Ovrclck350

Well, I'm about to purchase an 89 RX7 NA 5 speed for $800, and I'll be honest, I'm completely clueless to anything about this car. I'm fairly car knowledgable but these rotary engines are foreign to me. My previous cars are an 84 Nissan 200SX, 87 S10 Blazer, 92 Firebird, and my current 95 Camaro which will soon be for sale.

Any help on good first mods for this car, things to look for would be greatly appreciated. I'm mainly interested in Go-fast mods, not really handling mods. BTW, are there any turbo kits available for this car? I'm content having it as NA considering my other car I'm about to purchase should be in the 12's easy, but I'd like to have a turbo car because they're fun to drive.

Taranis

For $800.00 I'd be SERIOUSLY wary of buying it. But here's some basic things you can look at to see if the motor's in good shape:

- Pop the coolant cap, check for a gasoline smell. Gas in the coolant = No Sale.

- Check the oil for water or other wierd deposits on the dipstick or the filler tube. If you find any, beware... Ask the owner if he's used any engine treatments or additives. If so, you've probably got a ton of carbon built up in rotor housings. Walk away.

- Start the car and see if it smokes. It might a little during warmup, but after that, it should run smooth. Note: Sputtering during warmup is normal. Bring the RPM to 3K and hold it. The oil gauge should read anywhere between 45 - 60 PSI. Anything less, walk away.

Shut the car off after a minute or two and check the coolant at the top hose. Look for bubbles. Bubbles = exhaust in the coolant = overheating = blown motor. Again, walk away.

- Find out how well maintenance has been done. Oil RELIGOUSLY every 2,500 miles, coolant, plugs, wires and filters every 15K. Look over any documentation the owner's done to the car. Mantenance is crucial to the motor being in good shape.

- ask the owner if it uses oil. He SHOULD say yes (rotaries are made to burn oil). If he denies it, either the oil pump is going (leading to a blown engine the first time you drive it hard), or he's lying. Personally, I'd walk if he said "No".

Also, you should ask if he's ever opened the car up. Rotaries run better when they're NOT babied and last longer.

If you get thru all this, then drive it and listen for the "thunk" that indicates worn out U-joints. On an rx-7, that means replacing the entire driveshaft - about $450 new.

I'm sure there's more - but that's a good starting point.

As for the rest of your questions:

Turbos: Not for a NA. You can do a Turbo conversion, but plan on mega $$$ and a well known motor. NA rotors have higher compression than Turbo Rotors, so turbocharging an NA might blow the motor under moderate boost. It's debatable, but I'd recommend learning your car before attempting it.

Good go-fast mods: Exhaust, intake, fuel system upgrade, headers.. pretty much in that order.

Hope that helps..

Ovrclck350

Thanks man, I'll be sure to check all that out. The reason I'm getting it for $800 is it's a friend's car, and they want to get into something different and newer, and I offered that much for it expecting to get shot down, but because I'm a friend, they said alright.

copandengr

The weak point on any rotary is the carbon build up on higher mileage engines. This carbon is the result of the oil metering pump injecting lube oil into the combustion chambers to lubricate the apex seals. This is normal, but unfortunately lube oil does not burn cleanly and after 120 K or so you start to find enough carbon build up to cause the seals to stick and the subsequent reduced compression. This leads to flooding when starting the engine. There are temporary fixes for this, but eventually the rear rotor will spit out the apex seals. Result? Ruined rear rotor housing (for some reason it is almost always the rear rotor that takes a **** first), rotor and rebuild time.

The only real fix for this is to rebuild before the apex seals turn loose. This way you may be able to run the old rotor housings. This saves you about 400 bucks each. Rotors are fairly cheap if you shop around. A rex engine is easy to overhaul compared to a reciprocating engine. There is normally no machine work needed, and there is of course no valve train to cause more work. Rebuilding a rex is mainly tear down, clean, measure, reassemble.

You have found the right place to seek information about the rex. I could have saved myself a lot of headaches and money spent had I know about the rex's quirks four years ago.

