Seized motor (from rust). Suggestions?
 

Hey Everyone,

I'm a new member here and new to rotory engines in general, however I have been building different cars including turbo imports for a while. So not a complete noob : ) I'll try to give all the important details about the car and what I've done so far below. Any help is much appreciated!!

The car:

1993 Base RX7 Automatic
127k miles.

The story:

Okay, so here is the story I received from the person I bought the car from... The previous owner, let's just call him Jim, used to see this car in his subdivision sometimes when he was driving home. Apparently someone in his subdivision had owned it for a number of years (lets call him Bob) and used to roll it out of the garage and wash it. So Jim offered Bob some cash and bought it off him. The story goes that apparently the car ran perfectly fine but then Bob's mother started getting ill and he parked the car for 4 years without starting it. Jim buys the car from Bob and basically throws a battery in it and tries to start it but when he turns the key nothing happens. So he buys an EVO and throws the car in Craigslist where I found it.

Every car has a story. Usually you start to uncover bits and pieces of that story as you begin to work on the car. That is kind of what has happened for me this weekend and here are concrete facts that I know after today..

The facts:

1. When I went to look at this car it was noted that turning the key seemed to do nothing at all. No clicks, no dim lights, really nothing. Jim informed me that Bob was starting to install a "push button" start but only got as far as installing a button in the console and luckily he didn't begin hacking into the harness.

2. Once I got the car home and began diagnosing things I tracked the starter issue back to the ignition switch. The contacts inside the switch were all burnt up. I replaced that and the starter would spin freely when it was disconnected from the flex plate. Once connected to the motor, it would engage but couldn't turn the motor over at all because it was seized.

3. The motor appears to be seized from rust. I am coming to this conclusion based on the fact that the motor does appear to have sat for a number of years and the original spark plug tips were noticeably rusty once removed.

My theory:

From what I can tell, it looks like "Bob" started having an issue with his ignition switch which kept the car from being able to start. Bob took 5 minutes with a drill to mount a crappy switch and then got lazy or had family issues and parked the car. It then sat there for a number of years until the motor seized up. So far what I've found from working on the car seems to back this theory up. So basically, this whole problem could have been solved with a $130 ignition switch if Bob bothered to spend an afternoon diagnosing it. No worries though, if he had fixed it, I probably wouldn't have the car right now. So thanks Bob!

What I've tried to unseize the motor:

1. The starter itself (obviously), but it doesn't turn the motor.

2. 1/2" ratchet on the crank bolt with a huge cheater bar on the end of it. I've tried rocking the motor back and forth but it flat out doesn't budge. If I put enough force on it towards the left, I actually end up loosening the crank bolt.

3. Poured a product called "Evapo-Rust" ( ) down the upper intake. Let that sit for 72 hours and then tried the crank bolt again. Nope, still seized solid.

4. Removed the upper intake manifold and poured a solid quart of ATF down the lower intake manifold. That was only done about 1 hour ago.

Other things to try???

1. More ATF? Let it sit for longer?

2. Hit the crank bolt with an impact gun?

3. Remove the ATF and try Marvel Mystery Oil instead?

4. Pull the motor and try to tear it apart.

What I'm hoping for:

I do realize the chances of this motor coming back to life in good shape are slim. I have no delusions to that fact. At this point I am simply trying to unseize the motor and save as many of the parts from it as possible. In other words, If I can save both rotors and maybe a single housing, that is winning as far as I am concerned. Right now the motor isn't doing me any good completely seized up so anything is worth trying.

Sorry for being so long-winded for one of my first posts, I wanted to provide as much information as possible. I have been searching the various threads on here and Google and have tried quite a bit of what was suggested. I am posting this in case someone else can offer any additional advice or ideas to try and also to make sure I haven't forgotten any other ideas.

Thoughts?

Oh boy, to be honest......save yourself the hassle and pull the motor and take it apart.

This way you can see if anything can be saved. Even though you get it to turn over you risk just wrecking the internals.

Agree with Hybrid G.

If it's locked up that bad, it's a lot more than just a stuck apex seal.
Sound suspiciously like coolant seal failure and subsequent rusted out internals (hydrolock).

A link to Rotary Resurrection (coolant seal failure is in the middle of the page):

Rotary Resurrection home of the budget rebuild.


If it's sprung a huge leak, it's gonna suck because a lot of the internals may not be salvageable.
Good luck, my friend.

Solid advice, I am actually very close to biting the bullet and going this route.

Hey thanks for the link, I actually read that while searching for answers to this. I am starting to suspect you are right though about it being a coolant seal failure.

Okay, so switching gears here for a moment.. I've got a local JDM importer about 10 miles down the road that has a (supposedly) 68K motor/trans/ECU he is willing to deliver directly to my door with a 30 day warranty for $2,000. I'm leaning towards going that route and then taking the seized motor apart to check for damage.

Worst case scenario: The seized motor is no good and I'm down the $2,000 for the used engine and a transmission I needed anyway.

Best case scenario: I run the JDM engine and my seized motor turns out to be rebuildable (or mostly rebuildable). This would basically give me a spare motor. Thoughts on this route?

JDM motors tend to need a rebuild most of the time. Even with a 30 day warranty, you'll be performing a lot of work to build up the JDM block and install it, just to discover it's bad and have to take it back out.

They can tell you it 'has good compression' but that doesn't count for much IMO.

Thanks for the reply. This does seem to be the general consensus from what I've read here in the past. Well, I think the best course of action before I spend any money is to go ahead and pull the motor, get it stripped down, and see what kind of shape it's in. I'll update this thread once I get it pulled apart if anyone is curious as to the results.

Pull the motor apart. You are likely to do more damage pouring in various potions or forcing the motor to turn move. The last person I know that tried this attempted to pull start a seized motor and snapped the eshaft in half. I think I still have it in my shop.

rust doesn't just appear in these engines from sitting, regardless of them not having valves. this is what happens when you let coolant sit in the engine, trying to get it started won't accomplish anything except perhaps save you a very small amount of cleaning effort at the cost of possibly doing more damage to the engine.

I'll find that e-shaft. Quite the conversation piece :lol: