I have a 1988 GXL that the engine locked up while going down the road, lucky I was not doing 80 on the highway. Anyway I tried searching the forum for "carbon lock" and "engine seized" with lousy results, I do not know how to search yet, and need some help on the topic.
I am going out and try to turn the engine backwards to see if I can loosen whatever jammed the rotor. My question is: Can this be true carbon lock or did a piece of apex break off and jam the rotor?
The engine is a 13B atkins rebuild with 3mm apex seals, 68k miles on this engine that I installed 11 years ago. I have been pretty good about oil changes twice a year but I never tried doing the water injection treatment to loosen the carbon buildup. If I get it unjammed should I try and start it, or just crank it over and see if the piece goes out the exhaust port?

 

Odds are it's a seal or a seized bearing. You can try turning it backward but don't crazy with force. If it doesn't turn, best to take the exhaust manifold off to have a look.

 

apex seals don't normally carbon lock while running to cause a seizure, odds are the car ran low on oil and the bearings seized or the engine had some other natural disaster occur.

did you check the oil level? any oil leaks you didn't notice like a cracked iron? was the oil level switch connected?(the oil level switch wiring is frail and often breaks, leaving you with no warning buzzer)

 

I just pulled the oil dipstick out and it is just covering the "F", if the oil pump failed I would of seen a warning light? I was not looking at the oil pressure gauge at the time.

Moment of truth! I have a six point 3/4" socket on the pully bolt attached to my 1/2' drive breaker bar. Please be a piece of carbon!

All I did was loosen the bolt, pully did not move at all, it's really jammed up tight. So much for the cheap fix.

If it is a bearing, will it destroy more then the rotor & e-shaft?

 

Post your findings for the community

 

If the engine it stock i'm gonna guess the 3 piece apex seals did it in, probably looking at a rotor and housing

No matter what, engine tear down time

 

Since it loosened the bolt, there is a good chance the torrington bearing might have slipped. Did you have it in neutral with the clutch depressed - hoping you did? If not it's time for a teardown.

 

After twenty nine years of being a proud rx-7 driver I need to make the decision, fix this engine or throw in the towel! This is my only car, I am homeless and staying at my sister's, overstaying my welcome trying to find housing. So my priority is to find a place to live and I need a car now to do it. Even if someone gave me a rebuildable 13B core I would be hard pressed to come up with the money for the rebuild kit at the present time, and no place to do the swap. Should I tow it to a storage place, buy another car for now and wait until I am settled to see if I want to restore it as a hobby? What say ye!

Just when I thought I was out! They drag me back in!!

 

Sell the RX-7 to fund a daily. Priorities come first. You can always find another RX-7.

 

^this

 

Yep, put it up on Craigslist an hour ago for $1500. Got the guy that's sends a check for more than the asking price, sight unseen! Also a real possible buyer that asked for some pics.
Getting another rex down the road would not be the same, this was my only new car I ever owned! It was going to be fun having a back and forth with you guys and gals as I restored my baby.
The buyer is now offering to trade for a 2010 Mercedes that needs work. So everyone involved here on this forum are doing a great job keeping these unique vehicles roadworthy,

Goodbye,
Gary

 

pretty much, it is why we say that rotaries don't make good daily drivers. hopefully things look up for you soon, i wasn't far off from where you were not long ago and it's rough, especially when it seems like no one is willing to help, thankfully your sister is there.

 

DO NOT FALL FOR THE MORE MONEY SCAM. THEY ARE SCAMMERS FROM NIGERIA. I USED TO INVESTIGATE THESE. If by chance you fix the engine, remember to flush all lines, oil cooler and CHECK your oil metering pump and oil pump. This could have been your problem too.

 

I'm now in the beginning stages of restoring my 88GXL.

Here's what caused the seizure, the rear rotor bearing spun and as it destroyed itself caused the rotor to tilt enough to break a piece of the stationary gear!


Nothing salvageable as far as the rotors and irons go.

The rotor even distorted itself!

I found an engine on eBay, then got to thinking about what kind of restoration I wanted to do.
There is 140k miles and 34 years of wear and tear, so a replacement of the rest of the drivetrain is called for.
Found a rebuilt transmission on eBay and a new driveshaft from Mazdatrix.
I am now in the process of refinishing all the parts that attach to the engine, I didn't do it right when I installed the engine last time. Overtightened all the nuts and bolts which promptly rusted and froze up. This time I will be using anti-seize lubricant on every nut and bolt.

After dismantling the engine I came to the conclusion that carbon buildup on the rotors is detrimental to the lifespan of the engine. So the EGR valve and the OMP system have to go.
Once I get it running and on the road I need to address all the other issues that have occurred over the years.

I bought new S5 tail lights and a wing, always wanted a wing. Found a header for the exhaust system. I have a set of tenth anniversary rims I use with spacers, so this is no longer a stock automobile, that's what makes it fun. If I do the exterior right it won't look stupid!

I will need your expertise going forward, thanks for all your help!

 

Awesome news! Great to hear you were able to keep it around and are in a better place to be able to repair it and built it the way you want! Congratulations really, I just got back on the board from 2014 haha and have rebuilt my RX7 again, these are keeper cars for sure, so happy for you! Enjoy the process and post pics, make a build thread for it!

 

Good luck on the restoration & post up a build thread! But your apparent conclusion that carbon buildup killed your motor is incorrect. While carbon buildup isn't good, it's not what caused your spun bearing and seized engine. Spun bearings are the result of a lack of lubrication - loss of oil pressure/flow to the failed bearing. Figure out why that happened (i.e., oil pump/oil pump chain failure, massive leak, etc.) and correct that issue on the new build before thinking about mods like OMP & EGR deletion.

