Distributor Grinding

[AK260]

What is the significance of the vacuum lines leading up to the distributor? Could that pose any issues?

Check the size of tour cap as mentioned above - it could be that your 280z cap is just that bit different to the 280zx one.

The vac line provides a “load sensing” function. When wide open throttle, the vac drops to zero and advance becomes “base timing” + mechanical advance. When the throttle is closed or part closed the vacuum increases and the distributor adds vacuum advance. This is because the mix is leaner and needs more time to burn.

That last bit sounds counter intuitive but think of it this way: you have two plates with a dusting of gun powder that you will light with a match from the centre of each plate. One has a light dusting (lean) with large air gaps between particles, the other has a thick dusting (richer) with much smaller gaps. The one with the larger gaps between each particle will need longer to fully burn across the plate (hence you need more advance). So when cruising, or idling, you have more vac, leaner mix and therefore need more (vac) advance to get a full burn.

[moozieman]

1 hour ago, Zed Head said:

Wiggle the cap.

When Ive heard it grind in the past, I can typically reach the distributor and apply a bit of force on top of the cap to stop the sound before it stalls the engine. Simply pressing down on it keeps it from shaking and grinding. Could that really be the issue? I suppose that would be the best case scenerio!

Edited March 3, 2020 by moozieman

[Zed Head]

The cap should be very solidly locked to the distributor body.  No wiggle at all.  If you can press on the cap and see it move independently of the distributor body, that's a problem.  Take a measurement across the bottom of the cap.  Maybe somebody out here can compare to what they have.  Kind of sounds like you have the wrong cap.

[moozieman]

22 minutes ago, Zed Head said:

The cap should be very solidly locked to the distributor body.  No wiggle at all.  If you can press on the cap and see it move independently of the distributor body, that's a problem.  Take a measurement across the bottom of the cap.  Maybe somebody out here can compare to what they have.  Kind of sounds like you have the wrong cap.

I just did some research and the zx distributor appears to have an ignition control module (the little box thingy) on the side of it. Mine doesnt have that.

[Zed Head]

Still waiting for that picture...

[moozieman]

52 minutes ago, Zed Head said:

Still waiting for that picture...

I know... I appreciate your help. I'm gonna try to do it tonight. I live and work 20 mins away from my garage.

[moozieman]

21 hours ago, Zed Head said:

Still waiting for that picture...

 

[Zed Head]

That's a 280Z distributor not 280ZX.  Looks like the lock-down screw ins in place and tight.  Were both spring clips properly in their slots when you removed the cap?  They can be difficult to get in to position. I always have to use two screwdrivers, one to locate and one to apply pressure until it snaps in to place.  Can't get my fingers down there.

Did you check the cap for looseness when you wee removing it?  This was mentioned earlier as a possibility.  The cap should be rock solid on the distributor body.  Pressing on it should have no affect at all.

[moozieman]

7 minutes ago, Zed Head said:

That's a 280Z distributor not 280ZX.  Looks like the lock-down screw ins in place and tight.  Were both spring clips properly in their slots when you removed the cap?  They can be difficult to get in to position. I always have to use two screwdrivers, one to locate and one to apply pressure until it snaps in to place.  Can't get my fingers down there.

Did you check the cap for looseness when you wee removing it?  This was mentioned earlier as a possibility.  The cap should be rock solid on the distributor body.  Pressing on it should have no affect at all.

I was able to get the cap on securely, but I hadn't tried shaking it. i can try again though.

[Zed Head]

Have you started it?  What does it do?

[moozieman]

16 minutes ago, Zed Head said:

Have you started it?  What does it do?

It idles decently but then begins grinding during revs or when i try to put it in gear

 

[Zed Head]

Doesn't really sound like a distributor problem.