The Stovebolt Page Forums Home | FAQ | Forum | Swap Meet | Gallery | Tech Tips | Events | Features | Search | Hoo-Ya Shop
Work those trucks!




Share what you're up to this summer!

Stovebolt Site Search
 
Old Truck Calendars
Months of truck photos!
Nothing like an old truck calendar

Stovebolt Calendars

Check for details!


Who's Online Now
11 registered members (bowtietim, daveboy, GarlandFarms, bluesman, Canadian_guy, 1 invisible), 85 guests, and 3 spiders.
Key: Admin, Global Mod, Mod
Forum Statistics
Forums47
Topics115,097
Posts913,351
Members42,110
Most Online940
Apr 5th, 2017
Image Posting Policy
Previous Thread
Next Thread
Print Thread
Intermitent Electrical misfire on #6 #1308773
Sun Apr 28 2019 02:11 AM
Sun Apr 28 2019 02:11 AM
E
Eureka Jim  Offline OP
Shop Shark
Joined: Feb 2013
Posts: 197
Pahoa, Hiwaii
On my '48 GMC with a later model 228 engine. I have one of those visual spark testers where the plug wire goes onto one side of the tester and the other side of the tester goes onto to the plug. Using that, I found an intermittent weak spark on #6, the engine stumbling each time the spark showed yellow in color. I switched #6 wire with one of the other wires but the miss remained on #6. I compared the resistance of each of the spark plugs and #6 was much higher than the others. I also ohmed the wires and while they seemed OK I had a fresh set on the shelf so the truck got the new wires and also a fresh set of plugs.
The new wires and plugs have helped but the stumble is still there from time to time. Am I right in thinking that I should be looking at my distributor now? What am I looking for? Wobble in the shaft? Worn cam lobe? Other usual suspects?
Help is appreciated! Thanks, Jim

Re: Intermitent Electrical misfire on #6 [Re: Eureka Jim] #1308778
Sun Apr 28 2019 02:38 AM
Sun Apr 28 2019 02:38 AM
Justhorsenround  Offline
Grease Monkey
Joined: Apr 2005
Posts: 7,291
El Reno, Okla
Look inside the distributor cap for carbon arcing. If #6 you will find a line from the middle contact to the #6 tower. Good luck.🛠


Martin
'62 Chevy C-10 Stepside Shortbed (Restomod in progress)
'47 Chevy 3100 5 Window (long term project)


"I fought the law and the law won" now I are a retired one!
Support those brave men/women who stand the "Thin Blue Line" and lock up those on the wrong side of that line.

Re: Intermitent Electrical misfire on #6 [Re: Eureka Jim] #1308784
Sun Apr 28 2019 05:23 AM
Sun Apr 28 2019 05:23 AM
E
Eureka Jim  Offline OP
Shop Shark
Joined: Feb 2013
Posts: 197
Pahoa, Hiwaii
Thanks for the suggestion Martin. I didn't find any evidence of carbon arcing. However, the metal tab on the top of the rotor that contacts the carbon was getting kind of rusty---not a surprise here in Hawaii where it seems everything rusts---and the brass part was partially discolored black on its top side and rough to the touch as if it was burned. It also was kind of a loose fit on the distributor shaft. I dug up a new rotor and it snugged down nicely when I put it in. Could a sloppy fitting rotor cause a miss?
I started the engine up and it's firing on all 6 cylinders! Since the problem was intermittent I can't declare it fixed but everything I'm doing is helping. I won't have a chance to drive it until Monday but I'll report back after I put a few miles on it.
After all the things I've had to fix---$$$---it would be nice if it was just the rotor and not a worn out distributor!

Re: Intermitent Electrical misfire on #6 [Re: Eureka Jim] #1308785
Sun Apr 28 2019 05:55 AM
Sun Apr 28 2019 05:55 AM
S
Shakey61  Offline
New Guy
Joined: Mar 2019
Posts: 14
Columbia, Missouri
I had the same problem recently. Checked the usual suspects for a missing cylinder...plug, wire, cap. I found a lot of play in the rotor, and the distributor is worn. Replacing the rotor, and adjusting the points resolved most of the problem. It still misses occasionally at idle, so I plan on replacing the distributor too. I'm guessing the accumulation of factors caused the miss. Why it occurs on #6, I can't say.

-Kevin

Last edited by Shakey61; Sun Apr 28 2019 05:56 AM.

This is what happens when you live with a house-full of women, the wife and daughters name all the cars:
1960 Impala - "Frankie" (Frank Sinatra)
1961 Apache - " 'Mater Jr." (wrecker)
1972 SuperBeetle Convertible - "Juliet"
1976 SuperBeetle Convertible - "Olaf"
1988 Alfa Romeo Spider Veloce - "Romeo"
Re: Intermitent Electrical misfire on #6 [Re: Eureka Jim] #1308797
Sun Apr 28 2019 02:39 PM
Sun Apr 28 2019 02:39 PM
W
Wrenchbender Ret.  Offline
Master Gabster
Joined: Jun 2004
Posts: 8,035
Lenexa Ks.
Check the point gap. Sometimes there is just enough runout in the dist shaft or cam to effect only one cyl. if the points are too close together.
George


They say money can't buy happiness. It can buy old Chevy trucks though. Same thing.

1956 Chevy 1/2-Ton Pickup

Re: Intermitent Electrical misfire on #6 [Re: Eureka Jim] #1308869
Mon Apr 29 2019 02:19 AM
Mon Apr 29 2019 02:19 AM
5
52Carl  Offline
Master Gabster
Joined: Mar 2010
Posts: 7,983
Virginia
Does that distributor have a grease cup on the side of it?
If it does, take off the cup and make sure that the spring and friction disc which rides on the distributor shaft are all there.
This assembly of parts is designed to put a specific amount of lateral pressure on the distributor shaft to eliminate shaft wobble, thus eliminating inconsistent points performance.
Carl

Last edited by 52Carl; Mon Apr 29 2019 02:24 AM.
Re: Intermitent Electrical misfire on #6 [Re: 52Carl] #1308885
Mon Apr 29 2019 04:21 AM
Mon Apr 29 2019 04:21 AM
E
Eureka Jim  Offline OP
Shop Shark
Joined: Feb 2013
Posts: 197
Pahoa, Hiwaii

Carl, unfortunately there is no grease cup.

Re: Intermitent Electrical misfire on #6 [Re: Eureka Jim] #1308969
Mon Apr 29 2019 10:34 PM
Mon Apr 29 2019 10:34 PM
5
52Carl  Offline
Master Gabster
Joined: Mar 2010
Posts: 7,983
Virginia
It should have a grease cup. Replacement distributors commonly don't come with one, but there should be a threaded plug where one belongs.

Re: Intermitent Electrical misfire on #6 [Re: Eureka Jim] #1309210
Wed May 01 2019 07:41 PM
Wed May 01 2019 07:41 PM
H
Hotrod Lincoln  Offline
Boltergeist
Joined: Feb 2004
Posts: 18,595
Dellrose, TN
Even without a grease cup, there needs to be a spring and a phenolic disc riding against the shaft inside that hole. You can install a 1/8" pipe thread grease fitting and give it a very small shot of grease at every tuneup if you desire.
Jerry


The murder victim was drowned in a bathtub full of Rice Krispies and milk.
The coroner blamed the crime on a cereal killer!

Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!

Moderated by  Rusty Rod 

Home | FAQ | Forum | Swap Meet | Gallery | Tech Tips | Events | Features | Search | Hoo-Ya Shop
Powered by UBB.threads™ PHP Forum Software 7.6.1.1