AbecX

Alright, I have no idea about the rotary's ( like most people ) but I am picking one up this weekend, its an '86 5spd, n/a. The engine is flooded, but I am pretty sure I can get it to start if thats the case. What I would like information on is:


1. What is the common problems or basic tune up stuff to buy? For instance on a 302, its best to get wires, distributor cap, plugs, set the timing etc. . . when you buy one used.

2. What's the difference between the n/a motor and the turbo'd motor? ( besides the tubro )

3. Is $250 a good price for this car, it needs new carpet and seats, but thats not a big deal.

blu_gxl

1. same basic maintenance change ALL fluids. new plugs wires etc. only thing is make sure and get a compression test that's the only major issue.

2.differences, from what i know (not much about turbo models) the turbo is the only real difference. that and they are not as long lasting as the n/a due to extra stress on the motor and crappy drivers that mod them w/out the proper knowledge or safety

3. 250 is an outstanding deal assuming that the compressions good on both rotors.

james

AbecX

Thanks james, can I do a compression test just like I would on a regular engine , or is there something special involved. Is there a range compression wise I should be looking for, too?

Rottie

AbecX, as I was told, welcome to the rotory hell.....

We just got into them as well, and are in the process of getting our 88 up and running right. As for the compression test, you cannot do it the same as a piston motor. The rotory has three "compression" chambers per revolution, while the piston motor only has one. Therefor you must use a compression gage that DOES NOT hold the pressure (basically remove the check valve for the gage). Here is how we did ours:

1. remove the two upper spark plugs from the engine (these are the "trailing" plugs, not the "lead" plugs).

2. Unplug the crank sensor and the fuel pump.

3. install the gage in trailing plug 1 (front, top plug hole).

4. Have someone hold the throttle wide open and crank the engine for several revolutions. The gage will jump three times per revolution. These bounces should be about even. If only one "bounce" is down, it indicates a bad side seal, if two low, followed by one high then a bad apex seal could be at fault.

5. Do the same for trailing plug 2 (back top plug).

Our compression for a 13B motor is suppose to be at 85 PSI with no more than 21 psi difference between chambers.

I hope this helps....

blu_gxl

you will need a special tester or a modified piston tester. do a search for how to modify the compression tester i think it's a newer post. the range of compression is it has to be over 85 the best is 110-115. if it's lower compression than 85 you might be able to bring some back with the atf trick(do a search for this too)i had an 87 that had 70 on the rear rotor when i bought it did the atf trick and compression came back. oh and look up the fsm on fc3s.org for compression procedure because there is not a TDC i'M SURE.

james

Rottie

James, what does fsm mean? or for that matter TDC (it's not Top Dead Center in this case )

Thanks,
Rottie

stickgoat

I'd say that $250 is a great price for the car if the engine is just flooded. Especially if the rest of it is in good shape.

If the engine is flooded, try pulling the EGI fuse and cranking it a time or two. Replace the fuse and see if the car starts up now.

Other than that, if the engine isn't completely dead, check the compression and if all is well, go for it.

Evil Aviator

1) Oil, oil, oil. Change the oil and filter every 3 months or 3,000 miles. Castrol GTX works very well, and see the FSM (Factory Service Manual) for the correct weight for your climate. The beginning of the FSM has a maintenance checklist. Use synthetic oil in the transmission and differential (I like Red Line). For air filters, I recommend a K&N (drop-in or cone) which is good for 10 years or 1,000,000 miles. You may also want to change the fuel filter. Use NGK brand spark plugs, and get them from your local auto parts store, as Mazda will charge you 4x as much. You should change the thermostat every 80,000 miles, and be sure to use a torque wrench when reinstalling the thermostat cover, as it is quite common for people to break this component. The only thing that you need to get from Mazda is the thermostat, and maybe the oil filter. The FSM is at this link under How To's/Manuals:
http://fc3s.org/

I like the Fumoto oil drain valve (the plain F106), but it's only an accessory, and is not required.
http://www.fumotovalve.com/

2) The main differences between the NA and TII motors are the porting and compression ratio.

3) Yes, $250 is a good deal, even if the engine is toast.

You can learn more at these sites:
http://www.aaroncake.net/RX-7/
http://fc3s-pro.com/sitemap.html
http://www.monito.com/wankel/wankel.html
http://2ndgenrx7.freeservers.com/
http://www.iluvmyrx7.com/
http://www.mazdatrix.com/

AbecX

What if the engine is vapor locked? Just add some oil in the intake? Or can they even be vapor locked?

Evil Aviator

Vapor lock isn't a problem in 2Gen RX-7's, nor is it a problem in most modern cars. If you do get vapor lock, just let the car cool off for about 30 minutes so the fuel can return to its liquid state. Avoiding high octane or ethanol-enriched fuel in the summer will reduce your chances of vapor lock. The 86-88 RX-7's are rated for 87 octane (US Specs).