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'75 280z - trying to set timing


Neb

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My '75 280z isn't running yet, but I think I'm getting close.  I just finished going through the fuel system (new pump, lined tank, new filters, cleaned/checked function on all injectors, checked pressure, replaced hoses, inhaled copious amounts of gas fumes, etc)

Next up, I'm starting on the ignition.  I visually verified spark on all plugs when I did the compression check, and replaced all the plugs with fresh NGKs.  The plugs are wired in the correct sequence coming off of the distributor cap.

The car still isn't starting/running though.  Within the normal range of adjustment (with the distributor adjust screw still in place), the best I get is a few chuff-chuff-chuffs before it dies.  I was able to get it to very briefly come to life by removing the distributor adjustment screw and rotating it almost 20deg CW.  It revved to about 2k rpm for about 2 seconds and then died.  That was somewhat repeatable around that same point in distributor cap adjustment.

I dug into it a little further and set my #1 cylinder to TDC (utilizing the wife+stick+flashlight method), and then checked the marks on the block and the distributor arm position.  It doesn't seem like things are lining up as they're supposed to.  The mark on the pulley is somewhere in the range of -15deg, when (in my limited understanding) its supposed right around the 0deg mark.  The distributor seems to be past the #1 point, and I was under the impression it should be right at the #1.

I really don't trust anything in this car, so my next inclination is to pull the valve cover and make sure the cams are in the right spot as well for a third check. 

Or am I totally missing something obvious here.  Whats the next step?  Picture attached of the notch/marks on the block with the #1 at TDC (marked the pulley with a silver marker at the tick).  Thanks!

IMG_20180325_105242.jpg

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First question. Are you sure it's getting proper full? Pressure good, maximum 36psi, no air in the system from rebuilding the system. It could be firing on the fuel from the CSV and no fuel from the injectors

Do you have a timing light? It would be easier to crank the engine, check the timing and set it to 5 degree btdc. I say 5 because cranking speed is about 300 rpm and lower than idle speed. You can adjust it properly when it runs.

The rotor button gives a reasonable indication that the timing is in the right area, but the pickup coil under the rotor button is the before indication. One of the pointer of the 6 pointer star (reluctor rotor) under the rotor button should line up with the pick up coil or a fraction past it.

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15 minutes ago, EuroDat said:

First question. Are you sure it's getting proper full? Pressure good, maximum 36psi, no air in the system from rebuilding the system. It could be firing on the fuel from the CSV and no fuel from the injectors

Do you have a timing light? It would be easier to crank the engine, check the timing and set it to 5 degree btdc. I say 5 because cranking speed is about 300 rpm and lower than idle speed. You can adjust it properly when it runs.

The rotor button gives a reasonable indication that the timing is in the right area, but the pickup coil under the rotor button is the before indication. One of the pointer of the 6 pointer star (reluctor rotor) under the rotor button should line up with the pick up coil or a fraction past it.

Hmm good point with the fuel.  I checked pressure BEFORE I went through and checked the injectors (and it was ~36psi, so I'm assuming the regulator is good).  I definitely should recheck that now that I've been in there.  Would you still see ~36psi if there was air in system? 

I still need to grab a timing light.  I think the starter in my car is aftermarket, and turning the engine faster than 300rpm (I want to say it was hitting something like 700rpm), but I will double check that tonight. And I'll take harder look at the distributor.

What should the indications on the block look like if #1 is TDC?

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29 minutes ago, Neb said:

What should the indications on the block look like if #1 is TDC?

TDC should be at the top of your timing plate. The plate has timing makes from 0 to 20 degrees btdc. If you crank the engine, adjust the timing to somewhere in the top section of the plate. Once you start the engine, you can adjust if properly.

Just lining up the rotor button is not very acurate. The rotor has a "phasing" function because it has to transfer spark through a wide range of advance (from 8 up to 36 degree of advance).

If you do try to manually adjust the distributor (enough to start the engine). Line up the rotor button with number one spark plug terminal, remover the button and then adjust the distributor until the reluctor rotor fractionally passes the reluctor (see red circle in third photo). The metal strip in the reluctor is what you should line up. It is not very acurate, but it will be enough to get it started.

