Engine won't turn over... used to run fine!
 

I have just encountered a problem with my 88 RX7. It has not been driven this past winter, but I have been starting it up about once a week, with no problems. With the good weather I have just put it back on the road and been driving it around town for just under a week. I then took it for a good 3 and a half hour drive, which also went fine. Shortly after the drive I attempted to start it and the engine turned over about twice and then died because of a faulty positive connection on the battery. I fixed that only to realize that the engine seemed to have seized. The starter, which I checked and was fine, tried to turn over the engine without success and just "clunked" each time I turned the key. I wasn't sure if the engine had got stuck on some sort of compression stroke, and removed the spark plugs, but that didn't release any pressure. I also tried turning the main lug nut on the front of the engine, counter clockwise to try and free the engine. I had no luck here, as I couldn't budge the engine.

I'm desperate for advice on this problem. I know that rotaries do seize and carbon build up can be a problem but I always thought that it was only if they were left sitting for a long period of time. I had just done an oil change and everything was fine for the 3-hour dive. I even stopped for gas in the middle and turned off the engine. The car started up just fine.

Any suggestions? What should I do?

Sounds like a "spinned" bearing... Was your oil pressure OK before this happened?

I was watching the oil pressure most of the trip and it was fine, but didn't as much toward the end.... so I could have missed something. What is a "spinned" bearing exactly?

A spinned bering is when a bearing gets "stuck" to the ecxentric shaft and spins along with it either in a rotor or a stationary gear depending on which bearing got stuck or welded on to the shaft. This damages the shaft and the rotor or gear (once again depending which bearing seized). Hope this is not your case, I really hope I'm wrong here... It happened to me once and I had to replace the shaft and a gear...

Where should I go from here? Is there any other option then to take the engine apart? Also, why would this just randomly happen after the engine had been running problem free?

Make sure the starter drive is still not "stuck" on the flwheel teeth. Pull the starter and try turning it over by hand.

I did take the starter out... thinking the same thing as you, that it was jammed! The engine is still seized for some stupid reason!

Can anyone help?

Drain your oil and look for metal flakes in it... Also check for metal in the oil filter... I am assuming that you also tried to turn the engine by hand and have veryfied that it in fact is stucked...

this is what happened when my motor died...it made the clunk noise and seemed to be seized...it wasnt a bearing for me tho...i got a new starter and kept cranking it and tapping it till it it turned the flywheel...(while jumping the car at the same time)...when it finally started over i swear i heard it detonate (popping from within the block) then alot of afterburn and a super hot converter and that was it for my motor...hope your motor is aight good luck with it

I've been trying to turn the engine over with a 19mm socket on the main lug nut off the engine. I've been trying counter-clockwise without any success. I also tried spraying anti-seize compound in the spark plug holes to free it up but even after it sat over night I still couldn't budge it with the ratchet! I will have to check the oil.

I still really need advice on what I should do.... please help!

check the oil first and report back
spun bearing doesnt sound too out of reach.....

heh push the car put it in 5th and let off the clutch?/? lol

Okay... so I drained some oil and checked the filter as well. The oil seems perfect... no metal shavings at all. I just changed it about two weeks ago (20W50). So no metal visible in itl; or in around the oil filter!

I'm hoping this is a good thing.... Now why is my stupid engine still seized! This is stressing me out here. It is just such a wierd, random thing to happen out of the blue like this for no reason!

Any more suggestions of what the problem could be, or what to do!

Well when my bearing seized the oils was fine... Spraying anti seize in the housings will do no good if the bearing is welded to the E-shaft. The only thing that makes contact in there are the apex seals and side seals... Try another starter, if that does not work then it may be time for internal surgery... And no... it is not weird, bearings do get spinned out of the blue for whatever reason either poor lubrication or vodoo... Since you are working on the front bolt... go ahead and take it out and test the thermall pellet...

If standing in front of the engine, you need to try turning her clockwise (normal rotation direction), not counter-clockwise. Just a thought, doubt it will help much...

You could try taking all of the belts off of the accessories, then try turning it again. If she turns, one of the belt-driven components is seized...That's a reach too, though...

