Rotary Car Club - GSL-SE 6P 13B Finding TDC?

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GSL-SE 6P 13B Finding TDC?

How would a person go about finding TDC on a SE 6P 13B, when the front pulley is installed wrong?
I thought I saw it somewhere that the flat spot on the backside of the flywheel will be visible thru the inspection cover on the intake side of the engine. But, this brings up a new issue. The RB holley intake sits too close to the top bolt on this cover to get a socket on it. :banghead:
I certainly don't want to go thru the major hassle of dropping the header, to watch for an apex seal to go by the front exhaust port.

So, is there another way to locate TDC, without tearing into the front of the engine, or dropping the trans, to see where the keyway(s) are pointed? That would be even more work than dropping the header.

The fist time I faced a finding TDC issue, I grabbed a thick soft wire and pulled the L2 spark plug. You slowly rotate the engine by hand while 'feeling' with the wire until an apex seal touches it. You've just found BDC on the rear rotor and TDC on the front rotor. Back off a few degrees and install the pulley with the marks near the pin; it will be quite close.

Almost no 'work' involved using my method. Enjoy.

there is another similar method that I found while reading the net:
http://www.teamfc3s.org/info/articles/demystifying.html

Quote:

Now this next discussion is a real diagnostic dilemma. Properly installing a crank angle sensor is pretty straightforward. The eccentric shaft (crank) marks are first lined up, and a mark on the crank angle sensor driven gear is aligned to the crank angle sensor housing. The crank angle sensor is then slid into its bore in the engine. Everything seemed to be okay.

But with the engine running, idle quality and performance could drastically be improved by advancing (turning clockwise) the crank angle sensor. If I advanced the crank angle sensor's position by one tooth, performance was better. A few phone calls to a tech line, two Mazda experts and a little research said I needed to find TDC.

With a new TDC identified, I installed the crank angle sensor. Did it work? I'll let Figure 13 answer that question. Figure 13 is the trailing primary #1 pattern. The spark line is back to normal, as is engine performance. As I mentioned, I've run into this situation twice. I'm still not sure what causes the timing to change in the first place. It must be something in the engine, but what?

Well, I hope I've shed some light on these very interesting ignition systems. While most of us may not see these vehicles regularly, it can be very helpful to have a good understanding of how known good ones work. This knowledge can reduce our diagnostic time drastically. Good luck in your own Diagnostic Dilemmas!

Quote:

Here is the procedure I used:

Remove both rear rotor spark plugs.
Rotate the crank until you can see an apex seal (tip of the rotor) in the trailing spark hole. The trailing plug hole is restricted, making the seal somewhat difficult to see. Use a flexible light and a mirror. When the seal is seen, mark the crank.
Rotate the crank until you see the same apex seal in the leading spark plug hole. This plug hole is not restricted, which makes it easy to see the seal. Mark the crank.
Halfway between your two marks is TDC for the front rotor (#1) rotor.

Thanks! I never thought of using R2 spark plug holes to reference an apex seal, but it should work much the same as using R1 exhaust port. May not be 100% TDC, but dern sure close enough to know which way the pulley has to go.

Damn, why didn't that thought come to mind?

how can the pulley not be on tdc if there is a key way?

of did the GSL-SE 13b's have a removable timing crank pulley?

All 1st gen and earlier rotaries have a bolt on pulley with the timing marks on it. This pulley will fit the front hub any of 4 ways, as the bolt pattern is totally square, like a wheel & hub. The upside to these engines, they all have 3mm apex seals, or wider if you go old enough.

the FB 13B engines have 3mm apex seals?

never heard of that.

Yepperz, GSL-SE 13B has 3mm apex seals. The rotors are heavy as hell, though..... (~11.5 lbs)

Quote:

Originally Posted by Jeff20B (Post 51103)

This worked like a champ. Funny thing is, the pulley wasn't installed wrong afterall. The DLIDFIS was wired wrong. The pickup coils were wired up to the GM modules backwards, which had the polarity wrong. This put the timing ~90* off.
It's amazing how much better it runs with those wires swapped, and the dizzy dropped in at factory spec.......

congrats, glad it's fixed!

I'm glad too. The car was FREE.........

damn, that's the best deal ever.

The only way I could get my car to work was installing the distributor 180 out. I wish there was the internet back then.

The internet is the best invention known to man. Distances are no longer a factor when it comes to info. I love it.