Just about to start up the engine after 4 yrs

[Captain Obvious]

Maybe it's just camera angle. I just took a look for other similar pics and it could just be from the way the camera isn't dead-on towards the end of the shaft.

If it rotates straight and you can't wiggle the top around with a pair of needle nose, then maybe it's an optical illusion.

[Zed Head]

The issue of the flailing shaft top comes up occasionally with the guys that run EDIS or COP, since they don't need the distributor anymore.  Some cut the distributor drive off.  Some install a bearing in the top of the timing cover.  Others let it spin in the timing cover hole.  I've thought that it would be fine just using the cover hole as support, but design-wise it's not really lubricated and it's steel on aluminum, so that may not be right.  Working backwards you'd think that the engineers must have been using the distributor shaft bottom and collar as support for the top of the quill.  The distributor has what seems to be a precisely machined and located mount and the slotted collar holds the top of the shaft in place below.  So ti's designed as an assembly, I think.  The short answer is, it may not matter because the distributor shaft and bearing is doing the work.  Don't know, just guessing.

The procedure for setting that bottom screw seems right.  The 280Z's got rid of the A and the R but they still have a cast-in mark that seems to give spec. timing.  But there are no instructions anywhere about how to use it.  Maybe it's supposed to be obvious.  I dinked around with it when I started running out-of-spec. advance.  Tried to get the spark pattern centered or at least all on the rotor electrode so I could be sure I wasn't getting stray sparking to the wrong plug.  If you ponder what the distributor is doing during its advance mechanisms, you'll see that the rotor electrode-cap electrode relation moves around quite a bit.  I only got half coverage by the time I was done.

[grannyknot]

"The distributor has what seems to be a precisely machined and located mount and the slotted collar holds the top of the shaft in place below.  So ti's designed as an assembly, I think."

Zed you hit the nail on the head, not only does the slotted collar at the bottom of the distributor shaft locate and support the oil pump drive shaft, it does so without letting either shaft (oil pump or distributor shaft) touch the the timing cover hole.

Simple but precise, pretty much sums up Datsun doesn't it?

[grannyknot]

Okay, the engine roared to life this morning on the first try, always nice! So far no leaks.

I set the timing at 10* with a timing light, balanced the carbs at 800 rpm (still need half a turn of the fast idle screw to keep it from stalling but I'm sure I'll figure that one out)

But, the distributor is turned counter clockwise as far as possible in both the R/A adjustment and the underneath adjustment in order to get that 10* at the damper.

Here the small screw driver I am holding is pointing exactly where the #1 sparkplug contact is on the cap at TDC,

 

and this is with the distributor removed still at TDC,

Even though the oil pump/distributor shaft position looks right I think I should lower it and and turn it one tooth?

Would having the cam timing gear adjusted to #3 cause this?

Thanks,

Chris

[rcb280z]

Your distributor drive alignment looks to be off by about 5% or so, IMHO. That would explain the timing marks being off. Maybe Zed or someone can verify this. Im no expert but I think I'm right.

My dizzy info above was for the 280z dizzy Chris. You probably realized that anyway. I forgot about the differences between the 240 & 280 dizzy.

What is that in the bottom of the dizzy base in the 3rd pic? Almost looks like a washer of some sort. Something doesn't look right there but I can't put my finger on it.

Edited March 3, 2016 by rcb280z

[grannyknot]

It looks like a washer but it is actually an indentation cast into the timing cover, the flash makes it look strange.

So, I dropped the oil pump and re-clocked the shaft one tooth over to this,

which resulted in the R/A and the underneath adjustment in the dead centre of their movement and still 10* timing.       

After 30 min. idling at about 800 rpm while I played with the distributor and carb balance the #1 sparkplug looks like this,

The fast idle screw is still 1/2 a turn in to keep the engine from dying, not at all sure how to fix that yet and the tach is not working.

The linkage is balanced so both butterflies open at the same time and the carbs are balanced at 8kg/h on the SK Synchrometer. I haven't touched the jetting adjustments under the carbs yet as ZTherapy usually has those bang on.

I guess my next step is to start reading the SU forum.

Chris

Edited March 3, 2016 by grannyknot

[rcb280z]

Everything looks good to me Chris. Run her and see how she performs over the next couple of days.

ZTherapy carbs are sweet aren't they? I ran them on a 280 when I lived in Vegas and loved them.  

Edited March 3, 2016 by rcb280z

[rcb280z]

I did have to tune my SU's slightly. Needed more fuel. I assume it was because they were on a 280. 

[Mark Maras]

 Don't be afraid to adjust the mixture screws. They're the mixture fine tune on SUs. I'd start by dropping both 1/4 turn and check the plugs again in a few miles. Light tan is what you're looking for.

[grannyknot]

I figured out the fast idle screw issue, I just had the throttle adjusting screws turned too far out so had to compensate with the fast idle screw to keep it running. Turned them in 1 full turn, backed off the fast idle screw, re balanced. ZTherapy had the jet knobs (the two big ones under the carbs) at about 2 1/4 turns down but I found 2 3/4 turns worked best when doing the test where you quickly raise the carb piston. So that all seems to be running well now.

Just have to figure out why the tach isn't working now.

Thanks,

Chris

[grannyknot]

Got the tach working thanks to the late, great EScanlon, this is Enrique describing the early ignition in regards to the coil and tach pick up,

Posted 3 Feb 2006 · Report post

Mat M said:

...snip...While I had the car running I disconnected one of the B/W wires, and nothing happened, I replaced that one, and disconnected the other B/W wire, and the car died. So, I am ciphering that the B/W that had no effect would be the one to connect to the G/W.

...snip...

The "no effect" B/W is the one that goes to the coil in all cases, the one that killed the engine IS the one to connect to the G/W now that the resistor is gone. That's the initial power source for the resistor and then the tach.

As you have it now, the tach should be exhibiting "spikes" while starting the car.

Trust me on this, if you want a better understanding then continue reading.

When the engine is RUNNING (+) power from the battery goes through the fuse box and then to the ignition switch (via a W/R wire). From there it gets sent to the Resistor (via B/W wire #1) which then returns it to the Tach (G/W wire), the Tach then sends it to the Coil (B/W wire #2) and the system is energized and you can have spark at the plugs.

When the engine is being STARTED (i.e. the starter is engaged and running) the (+) power from the battery also goes through the fuse box, to the ignition switch (W/R). Here there is a "detour", the (+) is now sent DIRECTLY to the tach (G/W wire that receives the return power from the resistor), and from there to the coil (B/W wire #2 above). As you can see the fuse is totally bypassed.

When the engine is running the G/W wire FROM the ignition switch, used in the starter sequence is inop. The power gets returned to the G/W wire from the resistor and then to the tach. When you are starting the engine, the B/W wire that killed the engine when you removed it, is inop as the power is being sent DIRECTLY to the tach via the G/W wire and then the B/W wire that had no effect.

The power to the coil goes through one of two circuits BOTH of which go through the tach.

Hope this makes some sense. Trying to explain electrical circuits is tricky and can be very confusing.

E

I doubt you will find a better description then that. So basically I switched the two B/W wire around and everything is golden, so simple but it just never occurred to me. Thanks Enrique.

Chris