tj613tjtj

ok so the run down, this past weekend I was doing a cam swap on my 01 z28 I did everything correctly or at least I thought I did. when I started it all I heard was valves meeting pistons and then I tried to start it again and the motor seized after closer evaluation I realized that when I installed the new timing set I used the advanced timing keyway on the 3 key for the crankshaft and used the factory timing mark. causing the crank to be 150-160 degrees out of timing clockwise. I know I have bent valves but I don't know if I have holes in my pistons until I take the motor apart. for closer evaluation. what are you thoughts

G Atsma

My thought would be, no one knows what's in there until you take it apart. Guessing would be of no help here.

tj613tjtj

very true, I just hope no valves went through pistons. it was such a rookie mistake to make, I was in such a rush to get the motor back together. when I started it you could definitely hear 1 or 2 valves hitting pistons through each rotation. Im gonna pull the heads off this weekend.

Chris25

iTrader: (1)

Ouch man that sucks like he said wont really know the carnage till you pull it apart.

tj613tjtj

it most definitely does. hopefully the pistons are in decent shape so I can just rebuild the heads and call it a day but if one is cracked then I have to pull the motor

Chris25

iTrader: (1)

Yah it happens man just got to learn from it and put it back together.

GammaFlat

iTrader: (1)

I had a Honda 4 cylinder lose a timing belt. When it was "done running", it would spin very fast - as if no compression.. huh!? All valves were bent - no reliefs in pistons. I liked the car so much (87 civic) that I redid the head. Ran better than ever until 1 week later I was hit from behind. Car was totaled. Neck was stiff. Broke my heart.
I'm a little frightened that you're locked up. Best case is a bunch of bent valves - parts cost probably 300-ish with gaskets and all. Worst case is valves and pistons. If pistons are involved (you'll know when you get the heads off), it'll suck having to remove the engine but finding used factory pistons.... probably not so expensive with so many folks "upgrading".

Good luck in any case. I feel your pain.

JakeFusion

iTrader: (7)

Always a good idea to rotating the engine over by hand before firing it up. You'd have felt things "kick and stick" then.

But if the motor is toast, just pick up a junkyard 5.3L motor... better for a turbo anyway.

Dorito23

Any updates? Did you get the heads off yet? I'm doing a cam swap next month so I am definitely glad I read this. Just one more thing to be reminded of when doing the install. Curious to hear and/or see the damage done. Good luck!

tj613tjtj

So I got the heads off last weekends. The crank was 120 degrees advanced causing 7 exhaust valves to break. When they broke the broken valves flipped upside down and as the piston cam back up the valves punched through the pistons. I ripped the motor out on Sunday. Rebuilding it this weekend got new pistons and ls6 prc stage 2.5 milled .20 over so it will be sitting at 61cc with the cam it should clear no problem. Gotta rebuild the bottom end this weekend throw the heads and and then measure for new pushrods. I'll throw some photos up later today of the carnage.

tj613tjtj

if you are using a cloyes hex a just timing set with the swap make sure you get the instructions online for timing correctly bc they dont come in the box. The crank gear is a 3 key way for advancing or retarding timing per cam. So with that being said if you dont want to mess with it pick up a factory timing type timing chain set or just pick up an ls2 timing chain. Also when you are changing or taking off the oil pump YOU HAVE to unbolt the oil pan and drop it at least an inch or two to get to the lower oil pump bolt that connects the pickup tube. If you have any question mid swap feel free to ask.

td1168

iTrader: (2)

tj613tjtj

For all who are interested ended up rebuilding the bottom end, redid the timing and threw together some PRC ls6 heads with the cam and new injectors. After priming the motor, oil pressure spiked up and it started like a dream. Idles horrible and will shut off when stopped but nothing a tune cant fix. Cant wait to break in the motor and put her on the dyno