Think I blew my 3400

[alerored04]

On my way home tonight I pegged the car around a roundabout. RPM's jumped to 6k and hung there without shifting, I bumped the throttle to try to make it shift, I thought the tranny was dying since the car has 130,000 miles. As soon as I touched the throttle the RPM's dropped to 1K and whenever I touched the throttle they would drop to 500 and climb back up after I got off the throttle. I coasted to a stop, the car sputtered and died. I tried for a restart but all I could hear was a spinning starter, no compression, no cranking at all. Ideas? I am totally stumped.

[torq455]

sounds like the tranny didn't want to shift. if there isn't cranking then maybe the pinion isn't engaging the flywheel. funny that's a problem too. it possible your flywheel didn't come unbolted from the crank?

[alerored04]

Where would you start looking for issues?

[torq455]

make sure there is oil in the crank case and it's a good color. the check the tranny level and color, well at least the color. you can only accurately check the tranny fluid with the engine running and tranny hot. pull the starter and make it work with jumper cables. if it still just spins and won't kick the pinion out, then it's a bad solenoid. you might be able to take that apart to see if you can clean it up. otherwise, you'll need a new one.

when your engine held 6k rpm, was the tranny up shifting or down shifting? i've had a car that would down shift at WOT and not engage 1st and would miss the gear. if i kept WOT for 1 or 2 seconds more it'd grab 1st and leave skid marks. kinda like a stick shift down shifting without taking your foot off the gas and snapping the clutch out.

holding these engines at 6K rpm won't hurt them. the bottom end stock will hold fine to 7K rpm. the stock valve springs is the rev limitation.

[alerored04]

It just held 6k without shifting at all, like it was in neutral. I have LS1 valve springs so the rpms should not have hurt them unless the valves contacted a piston but I didnt hear any noises to make me suspect that.

[IsaacHayes]

Yeah my trans will do that if you have it in OD and it kicks down to 1st. It seems it goes from 4th to 1st but sometimes it will get stuck in neutral and you let off and it shifts. One time I did not let off and it finally shifted and did leave skid marks while going 30-35mph. I now keep it in D when in town, and it goes from 3rd to 2nd then to 1st, and never has issues. Plus being in 4th in town 35-40mph is silly it just upshifts/downshifts all the time.

Engine *should* be ok, maybe something else failed, and is also the reason why it won't re-start? Do you have a code? Is the motor turning over when starting or not? Did you try tapping the throttle any while starting?

[alerored04]

Compression on Cyl 6 is 0 and 4 is 25psi. I may be doing it wrong though, how tight should I be putting the check valve in there? Will it seal properly? I will most likely pull the starter and see what is up. Any other ideas?

[torq455]

if it won't turn over then you can get any compression. this sounds weird, like you broke either a cam or the timing chain. just an unusual group of things gone wrong.

[alerored04]

Well it is kind of turning over. I can hear a few pops. I just pulled it down to the heads. Those will come off tomorrow. So far there is nothing obviously wrong. All the rockers and pushrods are straight and there were no coolant leaks from the lim or the heads. I stuck a piece of wire in the spark plug holes and all the pistons are moving, even the ones which came up with low compression. I did not check the other cyls for compression. The cam looks like it is turning but i already removed the pushrods so I can't tell if it is fully rotating and opening the valves. Anyone know the best way to check the crank for damage?

[bszopi]

I'd suspect the cam before I suspect the crank. There have been 2-3 people recently who have snapped the stock cam in 2.

[alerored04]

Timing chain jumped and all the exhaust valves made contact with the pistons. The chain did not break cause before I removed the rockers I spun the motor by hand and all the rockers were moving. Very odd deal. Anyone know what a rebuild costs? My dad wants me to use a junkyard motor but I really dont want to do that since I would have to tear it apart to install my ported heads and manis anyway. Any suggestions on cheap things to do to make this more fun?

[IsaacHayes]

3500 top end swap? I'm not sure if the pistons are ok if you could re-use them as is?

I wonder if the older 99 and down chain is less prone to skipping.

[alerored04]

I have ported heads with ls1 springs so I will be staying with those as well as a 3500 uim. The pisons seem fine. They have small valve marks on them about the size of the end of your thumb but not very deep. I have spoke to two builders about it. One said he would definitely pull the motor down to check the pistons especially the rings, the other said the odds of damage with such a small indent are low and he would put it back together as is after fixing the chain. Opinions? How much more work is it to pull them to check once I am down to the timing chain? I will already have the oil pan off, can I take them out from the bottom without causing much more time and money lost on the deal? Are the rings and bearing reusable if I remove the pistons? Or at that point will I be into a full rebuild? I need to keep this as cheap and quick as possible since this is my DD and I just graduated from college and am jobless at the moment.

[SappySE107]

Pull the pistons/rods out the top and label them. I would tear it down and put some different pistons in there. Maybe bump the compression up as well. I wouldn't want those pistons in my motor, as its just a place for a crack to form.

[IsaacHayes]

Check that the exhaust valves are not bent too. You need to verify that. It may look ok but not seat.