motor tear down, busted #3 main cap, linebore question


wana steal it? meet mr9mm
Staff member
Nov 24, 2001
heres the short story-
i just purchased another motor and trans, and tore down the engine.

#3 main cap either broke when i took it out, or had just broken 2 miles before the guy parked it due to a flat cam lobe-

for what i can see there are no cracks in the block, everything looks good for 170K....

only the rear main cap bearing started to swuash out, maybe reynolds aluminum foil thickness, it just started to push from the crank flexing, or over revving the motor???

the car only went 11.8s at 115, but the miles are high...

i want to just throw new bearings,rings,cam,ect to get it running next weekend-

can i just get another main cap and put it in this block, or do i have to get it line bored for the mains?

basically, whats going to happen if i just put in a new cap and dont line bore it?

thanks for any help

You must have a line bore done if you put on a new cap. The caps need to be fitted properly and this is achieved by the line bore. Your bearing clearance would be way out of wack for that main cap and it wont fit correctly in the register.
so if another cap was put in, without a line bore, then it would shift the crank out of line and possibly bust the crank in half when making serious power right?

I doubt the crank would even turn over if a new cap was bolted on. Must be machined