Ok here is the deal. I just bought a 90' GTUS for $850.00 with a seized or locked up motor I was told. the car has 99k original miles and is 100% bone stock. I bought from an older guy who cruised it every now and then. he said 3 months ago it broke. I got the car to my house and pulled the spark plugs and put alot of ATF in the front and rear rotor housings. let it sit for a while then tried to POP start it while someone towed me, the motor would still not unlock. so here are my questions.



1) how does a rotary seize or lock up? what causes it?

2) what is carbon lock?

3) how do you fix the problem if ATF does not work?

4) do I have to tear the hole engine down and rebuild it?



I would like any useful help on this situation please. I may sell the whole car for what I bought it for, if I can't unlock the motor. or I may part it. but its a GTUS so I'd rather sell the whole car.

 

theres a rubber plug in the bottom of the tranny, get a big screwdriver and use that on the flywheel to turn the motor backwards.



mike

 

or have someone tow you in reverse.

Really though, forcing the engine like that is a great way to break it. you're going to either tear apart one of the housings, or destroy an apex seal. Try spinning the engine backwards by hand on the eccentric pulley, or getting a wrench into the bellhousing to turn the flywheel nut (like j9fd3s said).

 

I bought a 12a that carbon locked on me. I bought a can of Amsoil Power Foam.

I filled the intake, exhaust ports and plug wholes with it and let it set for days.

I bought a 2 1/8th large socket and breaker bar and started trying to turn the motor back and forth at the fly wheel. At first it would not move. Each day i would top the engine off with more Amsoil. Slowly I got it to move, and finally one day I could do complete revolutions. After i broke it free I would put in auto trans fluid and hand crank the motor over pumping all the cleaner and crap out the exhaust ports.

It is the motor i have been running for over a year now in my 79 with 7.5 compression on all rotors.

 

Thanks guys, I have only had the car for a day now, I will let it sit for 3-4 days before I try again. I ended up putting ATF in the upper manifold and that way it will drain in to the engine. I will try the reverse method.



1) how does it lock itself? I don't get it does the apex seal get out of place? from what I can tell it does not look like the motor has been abused or beat up. I did try to put a 19 socket on the eccentric shaft pulley and use a breaker bar to try to un stick it but no luck. I'm thinking the wrost right now damn.

 

Carbon buildup will cause them to stick. Carbon build up is the black stuff on the tip of fouled out plugs. ATF isn't really gonna break through the carbon as well as like the amsoil foam. The apex seals won't "get out of place." There isn't enough room for them to just slip out even then they'd be torn apart before they jam up the engine like that. Plus you can't really tell if the motor was beat on from the outside it's nothing that a good steam cleaning job can't fix. That's the risk in buying a car w/o an engine.