HAILERS

Here's an idea that might help someone who has lost cofidence in the timing marks on his pulley.

1. Turn the pulley til the mark you have for L is across from the fixed pointer.

2. Pull the Front spark plugs and screw two pieces of 1/2" soft CLEAR vinyl tubing into the sparkplug holes. The hose should be a foot/foot and a half long.

3. Place the open end of both pieces above the sparkplug holes. Get a squirt can and squirt some two stroke oil (has color in it) into the Lower vinyl hose and keep squirting til oil rises in the Top vinyl hose and until it gets about three or so inches from the open top of the hose. Stop there.

4. Now both hose will have two stroke oil in them and the level in each hose will be the same height.

5. Turn the front pulley incrementaly back and forth. As you turn the pulley in one direction, the oil will rise, then start falling. When it starts falling, start turning the pulley in the opposite direction. You should have caught on to the idea by now. The place where the oil starts falling is TDC.

6. Now mark the pulley opposite the pointer. If your origninal pulley mark was right, then IT should be just to the left of the new mark (if looking aft at the pulley).

7. What you can do is measure the pulley diameter with a pair of calipers and knowing that figure, figure out how far five degrees is in inches/mm to see if your pulleys original Lead mark is even close. All my pulleys measure 4.5" dia.

eriksseven

iTrader: (6)

Haha... Awesome. You're crazy. Don't know if I'll ever use your method--but you're still bad-*** for presenting the option.

Archive?

Captain Jean-Luc Picard

That's the hard way of doing it.

Just remove the sparkplugs from the rear rotor. Center an apex seal in the trailing hole, using a light and a mirror and a ratchet/socket on the crank pulley. Make a mark on the pulley adjacent to the locator pin when this is done.

Repeat for the leading hole, and make a mark.

Remove the main crank pulley, measure halfway between the 2 marks you made, and there is your true TDC for the front rotor (which is how engines are timed).

Now, stock timing is 5 degrees after, so you'll need to add that. Measure the circumference of the pulley and divide that by 360. Now multiply by 5, and add that amount to the centered TDC mark. Make your final stock leading timing mark by filing at an angle into the pulley.

HAILERS

It's the only Accurate method I've ever found, without taking the engine part and indexing it.

The method described at the bottom of this article is NOT accurate at all: http://www.teamfc3s.org/info/articles/demystifying.html but is good for getting a
General idea of where TDC is.

HAILERS

NO IT IS NOT. THAT METHOD IS NOT ACCURATE.

The reason it is NOT accurate is that the sparkplug holes are NOT equal distance from where the rotor is at TDC.

The sparkplug holes would have to be equal distance from the narrowest point on the rotor housing. Jpg attached. And the holes are Not equal distance from the narrowest place on the rotor housing.

The Wankler

iTrader: (14)

The ongoing TDC saga. Good advise there Hailers. Thank you!

Siraniko

iTrader: (13)

you guys are making life complicated. here's a simple yet very effective

https://www.rx7club.com/1st-gen-archive-71/ignition-main-pully-timing-525909/

HAILERS

No. I said Accurate. Not baseball field close.

It could be I don't understand that thread you posted. From what I read you remove that dust plate on the right side of the engine. Then turn the flywheel til you see where there is no lip on that area of the flywheel. So I ask, what are you aligning up with??

It seems as inaccurate as the looking thru the sparkplug holes and marking the pulley when a apex seal that comes by the Trail and then mark the pulley again when the same seal comes across the lead plug opening , and marking the distance b/t the two as TDC (it isn't and can't be TDC since the plug holes are not equal distance from the narrowest area of the housing.

I'm not being a hardhead about this. There was a invalid way posted on Octupus Net that might have applied to first gen but couldn't work on a second gen, and then for quite sometime I was a believer in the sparkplug hole method, until one day I noticed the sparkplug holes are not equal distance from the narrowest part of the rotor housing. There's NO way that is Accurate. It might be good for getting in the ball park, but that's it. At least on a series four the above applies.

I started being a worry wart about timing marks on pulleys when we had a thread on the TeanFC3S where alllllllll these people SWEAR that each pulley has marks specifically for that engine (I find that still hard to believe in mass produced engines).

So mabe you could clearify what parts you are matching against each other to have a nat's on timing mark??

And I know about how the keyway on the eccentric shaft when opposite the exhaust means that TDC is straight or 90* up from there, but there is No way to verify the keyway is Exactly 90* from TDC or exactly opposite the exhaust ports.

The Wankler

iTrader: (14)

I have a aftermarket flywheel.

Siraniko

iTrader: (13)

I will make it as simple as possible so your nobbness wont get confused.

1. remove the intake/exhaust side inspection plate.

2. rotate the motor until the flat side of the stock flywheel is facing the inspection or at 3:00. for aftermarket flywheel, remove the top inspection plate instead (slave cylinder).

3. now look at your stock pulley. the 10mm bolt near or at 12:00 position is your TDC.

Captain Jean-Luc Picard

YES IT IS ACCURATE.

MEASURE A HOUSING FROM THE HIGHEST POINT OF THE TROCHOID SURFACE, AND THE MEASURE FROM THAT POINT TO EACH OF THE CENTERS OF THE PLUGHOLES. It is within a cats whisker of being perfectly centered depending on how you obtained the "highest point" on the housing.

Don't make me break out the digicam and prove your *** wrong.

YOUR WAY IS NOT THE ONLY WAY. LEARN TO RECOGNIZE THAT.

