I was putting together my bottem end today so I could mark where to clearence the block for my 383. Everything was fine and turning over easy until I bolted on #5. I never got a chance to check bearing clearences today [will tomorrow] but Im guessing this one is going to be really tight? What can I do about this? Its a new scat 9000 crank, re-sized Gm 5.7" rods and arp bolts.

maybe the piston is fitting waay too tight in the bore. maybe pop it back out and push the piston in that hole upside down to see if that's where the extra drag is coming from.

Piston slides easy. I started checking clearences, all the mains were between .002-.003, and the one rod [#5] that stops everything is .0015", what are the limits for the mains and rods?

Did you check to see if the block needs a line bore.
JMOP Bob J.

Originally posted by Bob Johnson:
Did you check to see if the block needs a line bore.
JMOP Bob J. How does this affect the rods clamping effort on the crank journal?

I'm guessing that you've accidentally swapped two rod caps. Leave #5 off for now and continue installing the others. When you find another one that locks the engine, swap that cap with #5 and I bet you find the two that got mixed up.

I always spin my crank as I torque the mains down. And at say 25 pounds or so more or less, I use a BFT and a hard block of wood to set the thrust bearing first by a couple of whacks on the front and then a couple a whacks on the back!! Then I sneak up on the final torque numbers by spinning it as I do it in steps. This way I know if I have a problem b/c the crank would stop spinning!!

You might try it??

pdq67

You can buy .001 under or over size bearings if needed.

Put 'another' rod on that journal. If its also 'close' its the journal, if not, its the rod.

Originally posted by bored&stroked:
</font><blockquote>quote:</font><hr />Originally posted by Bob Johnson:
Did you check to see if the block needs a line bore.
JMOP Bob J. How does this affect the rods clamping effort on the crank journal? </font>[/QUOTE]Sorry, I started to think before I copleate the reading. graemlins/clonk.gif

Well I took #5 piston/rod and put it in cylinder #1 and bolted up. No problems spinning over. Then I took piston #1 and put it in cylinder #5, again no problems. So Im just going to change the bearings between the two and should be fine. Very weird.

You may have tried to install the rod cap backwards without knowing you were doing so. It sounds like you have a handle on it now.