graniteguru

iTrader: (1)

S5 JDM Turbo. I am having a difficult time with the timing. I line up the marks on the CAS (yes they are the proper marks) and then put the timing light on the engine. With the CAS cranked all the way clockwise, I can not quite reach the yellow mark on the crankshaft pulley. This is the original pulley that came with the JDM motor. whether it was changed or not I do not know.

The engine is running very rich at idle still and I suspect it is the timing. I read the link to "de-mystifying the rx7 ignition system" and I am curious if I could have assembled the engine wrong on the re-build or if the pully just is not going to work. Any help would be appreciated.

j9fd3s

iTrader: (3)

sounds like the CAS is a tooth off. just pull it out turn it one tooth from where you are and it should be right.

graniteguru

iTrader: (1)

Just remembered somthing...duh duh. When I bought the motor, it fried right away and the eccentric shaft was fried. I bought a used one from atkins and it did not have the thermal pellet (S4 Right?). I now have the S5 pulley on an s4 shaft. Any suggestions?

HAILERS

Series four have the eccentric shaft bypass valve under the main pulley bolt.

Did you try reinstalling the CAS "off a tooth" that was mentioned above?

The engine is assyembled (sp) right.

Maybe buy a series four pulley/hub. Or aftermarket pulley/hub from Racing Beat.

Or find true TDC using the fluid displacement method of your choice. Then remark the existing pulley.

Or the second jpg attached shows how to find TDC on a series four. It's a ballpark figure that's fairly close to TDC.

Once you find the TDC then find the circumference of your pulley and measure off from TDC to -5 and -20.

A first gen model of the 1982 range will bolt on with three of the four bolts. It has a mark for true TDC. So install it without tightening the main pulley bolt and align TDC. Then without moving the eccentric shaft, pull it off and install the pulley/hub you have. Mark TDC on that pulley from the fixed pin on the front cover. Then mark -5 and -20.

T2 vert

iTrader: (5)

Here is a post about timing marks being off, see post #7

https://www.rx7club.com/showthread.p...y+timing+marks

SpeedOfLife

iTrader: (16)

The pulleys can differ from the front hub. I tried using a front pulley from a core motor and the original hub and my timing was so far off I was boosting at 25% throttle because a **** ton of my fuel was burning inside the turbo. Sucked. *****. I think you can find TDC and make new marks on your pulley, or get a matching pulley for your existing hub, or get a matching hub for your existing pulley. Good luck finding a match though if you don't already have the old matching piece like I did.

graniteguru

iTrader: (1)

I found TDC by finding the tip of the rear apex seal in the Trailing Spark plug hole and making a mark and then finding the tip of the same apex in the Leading spark plug hole on the rear rotor. I then found halfway in between the marks on the pully and found TDC. I found that TDC was in fact about 15 degrees from the yellow mark (5 degree mark) to the retarded side (to the right). It now idles great but I am throwing code 12 and 18 and it is running very very rich at idle.

SirCygnus

iTrader: (1)

i see what you did. its just worded in a way that confused me.

1. Remove both rear rotor spark plugs.
2. 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.
3. 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.
4. Halfway between your two marks is TDC for the front rotor (#1) rotor.

graniteguru

iTrader: (1)

Exactly! couldn't have said it better myself. Oh. that's right I didn't say it better myself.

HAILERS

Did ya'all take into consideration that the sparksplug holes in a series five rotor housing are located different than the sparkplug holes in a series four rotor housing?

And did you take into consideration the method you used was for a series????? housing? So stating that, just how accurate is that method? Ballpark figure at best imho. and I'll let it go at that.

SirCygnus

iTrader: (1)

http://www.teamfc3s.org/info/article...fying.html#TDC

HAILERS

That's the same article I attached to a thread in a post of mine above. I've read that article before and for a period of time believed in it.

Then it occured to me that series four and five have the sparkplug holes located differently so that method cannont apply to both series cars unless one is looking for a ballpark figure for TDC.

The sparkplug hole location matters if that method is used.

In other words I don't believe that is a truly accurate method of finding exact TDC.

graniteguru

iTrader: (1)

What would you suggest Hailers? I am open to a different way.

SpeedOfLife

iTrader: (16)

Measurements. Angles aren't magic. If you do a little research I bet you can find out where the components are relative to each other and the block. I'd do it if I needed to, but I don't. I'm working on tuning.

