IF, (big if)  the problem is electrical and is isolated to #4, it has to be located somewhere in the dist. cap, rotor, plug wire, sparkplug, and or any of their electrical connections. I'd pull the dist. cap (wires intact), and pull the plug wires. Using an ohm meter. check the resistance in the circuit between the contacts in the cap with the corresponding spark plug wire at the boot end. They should all be similar. Let's hope you find high resistance in the #4 circuit.

3 hours ago, siteunseen said:

These guys will help you with your car, they love to help.

.https://forums.hybridz.org/search/?q=petronix&quick=1 

We are more original equipment hence the name "CLASSICZCARS"

Thanks Site! You are the best! Always looking for solutions!

26 minutes ago, Mark Maras said:

Let's hope you find high resistance in the #4 circuit.

Or a short to ground.  Not as obvious though.  At about 2:00.

 

6 hours ago, 72 Datsun 240z said:

Okay why dont you recommend solutions and better brands before i make my purchase. Perfect critic!

Been using Pertronix ignition and coil on my 240Z for about 20 years now. Works excellent.

I think we have been through this before several times.

The cylinder head needs to get pulled to see what the deal is with #4.

You bought vales and guides already, as seen in the pictures you posted. You replaced the Far 311 cam with a street able Schneider. What all was changed with the new cam? There is a lot more to that than just swapping out the actual cam.

With your new parts already bought and paid for just go ahead and take the leap. Have the head rebuilt, new valve seals that will not interfere with your cam's lobes. Make sure all valves are cut the same and seating properly.

Don't get in hurry finding a cylinder head rebuilder. Find one that is recommended by mechanics or even better some machine shops.

You've got time now moving to Spain and getting settled. Make a plan and budget. Don't waste time or money.

Edited February 6Feb 6 by siteunseen

On 2/5/2025 at 4:34 PM, siteunseen said:

You bought vales and guides already, as seen in the pictures you posted. You replaced the Far 311 cam with a street able Schneider. What all was changed with the new cam? There is a lot more to that than just swapping out the actual cam.

With your new parts already bought and paid for just go ahead and take the leap. Have the head rebuilt, new valve seals that will not interfere with your cam's lobes. Make sure all valves are cut the same and seating properly.

 

Don't get in hurry finding a cylinder head rebuilder. Find one that is recommended by mechanics or even better some machine shops.

You've got time now moving to Spain and getting settled. Make a plan and budget. Don't waste time or money.

Thanks Site!

On 2/5/2025 at 4:34 PM, siteunseen said:

You bought vales and guides already, as seen in the pictures you posted. You replaced the Far 311 cam with a street able Schneider. What all was changed with the new cam? There is a lot more to that than just swapping out the actual cam.

With your new parts already bought and paid for just go ahead and take the leap. Have the head rebuilt, new valve seals that will not interfere with your cam's lobes. Make sure all valves are cut the same and seating properly.

Don't get in hurry finding a cylinder head rebuilder. Find one that is recommended by mechanics or even better some machine shops.

You've got time now moving to Spain and getting settled. Make a plan and budget. Don't waste time or money.

Hi Site,

Good news i found a 69 year old Camaro carburetor mechanic and competition racer. He drove the car and determined there is lack of fuel when accelerating at low rpms. Car shouldnt hesitate when releasing the gas pedal. He also noticed spark plug in cyl one is not burning correctly and lot of fuel on cylinder 4. Unfortunately he is living in Tampa and will not be back until 2 to 4 months so he can take care of the car. He wants to deal with these issues and do a leak down test before taking the head out.

Edited February 8Feb 8 by 72 Datsun 240z

On 2/5/2025 at 3:19 PM, gundee said:

I think we have been through this before several times.

The cylinder head needs to get pulled to see what the deal is with #4.

Ok Gundee. Mechanic will certainly pull it out to see whats wrong. He also noticed lack of fuel in cylinder 1. Spark plug is not even tanned. Asides from that as temperature is rising to 3/4 he also suspects fan clutch should be revised. Which fan clutch would you recommend for this 72 which carries a champion 3 row radiatior?

On 2/5/2025 at 2:40 PM, Mark Maras said:

 IF, (big if)  the problem is electrical and is isolated to #4, it has to be located somewhere in the dist. cap, rotor, plug wire, sparkplug, and or any of their electrical connections. I'd pull the dist. cap (wires intact), and pull the plug wires. Using an ohm meter. check the resistance in the circuit between the contacts in the cap with the corresponding spark plug wire at the boot end. They should all be similar. Let's hope you find high resistance in the #4 circuit.

Just replaced the pertronix ignition coil with a brand new one and new 1.5 resistor coil as the old one was not measuring any resistance at all.   Just left it idling for 15 mins in the parkway. Lets see if the coil gets hot during traffic jams.