Johnny wick

No.

Mechanic says the carbs could suck fresh air at idle instead of the hot air trapped under the hood during idle and it could help avoiding the plugs getting sooty

Should the compression test be done after running the car or with the engine cold?

Well i made my order on ebay of both parts. Hope it solves the 4h cylinder issue of getting the ngk BP6ES spark plug black during idle at stop lights and traffic jams. Anyway i did a compression test yesterday with the engine cold and all cylinders measured 100 psi. So there should be no problems. Mechanic says in shoulf get an air conditioner or washing machine hose and tie wrap it to the mouth of the orange airbox and the other end through one of the holes near the air dam so it can suck fresh air at idle and avoid this situation. What do you think

Ok. Ill make my purchase on ebay right away. Shipping does affect the overall price sometimes.

Should i purchase these ones? They dont have brass terminals.

I have the original old hitachi dizzy

Which one should i buy? Bosch brand only?

Okay. As a recent update, after 2 weeks of not driving my 240z due to business trip to Athens, i decided to crank the engine yesterday, with the choke pulled to 3/4 for 45 secs and once the engine warmed i took to 100 mph at the highway. No backfire at the intake or at the exhaust even when releasing the gas pedal at 2nd gear going down hill. Nice aceleration. I took some pictures of plugs 4 and 2 for your ready reference. Do you think they look good? Or should i open the floats again in order to attempt to get the 1/16th below the nozzle at 2.5 turns clockwise? The actual measurements are the following: 3.75 turns clockwise for the front carb and 3.65 turns clockwise for the rear carb.

I can try this test. Distributor cap and rotor are not ngk believe me. Its some aftermarker brand cap and rotor i bought 2 years ago.

Ok. The only spark plug that turns sooty black is number 4. I would not like to invest money and labour on rectifying and changing all the valve stems and valves if it is not needed and it wont solve my problem.

Ngk blue wires are new. Rotor and cap are also new. I even have a pertronix ignitor installed there. Guessing will not solve the equation.

3.75 front and 3.65 rear carb. I guess that in order to set it both carbs to 2.5 turns i will need to close the gap between the float and the float lid more. Just if one is obessed with the 2.5 turns clockwise i guess. Car is running fine. Now i neee to deal with plug number 4 which has always been the problem and trying the car at long idle time during traffic

Ill do as Paul Mcartney wrote in one of abbey road's songs "step on the gas and wipe that tear away......."

I use atf but my can try 3 in one motor oil to see if it gets better at low speed.

No backfiring either through the intake or exhaust whatsoever. Running nice. I was wondering if before inspecting the plugs i should run the car hard and then shut it down and not as i am doing driving the car around accelerating every now and then, couple of stops on traffic lights and inspecting after parking the car in the garage.

Just took a 20 min ride along the highway at 6pm and a couple of fast traffic lights. Parked the car and pulled out plugs number 5, 2 and 4. Plug 4 now looks a little darker than 5 and 2.

Dont know how to do this. If you show me i can try. You mean closing the idle mixture knob fully? Please explain step by step approach

Ill test it today!

They are not sooted up. They sooted up in the past. I will drive it in light traffic today to see what happens

I have shorter and longer back again. Why do i need bp5es (hotter ) instead of bp6es?

I bought a couple of these valves in amazon. Car is speeding nice. Problem is during idle in traffic jams.

Okay i will turn the idle mixture knob of the front carb to 3.75 turns clockwise and test the car. Now we need to deal with the engine bay heat that causes the plugs to turn black due to the amount of heat inside during long traffic idle times. What if i find a hose and connect it to the air filter box and plug the bottom entrance of the box so it can suck fresh air during idle? Do you think this can be a solution? At this time it only sucks hot air.

what i am doing is pulling the choke for a minute while it warms up, closing it and then just drive slow until the engine warms up. After 6 to 7 minutes once it reaches half of the temp gauge i start driving normally and cruising at high speed and no problems whatsover. no backfire at the intake or at the exhaust even while realising the gas pedal at 2nd gear. Should i open the floats and close the gap even more? Am afraid i could leave the car too rich.

Plugs 5 - 4- 3- 2 after 30 mins of cruising at high speed. Idle mixture knobs set to 3.75 turns clockwise front and rear.