Hey Everyone!!

Yesterday I bought an 87 RX-7 XLE. I work at a gas station and I am good friends with the mechanic who unfortunately, has little experience with rotary engines but is a very good mechanic in all other areas. After he took my car for a test drive he determined that the Apex Seal was in fact not gone like the owner said it was, but that there was simply a carbon build up. He insists on using his own treatment concaction of diesel fuel and oil and then to drive the crap out of the car until the treatment runs through. I am very scared that the motor will blow up!! he says that there is a chance this could happen. He says if this happens that we will drop another motor in (like something from a 1/2 ton truck). Does anyone have an opinion on this? I read about using water for this method instead. HELP PLEASE!!

 

Welcome Lisa-san,

I don't know about this diesel fuel business, I can't see how that'd be a prudent idea. But there's lots of wacky angles on what this engine needs for any given problem; so maybe we've got a new one.

If you search ATF on here, there's a general consensus that AT fluid will loosen up carbon etc. It also works on flooded engines to build compression.

Additionally, don't let him put a damn v8 in there, that's blasphemy around here.

 

Thanks for your help!! Another stupid question...what is AT Fluid???

 

Automatic transmission fluid

And Yes the diesel fuel trick works pretty good for desolving carbon, I soak rotors in it for a week and the carbon just wipes off, now if it's a mixture of carbon and rust.....well then its hard to get them un-stuck.

Joe

 

Using ATF (automatic transmission fluid) is sort of a last resort and not recommended.
Here's why: http://www.aaroncake.net/RX-7/atftrick.htm

What are the symptoms of the car?

Where abouts do you live?

 

Yea a good idea is seeing if there are any forum members around you.. plenty of knoldge on this board and if one of them lives near you all the better.

 

thanks Joe, that just saves me a whole bunch of time. Off to buy soem deisel fuel. No more scrubbing for me!!!!


And yes, I would highly suggest to Lisa, that you try and find another forum memeber to help you out.

 

Hehehe no problem, I have also tried a mixture of ATF, diesel and gas, it seems to work just as well.
Also have a good set of dental picks nearby to get all the little hard to get spots. Old sideseals work good for cleaning out the sideseal grooves.

 

I live in Prince Edward Island Canada. It's funny guys, there are only 4 RX-7's here in my area. Mine, (the 87) two 91's and a 92. Two of the three cars (including mine) have supposedly bad Apex Seals. None of them are on the road right now because it's so darn hard to get parts for them in my area! Anyway, I'm not very fluent in describing car problems so I will give it my best....my mechanic friend would know exactly how to describe it to you guys but he would be look down on me getting advice online...he's just old fashioned like that! anway, the car is hard to start...I mean HARD. You have to put the gas peddle to the floor and it keeps turning/trying over and over. I actually flooded it a couple of times yesterday and we had to take out the spark plugs and dry them off. She's smoking somewhat and it seems like it doesn't have full power. It's really loud but I think that it might have something to do with the exaust or exaust pipe. I will find out exactly what the symptoms are in an hour and come back to offer a better expanation. I would like to think I can trust this mechanic because he's been working full time at this for almost 20 years, plus, he's worked on a lot of stock cars and what not....but you guys here obviously know your stuff really well, you own these cars!! hence why I am here looking for any advice or input. Thanks all.

 

That page was very informative thanks!! I'm depressed now though...looks like form what that page says, my motor will probably end up blowing up anyway... At least I got some decent rubber from the sale!!

 

If you want to know what is up with your engine, I'd urge you to do a compression test.

http://www.rotaryresurrection.com/ro...lder/comp.html


As for ATF; great lubricant, lousy carbon remover. And ATF attacking seals? Not everyone agrees with that page you read.

 

Yeah i read Aarons writeup and he's totally right, it doesn't attack the seals, the ATF just makes the rubber oil control rings....ummmm...what am i trying to say....it makes them not do thier job. So basically you use ATF in your motor, you'll likely end up burning a bunch of oil.

 

What about water? You fill a jug with water and put 2 hoses in so that both rotors get equal amounts at the same time. Plug it into a vacuum line (One for each rotor) and kink the lines (So no air sucks in). Then run it at about 4000RPM steady(after normal operating tempurature is reached) and drop the lines into water and unkink. Im not sure what amount of water you use but appearently its like 'Steam-Cleaning' the insides of the engine. Anyone know about this?

 

The water trick is a maintenance technique, not a fix. I don't know of anyone who has tried to use it to clean up an engine running badly as hers is...


And your description is not right. You run one vac line from the water. Your goal is to 'tee' into a vac line (or lines) on the car that will feed both rotors. And if you just drop the line into a water source and let it flow freely, you will both snuff the engine and contaminate your oil. You want to control and limit the flow - you never stop kinking the hose.

http://www.rotaryresurrection.com/ro...injection.html

 

AFAIK, the worst thing that ATF does to some seals is make them swell slightly on first contact. That's slightly. Not Stay-Puft Marshmallow Man territory or anything gross like that.

 

Oh Yeah, I forgot to ask...what type of material is the Apex Seal is made of? and does anyone know where I can get a diagram or pic of how the injecters are set up? Thanks again everyone for your contributions.

 

What is XLE? Do you mean GXL?

 

I can tell you that the original seals developed by Mazda were aluminum-impregnated carbon. I don't know if or how much it has changed since then (late sixties.)



The Factory Service Manual (FSM.) www.iluvmyrx7.com has scanned FSMs available for free download. Follow the links.


Now what are you up to?

 

Apex seal is some sort of special metal.... it looks almost like a razor blade.

I read over the posts, has your mechanic checked out things like.....

