Trying to get her started

[Matches]

Replacement engine is in and cranking, but not starting. Can't even hear it trying to catch.

Spark plugs are in the correct order, have spark and fuel.

Trying to figure out if the ignition timing is good or not. With the rotor pointing to the #1 spark plug wire, the timing mark on the crank pulley is WAY advanced. Looks like it would be +40 or 50 degrees.

I pulled the valve cover to see if timing marks could help me figure things out. I could not make heads or tails of it

So when I see these white painted marks ( no mark on the chain, but a 3 stamped on the cam gear )

The rotor is here

My best guess is, something is wrong. :stupid:

Can anyone help me sort this out? I really don't want to have to tow my Z to a mechanic!

[skunkteeth]

Im no expert, but it looks like the distributor/rotor is not installed correctled. The #1 position is usually 180 degrees from where you have it.

[xray]

Can't tell from exactly from the pics, but that doesn't look like TDC on #1 to me, so your "40 to 50 degrees" may be inaccurate. The marks on the timing chain and sprocket are likely reference marks for a chain replacement, but it's tough to say. Rotor appears to rest near the #3 position...

At TDC on #1's compression stroke, Both lobes on the Ex and In should be pointing away from the rocker/valve spring (both valves closed), which would put the rotor pointing at about the lower screw on the distributor in the second pic (actually, just a few degrees clockwise to that screw). If you're at all doubtful, pull the number 1 spark plug and insert a feeler or thin gauge wire into the chamber. While some manually turns the crank, feel the piston raise/lower and determine TDC from there. Then, mark the crank pulley where the timing pointer is, and refer to that as "0."

Cranking but not starting means that the starter is turning the ring gear. It does not confirm you're getting any spark, or that the spark is correctly timed to the compression cycle. How do you know you have spark and fuel?

Hope that helps,

Steve

[Curtis240Z]

Your picture indicate that your ignition timing is off at the least. Assuming you put the cam gear timing is correct, the first thing to do is turn over the engine until the timing notch on the damper lines up with TDC on the timing scale. Since it takes two revolutions to complete a power cycle, you have a 50/50 chance you have it correct. To verify check to see that both intake and exhaust cam lobes are facing up in a "V" pattern. If not, rotate the engine one more revolution and you have the correct power stroke for the #1 spark plug.

Now see where your rotor is facing and put on the distributor cap and see if the #1 spark plug wire is lined up with the rotor. If not then your distributor timing is off and you have two options. You can drop the oil pump and oil pump/distributor drive and realign it or you can move the spark plug wires around until they are lined up correctly with the rotor. If you forgot the firing order it is 1, 5, 3, 6, 2, 4.

Good luck and I hope that is all that is wrong.

[Matches]

Ok, so I will check again with the valve cover off to see what points where.

With the valve cover on, I was fairly certain that I did have TCD on #1 with the rotor pointing where it should, but the timing mark on the crank pulley was way advanced.

I know I have fuel because it comes out the fuel return line if I disconnect it, and spark because I took out the plugs and tested each one by grounding it and cranking the motor.

Thanks for the help guys

[Arne]

The mark on the crank pulley can be misleading if the engine is built up from mix-n-match parts. The pulleys and timing marks were not all the same for various years of L-series engines. When assembling the engine, you want to find TDC for certain (via cam lobe position and/or piston travel) and verify the timing mark, remarking it if necessary.

[beandip]

I think Curtis nailed it. He described the position of the cam vs. the timing marks on the dampener right on. I have a question though. Has this engine been all apart? I am asking because if the head has been off you could have the valve timing out of whack. If it is too far off the valves will hit the pistons. Have you heard any clunking when you are turning the engine over? If this engine was just from another Z and had been running in the past . I bet you have the timing 180* off. A common mistake. When the #1 piston is at top dead center, and the lobes on the cam are pointing up like a V , the timing mark on the pulley should be opposite the pointer . The rotor in the dist then should be pointing to the #1 plug wire on the cap. Position the rest of the plug wires according to the firing order. the engine should start. As long as the valve timing is right. If your cam timing is off , I suggest you take the car to a mechanic . Keep us informed on how this turns out. All the best, Gary

[xray]

Ok, so I will check again with the valve cover off to see what points where.