SirCygnus

iTrader: (1)

ok so lets do this properly. lets say if the apex seal is exactly at the bottom spark plug hole ( i cant remember if its l or t at the moment as im tired ) then what timing degree would it be for a series4 or a series 5? is there documentation to say what degree each spark plug hole is at for an s4 or s5 housing?

SpeedOfLife

iTrader: (16)

http://www.turborx7.com/porttiming.htm

SirCygnus

iTrader: (1)

uh... port timing != ignition timing.

SpeedOfLife

iTrader: (16)

I know but the illustration is useful.

HAILERS

You can find exact TDC by fluid displacement (mentioned in my first post).

You remove all four sparkplugs.

Then get two clear vinyl tubes from Home Depot or any hardware store. The dia would be the dia of the sparkplug holes. They'd be approx two feet long each.

You'd screw the yinyl tubing into the sparkplug holes a few threads. One into the Lead hole and one into the Trail hole of just one rotor housing. The other rotor housing does not get any attention. You removed the plugs out of it so no compression will be built up when you rotate the engine later in the process.

You'd support the open end of each tube above the rotor housing in any way you can (string, wire etc).

Prior to this you would have found approx TDC in any manner of your choice. Gotta do that before the next step.

You'd get your squirt can out and fill the can with engine oil or two stroke oil that has some color to it (helps to have color).

You'd squirt oil into the Lead tubing and keep squirting til oil starts to flow out the Trail tubing. You'd let the oil come almost to the top of each tube and stop before it gets to the very top.

At this point you might rock the E shaft back and forth inch or so each way to get air bubbles out. You'll see 'em rise up into the tubing as you do this.

You now have a rotor full of oil and two tubes with oil visable in them and the oil at the same level in each.

Now you grab the front pulley with a socket and turn the E shaft in one direction and watch the fluid in the tubing. What in general will happen, is the fluid in one tube will start risiing as you turn then as you keep turning it will now start to fall. When that poiint is reached you have found TDC.

So you now turn the E shaft in the other direction til the fluid in that tube starts rising again.......then starts to fall again. It's that point that TDC exists and you can make a mark on the front pulley. Put a piece of masking tape on the front pulley and mark it would make more sense.


You do this process several times for repeatability.

The idea is no more than visualizing a piston in a bore at it's bottom stroke filled with water. AS the piston rises to the top fluid is displaced. At the point the piston starts on its downward stroke the water starts to fall. That's TDC.

To prove it's right, I took a 82 RX7 hub and pulley (marks at TDC on that assy) and installed it on my 87 After I'd found TDC using fluid displacement method. I pulled the hub assy off after finding TDC then slid the 82 hub/pulley on the engine. The 82 RX mark mated with the fixed pointer on the front cover confirming the oil displacement method works.

It's messy to do this. You also have to do a little rocking of the E shaft to get the air bubbles out prior to getting down to businesss. Did I mention it's messy? Yes it's messy.

Also as you rock the E shaft in the process, some oil will escape into the next rotor chamber, so don't be surprised that the level in both tubes gets less and less as time goes on as you move the E shaft back and forth. God gave you a squirt can to refill the tubing if needed.

Also as you move the E shaft back and forth some oil is going to eventually make its way into the exhaust manifold and it's going to smoke upon start up the next time you start it up.

This method is cheaper than buying a RB after market pulley that has accurate marks on it.

To measure out the -5 and -20 after finding TDC you have to find the circuference of the pulley do a little pie are square routine thing and divide by 360*. Something like that.

AS far as I'm concerned its dead on the mark accurate. I'm not too worried about what others think. I know the sparkplug hole method is a good way to find a ball park but that's about all. Bye, bye.

Johny zoom

iTrader: (5)

Thanks hailers I used this method when I put the 13bt pulley and front cover on my rew. worked perfect. Its a little messy.

SpeedOfLife

iTrader: (16)

*copy, paste, save*

That's bad ***, Hailers.

SirCygnus

iTrader: (1)

hm... this is interesting.

j9fd3s

iTrader: (3)

another way is to take off the front pulley. when the engine is on TDC the key way ALWAYS is at 9 oclock.

SpeedOfLife

iTrader: (16)

Well ****, that's not bad at all... You mean just the pulley, not the hub, right? Any time I mention pulling the hub I want to make people aware of the Torrington bearing issue.

SirCygnus

iTrader: (1)

you cant see the key unless the hub is removed. unless there is a way to check via the flywheel?