Question re: Setting Timing on L24 ('72 240Z)

[Jughead]

Hi all,  I need clarification on setting the timing on my '72 240 Z correctly.  I've studied the available manuals, but am still unclear.  

I have changed plugs, wires, caps & rotor, points and condensor.  

I am using a strobe light to align the triangular pointer to the notch on the pulley.  I've chosen the 2nd notch from the left - with the notches on top, looking from the front of the car.  I chose this notch because the Haynes manual says that the left-most notch is TDC, and that each notch to the right of it is a 5 degrees advancement.  I've marked the pointer and notch with whiteout for visibility. I have verified that I'm on the #1 compression stroke by by making sure the rotor is coming up on the correct position in the distributor.

However, I cannot get the pointer to align with the notch!  When I turn the distributor body to align the pointer & notch, I can get them about an inch part, and that's by turning the distributor all the way to where the marking on the disti body shows all the way retarded.  Obviously, I'm missing something!

Any suggestions?  I'll report back with results...Thanks!!!

 

  

[Zed Head]

Could be that your damper pulley has slipped.  I assume that the engine runs and you are adjusting timing on the running engine.  And that your timing light is connected to the front, #1, cylinder.

Does the engine run well?  You could remove the distributor lockdown screw and keep turning the distributor if you think that it runs better the farther you turn it.  Idle speed will increase as you advance the timing, typically, if you're in the range of 0 to 20 advance.  Might just be the old oil pump drive shaft alignment problem.

Forgot to ask also, is it the original points distributor?

Edited September 14, 2020 by Zed Head

[jonathanrussell]

Another thing to think about.

There are two ways the ignition / distributor timing plate can be adjusted. First is the obvious way we all use to loosen the set screw on the back side of the distributor and then rotate the distributor so that the timing plate hits the Retarded or Advanced line we want. That plate though fastens to the bottom of the distributor with a set screw that screws up into the bottom of the distributor and the hole in the plate where the screw passes through is slotted and adjustable. If you loosen that screw, you can "macro" adjust / rotate the distributor. What I usually do is use the normal timing adjustment set screw (on back of distributor) to adjust the timing plate so that the distributor points to the middle line (not retarded, not advanced). Then, I start the car and check the timing with a timing light. If the timing mark doesn't line of with the TDC mark on the damper pulley, then I try and adjust the "macro" timing adjustment by loosing the set screw under the distributor and rotating the distributor....trying to get the timing light to show 0 degrees advance or TDC. Once done, I tighten the set screw under the distributor. Then, I adjust / advance timing to spec using the normal timing set screw on back of distributor and timing light.

If you can't get the timing in range then you may have a slightly more involved issue. As ZH mentioned, could be damper slip. Could also be the oil pump spindle gear is off- See FSM and Monroe book for details on setting engine to TDC (compression stroke) and checking the spindle direction (with distributor removed). Monroe does the best job describing a method for installing the spindle and turning the oil pump body 1/2 a bolt width clockwise while passing the spindle gear into the crank gear.

[7tooZ]

Is it running now?

Sounds like you are using the stock configuration of points. So you are using the mark that is on the farthest to the left (passenger side of the car). There are two points of adjustment on the distributor. The 10 mm on the firewall side of the distributor (photo below).

the other is on the opposite side closest to the front cover and is an 8 mm. Both give you some adjustment that will affect the timing.

Remember rotating the distributor only changes the timing not TDC. I assume TDC is a point half way between when the piston stops rising and when it starts to fall. Mark each and then split the difference. Mark your balancer or move the pointer if you can. 

My timing is currently set at 6 degree BTDC 

Edited September 14, 2020 by 7tooZ

[Jughead]

Which notch on the pulley should I align the pointer to?    I have a 72 stock 240Z.  It came with Emission Control, but I removed the air pump long ago and it's run fine since - until I changed the points, plugs, cap, rotor & condensor!  ? 

According the Haynes, static ignition timing should be 10 degrees @ 550 RPM.  Does that mean I use the 3rd notch from the left, since they're 5 degrees apart?  

I'm pretty sure it's the original distributor.  I'm using a timing light (and yes - it's connected to the #1 wire.)

I really appreciate help, guys!!

 

Jughead

[siteunseen]

My '72 has a deep V for zero at the bottom and each mark after that is 5 degrees coming up as in rotating clockwise looking at it from the front of the car. So I will say the 3rd notch would be 10 degrees coming up if that makes sense.

I found the thread that got me straight. It was hard for me to understand but with the help of the forum members I finally got it. Good luck!

 

[madkaw]

Sounds like it’s off a tooth

[Jughead]

Do you mean the timing chain at the cam sprocket? 

[madkaw]

8 hours ago, Jughead said:

Do you mean the timing chain at the cam sprocket? 

If your talking to me , you maybe be off a drive tooth from the oil pump gear . Have you removed the oil pump at all? Has it always been this far off. Is the tang at 11:25 o’clock at TDC ? Have you had the engine apart or oil pump out ? Is the rotor pointing at #1 spark plug at TDC - possibly the wires are one hole off