73 240z won’t start. Have spark

[Shawninvancouver]

I know how the points open and close I know how to set them. I just forgot that when I flipped the distributor over I forgot to do that.

my only other question was should the point be open or closed when engine Is it top dead centre and the rotor is pointing at spark plug number one is there any instance where the point should be open or closed or anything specifically about that?

Edited May 17 by Shawninvancouver

[Zed Head]

Rotating the distributor body will not affect the points gap.

I talked about when the points should be open in Post #11.

The points open and close each time the distributor cam lobes go by as described in the video I posted.  They open and close about 15,000 times per minute at 5,000 RPM.

Rotating the distributor body changes the time that the points open for each cylinder, in relation to the piston position as it moves up and down in the cylinder.  Rotating the distributor body is called "setting the timing".  The shaft with the lobes stays attached to the camshaft but the points move in relation to the distributor cam lobes because they are attached to the distributor body.

Rotate the distributor body as you watch the points and lobes.

 

 

[Shawninvancouver]

Ok zed I will do that.  But can you just answer the question I still don’t understand.  If the dizzy is slightly rotated wrong will the engine not start ?? Not even backfire or misfire. ?? Just no signs of starting. !! Then if I slightly rotate the dizzy it will start??

[Zed Head]

Actually it can be off by quite a bit.  It would probably start with initial timing set from -5 to 25.  A range of 30 degrees.

But there's a lot of other things that are unclear.  You never answered the question about where you were spraying the starter fluid.  You haven't removed a spark plug to see if it was wet.  You haven't verified that the timing was close to correct, or if it's even set to the compression stroke.  If you're firing on the exhaust stroke as, suggested by several, you probably won't hear a pop because the flame will just shoot out the open exhaust port.

You're looking for a simple single answer but there are many things that have to be right at the same time.  You need to create a check list then check each item.

You got spark, which is something, and you installed different carbs.  Lots left.

[Shawninvancouver]

Starter spray was sprayed in carb. Air filter was off. Carb piston was up and sprayed right through in to engine.  I’ve got to be 99% sure we had tdc correct. Valve cover was off and cam 1 2 was up like rabbit ears like everyone said.  Can the cams be up like rabbit ears and be on the wrong stroke? Can ears be up and it be on exhaust stroke? I swear my pal said he saw piston at top. 

[Shawninvancouver]

Starter spray was sprayed in carb. Air filter was off. Carb piston was up and sprayed right through in to engine.  I’ve got to be 99% sure we had tdc correct. Valve cover was off and cam 1 2 was up like rabbit ears like everyone said.  Can the cams be up like rabbit ears and be on the wrong stroke? Can ears be up and it be on exhaust stroke? I swear my pal said he saw piston at top. 
 

are these ears up??

[Zed Head]

They look up, so you're on compression stroke. but which spark plug electrode is the distributor rotor pointing at when you are at TDC on #1, and are the points close to opening, either about to open, open, or just closed.

You need to get those three things happening at the same time so that spark will be correct for all of the cylinders as the engine turns.  Compression stroke on #1, distributor rotor pointing at #1 electrode in the cap, points opening.  

If you can take a picture like the one above but with the distributor included, one with the cap on, one with the cap off, and with your plug wires identified in the cap that will tell a lot.  

We need to know where the rotor is pointing when #1 is at TDC on compression.  And we need to know that the #1 plug wire is attached wherever it is pointing.  And that the points are open.

p.s get everything set up with the valve cover and the distributor cap removed.  Rotate the engine by hand and watch the parts move.  You'll be able to figure out for sure when the points open on the #1 compression stroke and place your  dist. cap wires correctly.  Then replace the valve cover and try to start.

[Shawninvancouver]

Ok zed.  Well explained. Thanks for being pacient with me.  One other crazy question what happens if when I put the distributor cap on the rotor is in between two plugs which one is number one the one before or the one after or do I have to rotate the cap and until the rotor is pointed directly at one plug? This always seems to happen when I get the cap on the rotor is never directly at one. It’s always either before one or after one and I can ever figure out which one is number one ?  And also like you say once, I determine that and the compression stroke is at the top, I have to make it so that the points are just starting to open that is easily adjustable I guess.
thanks again. 

[Patcon]

I may be missing something but both cam lobes on #1 don't appear to be up in that picture...

[Zed Head]

You're right.  I thought the other lobe might not be visible behind the timing sprocket but lost track of the actual configuration, even though I had pasted the rusty cam picture earlier.  I dug up an eBay picture for reference just now, pasted below.

He wore me down, I should have checked.  Not sure how two cam lobes sticking up can be misinterpreted.

Still, all of the advice given by everybody in all of the numerous posts is good.  He just needs to get some of it done.

 

The picture below shows the #1 cam lobes.  The piston is not at TDC on compression stroke.

[Zed Head]

Here's an old thread with good stuff in it.  Excellent picture of lobes-up by Cliff/unseen.

Just realized that I have no memory of the ignition timing mark on the damper pulley ever being mentioned by Mr. Vancouver.  That's the other indicator of TDC.  Get the cam lobes up, rotate the engine until the timing mark is at zero.

The adventure is in trouble if TDC compression cannot be found with this information.

 

[Patcon]

@Zed Head you've done great. Very patient, very tenacious!