Rottie

We've aqcuired an 88 N/A RX-7. The car is now running, but needs work. After reading the Haynes manual on adjusting the ignition timing I'm a bit confused. Basically here is what the manual says to do:

1. Warm up the engine.
2. Hook a tach up to the car and check/adjust idle speed.
3. Attach timing light to L1 and verify yellow mark (first mark on pulley) is aligned with the pointer.
4. If not aligned, loosen crank angle sensor and rotate until marks are aligned.
5. Detach from L1 and put on T1, then repeat the procedure.

My question is wouldn't rotating the crank sensor for T1 put the L1 out of timing, or are there 2 crank sensors to adjust?

Can anyone clarify the timing procedures?

Thanks for the help!

dre_2ooo

HOLY ****!

Yea, there is only one CAS.


I never though of that HHMMMM.......

Rottie

Well, I'm glad it's not just me then!

So how did you time yours? Do you split the difference between the two, or is the leading more important than trailing?

This is my first rotory, so forgive me, I'm use to the old fashion piston engines.....

Also, is it true GM put the rotory motors into the early monza cars?

dre_2ooo

Yes it's true, they even had a 4-rotor corvette at one point

I put mine to the leading since they are more important....

Here is a good explanation of rotary ignition:

http://www.rotaryengineillustrated.c...nition101.html

*notice there are THREE sparks/combustion*

Rottie

dre_2000, thanks for the link, that site is very informative about the rotory! From thier decription it sounds like the trailing will fire 15 degrees after the leading regardless, making the timing mark irrelevant for the trailing plugs. I'm still not completely conviced on it though, why have two marks to check the timing then?

Can anyone shed light on this?

Thanks,

Felix Wankel

It was meant for one, but they never produced any. They still had the big trans tunnel for it.

Green

just line it up with the leading1... That's what I do

HAILERS

If after setting the Lead to its mark,then taking a look at the trail plug and finding that it, the trail, is not on its mark, would suggest there is something wrong with the ECU or the signal from the cas. Can't adjust the cas without effecting both.

Rottie

So, basically set the Lead timing, then check the trail timing for accuracy. If it's off, check/replace the CAS and the ECU.

As for the cars, what else should I check? Are there other common problems with these cars, like the flooding issue (which apparently is not easy to fix)? What does the Starting Assist Fluid do? Does it act like a starting fluid injected during startup?

Thanks for all your help! At least it starts and runs right?

HAILERS

The way I understand it, that cold start fluid system was supposed to be removed by some factory bulletin. I don't know that for a fact. I just read it on this forum. I've disabled and capped off that on my cars. It was meant for really cold climates to start the car. Not needed.

There's a free download of the factory manual at http://iluvmyrx7.com that can give you more info on how it was/is supposed to work.

I've rebuilt all my engines and don't have any flooding problem. I do have a fuel cut sw in each car just incase. Those were put installed because I notice that a fresh rebuild will on occasion be prone to flooding because the compression will be low until it gets some miles on it. Low compression can do nothing but exasperate the flooding problems.

Rottie

Hailers,

Thanks for the link! So the start fluid is basically a cold start injection, not needed for anything above freezing?

As for the flooding problems, I'm confused as why low compression would make the problem worse? Wouldn't low compression allow for fluid to leak out rather than keep it in?

Thanks again!

dre_2ooo

Compression + Fuel/Air + Spark = BOOM!

Fuel/Air + Spark - Compression = Fuel condensation

Fuel Condesation = FLOODING.

Rottie

dre_2000: cute

I'm still in piston engine mode. I'm just curious as low compression usually indicates bad rings/valve seals on a piston motor, which would not cause flooding, but on a rotory, low compression induces flooding. It just seems strange that's all. Basically, the fuel has nowhere to go except staying in the chambers (unlike a piston where is is forced out the exhaust or through the bad rings/valve seals). Just curious.....

Thanks for all the help everyone!

NZConvertible

Regarding the crank angle sensor, it doesn’t actually set the timing, the ECU does that. The CAS (as the name implies) tells the ECU where the engine is in it’s revolution, and how fast it’s turning. By changing the physical orientation of the CAS, the ECU gets sent that signal at a different time, so it fires the plugs at a different time. When you “set the timing” as per the FSM, you’re simply making sure the ECU gets the correct information on exactly where the engine is, so it can correctly calculate when to fire the plugs. This is basically how all engine management systems work, piston and rotary.

Felix Wankel

You know how when a piston engine gets REALLY flooded, and the gas seeps past the rings and into the oil pan?

It can't do that with a rotary, it just puddles up at the bottom of the rotor housing, washing what little bit of oil is in there off, and fouling your plugs out when you go to start it up. That why they don't ''unflood themselves'' by sitting like a piston engine does.