Engine clearance specs

[pivichot]

So, I think I got bad news. The crankshaft main bore are not all round. Here is an excel sheet with the measurements. The dial bore was set to 2.4412 with max being 2.4420. The 1st and last main were good, since they were within spec but still weren't round.


Also, what ARP says of the block needing to be line-honed is true. Installed the ARP hardware and everything was off. I checked more than 10 times to make sure the gauge was always zero. Even checked the micrometer to see if it was calibrated and it was dead on on zero.
I think I may need to take it back to the machine shop

[gadget73]

Not sure what the OOR tolerance is, but thats 8 ten thousandths of an inch. Your chart seems to indicate .0006 difference on the center journal though. OOR tolerance is specified at 0.0005". Now you get to decide how picky you wish to be. Its probably good enough, but if you want it dead nuts it needs to be align bored.

Torque on the caps will distort things. The measurements should be made with the caps on and torqued down, since that reflects what the bearings will "see" when installed. I doubt that you'd get much difference with the ARP hardware vs the stock at the same torque value though. Torque is torque as far as the caps are concerned.

[pivichot]

Not sure what the OOR tolerance is, but thats 8 ten thousandths of an inch. Your chart seems to indicate .0006 difference on the center journal though. OOR tolerance is specified at 0.0005". Now you get to decide how picky you wish to be. Its probably good enough, but if you want it dead nuts it needs to be align bored.

Torque on the caps will distort things. The measurements should be made with the caps on and torqued down, since that reflects what the bearings will "see" when installed. I doubt that you'd get much difference with the ARP hardware vs the stock at the same torque value though. Torque is torque as far as the caps are concerned.

Just got the block back from the machine shop. The owner said that it is okay. He measured a difference of 0.0010 on the mains throughout. He said that it is fine since the oil clearance is allowed to be a little loose compared to stock. That he has done this on several engines and its okay. Just said to run 10w-30 oil in it. If he says its good, I guess I can't complain. He also said that if I have it aligned honed and then disassemble the engine once it runs the same thing will happen to the block.