darth_linux
Active Member
What do you notice? This is after 350 miles on the highway with 87 octane unleaded. About 24 gallons used.
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Interesting spark plug coloration
- Thread starter darth_linux
- Start date
livininharrow
Senior Member
i notice 5 plugs are missing.
my5thmopar
Member
Looks good to me. Color on electrode is halfway up arc. Seems carb is adjusted correctly. But....What's the oil on side of plug, valve covers leaking? Craig
darth_linux
Active Member
Yeah, not sure about the oil. There's no visible leaks that I can see. At first I thought it might be leaking from the combustion chamber itself and that the plug was slightly loose, but I don't know now.
I was curious about the reddish areas. It's only reddish for about 120 degrees of the center ceramic area, the rest is almost white. Perhaps that's just from fuel additives?
I'm gonna pull the other 5 this weekend and take a look. I agree they look pretty good, which tells me that the main circuit of this carb is set up pretty right. The exhaust stinks to high heaven at idle though, so I suspect the idle circuit might be real rich. Gonna bust out the vacuum gauge, timing light, and tach this weekend to see what I can do to make it idle more smoothly and less stinkily.
Looks no different than what our '66 Newport 383 2bbl looked way back when. No issues with carb jetting, etc. Coloration is from fuel additives and is of no concern. Nobody messed with 2bbls back then, so everything should be fine.
As to the smell of the exhaust, before starting the warm engine, gently turn each of the idle mixture screws inward to very lightly seat them, then turn them back out 1.5 turns for the base setting. Then after starting the engine, check the hot base idle speed against the factory spec in "P". Then turn each screw outward .25 turn and see how the idle speed reacts, then put it back where it was. Same with the other idle mixture screw. From there, aim for the highest idle speed, then adjust the idle speed screw down, if needed. Now that things have been optimized, fine-tune that by turning IN the screw until a 20rpm drop happens, then back. Same with the other idle mixture screw.
After doing all of that, then increase the engine rpm for about 30 seconds or so, then gradually let it come back to idle. Then check the smell and see how intense it might be (hopefully minimized).
Way back when, I tried to use a vacuum gauge to do the idle mixrure settings, with mediocre results, to me. Never could get the vac readings at idle it seemed that I should. Ended up getting a quality dwell-tach and THEN things happened like I wanted them to. Much more accurate and repeatable.
The ign timing at idle should be at 12.5 degrees BTDC. Vac advance hose unplugged and plugged. Hooked to ported vacuum. According to the factory service manual, the centrifugal advance should not start until about 1000rpm or so, well above the hot base idle speed. I'm presuming it is NOT a California-sold Cleaner Air Package car.
Oil in the outside of the plug hex is probably from a seeping valve cover gasket, like always. Many seeps will not hit the ground, so you don't know they are there until you might pull the plugs out to look at them. No problems.
IF the spark plugs are "loose", you'll know it. When putting them back in, screw them in with your fingers, or in a socket, finger-tight. Then go about 1/4 turn past that to compress the gasket. You're done. With a drop of engine oil (from the end of the dipstick works well) on the threads, too.
I understand the desire to "kit" the carb, but as long as everything works well, the ONLY thing you might gain is to know how everything is. No significant improvement in how things run, usually, as I recall. And . . . it might be worse afterward as what ever was making it work decently well got disturbed, fwiw.
Enjoy!
CBODY67
As to the smell of the exhaust, before starting the warm engine, gently turn each of the idle mixture screws inward to very lightly seat them, then turn them back out 1.5 turns for the base setting. Then after starting the engine, check the hot base idle speed against the factory spec in "P". Then turn each screw outward .25 turn and see how the idle speed reacts, then put it back where it was. Same with the other idle mixture screw. From there, aim for the highest idle speed, then adjust the idle speed screw down, if needed. Now that things have been optimized, fine-tune that by turning IN the screw until a 20rpm drop happens, then back. Same with the other idle mixture screw.
After doing all of that, then increase the engine rpm for about 30 seconds or so, then gradually let it come back to idle. Then check the smell and see how intense it might be (hopefully minimized).
Way back when, I tried to use a vacuum gauge to do the idle mixrure settings, with mediocre results, to me. Never could get the vac readings at idle it seemed that I should. Ended up getting a quality dwell-tach and THEN things happened like I wanted them to. Much more accurate and repeatable.
The ign timing at idle should be at 12.5 degrees BTDC. Vac advance hose unplugged and plugged. Hooked to ported vacuum. According to the factory service manual, the centrifugal advance should not start until about 1000rpm or so, well above the hot base idle speed. I'm presuming it is NOT a California-sold Cleaner Air Package car.
Oil in the outside of the plug hex is probably from a seeping valve cover gasket, like always. Many seeps will not hit the ground, so you don't know they are there until you might pull the plugs out to look at them. No problems.