With the valve cover on, I was fairly certain that I did have TCD on #1 with the rotor pointing where it should, but the timing mark on the crank pulley was way advanced.

I know I have fuel because it comes out the fuel return line if I disconnect it, and spark because I took out the plugs and tested each one by grounding it and cranking the motor.

Thanks for the help guys

I know you were fairly certain, but the pics you have supplied prove the TDC determination you made to be incorrect.

Pic #1 is of the standard positioning of spark plug wires on the distributor of a 240Z. #1 is where I stated earlier, just clockwise to the front distributor cap retaining clip. Yours, as I mentioned earlier, is pointing to #3. Based on your first pic (edited below), the #1 exhaust valve is open, and intake is closed. That is very much not TDC.

Disregard your crank pulley's indicator until you have TDC determined by direct observation as I outlined in my first post. It is not uncommon for the pulley's indicators to shift as the rubber between its components wears.

In re: fuel....you have fuel at the return line, and that is well and good. You didn't mention what the state of your carbs is...if they are old, the float needle and seat/grose jet/whatever my be stuck closed, and fuel will bypass the float bowl and stay in the supply/return system. If they are new and there's fuel in the float bowl then you can disregard fuel issues for now.

[Matches]

OK updates at long last.

After following the advice of xray and Arnie, it seemed as though the rotor was way off mark. So I dropped the oil pump and fussed with things until I got it right.

Here are photos of my results:

See the rotor pointing to the #1 spark plug wire, and the crank pulley timing mark @ the zero point.

When like this, the cam shaft looks like this:

10 o'clock and 2 o'clock right?

So everything is properly aligned for TCD right? Spark plug wires go just like the photo xray posted.

STILL WON'T START!

Is it time for me to buy a compression tester or am I still missing something?

New cap and rotor, ignition coil is only a few months old, new spark plugs and wires, carbs are rebuilt from Z Therapy and where running great on my old engine exactly as the are set now. I know there is fuel because there is fuel on the spark plugs after cranking. I know there is spark because I grounded out each plug and cranked and looked for spark. Got it. Looks weak, but I figure its an old car and that is probably what it looks like.

Thanks so much for all the help so far. This is really frustrating.

-Matt

[beandip]

The cam lobes look like they are in the V as best as I can tell in the bottom photo. But is is it on the compression stroke? With the plugs out put your finger over the hole and have someone spin the engine . You will know when the piston comes up on the compression stroke. You can do this with the car in gear and pushing it turning the engine over. Shine a flash light in the plug hole and you will see the piston rise to the top. Now if it is on the compression stroke the cam lobes in a V the timing mark should be at the pointer. Now if this is what you find , remove the cap on the Dist note where the rotor is pointing. This is now #1 connect the plug wire to this corresponding port. then follow with the rest of the plug wires in the FIREING ORDER. I have see guys do them 1,2,3 and so on , FIREING order. The engine should start. Now if the cam , or head has been removed , then all bets are off because you could have the valve timing all off. This is an entirely different matter. Assuming all is correct , then with a timing light set the timing. The degrees of advance will depend on what ignition you have, it looks like a stock 240 dist. Set the timing at 10* BTDC . About where the mark is to the pointer in the picture. My bet is that your 180* off. You have set the timing on the exhaust stroke instead of the compression stroke. A common error. Gary

[Nissanman]

There is a similar discussion on this problem which you might find helpful, http://classiczcars.com/forums/showthread.php?t=27188

As previously mentioned, you may need to work backwards to determine where the TDC pointer and crank pulley notch need to be.

It is the KEYWAY on the crank that will tell you piston TDC.

[ktm]

Hmmm, your timing indicator is on the driver's side? On both my old L24 and my L28ET, the timing indictor on the block is on the passenger side and not the driver side. TDC would be the TOP mark on the indictor. If the indicator is on the wrong side of the block, your timing is quite retarded.