Probably would start by taking the oil pan off and checking torque specs and just seeing if anything is out of place.

Did you blue print, measure each and every possible part of the assembly? Because how can any of us help?
Since we are to guess, sound like you tossed a rod bearing.
I'm sure you cleaned the mating surfaces with some sort of alcohol. Yet this things can happen. Drop pan and you will know.

Sounds like a rod knock if it varies with rpms

scrappys93talon said:

Ok so i have a 2g
Rebuilt another engine with all new bearings and a built head w/ crower 272s
And come to avail i start the car after priming the oil pump and im getting a knock from the bottom end, and when i rev it up it sounds like the police at the front door.
End play is within spec, rods have new bearings and mains were replaced with king xp bearings

Click to expand...

You can't just slap new bearings on an old crank and call it a day, which is what it sounds like you did. The original bearings wore into the crank and now the new ones are out of tolerance. So the crank potentially has a flat spot on it where the old bearing wore into it, new bearing is perfectly round so you will have problems

chrysler kid, Yesterday at 1:16 PM #5

You can't just slap new bearings on an old crank and call it a day, which is what it sounds like you did. The original bearings wore into the crank and now the new ones are out of tolerance. So the crank potentially has a flat spot on it where the old bearing wore into it, new bearing is perfectly round so you will have problems

Sorry man but that is where you are wrong,
The bearings ONLY eat into the crank if you spin a rod/main bearing which i didnt
When you use bearings on a good crank with good oil supply, durring the initial break in process the crank will ware the bearing slightly.
From what ive found the act 3100# xx series pressure plate was way too much on my engine and was forcing my crank to lock down on my thrust bearing, after changing my clutch to a 2100# pressure plate, i heard the knock.
With the help of dsm pat on here comeing by tonight we found that the thrust washer prematurely failed from the force lock from the pressure plate, thank god i have an extra set of acl tri- metal mains

miliman13 said:

Did you blue print, measure each and every possible part of the assembly? Because how can any of us help?
Since we are to guess, sound like you tossed a rod bearing.
I'm sure you cleaned the mating surfaces with some sort of alcohol. Yet this things can happen. Drop pan and you will know.

Click to expand...

Yes i blue printed the motor, did the same on my stroker too, up until i raced a nitrous sbc and threw 30psi at it, that told a couple of rods to spit bearings since the oil pump was out flowing the oil return from the head to the pan (oil pan was almost empty while the oil was trying to drain from the head and turbo back to the pan durring hard acceleration )