I pulled of my pulleys today because I am positive that I have set my timing wrong.

Well after some searching, I found out that the 12a and the 13b pulleys are different, the 12a pulley will go on anyway, and the 13b will only go one one way.

Well i didnt get any pulleys when I got my 13b, so I filed one of the holes to fit. Now the car wont start so I know my timing is horribly off.

How can I find top dead center? I thought that the little drilled dot on the pulley hub was TDC but I am wrong. Tried it today and no start. I also tried the method of looking at the apex seal through the spark plug holes, and that didnt work either.

The last idea saw si to pull off the pulley hub and align the key to the 9 o'clock position and 12 o clock would be TDC.

Well I dont imagine that I could remove the front fub without removing my radiator, I would need to get an air gun to get teh thing off.

Now I just thought of something, could I put the car into gear so the engine will not move easily and then use a socket wrench to get it off?

But anyway what is the correct method to find TDC?

 

I've found that poking a semi thick wire into the L2 plug hole and hand cranking the engine untill the rear rotor's apex seal contacts the rubber insulation of the wire, will show you when it's at TDC on the front rotor. When the wire no longer easily slides in and out of the hole is when the rear rotor is angled correctly, and since the rotors are phased 180º apart, it means the front rotor is at 0º or TDC.

It'll actually be a little past TDC when you're squishing the wire, because true TDC is when the rear apex seal is right between your T and L plugs. However, this method is accurate enough to get your pulley aligned to the closest set of holes. I'm thinking the Trailing or "red mark" on the pulley will be closer to the pin, simply because the wire trick requires the engine to be a few degrees past TDC and all that.

To tell you the truth, I'm not sure if I've explained it very well because I know this wire trick backwards and forwards and I sometimes don't explain things to others in a way that's conducive to teaching them how to do it. I'm wouldn't have made a very good teacher, in other words. Good thing I found rotaries.

Good luck.

 

Do we still call it TDC in rotaryspeak?

 

I think it should be officially changed to First Point Of Firing, lol

~T.J.

 

Ok, the first method I tried was putting marks in between the two pullies and then putting the final mark in between the two marks.

So I'm going to try stabbing the CAS at when the apex seal is at the leading hole, as this is also where that little dimple is on the pulley hub. Makes sence. I'm going to try it tomorrow and see what it does.

And you guys are right.... I dont think we sould be calling it TDC anymore. We call our crankshaft an eccentric shaft, so lets call TDC the first point of firing, LOL. Good name Tj.

 

Haha, thanks. I was going to say "best point of firing", but thats definatly debatable .

~T.J.

 

How about First Firing Position, or FFP?

until we discover what Mazda calls it, that is!

 

Mazda calls it TDC in their research papers, then again they refer to the rotor housings as cylinders, and rotors as pistons.

 

It's a rotary piston engine. Ew. I'd rather call it a rotary engine. And if it's got pistons, I call it a boinger.

L1@0º is what I call it. Then again, FFP is a little shorter to type and refers to the dizzy and main pulley, while L1@0º is more rotor specific, and since both L1 and L2 can fire at the same time, it uh... never mind.

Actually, when I see FFP, I think of PPF or Power Plant Frame of an FD. I dunno. I've got 20B on the brain right now.

Goodnight, everybody!

 

The way i was learned when i was still small :
The key in the eccentric shaft should lay horisontal with your sump,the the engine is at tdc on the first rotor.

Tdc will then line up on the pulley and the engine marker.

What about.... RDC...seeing that the engine turns clockwise,and get to max compression on the righthand,and not on top!

 

my vote for First Firing Point (FFP)

Jon

 

TDC is TDC... plain and simple... When the apex seal is at the highest centre position on the front rotor.

It has nothing to do w/pistons. Think about it. Actually TDC makes more sense for rotarys then piston engines as pistons are just and the highest position and our rotors are at the highest position and dead centre of the housing (apex seal).

 

Karis has it pretty good. When the front rotor is closest towards the plugs, and the rear is furthest away, it's at RTF or "ready to fire" position.

If we all ran our engines "plugs up" like they do in some airplanes, then TDC would make sence.