Car has been down for the past 2 months.. blew the 6 speed and went ahead and got a rebuild on it.. along with..


Moser 12 bolt.. ls6 intake.. cam.. clutch dual springs and the works...ARP rod bolts..

Car is a 2000 SS/ Ls1

Got all the parts and tore it down to begin the install... cam and valve springs first.. everything looked good... Next were the ARP rod bolts. During the ARP rod bolt install... after 2 or 3 of the rods were done we went to spin the motor over to get to the next one and it hit on something and caught.. wouldn't spin anymore in that direction. Instead we spun it back the other way and it hit again... after about 1/2 or 3/4th of a turn... the motor will hit again... we chalked it up as something in the flywheel hitting with the clutch or maybe the pistons hitting the valves...

We finished the rod bolt install.... reassemble everything and tore out the transmission to check clutch and flywheel.. pulled both.. motor still would onlyo turn 1/2 or more one direction.. hit.. 1/2 or more the other direction... and hit...

We undid the valve train.... it still hit.

We figured something maybe had fallen in the cylinder or 2 and was preventing the motor from turning over all the way... we pulled both the heads... nothing in the cylinders.. and it was still hitting.

Basically everything aside from the bottom end is off.. and the motor is still hitting and catching on something.

Any input would be appreciated... I guess pulling the motor and checking out the bottom end again is all we can do.. but I was hoping to get some ideas of what could be wrong before we go looking blindly..

All help is most appreciated... thank you.

 

Seems like a con-rod hitting the block.

Did you go stroker and forget to notch the block (not sure if you need to grind an LSx block)?

Failing that, possibly bearings out of round (clearance issues)? What is the
clearance between bearing and crank?

Connecting rod bolts: How did you install the rod bolts? What torque did you use?

 

This is a very simple set up.. its a stock Ls1 that we were adding rod bolts too.

The way they were installed was per ARP's instructions. Remove one bolt... replace with theirs.. torque 3 times at 45 ft lbs, torque.. break loose.. torque.. break loose.

The motor will turn fine for about 1/2 or more turn in one direction.. then hit something hard.. you turn it back the other way and it hits hard again.

 

is it posible that the head of the rod bolts are hitting the block or are the bolts longer than the factory ones and the threds are catching?

 

i am guessing the rodbolts hitting the oil pan

 

If it would turn over before, and the only thing that has changed are the rod bolts, then there's your problem. Take one of the old bolts and compare it to the new ones. Betcha find that the head is longer/fatter or something like that. Clearence on LS1's is tight to say the least from the factory. Gotta check it out! Hope you get it

Dave C.

 

STUPID Question...maybe.

Are you sure you did not drop a lifter while the cam was out?

Other wise it has to be the bolts but that is very odd as I know others running them with no problems.

Good luck man and let us know

 

The oil pan was off and the motor was catching still.... we didn't figure it'd be a bolt hitting so we didn't even look.


Will be pulling the motor soon.. keep throwing out ideas.

 

If I had to take a guess from what you've originally said, I'd say you have a piston/con rod in backwards. The con rods only fit on the crank one way. If it was installed backwards, it will bind up.

Since you were changing rod bolts, the heads had to be off. There's nothing that could be on the engine that would prevent it from rotating. I've seen things like too long of a bolt installed into a hole and it hits a gear or something but there's nothing like that in your setup that would cause that problem.

Other than a con rod installed backwards the only other thing I could think of is that one of the rod bolts is hitting on something like the block or the cam.

 

This is a stock bottom end ls1.. the bottom end has never been disassembled except to do the rod bolts... one bolt was removed.. replaced with the ARP's.. torqued 3 times to spec... repeated for each of the rod bolts... so I don't see how one could be in backwards.

 

did you find it yet?

 

Was the piston and rod pulled from the engine to change the rod bolts? If so then there's always a possibility it was reassembled backwards. Are the piston tops flat, dished, domed or any feature that can distinguish correct orientation?

Maybe a rod cap was installed backwards. Tangs on the bearings should be on the same side.

Until you tear it apart to inspect what's wrong, anything suggested can be possible.

 

The rods and pistons have never been out of the car, the rod bolts were installed as fallows.

One rod bolt was removed... a new one was installed. One was removed... a new one was installed. Never more then 1 stock rod bolt out of the car at once.

 

Well, I'm going to have to go with Ellis on this one then. If you got past doing the very first rod bolt swap and it still turned over, then the bolts are fine most likely. You said you pulled the valvetrain as well. Almost has to be a lifter dropped. The LS1 lifter keepers (that the right description) are very good at holding the lifter up when fairly new, but they can slip out pretty easy when the motor has some age on it. Pull a valve cover and look down in there to see if you have a lifter missing from the gallery...

Dave C.

 

Yeah you can't be sure that those lifter keepers kept the lifters up away from the cam.

That or if the cam was moved and is not lined back up straight.

Bret