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Old 06-12-2010, 04:32 PM
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Can't turn engine by hand

I'm building a chevy 350 and i just put the crank and pistons in. The problem is that when i tighten more than 2 of the rod caps down the engine won't turn by hand. I could turn it with the flex plate before i took it apart, but now it won't budge if the rod caps are torqued down.
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Old 06-12-2010, 04:48 PM
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35 to 40 lbs. with torque wrench on crank nose bolt. With only 2 rods you should still be able to turn by hand. Check clearance / cap orientation etc.
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Old 06-12-2010, 04:55 PM
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thats the problem, i have the stupid crank with no balancer bolt so it's hard to turn it with the flex plate.
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Old 06-12-2010, 05:14 PM
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Also check the rod direction. Look where the bearings ride in the rod, each bearing has a lock, the locks should be on top of one another and the locks should point to the outside of the block. Also check the bearing clearance, if it`s off, even by a few thousands, it`ll make it too tight to turn.
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Old 06-12-2010, 07:37 PM
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Alright, here's what's going on: I have torqued all the rod caps down except for the #5 cylinder and it turns nice and easy, but as soon as i put even 10 pounds of torque on the #5 cylinder rod cap it won't move at all. I've tried using the caps from a different rod, with the tab facing towards the outside and inside, and anything else i could think of. I don't know what to do.
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Old 06-12-2010, 07:42 PM
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Then you`ll have to have the clearances checked. Don`t never mix rod caps, mixing them can cause disasterous results. This is why it`s recommended for novice engine builders to number both rod caps so they all go back in the same hole they went in and the caps don`t get mixed.
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Old 06-12-2010, 07:45 PM
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I've got them all in the right place thats why i don't know what's going on with it.
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Old 06-12-2010, 07:48 PM
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The pretty much all that`s left is the bearing clearance is off.
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Old 06-12-2010, 07:57 PM
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Alright, i'm gonna have a mechanic check it out.
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Old 06-12-2010, 09:07 PM
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did u have the crank turned down. After all of the pistons are installed you should be able to turn the engine over with around 45 ft lbs. of torque. How are you installing the bearings? Are you installing the bearing on the rod and the cap and then applying assembly lube or are you putting assembly lube on both sides of the bearings? I have heard if you put assembly lube on both sides you will run into problems. Do you have a dot or dimple on the top of your pistons? The dot on the piston should face the front of the engine with the tangs facing the oil pan rail. Are you using the correct size bearings? Take the crank to a machine shop and have the sizes checked.
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Old 06-12-2010, 09:21 PM
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Quote:
Originally Posted by DoubleVision
Then you`ll have to have the clearances checked. Don`t never mix rod caps, mixing them can cause disasterous results. This is why it`s recommended for novice engine builders to number both rod caps so they all go back in the same hole they went in and the caps don`t get mixed.
hhhmmm.... that would mean "Always"...
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Old 06-13-2010, 02:44 AM
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If you had the rods resized, the shop might have inadvertently swapped it w/another 'wrong' cap.

I'd return the rod and cap to the shop and have them re- resize it to make the rod fit correctly.

Then you should recheck all the clearances before going ahead w/a the assembly.
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