.

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