Ignition Timing

Makesy

Club Member
Whilst most of you appear to be enjoying yourselves at Donnington, spare a thought for those of us who are garage-bound!

I am struggling with ignition timing - something that I have read up a fair bit on, but can't quite grasp. Can anyone help me with some simple explaining?

I think I've found TDC (lobes on the camshaft are facing outwards on cyl 1) but my rotor doesn't face the marked #1 point on the cap (is this normal?)

My car has hardly started since I got it so I've no reference point to be sure what is "right"

I'm in the process of installing a new EFI system so I can't fire it up to check just yet, but just seeing if my car is set up as it should be.

Pic below shows the rotor at roughly 9 o clock, where the #1 mark on the cap is at about 4 o clock
20190504_204729.jpg
 

jonbills

Membership Secretary
Site Administrator
Whilst most of you appear to be enjoying yourselves at Donnington, spare a thought for those of us who are garage-bound!

I am struggling with ignition timing - something that I have read up a fair bit on, but can't quite grasp. Can anyone help me with some simple explaining?

I think I've found TDC (lobes on the camshaft are facing outwards on cyl 1) but my rotor doesn't face the marked #1 point on the cap (is this normal?)

My car has hardly started since I got it so I've no reference point to be sure what is "right"

I'm in the process of installing a new EFI system so I can't fire it up to check just yet, but just seeing if my car is set up as it should be.

Pic below shows the rotor at roughly 9 o clock, where the #1 mark on the cap is at about 4 o clock
View attachment 33157

That pic doesn't look too wrong to me. That rotor is in the area I'd expect it to be at TDC (although it could still be out enough to not run)
The #1 mark on the cap should be nearer where the rotor is than 4 o clock. 4 o clock sounds like the caps on the wrong way around.
Is #1 lead conected next to the #1 mark?
 

jonbills

Membership Secretary
Site Administrator
I'd suggest remove the distributor and mount and let's see the alignment of the distributor drive tang. Its possible for the oil pump/Distributor drive spindle to be timed wrong and the distributor and ht leads setup to compensate for it.
 

Makesy

Club Member
Thanks Jon. I will give that a go and report back.

The dizzy cap only goes on one way (I believe I have a 280zx distributor but can't be sure). So I can't just flip it.

Having never removed the dizzy, is it possible this has been installed incorrectly?

The #1 lead is at the #1 on the cap but as I said, I've hardly had the car running at all, and certainly not with any consistency
 

MaximG

Well-Known Forum User
Thanks Jon. I will give that a go and report back.

The dizzy cap only goes on one way (I believe I have a 280zx distributor but can't be sure). So I can't just flip it.

Having never removed the dizzy, is it possible this has been installed incorrectly?

From the looks it's a 280zx dizzy and yes it is possible for the distributor to be in the wrong place if the oil pump has been out previously and it's drive hasn't been put back properly. When I first got mine number one was timed to number 6 cylinder so it is possible. Ran absolutely fine until I took all the leads off to replace them and didn't notice it was wrong.
 

jonbills

Membership Secretary
Site Administrator
Here's my distributor showing #1 lead. It's 180 degrees from where you're saying yours is I think. Is it a moulded mark, or just a mark made by the owner like mine?

DSC_0266.jpg

Your distributor body may be a few degrees more clockwise than I'd expect, but really it does look about right.
#1 should be at 9.30 to 10 o clock.

The cam lobes are in about the right place. Are the timing marks at zero?
 

Farmer42

Club Member
I have the same dizzy as you and no. 1 lead is not where it is marked on the cap, it is the next one round (anticlockwise). As long as your cam is in the right place i.e. at top on no.1 cylinder, your crank pulley shows TDC, you can use whereever the rotor is pointing as No. 1 cylinder, remembering to mark it as no.1 and then use the firing order from there. That should do it to enable you to set the static timing advance.
 

Makesy

Club Member
Thanks guys.

The cap has a moulded mark at about 4pm which I had assumed was #1. It isn't hand drawn like yours, Jon.

From what you guys are suggesting, I should ignore this and use the current rotor position (TDC) as #1.

Just to double check, I took these photos tonight, of what I think is TDC. It more or less shows the same as my last pic, but it is just for my sanity!

Excuse my ignorance, but how do I check the timing marks are at zero, Jon?

20190505_175254.jpg
20190505_175233.jpg
 

jonbills

Membership Secretary
Site Administrator
Yep, that still looks right. [emoji4]
For the timing marks, they're on the timing cover and the crank pulley.
There are a couple of variants I think, one with a pointer on the timing cover on the spark plug side of the engine and notches on the pulley with the last big notch being zero or tdc. The other variant has only one mark on the pulley and a plate with numbers on the timing cover on the exhaust side of the engine.
IMG_0565.jpg
 

Makesy

Club Member
Without seeing your image above, I took this picture of the chain. I haven't cranked it round since my last pic of the cam/dizzy at TDC. Not sure if this is of any use?

I will have a look for the marks you mentioned later tonight.

Cheers
 

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Makesy

Club Member
Haha, good to know something is good with the car at least!

Sorry Jon, I'm not sure what I'm looking for on your picture. I can grab a few pics from that area of the engine tonight.
 

Makesy

Club Member
Sorry for the delay...

I can't find anything of significance, but maybe you can see something I can't?

20190518_164355.jpg 20190518_164400.jpg 20190518_164411.jpg
 

jonbills

Membership Secretary
Site Administrator
In pic 2 there's a thing with a serrated edge overlapping the crank pulley, might be what we're looking for.
Also check the other side of the pulley, the exhaust side.
 

Farmer42

Club Member
In pic 2 there's a thing with a serrated edge overlapping the crank pulley, might be what we're looking for.
Also check the other side of the pulley, the exhaust side.

That is correct. That is the timing indicator. The timing marks go up in intervals of 5 degrees BTDC with the 2nd one TDC (indicated on pic). There should be a notch on the crank pulley that indicates TDC when it lines up with the mark on the indicator but you need to make sure it is for no.1 cylinder by ensuring the cam and piston are in the right place. You should then ensure you mark the dizzy cap no.1 where the rotor points and follow the firing order from there anticlockwise. You might have to turn the dizzy slightly to get the cap to align with the rotor ( the pointed bit inside the dizzy should be at the top of the lobe on the dizzy shaft).

You should be aiming for 10 degrees BTDC (advance) for static timing. You probably know all this anyway but doesn't hurt to say again.
 

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