my 84 won't start and i just re-build engine. Help please

 

We're gonna need way more information than that.

What does/doesn't it do? Does it crank? Are the spark plugs wet or dry? Is there fuel in the float bowls? Do you have spark?

When you rebuilt it, did you do any porting? What rebuilt kit(s) did you use? What parts did you replace?

Dude, you can't expect us to magically know your problem without any info!

But if I had to guess I'd say it's your Flux Capacitor actin' up

Jon

 

Did you check the difibulator rabulator? Some times it gets overlooked too.

 

Better hope its not the difibulator rabulator... Those things are pricy man. I paid almost 600 bucks for mine when it went out, and it was USED!!!

 

What the &(*&^ is a defibulator regu....?
I have rebuild several engines from several years and never had any problems whit anything outside the engine.
Make sure the engine turns freely, (which you should have done before dropping it in). Make sure you have power to the coils, that the distributor is place in correctly. Also make sure your cables aren't cross. Of course you need fuel.
Now is it a 12A or 13B. If it is a 12A and everything outside the engine checks, there is a good chance you place the rotors in the wrong order, (front in the back, or two fronts or backs).
Make sure you have a fully charge battery or a professional grade charger. Like Vipernicus said, we need more info...

 

my money is on a vacuum leak

 

josequi PMed me about this problem, I don't know much about the 12A's so i sent him here. From what he told me it's just cranking and back fireing but never starts.

 

If everything in the engine compartement, outside engine accesories, ckeck ok, he may have the rotor out of order like I mentioned earlier. I will recheck the distributor setting, wires and power to the coils. Also, check to ensure that the ignitors work.
Is he running headers with performance carb, or stock setup?

 

Timing.

 

Ok, first I apologize for being so general. My engine is a 12A. I never took one apart before but there is always that first time for everything, considering that I'm on the air force and bomber aircraft mechanic; shouldn't be to hard to read a manual and do it. When I re-build the engine I used the mazdatrix re-build kit specific for my motor. One thing from the previous threads is intriguing (the order of the rotors) How do I know this when they look exactly the same? Another thing is the timing. How can I properly time the car without being running? My apex seals are in great condition. My rotor housing is good but there is a little gauche on the bottom of one of them. I understand compression occurs in the upper part of the housing towards the plugs, these sides where perfect, so compression is not affected in the combustion process. Like I said before the motor turns freely, spark plugs are in the right location (if anyone is interested I bought NGK plugs considering they are the best for this motor) when the motor turns it back fires and does nothing else. I don't know what a difibulator rabulator is, so any guidance would be appreciated. If the gouch on the rotor is the problem, well; could some body guide me to someone selling a 12A or (13B if I can use the carb) with plans to upgrade to turbo later when $$ falls from the sky.

 

As you'd know from being a mechanic, gasoline engines need air, spark, and compression -at the proper times - to run.

Fuel is getting to the engine, since its backfiring. Likewise air, or fuel wouldn't be going into the engine...

Checking spark is easy enough. If the plugs are sparking, and in the proper order, then check the timing.

 

Since you stated it is backfiring, I guess that proves you are getting fuel, spark and compression. Maybe not enough for the engine to run, but thet are occuring. Likely the distributor is not properly timed with the front rotor. Since the front pully can be installed at any of 4 different positions, it can be hard to know when it has been installed in the wrong position. This further impedes getting the distributor in the correct position.
If memory serves me right, I believe someone posted about the e-shaft keyway needing to be pointed towards the top when the pully is installed.

 

The top? I'm pretty sure it's the 9 o'clock position. You can also take off the access cover off the back to see the flywheel and make sure the dimple is in view.

 

I did say "if memory serves me correctly", I just forgot to add that it doesn't do this with any consistancy
However, At least by posting that, I hope that others who do this regularly can/will correct me if I am wrong, cause I very well could be.

 

The rotors do look alike as you look at them from the top. Now, if you position them with the gears oposite ea other, (1 to the rear & 1 to the front), and look at the form either side, you will notice the indentation on the sides is oposide on ea. here is a pic. As far as the pulley it really does not matter wether it is at 9 0'clock or 7:35, just got to make sure the actual belt pulley and the scentric shaft pulley, (see pic), never been separated. Rotate engine until the firtst mark, (proper engine rotation) is on the front cover indicator. Rotate shaft on distributor until mark is align and insert, sould start.
You mentioned, "the apex seals are good", are they used, or new? If they are used, did you worked them even?

 

backfiring points to timing which has four possibilities, I suggest you start limiting the possibilites by trying all four positions on the distributor cap with only one of the leading plugs attached. This will get you close. It is possible to mess up your apex seals by using the wrong timing. Hence the reason for trying only one leading plug.

Also get use cheap auto lite plugs. When doing my initial start up, the original plugs fouled. The engine ran great with some old plugs that I removed previously after +150 k miles. The auto lites ran ok, but had carbon all over them (excess oil or fuel/ air to rich). When I replaced them with new NKG, the plugs looked healthy.

ps...".......won't start..........?" start doing what?

 

Have you gotten your car started? Hopefully we were able to help you out...

 

well to be honest I haven't got the car to start. Something else I notice is the right side of the nicki carb (the big one) is getting full preety quick. So I got the hybrade rebuild today, just in case. I still kind of worry about getting this thing going. I waited so long to get my hands on one of them and now is pain after pain. Like I said before I'm on rapid city SD, and there are only two RX-7 first gen in town; Mine and some automatic. No mechanic wants to take a look at it so all the help I get from here is the only help I'm going to get. Thanks evreyone for sticking arround.

 

Double check your timing. Ive had simular problems after a rebuild and it was timing related. Coming from piston engines the dual ignitions in rotaries is very comfusing to everyone. And dont forget to double check that the plug wires are in the correct locations ie leading coil to leading spot on cap etc etc. Finally if that checks out pour 1 teaspoon of motor oil in each trailing spark plug hole (turkey baster helps a lot here). If it then runs and dies your compression is too low.

 

yep, gonna beat that horse in the face..... T I M I NG has got to be a key factor here. make sure you stabbed the distributor perfectly. i've gotten mine off by ONE tooth and had the saaame problems. had to re-stab that bitch a few times before it set right in on the correct one. and also it's easy to get the coils mixed up. leading is the one closest to the shock tower.

 

Timing is most likely. Do easy part first: make sure plug wires are correct: "T" means "top" and "trailing", "L" mens "Lower" and "Leading". Make sure timing marks on pulley are visible: dab with white paint if necessary.

Does anyone have a good way to 'static time' the 7? Lacking that, using a timing light during starter cranking will probably be wrong, but it should be close. Bold mechanics have been known to leave the distributor pinch bolt a little loose and then rotate distributor slightly while cranking to find the sweet spot (don't look at me like that!).

B