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Spark Plug Recommendations and Cold Start Fuel problem
https://www.slantsix.org/forum/viewtopic.php?t=37257		 Page 1 of 1
Author:  Krooser [ Sat Sep 26, 2009 3:20 pm ]
Post subject:  Spark Plug Recommendations and Cold Start Fuel problem
I'm usually not the guy who asks these real basic questions.

I've always used platinums in my late models but does anybody have any real experience putting these in an '84 SL6?

I also am having a problem with the engine not starting after sitting several days... a quick shot of ether makes 'er fire right up. I'm thinking a bad fuel pump... just replaced the filter today so we'll see if that helps.
Author:  adiffrentcity [ Sat Sep 26, 2009 7:03 pm ]
Post subject: 
If the filter doesn't help you may want to check for a stuck float. Mine did the same thing and I thought of the pump as well, because gas did not appear to be moving through the plastic filter. In the end pulled the restrictor from the carb fuel inlet after blowing my lines, that wet the float and it fell. Car started right up after that.
Author:  64 Convert [ Mon Sep 28, 2009 1:54 pm ]
Post subject: 
I've owned a bunch of carbureted, OHV Mopars, with lots of different engines, and the only one that started easily after sitting several days was a '69 Dart slant. Every other one required a lot of cranking to fill the carb before it would start. That is especially true here in Texas summers where hot-weather evaporation quickly empties the carb. It made no difference if it had a 1, 2, or 4-bbl carb, and one manufacturer didn't seem any worse than any other. It also made no difference if it had a manual, automatic, or electric choke, or how it was set. Even my new vehicles had the problem, though it seems to worsen as they age.

I also owned several Chrysler flatheads, and for whatever reason, I don't recall having the problem with them.

Putting a mini-starter on my 318, '73 D100 helped a lot, but only because the fuel pump is working so much faster.

Why that Dart started so well is a mystery to me, but all you had to do was set the choke and it would fire on the first turn of the starter.

If anyone has a good answer for you, it will make my day too.
Author:  SlantSixDan [ Mon Sep 28, 2009 1:59 pm ]
Post subject: 
If you buy platinum plugs, use a good brand, which means no Bosch and no Autolite. My preference is for NGKs, which are still well made in a first-world country. There are two advantages to platinum or iridium plugs: they last longer, and because one or both electrodes is smaller, they require less voltage to fire across any given gap, which in turn means the gap can be enlarged for better combustion without increasing ignition secondary voltage.

Try doing the Fuel line mod and see if that helps your starting situation.
Author:  Krooser [ Thu Oct 01, 2009 5:50 am ]
Post subject: 
Quote:
If you buy platinum plugs, use a good brand, which means no Bosch and no Autolite. My preference is for NGKs, which are still well made in a first-world country. There are two advantages to platinum or iridium plugs: they last longer, and because one or both electrodes is smaller, they require less voltage to fire across any given gap, which in turn means the gap can be enlarged for better combustion without increasing ignition secondary voltage.

Try doing the Fuel line mod and see if that helps your starting situation.
I'm thinking that MAYBE the heat from the exhaust is allowing enough gas to vaporate from the carb and that, along with any small carb gas leaks, may be draining the fuel bowl and preventing the engine from starting after a few days.

The carb is VERY dirty and geasy looking... so bad mere carb cleaner won't touch the grime... maybe a hint of the leak?

I'm going to insulate the fuel line before I go back to work and let it sit for a few days... film at eleven.
Author:  Daddiojoe [ Thu Oct 01, 2009 6:55 am ]
Post subject: 
As far as plugs go--

I just looked at some Champion platinums yesterday (oops--should have written down the part number, and I'm at work). They were listed as hecho en Los Estados Unidos, so that was helpful.

BUT--the listing given had about half and inch shorter reach than the Autolites I had in my truck.

Is there a platinum/iridium out there with a longer reach?

Thanks,
Joe
Author:  Daddiojoe [ Thu Oct 01, 2009 2:57 pm ]
Post subject: 
Clarification__

The short reach Champion platinum plugs are 3025 s.

The long reach Autolites are 985 s.

Are there any long reach platinum plugs out there?

Thanks,
Joe
Author:  SlantSixDan [ Thu Oct 01, 2009 4:44 pm ]
Post subject: 
Quote:
I'm thinking that MAYBE the heat from the exhaust is allowing enough gas to vaporate from the carb and that, along with any small carb gas leaks, may be draining the fuel bowl and preventing the engine from starting after a few days.
Could be.
Quote:
The carb is VERY dirty and geasy looking... so bad mere carb cleaner won't touch the grime... maybe a hint of the leak?
Give it a closer look. Carburetor operation and repair manuals (and some training movies) are posted here for free download. If you eventually decide you want a new carburetor, drop me a PM.
Author:  Aggressive Ted [ Thu Oct 01, 2009 7:31 pm ]
Post subject: 
Krooser,

Yes, I use UR4 NGK plugs. They wear well in the SL6. I have a 78 peanut plug head on my 74 block. Click on the red link below my name and you can see what they look like after 60,000 miles. Once the picture comes up double click on it for a full screen view and slide show mode......
You will see the fuel line mod and heat deflector I made for under the carb. It really helps especially in 100 degree weather.

You might need to add a little gas dryer/alcohol in the tank from time to time to keep the moisture to a minimum. :)
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