Help spark plug reading

cabledog · Jan 21, 2019

65-440 said:
Very nice ! 5" at idle ? What's the engine build ? That seems extremely low, unless its got a hefty cam in it ..... you're not taking the reading from above the throttle plate are you ?

I'm taking reading from the port at the bottom of the carburetor. Not the pcv one but the other smaller one.

hunt2elk · Jan 21, 2019

65-440 said:
Yes, this is known ... however it can dump fuel at idle. ... ever have one blow out ?

No, never had one blow out. I did spend a lot of time playing with 2.5 through 12.5 valves in a couple of my cars last summer with an air/fuel meter and seeing what effects they made to the total tune.

Bill Monk · Jan 21, 2019

cabledog said:
I'm taking reading from the port at the bottom of the carburetor. Not the pcv one but the other smaller one.

As long as it's below the throttle blades, you're good

65-440 · Jan 21, 2019

hunt2elk said:
No, never had one blow out. I did spend a lot of time playing with 2.5 through 12.5 valves in a couple of my cars last summer with an air/fuel meter and seeing what effects they made to the total tune.

If you have one blow out, or put one in that opens before your idle vacuum reading then you'll see how it affects the idle mixture ! You're right, they're technically not part of the idle circuit but can definitely affect it in a negative way.

cabledog · Jan 21, 2019

So when looking at timing is it advanced to the right or left of the 0 hole?

cabledog · Jan 21, 2019

Okay so the car was already set up to 18 initial and 36 full advanced. That's good isn't it?

65-440 · Jan 21, 2019

cabledog said:
In fact I only have 1 vacuum line hooked up right now and it goes from the back of the carb into the right side of engine block

This confuses me ... are you referring to the pcv ? I still think 5" is low ...... my 65 coronet had a .030" over 440, 11:1 compression, racer brown 520" lift cam and I was getting 6" at idle ....
I'd double check that reading then start looking for vacuum leaks .... your timing sounds ok

Bee1971 · Jan 21, 2019

Is that top picture the Autolite 85 ? Looks COLD and not a lot of miles

The NGK XR4 is a hotter plug

NGK XR4 = Autolite 86

NGK XR5 = Autolite 85

Me like NGK

And that picture of the NGK s looks much better other then they are wore on the electrodes

cabledog · Jan 21, 2019

Bee1971 said:
Is that top picture the Autolite 85 ? Looks COLD and not a lot of miles

The NGK XR4 is a hotter plug

NGK XR4 = Autolite 86

NGK XR5 = Autolite 85

Me like NGK

And that picture of the NGK s looks much better other then they are wore on the electrodes

Yes top is autolite 85. I was thinking of putting in a xr4 in one cylinder to just see how it does compared to the others.

Bee1971 · Jan 21, 2019

My Mopar 284-484 Cam in my 383 of old , only ran about 7-8" s of vacuum at idle

You could bee running the Mopar 292-509 Cam with the 4 speed

cabledog · Jan 21, 2019

65-440 said:
This confuses me ... are you referring to the pcv ? I still think 5" is low ...... my 65 coronet had a .030" over 440, 11:1 compression, racer brown 520" lift cam and I was getting 6" at idle ....
I'd double check that reading then start looking for vacuum leaks .... your timing sounds ok

I drove around today with vacuum gauge and idle is around 6 but isn't smooth

cabledog · Jan 21, 2019

Bee1971 said:
My Mopar 284-484 Cam in my 383 of old , only ran about 7-8" s of vacuum at idle

You could bee running the Mopar 292-509 Cam with the 4 speed

I called Don and he suspects it's the 292 I believe. Whichever the bigger one is.

Bee1971 · Jan 21, 2019

cabledog said:
Yes top is autolite 85. I was thinking of putting in a xr4 in one cylinder to just see how it does compared to the others.

How many miles you have on those Autolites ?

Like I said that one picture looks Cold

Bee1971 · Jan 21, 2019

One more thing , that car is Awesome

Can you post a clear picture of the Window Sticker ? Fender Tag ?

Man , some factory sweet sweet options on that car WOW

cabledog · Jan 21, 2019

Bee1971 said:
How many miles you have on those Autolites ?

Like I said that one picture looks Cold

About 100 miles

Bee1971 · Jan 21, 2019

Thanx !

Love The Colored Bumper Group

And of Course 4 Speed

Try The NGK s and see

Bee1971 · Jan 21, 2019

cabledog said:
I called Don and he suspects it's the 292 I believe. Whichever the bigger one is.

That would explain 6" s of vacuum

PurpleBeeper · Jan 22, 2019

cabledog said:
Okay so the car was already set up to 18 initial and 36 full advanced. That's good isn't it?

Your timing is just fine. You probably need about a "35" power valve. With the engine FULLY warmed up, try to adjust the idle up/smoother adjusting the idle mixture screws & you should be very close.

69BBody · Jan 22, 2019

Maybe it's the angle of the photo, but some of the gaps don't look to match one another.

cabledog · Jan 22, 2019

69BBody said:
Maybe it's the angle of the photo, but some of the gaps don't look to match one another.

Yeah the gaps were different in the old plugs. I gapped the new ones to 35.

Help spark plug reading

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