How many miles on the engine internals?

I've tried turning the engine both ways just in case... but it's totally stuck. I'm pretty sure it is a seized bearing. The engine has 190,000 km on it so obviously that's a fair bit!

How big of a job is it to fix this seized bearing... does the engine need to be completly taken apart? I just want to know what I'm getting into, and what's involved? Thanks!

according to him, youre gonna have to replace a gear and the e shaft...which requires tearing the engine apart.

Ya I've been looking at the diagrams of the engine internals, and it's definitely clear that the engine will have to be totally taken apart if this is the actual problem.

Since it does have high miles what else should I be looking at replacing? Or can I get away with just replacing the eccentric shaft and needle bearing?

Complete tear down and rebuild, probably...All seals, whatever the bearing damaged (if that's it), etc...

Is there any way to know if it is something else... or do enough signs point to it being the needle/pilot bearing seized to the eccentric shaft?

I'm trying to think good thoughts and maybe it will be something really easy to fix! Wishful thinking probably but does anyone know what else it could be... I've ruled out carbon lock!

Is there any way to know if it is something else... or do enough signs point to it being the needle/pilot bearing seized to the eccentric shaft?

I'm trying to think good thoughts and maybe it will be something really easy to fix! Wishful thinking probably but does anyone know what else it could be... I've ruled out carbon lock!

Probably not the pilot bearing at the back of the e-shaft, that's a fairly puny guy...

Take the exhaust manifold off of the side of the engine, and look into the ports for damage to the rotors or apex seals, that's about as good as it gets unless you have a boroscope handy...

Haha, it seems like people on this forum just make up answers as they think of them...theories, I guess. Here's the reality.

Most rotaries, especially mid to high mileage nonturbos, die from apex seal failure. The apex seals are thin wafers of metal that are spring loaded and slide in and out of a slot at each tip on the rotor. Stock seals have 2 long, thin pieces that form the seal, the upper of which does the compressing, and is the only one that wears. With time, the upper part wears down quite a bit, sometimes almost half it's original height. As this happens, the top piece tends to wiggle around, since it sits closer and closer to the open end of the slot as it's pushed up. Finally at some point, without warning or reason, it'll either break (*due to being weak and thin) and the pieces will fall out of the groove and do damage to everything else in that chamber (rotor, housing, and subsequent 2 seals), OR it'll fall out of the groove as a whole and do the same damage on subsequent rotations. Normally this happens at speed, with the momentum of the car (in drive) forcing the seal to break, tear off chunks of the soft rotor and rotorhousing, and get pushed on out the exhaust and keep on going (albeit with a large loss in power due to loss in compression).

However, on rare occasions (like this one apparently) these same events occur on shutdown or startup. Anytime you accelerate, decelerate, start, or shut off an engine, the top edge of the seal tilts one way or another (the engine is either applying power outward such as during startup or acceleration, or power is being applied backwards into the engine from the flywheel or drivewheels when decelerating or shutting off). So this tilting action just so happens to coincide with the seal finally coming out of the groove. However, at low rpm/low momentum times such as startup or shutdown, there isn't enough force to make the seal break and get pushed out, so it just wedges in place between the rotor and housing, and locks the engine up. Even if you do apply enough force (for instance, rolling and clutch dumping) in either direction, and make the engine break loose and turn again, you will have done the same damage that was started anyway...you'll break the wedged seal and force it out of the way, but the engine still requires rebuild.

Thanks a lot for the great advice! Now in this fairly rare case, will there be very minimal damage to the rotor housing etc? If the engine were to be re-built what would have to be replaced besides the apex seals? Would the re-build require faily little new parts since there probably isn't much damage and therefore not cost as much?

Ageman,

Listen man. Almost the same identical thing happened with me last year. Car ran fine, then, out of no where, I went to start it, and it was seized. In other words, the motor seized but not while it was running. Bottom line-I had to rebuild. Cant get around it. And from the sounds of things, I wouldnt attempt this yourself. Youre looking at (realistically) 1200-2000 for complete rebuild (all parts, labor, and install). Eventually most of face this...but there's no way around it :)