*fuel pressure- could be low due to old pump OR clogged filter
*fuel injectors- could be dirty/leaky and will effect engine performance
*Vaccum leaks- brittle hoses may leak vacuum and cause idle and perf issues.
*spark plugs- if old and dirty, will effect start-up and perfomance
*Cap/rotor/plugs general maintance
*Old gas in tank- car may not even run right and could clog up filter (my case!)

The best bet is do an engine shampoo, so you can identify everything clearly..... and tackle things one by one.

 

www.mazdatrix.com has pictures of everything.....

Goodluck and with some trouble shooting you'll have your car running..... fairly inexpensively.

 

I thought the water trick was for cleaning out carbon buildup. Im almost certain thats what the write-up said. And I was told you let the hose flow freely and you can Tee it (which most people appearently do) but you have to rev the engine higher than 4000RPM.

I've never witnessed or done this myself, Im just going by what I've read and been told.

 

That is its only purpose. When I said I hadn't heard of anyone doing it in a case similar to hers, I meant that only that, and that I have no helpful info about her trying it. I should have been clearer about what I was and wasn't saying there. Sorry.



I provided a link in my 2nd-last reply to what I consider to be the definitive write-up.



That *will* snuff the engine. The engine already struggles quite a bit with the flow substantially stemmed. Water doesn't combust, remember?

Here's what happens when you try to flow as much water as possible:

https://www.rx7club.com/showpost.php...6&postcount=10


That's my post, exactly two weeks ago.





I've been doing it myself (and showing others how to do it) since I first learned about it about 3-4 years ago. I'm not trying to mislead you or anyone else.

LisaG's problems could be due to any number of things. A compression check will tell her instantly if it's b/c of something within the engine. If it isn't, it could be something as simple as one or more bad plug wires or coils. If she'd do the test and share the results with us, we can do a better job of coaching her on how to deal with the car...

 

Wow, lots of opinions and advice here, and most of it is accurate. Still, if you're not familiar with these cars (or cars in general) you're probably finding this whole thread to be somewhat overwhelming. Your problem could be something other than carbon-clogged seals, but I'm guessing your mechanic would have been able to find a fuel or ingition-related glitch if that were the primary cause.

As one of the above posts illustrated, these engines have several "Seals", and the apex seals are the ones that most people think of when somebody mentions the rotary engine. These seals are hardened steel "bars" about 80mm long x 10mm tall x 2mm think, and in your car are a 3-piece unit that as an assembly comprise the above dimensions.

There are six of them in your engine, and they fit into grooves at the apexes of each of the two triangular "rotors" in your engine. Each apex seal has springs under them to keep the seals in contact with the rotor housing as the rotors spin, sealing in the air/fuel mixture to provide good compression as the engine goes through its compression sequence.

As the engine accumulates many miles of use these grooves that the seals sit in may become plugged with carbon (or rust/ carbon if the engine has sat for a number of years). The side seals and corner seals also become plugged and seized in the same manner. This prevents the seals from floating freely in their grooves, allowing the compressed air/fuel mix to escape into adjoining chambers rather than being fully compresed, which means you have lower compression. As a result, not only is power reduced, the car has to crank over several times before it starts. The fuel injection system and it's associated computer continue to feed fuel into the engine as you're cranking it over , but since the car isn't starting right away this fuel just continues to accumulate inside the engine, flooding it.

To un-flood the engine, open the fuse panel (located under the dash on the far left side) and find the fuse for the electric fuel pump. Pull this fuse and then crank the engine over several times. This prevents fuel from being pumped into the engine and expels the accumulated fuel in the engine Then re-insert the fuse and try starting the car again.

The fact that your mechanic didn't try to sell you a new engine right away but rather offered a solution leads me to believe that he's one of the more honest ones. It would be wise to continue to do business with him and even share with him any info gathered from this site, ie: help him to help you.

If you do go ahead and have an ATF treatment done you will need to first disconnect the exhaust manifold. (An added benefit here is that with the manifold off you can get a flashlight and screwdiver and actually view the apex seals as the engine is slowly rotated by hand, stoppin each time an epex seal sweeps by the exposed exhaust ports. Use the screwdriver to push inward on each apex seal to confirm that it is floating freely on its springs). If you don't disconnect the exhaust, when you run the car (after the ATF has been sitting in the engine long enough to soften all the carbon) all of that loosened carbon will clog the catalytic converters (cats). Once the huge cloud of smoke dissipates after several minutes of *very loud* running, simply reconnect the exhaust and then go door to door apologizing to your neighbours .

BTW, there is a guy (19-ish) living in the Moncton area who is a new owner of an '86 RX7. (What's the toll for crossing the Confederation Bridge these days?) He posts under the name "hellonwheels" and *may* be able to help you out with this. I don't know him so I can't say for sure. And I think your car is a GXL, since Mazda never produced an XLE. You have all power options and cruise control, right?

 

Another (perhaps easier for you) way to unflood the engine as Aviator 902S has described, is to pull a fuse in the engine bay (where there are only 5 fuses). The fuse that you want to pull is the green "EGI" fuse in the engine bay fuse box. It's right by the shock tower on the driver's side.

Also, if you're having flooding problems, when you start the car, floor the gas pedal while you turn the key.

In terms of describing how the car runs, start with the idle. When the car is just sitting there running, is it fairly smooth? Does the car shake fairly violently? etc.

As for the "water trick," I'm not suggesting that it's completley invalid, but I've never heard of anyone solving any problems with it, so if I were you I'd focus my efforts elsewhere.

 

I plan on utilizing the water trick when I get my EFI working properly on my 2nd Gen.