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Username Post: Timing issues
Forum Newbie
Posts: 66
Loc: Harrisonburg
Reg: 03-15-15
01-01-18 06:41 PM - Post#2719727    
    In response to IgnitionMan

  • IgnitionMan Said:
"Those guys" WHO?

Dieseling can be from a lot of things, like not enough timing to allow the carb to idle the engine down, as you have now with no vacuum advance. Getting the vacuum advance set up correctly will help lower the idle speed by closing the carb down a bit, so it doesn't Diesel the engine, no matter the engine speed.

With hotter engines, incorrect idle speeds, incorrect timing/vacuum advance, and other factors, like carbs not tuned because of the other stuff, yup, idle quality can stink pretty bad.

When you get the vacuum advance and carb dialed, 195 deg/F. will work just dandy.

NO PCV system, NOT GOOD. Most people don't get this right very much, but there are a whole lot of different PC valves, in both vacuum level, and actual air volume flow, get just one of those parameters incorrect, makes for a really unhappy camper.

What specific idle rpms, and, if automatic, in and out of gear, please.

I emailed Dave the ignition guy. He emailed me right back with instructions on how to modify the vac advance.

The PCV system I had was absolutely draining my oil pan dry. I even tried a new PC valve and it still sucked oil through the intake. Now that the rings have seated I guess I could try it again. What happens with no PC valve? Which PC valve is a good one?

My truck idle's at 800 rpm. Manual transmission out of gear. Idle vacuum is 18 inches. Idle quality is very good. My AFR gauge reads 14 at idle.
'83 chevy K20, 383, Scat Crank, Comp Cams 08-408-8, Etec 170's, sm465
'97 chevy 1500 Silverado, 350, 4L60E

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