HAILERS

That does not make sense. Have two different people do that and you'll get different result. One guy will rotate it maybe a quarter inch further than the next person. The timing mark won't be in the same place for one vs the other. There's nothin indexed in your method. There's no matching marks etc, only a general remark about having the flat facing the inspection area.

Like I said, an accurate method, not a ballpark figure. That method is noting more than stating the keyway in the E-shaft should face the exhaust side of the engine. There's no accuracy to it, just a general idea of where TDC would be.

You evidently don't see it that way. So be it. By the way, the apex seal in the sparkplug holes would be much more accurate than that way.

scathcart

Its bullshit.
There are two stock main pulleys.
There are two stock main hubs.
Mazda sells each hub-pulley as a combo unit. The change, like everything else, seemed to have occured mid-1988. But with reman and rebuilt engines, who knows whats correct or not at this point.

From the factory, the hub and pulley are matched. The problem comes when people install a new stock hub or a new stock pulley. It may match the hub, or it may not.

So, your timing with a stock pulley is either correct, or its off. An easy verification is to turn the timing keyway to 9 o'clock, and then check the timing location. The yellow mark should then be just to the left of the timing indicator, by 1/3 the distance between the two timing marks. If it is not, your pulley is not matched to your hub.

I always make sure to verify the stock pulley-hub with a degree wheel during engine rebuilds, but simply lining up the keyway to 9 o'clock and checking the yellow (5*ATDC mark) has always proved accurate to within a degree.

HAILERS

Your clueless. Go find a engine builder and have him show you where the sparkplug holes are and watch him measure the distance b/t each plug hole to the narrowest point on the rotor housing.

scathcart

This method does not determine TDC to within tolerable levels of accuracy (within a half degree) when compared to a degree wheel on a dissassembled engine.

Its especially true since the plug placement is altered between S4 and S5 housings.

Captain Jean-Luc Picard

Hailers, I was going to post my message and let you and your pipe dream be, but since you insist on thinking that your way is the only way, I guess I will have to publicly embarrass you.

Lets take a standard FC housing.



After some measuring, here is the highest point on that side of the housing.



Also here are the centerlines of each hole.



With the stage set, let's measure between the centerlines.



Looks like about 52mm. We'll make a mark at 26mm to signify halfway between the holes.



WTFBBQ11ty!!! They line up!! This means that the plugholes are centered on the high point of the trochoid surface.



Sucks to get owned by a noob I guess.

I guess if using a series 4 or older housing with the shorter plug spacing (about 3mm) then this could throw results off by about 1-1.5 degrees on the crank...not really a critical amount unless you are tuning on the ragged edge of a turbo engine, which you probably shouldnt be doing anyway.

Or, of course, there is always the pipe dream presented above in all it's glory, which has not been proven to work any more accurately.

Captain Jean-Luc Picard

Oh, and no hard feelings here..if you would like me to school you on the whole hub/pulley/timing mark issue I will gladly do so, with photos to explain it all. It is a little complex, but it is the truth that if you swap pullies onto other hubs you can have timing marks be off significantly.

dguy

iTrader: (8)

How bout you just buy some new pulleys? Just messing, HAILERS. On a side note from what I remember about the pulley is that its a 360mm pulley, every mm is 1 degree. I don't have concrete data however I do know that on a stock 2nd gen pulley the marks are exactly 20mm separated.

Captain Jean-Luc Picard

IF memory serves, s5 and s4 main pullies are different outside diameters, slightly.

dguy

iTrader: (8)

This would have been from an s5, however I think you're incorrect on the pulley diameter being different.

Captain Jean-Luc Picard

here are 3 pully sets I have, unmolested from core motors.

First measurement.



Second measurement...



Both those measured 4.5" though the flash glare keeps you from seeing it.

Third measurement...



Wait...what happened? Let's compare those...



So indeed they are different.

HAILERS

Let's see. Where was I. Oh yes. You are clueless and have your head stuck up your dark spot.

A series four housing looks like the one in my jpg. The Lead and Trail are not the same distance from the narrowest part of the housing. The Lead is closer and measures .7" away. The Trail measures 1.1".

I found the HIGH point on the housing with a dial gauge and made the mark on the side. Then measured the distances. Then took a scan of the housing with two blue coated weldiing rod laying in the bottom of both holes.

Anybody who even just picked a S4 housing up and looked, can tell their not the same distance apart.


Here's a helpful hint: I'd suggest you stay away from machinery and get a job in waste management.

Captain Jean-Luc Picard

Excellent lack of rebuttal to the PROOF offered above. You have a future in politics.

I guess you really can lead 'em to water, but you can't make 'em drink.

HAILERS

No. Waste Management is a bit too complicated for you. Get on welfare. It's your best bet. No proof my royal ***. Lack of vision? You call those half *** scribbled mark-a-lot lines proof? Get real.

A half blind person can look at the welding rods and compare their location to the narrowest point on the housing. Not even close.

Anybody with a series four rotor housing, take a look at the location of the holes and you'll see what I mean.

NZConvertible

Mister I-type-in-huge-capitals-so-I-must-be-right; S4 and S5 plugs are in different places. Either the leading or trailing plug (can't remember which) was moved for the S5. Your housing is an S5; Hailers was obviously measuring an S4 housing. That means Hailers method is accurate for all FC housings (and any Mazda rotary engine) whereas yours only works on S5 housings and maybe later ones (but not when you use a huge marker).

Next time you might not want to make such an *** of yourself in your first post, in case you get proven wrong again...