240z running, and now it’s not….

[dotMorse]

Afternoon all.

I took my car to a rolling road and they picked up that the mechanical advance was not working. At this point the car lacked power but ran fine, just quite rich. (Did a 60 mile round trip with no problems)

When I got back I disassembled the distributor and found the cam lobes were stuck solid. Pulled them apart and cleaned them up. Now work as the should. I reassembled the distributor and also noticed my timing on the oil pump shaft was out a tooth so I also corrected that. Now get the 11.25 orientation. (Previously I had to crack the distributor fully in one director to get 10degrees advance)

I reassembled everything and checked the timing using a test light and verified the rotor was pointing at ignition lead to cylinder 1. This was set to 10 degrees BTDC and with a wiggle on the rotor the light goes off and on.

But it now doesn’t start.

Since then I have checked:

I am getting spark as I have checked all plugs with a spark plug tester
I am getting fuel as some of the spark plugs when I pulled them as wet from flooding the engine I guess. They smell of fuel.
I cranked the engine for 10sec at full throttle to try and clear the fuel build up
I have checked the points gap at 0.50mm at the peak of the cam (running manual points)
I have fullly charged the battery
I have tried with choke
I have tried with and without air filter
I have checked TDC with a piston stop
I have cleaned and rebuilt both carbs and reset to 2 turns on the mixture screw

What am I missing? It does not even almost fire at any point. Occasionally I get a back spray of compressed fuel out of the carbs.

Run out of ideas now. Any help?

 

[MCBladeRun]

You need 4 things to get combustion in an engine:
Air
Spark
Fuel
Compression

Car was running fine before and after you've disassembled the distributor; it no longer runs.

I think it's definitely spark missing from the equation here - you've got wet spark plugs. You've tested the spark plugs with a spark plug tester - are you sure this is functioning properly?

I think the best test is, with assistance, check each spark plug, with their own plug lead, 1 at a time against the earthed metal of the engine (cam cover for example). Whilst your assistant starts the car over.
Checking for a spark at the end of the spark plug.
Do this for each of them.

Even if you had the wrong timing, you should get spark, albeit at the wrong time.

Turn down the fuel by half a turn on those screws, you don't need a lot of fuel to get it going, you're trying to get this working and you'll get no chance if the spark plugs are soaked. It's the fuel vapour that is flammable, not the fuel itself.

Hopefully more advice will come from others

 

[Mark N]

Did you follow the FSM exactly when installing the distributor drive spindle?
If not, there is the possibility that it is 180 degrees out (4:55 if you like).
If that is the case, it would be firing on the wrong stroke (on the end of the exhaust cycle instead of the compression cycle)

 

[dotMorse]

Thanks for the tips.

If the rotor was 180degrees out it wouldn’t point at cylinder 1 when at 10degrees btdc?

Just trying to cancel everything out before I drain the oil (again)

 

[jonbills]

Check the leads haven't been moved up one (because of the mistimed drive spindle)
153624 anticlockwise.

Also, you dont have to drain the oil to take the pump off. The oil is in the sump, not the block
Also, can you give us a pic of the drive tang at 11:25 and the cylinder 1 cam lobes up.

 

[Farmer42]

Check the leads haven't been moved up one (because of the mistimed drive spindle)
153624 anticlockwise.

Also, you dont have to drain the oil to take the pump off. The oil is in the sump, not the block
Also, can you give us a pic of the drive tang at 11:25 and the cylinder 1 cam lobes up.

If you have moved the dizzy drive shaft, your previous number 1 post & lead is probably no longer as Jonbills has said. If its spitting fuel back out the carbs, its too far advanced so that does indicate that your leads are 1 post out of sync.

 

[dotMorse]

So like an absolute idiot…I found my stupid mistake.

I had independently verified TDC and the cam lobe position and the distributor rotor direction. But between each time had tried to start the engine.

I took off the cam cover and the distributor at the same time and surprise surprise…it was 180 out of sync. Lobes were down and the distributor pointing at cylinder 1.

F***ing idiot.

Reinstalled the oil pump shaft the correct orientation and started instantly.

Thanks all. Back to basics for me now and to read a beginners guide on how to build an engine.

 

[Texasroadrunner]

Good debug session and lessons learned. My only suggestion into the future is to replace the points with a Pertronix magnetic pick up. They work great and never need adjusting. Get their matching coil for the Igniter you purchase. See https://pertronixbrands.com/pages/search?query=Datsun-240Z I run these on my '72 Z and love them and you can ditch your ballast resistor. You can also open up your plug gaps with the higher voltage spark you'll have.