 

I jacked the front of the car up by the oil pan. It was flattened a bit on the bottom! The oil pickup screen was probably in contact with the bottom of the pan. Would this cause a reduction in the amount of oil fed to the bearings? This was the only problem I noticed. I replaced the oil pan. What other reasons do you know about that would cause a bearing failure like this?

Carbon buildup had nothing to do with the bearing failure, I found a great deal of carbon buildup on the rotors, and it made me think, how can I prevent this buildup on my next engine?

front rotor carbon buildup
The idea is to stop any exhaust gases and dirty oil from getting into the rotors. So I am going to use pre-mixing only. I removed the EGR valve and the entire OMP system. This will allow only the cleaner burning 2 stroke oil into the combustion chamber.

What do you recommend for the amount of oil per gallon of gasoline when you delete the OMP? 2oz. or 1oz.?

 

Hard to say without seeing it, but if the oil pan hit something and was bent/damaged, it's quite possible the oil pickup tube was damaged too. May have been broken off completely, bent/"re-positioned" by the hit or cracked where it would be sucking in air instead of oil. Or it may have been bent/kinked to the point of being too restrictive to flow enough oil.

IMHO, it is foolish to delete the OMP on a stock car with the factory ECU. During deceleration/overrun conditions (e.g., lifting off the gas at high speed/high RPMs on a highway to coast down for slower traffic ahead), the stock ECU will cut fuel to the injectors, which means that if you've eliminated your OMP and are relying solely on pre-mix in the gas, so your apex seals won't be getting any lubrication under those specific conditions. So if you still want to add premix WITH a functional OMP system, you can add 0.5~1.0 ounces per gallon of fuel.

 

Very good point! I did not realize that the ECU cut off the fuel to the injectors on deceleration! Looks like I will have to put it back on, thanks.

By the way, the oil pickup tube was not damaged, just the screen seemed slightly flattened on the bottom but there was still a 1/4" space between the screen and the end of the tube! Perhaps it was just a spun bearing? Does the bent locating tab let go for no good reason?

 

glad to see you were able to keep the car and (presumably) turn things around, life-wise.

i can offer other possible scenarios ...

as someone stated earlier, unless there was a terrible clearance involved, the only way you're really going to spin a bearing is by inadequate or no lubrication.

did you ever notice the oil pressure fluctuating or being erratic at any point? maybe the o-ring on the front cover blew out at some point????

you can also check the stationary gear against the rear side housing and see if the holes were not lined up. i read that the Renesis rear stationary gears are a little off center.

 

Thanks for the reply, the other three bearings looked fine, and the e-shaft looks great, even where the bearing gave out! I was surprised! The front cover o-ring looked good, so I am coming to the conclusion that the bearing just spun for no real good reason.

Afterall, Atkins did use the old bearings in this rebuilt engine, and I put another 70k miles on them. I guess things just happen.

 

I found another rebuilt 13B engine and I am in the process of swapping it into my car.
I am taking great care to refurbish all the parts I am reusing to make sure that they function as required.
At this stage of three decades of age things are in need of a bit of care, nothing should be taken for granted!
Thanks to all your input for making things go forward!

 

Awesome, love seeing the dedication. Keep us posted how things go.

 

Hi everyone, things are looking up for me now!

I found a place next door to swap out my drive train.

I am in the process of detailing all my existing parts that I still need.

My discissions going forward are to keep the OMP working, add some pre-mix to the gasoline, use synthetic gear lube in my rebuilt transmission for smoother shifting

Use conventional 10W-40 oil changed twice a year.

Deleted my EGR and Air pump system since I no longer have catalectic convertors.

If everything goes well I should be driving it down the highway this year.

These automobiles are unique, and everything we do to keep them on the road is important! .

 

Hi everyone,
Spring is upon us; love is in the air! Yeah, right.
The weather is warming up, time to get on with the reinstallation.

I moved my engine hoist and the engine (still mounted on the stand) back to the car. It is stored next door. I brought the transmission over last fall and wrapped it up securely.
Yeah, people stopped and pointed as I dragged the engine around the block by hand! Screw them.

I am left to my own devises doing this, so I want to record what I am doing to put it back together.

First thing is to finish putting certain parts on the rebuilt transmission.

I installed the divider into the notch on the bellhousing in front of the starter, hard to source and the one I got was very brittle.
I saturated it with water thin superglue and then coated it with that rubbery plastic dip for tool handles, worked out very well.

Next, I installed a new clutch slave cylinder with a new condenser attached under one of the mounting bolts.
I found some conductive grease to use on all the grounding connections such as this.
By the way, there are two of these wired condensers on the car, which have to do with reducing the RFI interference for the audio system only!
This condenser is connected into the oil pressure sensor.

Then I swapped the speedometer driven gear from the stock 20 tooth to a 19 tooth from a convertible.
I put on larger diameter tires and rims from a 10th anniversary RX-7. The new gear increases the speedometer speed by 5%.

And of course, a new throw-out bearing and clutch was installed.

I am taking great pains to not rest the weight of the engine onto the oil pan.
I do not want to put any strain on the gaskets and studs that might cause them to seep oil down the road.

So, with the engine still mounted onto the engine stand, I will make a sling for the transmission.
Using the engine hoist, I will be able to align the transmission input shaft so that it goes into the pilot bearing easily.
I will be using lithium grease for the pilot bearing and moly grease on the clutch splines. Not too much as to not contaminate the clutch plate surfaces.

Once I have the engine and transmission mated, I will add two more lifting points to the engine for a total of four attachment points and attach the engine to the hoist.

I will be showing pictures of all this going forward, once it is separated from the engine stand, I will install the motor mount and P/S- A/C bracket to the side of the engine using a torque wrench to specs.

Then the big day will be upon me!