ss496

iTrader: (7)

i started putting together my motor tonight, and after checking everything with a plastiguage, then torquing the main caps, the crank wouldnt spin. took it all apart. everything seemed aok, tried it again, and it still wouldnt spin. Im pretty sure the problem roots from the thrust bearing (#3) any suggestions

specs:
LS2 block std.
Stock GM crank turned 10 with matched clevite 77 bearings
ARP 12 pt main studs
GM bearing caps

BTW this is my first shortblock


TIA

edcmat-l1

iTrader: (10)

Are you sure you have the main caps on the right way? If you think its the thrust, take all the main caps off, except for the thrust, torque it to 18 ft pounds (no need to torque it to specs at this point) and see if the crank spins.
I would bet you have one or more caps on backwards. They can go on either way.

OneQuickCoupe

iTrader: (1)

Also take a look at the crank journals, (main and rod) to see if the crank grinder went all the way out to the edge of the counter weight. If he left a gross radius at the edge, your bearing may be touching in the corner not allowing the crank to spin.

D.J.

67RSCamaroVette

iTrader: (63)

we torqued the center cap only (25 ft-lb) and it will not spin. crank spins freely if just placed in the block. bearing only fits one way in the cap...

OneQuickCoupe

iTrader: (1)

What kind of clearance do you have on that center bearing using your plastiguage? Or that thrust is kicking your butt. If you have some Dyekem layout dye paint it on the thrust surface. Install the cap and just snug it down. Rotate the crank then remove the cap. Look at the Dyekem to see if it's hitting on both sides, (front and rear). It should give you an idea of where the problem is. If you don't have Dyekem use a Magic Marker. The only other thing I can think of is the crank is bent or the crank grinder F'ed it up some how.

D.J.

LS1MCSS

iTrader: (18)

My bet would be the radius on the journals.

edcmat-l1

iTrader: (10)

Do you have the MAIN CAP on backwards? You can install them either way.

OneQuickCoupe

iTrader: (1)

edcmat-l1,

I thought he checked that before his last post. I'm with you on this.

D.J.

mark AJB

did you start with a bare block if so the bearings have a spec order they go in.

edcmat-l1

iTrader: (10)

No they dont. They're all the same except the middle one. Its the thrust bearing.
The cam bearings have specific locations and cannot be interchanged.

Darren P

iTrader: (1)

when my engine was put together it had the same problem

it was the Thrust bearing

the main cap needs to have a small angle ground onto the corners

if you look at the bearing it has a 45 degree angle on the inside corners

67RSCamaroVette

iTrader: (63)

the caps are in the correct direction. all other bearings are fine. it's the thrust bearing. we'll check for the angle and for a contact patch. it's not bearing diameter, plastigauge checks out fine at .015.

N4cer

iTrader: (11)

So at least we know your clearances are already too tight right?
Be SURE those caps are on right. 1-4 the tips face rearward, and 5 faces forward.

OneQuickCoupe

iTrader: (1)

.015"?, or .0015, It must be the second one, correct? A little on the tight side.

D.J.

ss496

iTrader: (7)

the journals all seem ok, and the caps are all in the correct direction. i have been told by two people to sand the bearing down using sand paper on a piece of flat glass. any have experience with this?

edcmat-l1

iTrader: (10)

If you think its just the thrust bearing, install the rest of the caps and torque to 18 ft lbs and see if it spins.
Then if thats good, take the crank back out and see if the thrust bearing fits in the crank with the crank and bearing out of the block.

Whistler

iTrader: (46)

Did you seat the thrust before torquing it down? How much endplay do you have? Factory is .0015-.002, but you can have as much as .005-.007 If there's a problem with the radius on the main journal you will probably have none at all.