Seized 355 help

[Camaro96]

Sorry to hear that you will have to go through all that work to pull her back out. That's not too bad if you have a 2 post lift. If you do not its alot more work to remove engine back out with out the lift.

I have reread your initial posr somewhere I missed that you had a standard transmission with a McLeod clutch.


As for my experience with the lt1 2nd generation engine you are right they are externally balanced. When I rebuilt mine I took the rotating assembly with harmonic balance hub and flex plate along with the rotating assembly and had it balanced. The original rotating assembly was balanced with your original harmonic balancer and hub and original rotating assembly along with the flywheel or flex plate was all balanced together from the factory when the car was built. With that being said. When you upgraded the rotating assembly changed the parts that were balanced originally with the harmonic balancer and crankshaft hub and flywheel being upgraded it all needed to be balanced to work together in harmony.

Did. The engine rotate on the engine stand?





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[BALLSS]

OP

you need to pull the engine and tear it down to find WTF this happened. The metal shavings are likely from the "problem", not the "cause" of the problem.

from this side of the internet can't say why or what happened. The motor got rebuilt by you or someone...and something was not done right. Sounds like you have spun bearings to the point the crank & rods have seized together. If it ran long enough maybe the pistons seized to cyl but from what I gather it didn't run that long

Balancing...."most" balance rebuilt motors "internally" meaning the harmonic balancer (stock is already zero aka neutral balance) and the FW/flexplate need to be zero balanced (stock are not)

your McLeod twin FW has a weight that screws on for stock "external balance" motors and without is "neutral balance" for internally balanced motors. you don't need to include a harmonic balancer and FW in the balancing procedure for the rotating assembly IF it is a internal balanced motor and IF the harmonic balancer and FW are zero aka neutral balanced. It is highly recommended you have your FW, floater & PP of the twin separately neutral balanced to confirm they are if building a internal balanced motor. My "new out of box" neutral balanced McLeod twin was 26 grms out of balance. Because the 4 holes drilled in FW removed 26 grms. The machine shop put 3 screws with washers in the holes to zero it out.

once your motor is apart a qualified machine shop can see if the crank is salvageable to be ground down, same for the rods. If all is junk you can either get a junkyard motor and harvest the rotating assembly and do this again or get a stroker crank/rods/pistons and go that route

[Down]

I'll be taking it with the FW/jegs hub & see if any of it was the cause. I really think having no weights on an externally balanced motor fkd it up just running the motor in the air/moving the car. I'd like to see what the cause was, also where my misfire lies. Was horrendous.

Only thing that sucks is the person I bought it from didn't tell me if it was internally/externally balanced, what oil to use, & I just found out the LE2 heads in this motor..... aren't Lloyds' heads. This is more devastating then anything. Was flat out lied to & taken advantage of. I don't even want to say how much I've got into this. Really is aggravating/depressing. Guess I'll have to live & learn. It's been a few years & of course there's no contact info available/not responding.

If it's too much to repair guess I might be parting it out if I can't find a good long block for now. Really don't want to send this 97 SS to the crusher. Only has 60k miles on the car too. Full suspension, even has a few parts from INTIMID8Rs car (sheet metal intake w/tb) from speed Inc not installed yet. IForged wheels, ls1 brakes, just sucks I guess.

Sorry for the vent/rant.

I'll update yal when it's been sent to the machine shop.

[bufmatmuslepants]

Pull a head, or use a harbor freight camera thing and peak inside a spark plug hole. Are the plugs out when you try to turn it over? If there is debris in there, and it scarred a wall, and you are already 0.030 over, you may need a new block if 0.040 can't save it, 0.060 might but you'll get mixed opinions on 0.060 over.

[Camaro96]

Pull a head, or use a harbor freight camera thing and peak inside a spark plug hole. Are the plugs out when you try to turn it over? If there is debris in there, and it scarred a wall, and you are already 0.030 over, you may need a new block if 0.040 can't save it, 0.060 might but you'll get mixed opinions on 0.060 over.

I agree with bufmatmuslepants I had an issue when I pulled my engine and built a 355. While I was attending mechanic school. I had issue with the engine passing oil thru the exhaust and took it to a local performance shop to have it looked at and he took a bore scope down one of the spark plug holes and said there were gouges in the cylinder walls. He wanted to sale me a caprice engine and install it and by the engine that I just built for 500. I declined to have then engine Sale or swap. When I pulled the engine down it was just having the plugs removed from the bottom of the intake. I decided to stroke the engine to 383. The gouges that he seen with the camara were just the cross hatching done when the machine work was done. I think you may just start to disassemble the top end and try to rotate the engine as you take each part off until you find the cause. Good luck it will be interesting to hear what you find. Please let us all know what you find.

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