Old 283 spark plug gap - The 1947 - Present Chevrolet & GMC Truck Message Board Network

AnlaufJohn · 12-12-2009, 07:47 PM

Well, the plug wires are toast. Old Yeller was running a bit rough in the extreme cold last week. Found some sparks under the hood flying around the spark plug wires. OK, new wires, new plugs, right?

The factory manual shows gap to be set at .035. Is that still the norm? I read some of the 'spark plug gap' threads, and they seem to apply to HEI or 383 or Vortex engines.

Here some info:
1966 Chevrolet C-10 with 283 V-8. Odometer shows 41854 miles, but how many times has it gone around? Heads don't show any signs of being opened up before. I had the carburetor rebuilt by an old mechanic I have known for 15 years.

Mine is running with points and condenser, 2 bbl carb with manual choke (new cable installed this weekend) and manual 4-speed transmission. I have to say, I love the low gears in 1st and reverse. This truck loves to back into its parking space at an idle.

I have a few days until I open the hood, so please let me know if I can open the gap up, or stay the course.

AnlaufJohn
Springfield, Oregon

Big Fenders · 12-12-2009, 08:55 PM

If your not running HEI then .035 is the correct gap for your plugs.
Bob

markeb01 · 12-13-2009, 02:49 AM

If this truck is a keeper, I would really recommend installing a Pertronics kit or HEI distributor. My experience is they are both completely reliable and eliminate the misery of points. With either the HEI or Pertronics the plug gap can be opened up to .040.

The sucky feature of points, is that as they age, the rubbing block wears down, closing the gap and changing the dwell. Point gap/dwell has an effect on timing, and when the points wear the timing changes. And then there's the issue of the points burning and pitting. With an electronic conversion kit or a swap to HEI those problems just go away, making life with an old truck a bit simpler.

62gmc910 · 12-13-2009, 05:24 PM

I used to set my plugs at .032
HERE are the quick set points instructions
warm the engine shut off open the points window insert hex key in adjuster screw
start engine run at idle, turn screw clockwise until engine starts to miss,
turn screw 1 turn CCW then 1/2 turn clockwise (to preload spring)
If the points are servicable this will set the dwell to 29-31 degrees
That old engine should have series three oil (turbo diesel http://www.bobistheoilguy.com/forums...oard=22&page=1
Good luck and look after that old truck

AnlaufJohn · 12-18-2009, 12:48 AM

It funny that markeb01 suggested gapping the plugs at .040. My best friend, a former ASE Master Technician, said he would gap them at .040.

So far, so good. New wires ( why would wires go through the motor mounts?) new AC plugs (R45) and a new vacuum advance. Wow, that motor is alive again!!

Very mild temps, around 45F in the morning, so very little choke action is needed. I figured out that the plugs I had in earlier were a bit cooler. That may have added to my cold running issues.

AnlaufJohn
Springfield, Oregon

12-12-2009, 07:47 PM	#1
AnlaufJohn Registered User Join Date: Feb 2009 Location: Lebanon, Oregon Posts: 130	Old 283 spark plug gap Well, the plug wires are toast. Old Yeller was running a bit rough in the extreme cold last week. Found some sparks under the hood flying around the spark plug wires. OK, new wires, new plugs, right? The factory manual shows gap to be set at .035. Is that still the norm? I read some of the 'spark plug gap' threads, and they seem to apply to HEI or 383 or Vortex engines. Here some info: 1966 Chevrolet C-10 with 283 V-8. Odometer shows 41854 miles, but how many times has it gone around? Heads don't show any signs of being opened up before. I had the carburetor rebuilt by an old mechanic I have known for 15 years. Mine is running with points and condenser, 2 bbl carb with manual choke (new cable installed this weekend) and manual 4-speed transmission. I have to say, I love the low gears in 1st and reverse. This truck loves to back into its parking space at an idle. I have a few days until I open the hood, so please let me know if I can open the gap up, or stay the course. AnlaufJohn Springfield, Oregon

12-12-2009, 08:55 PM	#2
Big Fenders Registered User Join Date: Mar 2008 Location: Tucson Arizona Posts: 264	Re: Old 283 spark plug gap If your not running HEI then .035 is the correct gap for your plugs. Bob

12-13-2009, 02:49 AM	#3
markeb01 Senior Enthusiast Join Date: Feb 2007 Location: Spokane Valley, WA Posts: 8,356	Re: Old 283 spark plug gap If this truck is a keeper, I would really recommend installing a Pertronics kit or HEI distributor. My experience is they are both completely reliable and eliminate the misery of points. With either the HEI or Pertronics the plug gap can be opened up to .040. The sucky feature of points, is that as they age, the rubbing block wears down, closing the gap and changing the dwell. Point gap/dwell has an effect on timing, and when the points wear the timing changes. And then there's the issue of the points burning and pitting. With an electronic conversion kit or a swap to HEI those problems just go away, making life with an old truck a bit simpler.

12-13-2009, 05:24 PM	#4
62gmc910 Registered User Join Date: Nov 2009 Location: Cremona AB Canada Posts: 370	Re: Old 283 spark plug gap I used to set my plugs at .032 HERE are the quick set points instructions warm the engine shut off open the points window insert hex key in adjuster screw start engine run at idle, turn screw clockwise until engine starts to miss, turn screw 1 turn CCW then 1/2 turn clockwise (to preload spring) If the points are servicable this will set the dwell to 29-31 degrees That old engine should have series three oil (turbo diesel http://www.bobistheoilguy.com/forums...oard=22&page=1 Good luck and look after that old truck __________________ 62 GMC 910 short fleetside 454 super t10 14 bolt w/gov lock 70s c20 front discs (built in the 80s) 65 GMC 930 dualwheel 292 4spd all origonal 39k mi(my sons truck) 63 GMC 950 camperized school bus, (Gus the bus) 350 4speed 2 speed rear 64 GMC 950 "spare" bus 283? 4speed detroit locker 53 GMC 1ton dual wheel bus 78 GMC c25 short course off road race truck(son's truck) 355 th400 14 bolt (www.wheel2wheel.ca) 88 Peterbilt 379 longhood (hauls race truck)

12-18-2009, 12:48 AM	#5
AnlaufJohn Registered User Join Date: Feb 2009 Location: Lebanon, Oregon Posts: 130	Re: Old 283 spark plug gap It funny that markeb01 suggested gapping the plugs at .040. My best friend, a former ASE Master Technician, said he would gap them at .040. So far, so good. New wires ( why would wires go through the motor mounts?) new AC plugs (R45) and a new vacuum advance. Wow, that motor is alive again!! Very mild temps, around 45F in the morning, so very little choke action is needed. I figured out that the plugs I had in earlier were a bit cooler. That may have added to my cold running issues. AnlaufJohn Springfield, Oregon



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