IF the spark plugs are "loose", you'll know it. When putting them back in, screw them in with your fingers, or in a socket, finger-tight. Then go about 1/4 turn past that to compress the gasket. You're done. With a drop of engine oil (from the end of the dipstick works well) on the threads, too.
I understand the desire to "kit" the carb, but as long as everything works well, the ONLY thing you might gain is to know how everything is. No significant improvement in how things run, usually, as I recall. And . . . it might be worse afterward as what ever was making it work decently well got disturbed, fwiw.
Enjoy!
CBODY67
darth_linux
Active Member
Great information CBODY67, thank you for your time.
FOLLOW UP QUESTIONS:
*the FSM specifies 12.5 BTDC (8-70) @ 500 RPM (14-40) in Neutral - that seems like a pretty low idle to me. Shouldn't it be more like 650 RPM?
*the carb currently on the car is from an early '70s dodge 383 truck, and a kit for this carb seems unobtainable to fix the worn accelerator pump (stumbles on accel from idle). I found a WWC that seems to be the correct 65-67 383 unit, but is in need of at least a tear down and cleaning, as it is pretty gummy. My plan is to clean and kit this carb and replace what is on there now. I was told that when it was pulled off a '67 Polara 20 years ago, it ran fantastically. I wasn't able to find an actual WWC 3-262 for under $300 anywhere, but this is a plain jane WWC model I got for a great price, so I'm hoping there isn't any mysterious mojo missing from the WWC that the 3-262 had. I've rebuilt about 20 carbs over the years, so I feel pretty confident in not making this one any worse. Thoughts?
*would I benefit from changing the plugs back to the J14Y or do the RJ14YC seem to be just fine?
thanks again!
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rags
Senior Member
yep. coloration is commonly seen on plugs of modern engines that run very clean.
The hot base idle speed might seem low by modern standards, BUT it IS correct for that car and carb(s). Might go to 575-600 if it makes you feel better, but not necessary at all. Past that, transmission engagement into "R" will increase in harshness, from "N" to "D", not so much as the accumulator is in the "D" fluid circuit to cushion the engagement. The accumulator is not in the "R" circuit.
Remember, too, that what the FSM lists IS what they spec'd things for back then, after thorough testing and such. Some things might be tweaked a bit (as front end alignment to accommodate radial tires), but TWEAKED is the operative word, here.
Enjoy!
CBODY67
Remember, too, that what the FSM lists IS what they spec'd things for back then, after thorough testing and such. Some things might be tweaked a bit (as front end alignment to accommodate radial tires), but TWEAKED is the operative word, here.
Enjoy!
CBODY67
3C's & a D?
Senior Member
The spark plugs look good to me. I'm more interested to know how you travelled 400 miles on 12 gallons of fuel?
darth_linux
Active Member
That would be a brain fart. It was more like 350 miles on 24 gallons. I’ll edit the original post. Sorry.
my5thmopar
Member
Old fuel will stink and burn your eyes at idle too. CBODY67 gave you good advice, it's probably just a tweak of the carb. Craig
darth_linux
Active Member
Yep, I reset the idle screws - they were 3.5 turns out! This carb, being for a truck, wasn't real happy at 1.5 turns for the idle screws, as the idle speed screw was all the way extended and it was too slow to stay running, so I turned the mixture screws out to 2.5 turns, and that gave me some adjustment back so I got a pretty steady idle at 600. I'm gonna work on it more tomorrow with the dwell meter and timing light to make sure the timing is right, and then revisit the carb adjustment. I have the correct carb on the bench ready for a long soak and rebuild, and then I can hopefully get the correct idle settings, idle speed etc.
thanks for the replies everyone.
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70bigblockdodge
Old Man with a Hat
Hard to see for sure (my eyes aren't what they were), but I would say you need more timing. Should have a band around the bend on neg electrode. Closer to the tip is too much timing toward threads is not enough.
darth_linux
Active Member
Good catch! I'm doing the timing tomorrow. Who knows what it is right now. Runs decently, but 1-2 degrees either direction can make a huge difference between running decent and running excellent. Thank you!
70bigblockdodge
Old Man with a Hat
12.5-14 is usually good on a big block.
Personally I would ditch those lawn mower plugs, but some people like them, I've never had good luck with them.
Personally I would ditch those lawn mower plugs, but some people like them, I've never had good luck with them.
Knebel
Senior Member
I would try: 2° more or less of total timing and put in 1 or 2 step leaner mainjets. Then maybe lean out the idle a smudge too (like 1/8 turn on an idle mix screw).... and see how it behaves....
darth_linux
Active Member
Thanks. Since posting this question, I've replaced the distro and added electronic ignition with the HiRev7500 kit, gotten the timing set correctly, put the correct carburetor on the engine (after rebuilding it) and adjusted the mixture. It's running MUCH better now . . .
Knebel
Senior Member
Awesome! I didnt read the while thing. I am glad you got it running!
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