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jalexquijano

Faster response when speeding from 1st geat on my 240z and other issues

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I have set the timing on my distributor which has a petronix ignitor device and flamethrower coil to 12 btdc at idle. I would still like a faster response when revving from stops at 1st gear. Both carbs have been set to 2.65 turns clockwise.


2 days ago i raced the car 20 mins and came back to the garage, open the Hood and took both spark plugs 3 and 4 out. they look like brownish to black as per the picture. I have also noticed that when the car is cold, i need to drive it with the choke on for 5 to 7 mins. Is this normal?? I have removed that inline heat control manifold thermostat and have only a 160F (71C) thermostat installed, nothing else. The coolant line that goes on the rear of both carbs was shut down, to avoid percolation at the float valves.


Questions:


1. How can i warm up the car faster when cold? Leaving the choke on for 5 to 7 mins will do any harm?


2. How can i get a faster response from stops? Should i move the distributor timing to 14 btdc?

ngk bp5es rear last.jpg

ngk bp5es front last.jpg

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To me your choke description is accurate. It shouldn't hurt anything as long as you don't always run it with it on. I wouldn't advance it to much more to avoid detonation. You could advance a couple more but listen for any pinging. How old are those plugs? If new it looks a little rich to me. 

Also in my opinion the Z's like 180 thermostats. I know Pamama is hot but where does your gauge sit when fully warmed up? 

Edited by JSM

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On ‎02‎/‎23‎/‎2017 at 10:43 PM, JSM said:

To me your choke description is accurate. It shouldn't hurt anything as long as you don't always run it with it on. I wouldn't advance it to much more to avoid detonation. You could advance a couple more but listen for any pinging. How old are those plugs? If new it looks a little rich to me. 

Also in my opinion the Z's like 180 thermostats. I know Pamama is hot but where does your gauge sit when fully warmed up? 

Well i set the timing to 14btdc at idle. Seems fine and good response when warm after 6 mins of choke. The engine does not crank if i dont pull the choke in the mornings!

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2 minutes ago, jalexquijano said:

Well i set the timing to 14btdc at idle. Seems fine and good response when warm after 6 mins of choke. The engine does not crank if i dont pull the choke in the mornings!

The fuel that is in the nozzles at night when you shut the car down will evaporate overnight.  Dropping them down with the choke allows them to refill.  I think you finally have the carbs adjusted correctly and you say it "seems fine and good response..." so shut the hood and drive the tires off it. :)

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I think what you are looking for is more Horsepower.  The car can only be tuned to a correct setting. Their is not much to be gained from going leaner or richer from correct. Does the car stumble?  Does the exhaust pop and spit when you are off the gas slowing down?  The 240Z is a peppy car, but by todays standards it is not a race car. 

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it does not stumble! it does not spit when slowing the gas down. I have both carbs tuned at 2.65 turns clockwise and with NGK BP5ES (hotter) sparks to avoid stumbling and tendency to shut down when rpm drops from 950 to 600. Mechanic is ready to adjust valves on the car but cold!! If i increase the turns on both idle mixture wheels, the mixture will become rich and then the spark plugs will start to foul at idle!

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2 hours ago, jalexquijano said:

it does not stumble! it does not spit when slowing the gas down. I have both carbs tuned at 2.65 turns clockwise and with NGK BP5ES (hotter) sparks to avoid stumbling and tendency to shut down when rpm drops from 950 to 600. Mechanic is ready to adjust valves on the car but cold!! If i increase the turns on both idle mixture wheels, the mixture will become rich and then the spark plugs will start to foul at idle!

How much farther are you turning the mixture wheels past 2.65 to get the plugs to foul. It sounds like you're making progress. 2.65 is in the ballpark. Personally, i'd start leaning it out a little more (2.5, then 2.375, 2.25 etc.) to see the results. How do your plugs look at 2.65? Any particular reason that your mechanic hasn't set the valves yet, hot or cold? I rarely ever set the valves when the engine was cold unless the valve train had been apart. The warm valve setting is the final step.

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Picking up the car today! Mechanic charged US$45.00 for valve adjustment. He said they just needed Little tweaking. Ill post some pics of the spark plugs at 2.65 turns. 2.5 is too lean!!

It is normal to start driving with the choke pulled for 5 to 7 mins until the car warms up? Remember i removed the inline manifold thermostat from the system to avoid warm wáter travelling on the rear of the carbs thus causing fuel percolation.

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Did stopping the hot water fix your percolation or whatever was causing it from "stuck in traffic" you kept on complaining about?  If it did, move on.  If it didn't run the rubber fuel rail as was suggested umpteen times, change the carbs back and don't use the choke if it bothers you that bad.  45 year old car remember.

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i was just questioning about the choke time and if it was safe to use the car when cold with the choke pulled for 5 to 7 mins until it warms up?

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4 hours ago, jalexquijano said:

It is normal to start driving with the choke pulled for 5 to 7 mins until the car warms up?

For comparison....I just went for a drive in my '71 240Z.  The outside temperature is 82º.  I have an electric fuel pump.  I pulled the choke lever "open & close" a couple times before leaving it pulled all the way back.  The Z fired right up and I drove away.  I eased off on the choke after about a minute and a half and completely closed it after about two minutes of running time.  All was good.

Dennis

 

 

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Opening and closing the choke before he starts it drops the nozzles and they refill with fuel right?  I pull mine all the way back and crank it, let it run for a minute or two and then go half choke.  Drive out of my neighborhood which takes about 2 or 3 minutes then get on the main roads and close the choke.  

I think his choke time is close to what I do and he's worried for no reason.

From all his past post he wants someone to say YES or NO.  So can you or anybody else tell him YES or NO?

Everything I've ever had with a manual choke has been different.  My Exmark mower has to be choked EVERYTIME I crank it no matter how hot it is.  I can run it for an hour and turn it off for 5 minutes and it won't crank with out choking it.  I guess it needs the throttle blade closed to pull the fuel in?  

Jalex do you have to choke it throughout the day or just first thing in the morning?  Do you let your pump run for a couple of seconds to fill the lines and float bowl or do you immediately crank your car?  If you read the definition of "choke" I think you'll ease your head/mind.

 

 

 

 

Edited by siteunseen

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49 minutes ago, siteunseen said:
3 hours ago, jalexquijano said:

i was just questioning about the choke time and if it was safe to use the car when cold with the choke pulled for 5 to 7 mins until it warms up?

From all his past post he wants someone to say YES or NO.  So can you or anybody else tell him YES or NO?

 

 

 

 

 

So, if a simple Yes or No is all that's needed.........

YES!

Totally safe.  The car won't catch fire, drive into a ditch, or tip over because the choke is open.  However, for 46 years, I've judged when to back off on the choke by performance feel, not by looking at the temperature gauge or the clock.  That's been my experience in starting and driving in ambient temperatures ranging from minus 20 degrees to 120 degrees F.  Real seat of the pants driving just like knowing when to shift by sound and feel rather than looking at the tach.  The Z is a car for all seasons.

Dennis

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One way to get a faster response from stop is to let the engine rev to yellow line BEFORE transmitting it's power to the rest of the drive train.

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thanks! Sorry for the late reply. I just wanted to know if driving for 5 minutes with the choke pulled until the car operation becomes normal is ok. thanks.

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 If you push the choke off too soon, the engine will stumble (mixture is too lean) when you accelerate or it will die at idle. Keep in mind the choke can be used in any position as the engine warms up. Ideally, one gives the engine only as much choke as it needs during the warm-up cycle. As the engine gradually warms, the choke can be gradually pushed off.

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