Driving a good rex is about the most fun you can have with your clothes on. The little bastards are addictive. I bought my '86 rex to get my 16 Y/0 daughter a car to drive. Once I drove it I found it to be too much car for her, and besides, her old daddy deserves to have a little fun now and then too. Needless to say she is almost 20 and has a Honduh. I still gots my rex. I prefer driving it to my nearly new Dodge Ram Club Cab. I am 48 and feel like a kid every time I get in my rex. It simply feels good to drive it.

copandengr

I forgot to mention the tranny. N.A. trannys are fairly reliable, but they do have a few areas that are of concern. If you drive this car and notice any grinding when down shifting it is a good indicator the synchros are going bad. They are not very expensive to buy (about 35 bucks each) from a Mazda dealer but tearing the tranny down is a bit of work.

Also check the shifter for play. If you can move it up and down or side to side (I am talking about the base of the shift lever here) the plastic bushings are likely worn out to the point of not even being there. This is an easy fix, the bushing kit is somewhere around 30 bucks and it is a simple job to put them in.

The interior plastic trim is notorious for cracking. Most of this stuff is expensive to replace with new pieces.

Check out a web site for a company called Mazdatrix. You will get a good idea of parts costs there, and you will also find an FAQ section. This section deals with the most common rex problems.

Evil Aviator

http://www.aaroncake.net/RX-7/

Ovrclck350

That site is awesome.

vaughnc

Simple - get a compression test from the mazda dealership. If the numbers are good - congrats on a cheap/wise purchase. Check with your regional rx7 club to see who's your local rotary expert mechanic. You might have them check out the 7 as well.

a few pics of the 89+ NAs.





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vaughnc

If this is your first rx7, your in for a real treat. These cars have one of the largest followings, have TONS of performance upgrades, bodykits, accessories, magazines, custom mods, and userbases.

rxspeed87

damn man welcome on over here

dont tell me all my talk about the rx-7 on your camaro forum kinda made you a little interested now


you will love the car though if you get one in good shape


these things can last forever, but if you dont take care of them they can break a lot easier then a piston motor. just make sure you change the oil all the time keep good plugs and wires in there and so forth just basic car care and also open the car up on the road sometimes to help clean that carbon out (carbon is big no no it a rx-7) and you should have a car to last you for some time now


also if you do go out and buy the car if you dont have to drive it for a while you might want to take out the leading plugs and let the motor sit for atleast 24 hours in ATF. that stuff cleans out the carbon build up in the car and will help it run better. all you do is take the leading plugs out pour some ATF in somehow then bump the starter and just keep doing that a few times to make sure you have lots of ATF in all 3 of the rotor faces on each of the 2 rotors.


also another thing that is to work well is get the car warmed up and then let it suck some water through a vac line on the front of the dynamic chamber not enough to kill it but if you do it right you should see steam come out the back and this is to help break up the carbon also


the apex seals are to move and if you get carbon in there they stick and do not follow the shape of the rotor housing and you start to lose compression...

oh yeah if you do the ATF treatment you will want to change your plugs they fould real quick after that and maybe an oil change

rxspeed87

hey one other thing

There are a few ppl here who seem to know there stuff like mazdaspeed7,evil aviator, hailers, irv Keith's dad, pineapple racing, soul assassin and there might be some others that I forgot to mention. but any of the above are real helpful with giving you a hand.

we also have a live in prophet of the rotary gods known as reTED.. if he says something about these cars then it must be true. this guy really knows his **** about them.

and we cannot forget about out forum clown node
he knows his stuff for not having a rex but then again what else could he do since he is not out there having fun like the rest of us...

NCsublime

Yeah, that's all good info. I'd really encourage you to let it soak in ATF (it will smoke like crazy for about 30 min when you start it-be easy on it and gradually increase RPM once you drive it-better yet, post on here if you get it and I'll (or someone else will) post a link to a good write-up on this. You may also want to unhook a vacuum hose as mentioned above and stick it into a container of water while holding the RPMs at about 3500. It will bog down due to the watered down solution, but just hold the RPMs up to compensate for the drop. I wouldn't do too much at a time. Maybe a liter at a time. Chances are you'll notice a significant difference in power/gas mileage if you do one or both of these. Treat it well and it will return the favor.

Good Luck,
Derek