[steve25]

When the motor die’s will it start right back up)

If so then your not running too rich low rpm or at idle, but your lean and or your Distributor is at fault.

Most likely cause then of a high none stable idle speed and the motor dying at idle is a vacuum leak or the throttle is not going all the way back to idle or your mechanical advance is hanging up and not dropping all the way back to your base timing setting.

[HWYSTR455]

What carb?

Any idea what your SCR is?

What head gaskets did you use when you replaced them, 1016s?

What intake gaskets?

What rear gears?

Steve25 & chiphead are pretty on target with line of thinking, colder plugs, 32 degrees TOTAL timing, rocker adjustment/setup, vacuum leak.

If your SCR is up there, a 2802 might be a better choice.

I was just commenting on another thread about NGK XR plugs, and NGKs in general, the temp jumps are in like 1.5 step each time, so they don't cross like one would think. I literally ran into this myself, and realized I was running a hotter plug than I thought.

There's also folks complaining many plugs these days are knock-offs, counterfeit, and may not be getting what you think.

Pics always help, post some.


.

[MIke L]

Originally Posted by HWYSTR455

What carb?

Any idea what your SCR is?

What head gaskets did you use when you replaced them, 1016s?

What intake gaskets?

What rear gears?

Steve25 & chiphead are pretty on target with line of thinking, colder plugs, 32 degrees TOTAL timing, rocker adjustment/setup, vacuum leak.

If your SCR is up there, a 2802 might be a better choice.

I was just commenting on another thread about NGK XR plugs, and NGKs in general, the temp jumps are in like 1.5 step each time, so they don't cross like one would think. I literally ran into this myself, and realized I was running a hotter plug than I thought.

There's also folks complaining many plugs these days are knock-offs, counterfeit, and may not be getting what you think.

Pics always help, post some.


.

HYWSTR455

I tried looking for the thread you mentioned commenting on about NGK XR4 plugs and how NGK plugs in general change thier heat ranges in 1.5 increments but couldn’t find it.

Can you please let me know which thread your comments are on?

Thanks
Mike

[HWYSTR455]

It was kind of insinuated, but if you look at cross reference charts you will be able to see it.

This is the thread I made similar comments on:

https://forums.maxperformanceinc.com...=885230&page=2

So an XR5 plug roughly translates to an AC R45S, and an XR4 roughly translates to a AC R43S. The AC R44S falls in the middle.

https://ngksparkplugs.com/wp-content...rence_2019.pdf

When you say '2-steps colder' it has a different meaning in one brand than some others. That's the point I was trying to make.


.

[MIke L]

Originally Posted by HWYSTR455

It was kind of insinuated, but if you look at cross reference charts you will be able to see it.

This is the thread I made similar comments on:

https://forums.maxperformanceinc.com...=885230&page=2

So an XR5 plug roughly translates to an AC R45S, and an XR4 roughly translates to a AC R43S. The AC R44S falls in the middle.

https://ngksparkplugs.com/wp-content...rence_2019.pdf

When you say '2-steps colder' it has a different meaning in one brand than some others. That's the point I was trying to make.


.

Thanks,
I thought the XR4 was eq to the ac R45 and the XR5 eq to AC 43/44. at least that’s what I’ve been reading.

Thanks for replying

Mike

[HWYSTR455]

Yeah, I had it backwards.

.

[Ronj1969]

Originally Posted by steve25

When the motor die’s will it start right back up)

If so then your not running too rich low rpm or at idle, but your lean and or your Distributor is at fault.

Most likely cause then of a high none stable idle speed and the motor dying at idle is a vacuum leak or the throttle is not going all the way back to idle or your mechanical advance is hanging up and not dropping all the way back to your base timing setting.

Steve25 yes it dies actually right before it gets to the stop sign but then starts right up again.
Is there a way to richer that up ?

[Kenth]

With A/T idle rpm´s and mixture screws needs to be adjusted in "D".

What carb and how many turns out from lightly seated are the idle mixture screws?

Is the carb idle/lowspeed circuit adjusted/modified for todays fuels?

HTH

[Ronj1969]

So the carb is the stock 1977 quadrajet 4-speed carb. I’ve always adjusted by closing air mixture starting engine then then turning the mix screws with a vacuum gauge hooked up once I hit the peak vacumm. Stop then repeat on.The other side I believe it should be about 17lbs ? From the Egr Vacum