Engine partially locked up

[Dirtyl3um]

Alright so im trying to figure out what on EARTH happened. Here goes....

So i bought a motor and transmission from this kid for 400 bucks and put it in my project car. I also put an exhaust cam from another car on the intake side to raise compression a bit. Ever since i got the car started it had this obnoxious noise that sounded like marbles under the valve cover. Since there are no chain guides ( i did a top end rebuild) i figured i just needed to shim the lifters and that they were the culprit as far as the noise was concerned. Today i measured all of the valve clearances and only 1 was out of spec, and it was only .001 off. I figured while i had it taken apart i would make sure everything was nice and to spec. Now all my intake clearances are .013 and my exhaust are .014. Tada. turned the motor over by hand and it all seemed like it was going well. I put everything back together and go to start it. When the motor turns over i still hear the marble noise. My battery was all but dead so i jumped the car and tried to start it another time or two. Then it clicks, like the motor is locked up. So i get out a ratchet to see if i can crank the motor by hand and no bueno. Its the weirdest thing ive ever seen because the motor will turn about halfway over, but there is a point counter clockwise, and clockwise where it will no longer rotate. I thought maybe somehow the cam slipped, or there was a sticky lifter so i detatched one cam sprocket and took the spark plugs out of the motor and still the same thing. Then i emptied the oil and there is NO metal in it whatsoever.... ?????????????

I have NO idea what the issue is, All i can think of is maybe the cam bearing is jammed at that point for some reason? maybe that was the marble noise, and now its just locked up? Any idead would be amazing

[rblover]

sounds like a spun crank bearing, I had the same symptoms on my rb20 I bought the car from a guy who said it was just the starter, but turns out the main thrust bearing was crushed from a shotty transmission job, and that was that, so had to do a complete rebuild on bearings.

[Dirtyl3um]

dang okay, thats what i thought too... I accidently wrote cam bearing instead of crank bearing at the end of my last post.... I had a long frustrating day. lol Dang that sucks... guess its out with the motor and back into the garage....

[compactfean]

Ive seen valve seats detatch and drop into cylinders and lock stuff up...usually ending in a busted piston.

[240s_are_the_best]

maybe the cam was a few teeth off and the valve was hitting a piston? just a guess. when i built my motor i accidentally swapped the cams and it done the same thing you are describing.. turned over a half turn and wouldn't go any more. im just glad i spun th engine over by hand before i put it in and tried to start it.

[float_6969]

Yea, I'd pull the valve cover and make sure you don't have a broken cam. If you do, it can keep one set of valves open enough to contact the piston and prevent the motor from turning.

If I'm right, you're REALLY lucky that battery is dead, because the starter should have more than enough grunt to bend that valve and move it out of the way of the piston.