Dist-01.jpg

Dist-02.JPG

Dist-03.jpg

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fuel pressure check (36 psi).

Spark check (observe while cranking).

EFI check (listen for injector clicking with stethoscope).

are the plugs coming out dry after trying to start? if so prob no fuel if spark is good.

 

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If you checked your timing and it is ok and you have spark at the plugs then I would grab a can of aerostart and see if it will start on that.

If you spray it in the intake (air filter removed) you should be able to get it to fire and run, all be it very roughly by spraying it every second or so.

Now if you can get it to do that, you have problems with your fuel delivery. 

That would be my next step. Work one problem at a time, solve it or cancel it out and move on to the next.

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21 minutes ago, EuroDat said:

If you checked your timing and it is ok and you have spark at the plugs then I would grab a can of aerostart and see if it will start on that.

If you spray it in the intake (air filter removed) you should be able to get it to fire and run, all be it very roughly by spraying it every second or so.

Now if you can get it to do that, you have problems with your fuel delivery. 

That would be my next step. Work one problem at a time, solve it or cancel it out and move on to the next.

Great info.  I'll get in there tonight and check fuel pressure, verify spark/wet plugs, and then start on the distributor.  I do have a can of starting fluid, so I can give that a shot if I get that far. 

I really appreciate the help and pictures.  What a great forum!

Edited by Neb
grammar
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Vrooom!  Its alive :D

I went to check the pressure in the system and bled a fair amount of air out in the process.  Got it to a steady ~38psi and then moved on to checking the plugs.  All 6 were wet and showed spark.  Put everything back together and it still wouldn't start.  So I went back to the distributor cap and started working it CW.  Eventually it kicked right off and ran.  I rotated the distributor cap CW until it was smooth and let it run for a few.  Then fuel pressure started to drop off and it died, which was a pretty big disappointment.. until I realized my little fuel can I'd been using in place of the gas tank (pulled for cleaning/lining) had run dry and fallen over.  Refilled it, re bled the system, and its starting/running consistently now.  f

Ended up with a couple questions though:

I couldn't get the CSV to click with my improvised (2xAAs and a switch) 'injector stimulator'.  Does it run off a different voltage than the other injectors?  Or is mine shot..

My fuel pressure while at idle when running was only about 28psi (picture below).  That being said, it idled smooth and was responsive and revved fine.  Is the fuel pressure supposed to stay at 38 or so while it is running?

My distributor cap required a significant amount of adjustment (picture below) to get it to run properly.  I'm assuming whoever installed the distributor didn't align it correctly?  I'm thinking if I just advance the spark plug order 1 plug and then grab a timing light I'll be able to get the timing set.

Anyway, you guys were great and definitely pointed me in the right direction, very much appreciated!

IMG_20180327_200946.jpg

IMG_20180327_200416.jpg

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You might be okay with moving the plug wires one over.  Worth a try.  That's pretty far off but it looks close to 60 degrees, which would be one wire spot rotation.

How do I learn to braid my distributor wires like that?

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49 minutes ago, Neb said:

My distributor cap required a significant amount of adjustment (picture below) to get it to run properly.  I'm assuming whoever installed the distributor didn't align it correctly?

With the Datsuns it's the oil pump and distributor drive quill that is out of adjustment.  Once the oil pump is installed the drive quill, or shaft, is locked in to place on the crankshaft gear that turns both the oil pump and the distributor.  (Never really put the whole picture together before).  The oil pump is below and the distributor above, but they both get their energy from that long spindly shaft.

So what you're really seeing is a function of how many teeth off the the drive quill is, to the crankshaft drive gear.  That's why people use vise-grips or rubber bands to hold it in proper spot , before matching the oil pump to it, to get the distributor right.  The oil pump doesn't care, but the distributor does.  Also why there's no "180 off".  We could count the teeth on the gears and come up with the various points of "off".  I'm surprised we haven't done that yet.

image.png

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