y2k_ta

iTrader: (80)

Strangest thing ever. I have a 4.8L engine that I freshened up back in June. I put a Comp Cam, Valve Springs & Pushrods along with a set of Harland Sharp Rockers. I adjusted everything and it rotated by hand just fine during the whole process. I added fresh oil and buttoned everything back up. The last thing I did was install the underdrive pulley, and it was rather snug. Way tighter than any previous builds I've done. I did use a baby sledge to tap it into place. Was that my major screw up?

Fast forward to this week. I wanted to swap out the trans, and discovered that the engine won't turn over by hand at all. Even with all the plugs out & a cheater bar it still won't budge.

I wrestled the trans out of the torque converter since I was replacing it anyway. I had to do it that way because I couldn't rotate the engine to undo the torque converter bolts. One of my thoughts was that I moved the shifter point into gear while undoing the cable & bracket. With the trans in gear, that would have kept it from rotating. Well I tried all the gear selections without any luck there. Anyway, it still doesn't budge even with the transmission removed.

Now what the hell happened? Could the Crank Pulley be too tight or binding it up somehow?

I have a new transmission to put back in the car, but don't want to if I end up having to pull the motor.

Any suggestions would be appreciated. I've tapped my brain out trying to think up scenarios.

Scott

twelver12

iTrader: (3)

pull the crank pulley off and try again, i highly doubt it would lock up just sitting there

i have a 76 ford fe block that has been sitting outside for 20 years and still turns over just fine by hand

HotSilverBird

Using a hammer to install a crank pully is a BIG NO NO!

EricD

iTrader: (2)

You should have used a longer bolt to get the pully started on the crank snout and then pop the new gm one in , or better yet use the proper crank install tool with a bearing, how hard did you bang to get it started , Eric

EricD

iTrader: (2)

Would you believe i had a friend take a crank pully off with and impact gun on and lq4 that we changed the cam in , i wont tell you what i called him when he told me this , Eric

01ssreda4

iTrader: (96)

I would squirt oil in the spark plug holes and let it sit. Rings could be rusty from sitting so long. Dont hammer the pulley anymore That wil **** your thrust bearing up.

wytry

iTrader: (6)

I put mine back on with an impact.

nysbadmk8

Ditto.

y2k_ta

iTrader: (80)

That's what I was afraid of.....I guess I knew better.

I did use the old bolt to get it started on the crank, but the pulley was really tight. I tapped it a few times, tightened the bolt, tapped a few more times & so on and so forth.

I poured some Marvel Mystery Oil into each cylinder last night. I'm letting it sit for a little while longer before I try breaking it loose. I certainly hope that is the problem.

nysbadmk8

Im betting on a fucked up thrust bearing... If you hit it with any amount of force.

incbed

I am pretty sure the problem is that the rings are rusted to the cylinder walls,,,,Did you completly refresh the engine as in all new gaskets,,rings,,bearing,seals????/or did you just add a cam,springs,and push rods???

I have removed a 5.3 with 125,xxx miles on it from a GMC Sierra that had been involved in a head on collision and the front bumper and everything else was pushed into the front of the engine including into the harmonic balancer. After the front end was cut off the engine was removed inspected for block damage that may have been caused by the impact the engine recieved. The engine was then installed in a friends Silverado that he is still driving with now about another 30,xxxx added to that engine with no problems.

I wouldn't use a hammer to install the harmonic balancer ,,,but I know that by him using a hammer isn't going to lock the engine up if any damage was done by using the hammer then it would have been damage to the Crank bearings,,,which bad or damaged crank bearings is not going to cause the engine to lock up.It will cause it to knock and loose oil pressure ,but not lock up.

Just my 2cents ↑↑↑

y2k_ta

iTrader: (80)

The engine had just a little over 50,000 miles on it when I bought it. I didn't tear into the bottom end at all. I just swapped the cam, springs, push rods & lifters.

I pulled the crank pulley off this morning to see if that was the cause. It's still not budging.

WetChicken

iTrader: (1)

I also vote rings. when you freshened it up, did you run it at all? If the cylinders were dry, without lubrication that leaves them wide open to moisture.
Yank the pan and/or heads and take a look at the cylinder walls. You might be able to peek through a plug hole, especially if you can borrow a little camera.

y2k_ta

iTrader: (80)

Nope, I didn't start it. I wasn't far enough along with the wiring to do that at the time.

y2k_ta

iTrader: (80)

I just went out and was able to break it loose! Thank you for all the helpful suggestions! I really appreciate how helpful the membership is here.

Scott

adkunlimited

so what was the problem?

y2k_ta

iTrader: (80)

I would have to assume that some or all of the cylinders took on some moisture at some point after June, and just seized it up. I guess the Marvel Mystery Oil penetrated enough for me to break it loose. Nothing sounds out of wack when I rotate it, so that's a good sign.

adkunlimited

oh ok, well im glad you got it to turn. good luck with the build