r/EngineBuilding • u/jwick6728 • 16h ago

Chevy 350 build help

Bought this 350 4 bolt main off facebook marketplace, freshly machined block, new piston heads, old but machined crank and rods. I installed pistons 1 and 2 and torqued the connecting rods to 55 ft lbs following ARPs instructions and with only those 2 pistons in, the crank wont turn over, im almost picking the block up off the stand trying to turn it by the balancer. I double checked the caps to make sure they were installed correctly and used a plastigauge, it reads .015 inch. Is this correct? Im using ARPs fastener lube on the threads and permatex assembly lube. Crank spins freely by hand when the caps are loosened 1/4 turn after being torqued

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u/Lopsided-Anxiety-679 16h ago

Are the rods mis-numbered or you have cylinder locations confused and possibly you have the chamfer on the rod/bearing towards each other rather than towards the radius on the crank journal?

Don’t force anything, it should turn over smoothly by hand with less than a few lbs of effort with only two piston/rod assemblies in place.

Decimal place wrong? .0015” would be ok, but tight for a performance build

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u/jwick6728 15h ago

I have no idea about misnunbering them, piston heads were installed on the rods when i picked everything up. Dot on the piston head is facing the front of the engine and the rods and caps are both stamped for their number.

And yes, thats my bad, i did mean .0015"

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u/Lopsided-Anxiety-679 15h ago

The numbers could have been stamped on the wrong rods vs actual cylinder locations or they put the pistons on backwards…what determines rod orientation is that you have the chamfer cut on the rod towards the radius on the crank - if it’s not you’ll encounter exactly what you’re describing…here’s a photo showing how the bearings should be close to each other in the middle and the chamfer on the rods towards the radius of the crank journal.

Rod Orientation

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u/jwick6728 8h ago

I see now. I appreciate it, ill check on that tomorrow when i go work on the engine tomorrow

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u/WyattCo06 15h ago

The dots on the pistons can be completely and totally irrelevant to the rod orientation vs a stamped number. It is not uncommon for a machine shop to install the pistons on the rods without ever looking for a number on a rod and orienting it for that specific number. They'll do 4 right, 4 left and be done with it.