How fast do you go through spark plugs?

[hunterguy86]

On sunday my K5 was running with a dead miss. Earlier in the day it drove ok but seemed to be a little down on power.
The fuel mileage had dropped off in the passed week.
That night it began running with a bad miss. The next day I replaced all the plugs and wires. Now it runs fine again.
The thing that I'm concerned about is the fact that it has been only about 9000 miles since I last did plugs.
What could have caused this? I have all the plugs on a piece of cardboard, labeled by cylinder number.
I can post pics if it will help.

 

[diesel4me]

should last longer...

Even with point style ignition, plugs should go 20,000 miles..many newer trucks go 100,000 miles with the same plugs..many times I've replaced plugs when I first get a "new" truck,and didn't ever have to look at them again..

Of course,many things can cause them to fail prematurely..fouling from an over rich fuel air mixture,worn rings allowing oil to foul them,bad plug wire(s) or distributor cap,and low compression can cause plugs to fail rapidly..

Some plugs are just crappy to begin with..I've seen many GM small blocks that ran WORSE after putting new "Bosch Platinum" plugs in them!..they skipped like they had a dead cylinder..guess they are a waste of money in a V8 Chevy motor..I'd use AC-Delco's or Autolite NON platinum plugs in my own vehicles..only engines that specify platinum plugs should get them,they don't seem to work well in older engines in my experience..

 

[hunterguy86]

I run AC Delco Plugs and gap them at .045" per the underhood sticker on my 86 k5. I used bosch 8mm wires from O'Rielly autoparts.
Should I do something diffrent here?

Cylinders 1,7,4 and 6 look to be oil fouled (dark black in color) which is possible since the motor has 217K on her.

Things seem ok now. I just want to do everything right to make her last as long as possible.

 

[dyeager535]

If you are oil fouling the plugs, it's really an engine problem. You can try opening up the gaps (.060" will still work) but if the tips are getting coated in oil, not much you can do. I know there are band-aid fixes for the plug fouling/burning oil issues, but the real solution is valve stem seals or rebuild if the rings are where it's coming from.

 

[pauly383]

I replace mine , once a year in the spring whether they are good or not . I love my truck that much ( 4xcrazy says I am anal , I say he's cheap )

 

[dyeager535]

I don't replace mine unless they visibly look broken or worn, or I'm having problems on that cylinder. If they are just covered in soot/gunk, hit them with a wire wheel. It hurts nothing, but make sure to blow them out with compressed air or bathe them in solvent to try and keep any extra junk that you dislodged out of your motor. It'll take a lot of plug cleanings to save up for an engine rebuild, but it's still money not worth spending if they foul fairly quickly.

Even dropping a plug a short distance can destroy them, or just trying to install them with a socket at a bit of an angle.

Luckily I scored something like 24 AC plugs for my engine from ebay for like $5, so I'm not too worried about replacing them.

 

[Hossbaby50]

With a carb my truck fouled plugs sometimes mostly with carbon buildup. I would take a wire brush to them and put them back in unless they were real bad. When I did the fuel injection swap I installed a set of AC Delco's. The FI swap was 3 years ago and the truck has the same plugs. I pull the plugs every so often but they all look perfect so I stick them back in and keep going.

I only use AC Delco plugs now on the K5 since that is all it needs. My Jeep CJ5 also get Delcos. When I had the carb on my K5 I ran Champion truck plugs with good success. They didn't foul as often as the Delco's did. I also had MSD ignition with the carb before I did the FI swap and that helped keep the pulgs from fouling with the better spark & more open gap.

Harley

 

[rjfguitar]

I can top ya....

Number 8 cylinder in my 406 oil fouls it's plug about every 1,500 miles, back when I drove it a lot.

 

[Hossbaby50]

I can top ya....

Number 8 cylinder in my 406 oil fouls it's plug about every 1,500 miles, back when I drove it a lot.

My Jeep w/304 V8 has got that covered. It oil fouls 2 cylinders in about 1000 miles or less. The motor also doesn't read any oil pressure at warm idle in the summer with straight 30w oil. It runs like a raped ape though for a stock motor that is 30+ years oil. It needs a rebuild but it still starts and runs like a top except for the whole oil fouling and oil pressure thing.

Harley

 

[superwrench]

Heres a little food for thought. Most plugs are not desgned to burn oil so consiquently the fouling of the plugs. The little trick we use is in our older race car motors we put in lawn mower plugs, alot of these are designed to run or burn a gas/oil mix. Cuts down on plug fouling. Now I know someone is going to say its a dumb idea, but it works. You just need to get a plug that has the right length threads, right heat range, your parts people can help with this. Example-- In the older chevy heads we used a champion J8C, or a J6C plug.

 

[onetonbb74]

my 1979 brown k10 went threw plugs every 1000 miles, only 98,000k on the motor. The motor used a quart every 250 miles. I drove it accross the United States, and had to change the plugs every morning in the motel parking lot. It never gave me problems as far as starting, but I got tired of it so i changed out the motor with an 1974 motor that still runs on leaded gas. That motor is now in my 74, and i havent changed the plugs in 30,000 miles. This motor uses a quart every 3000 miles and has 150,000 on the ticker now. With 216k, id expect at least 5 cylinders bad and lots of spark plugs fouled.

 

[adamforsythe]

I have replaced all 8 of my plugs in my 350 3 times in the last month and 1/2. I'm running a little rich. hahaha plus I think my carb is going south. I will have the mechanic look at it when I go for a sticker. He is a awesome builder. Plus I really trust him he goes beyond the call of suty when he works on my stuff and other peoples stuff.

 

[4xcrazy]

I replace mine , once a year in the spring whether they are good or not . I love my truck that much ( 4xcrazy says I am anal , I say he's cheap )

what are these things you are calling "spark plugs"???




















seriously, from personal experience, and in my own personal opinion, the Bosch plugs are absolute JUNK, hope you're not running those. I only use AC Delco plugs, and have never had a problem with them.

I did aquire a set of Splitfire plugs awhile back, i ran those for about 2 years before i pulled them just to do a tune up, nothing really wrong with them, they never gave me any issues, always fired.

And Paul is right, i am a cheap bastard, i just can't see spending the cash on parts, when there is nothing wront with the ones currently being used,,,,like AIR FILTERS, i have NEVER seen someone change an air filter so much,,,,PAUL

 

[broncoman6524]

so i guess the general consencus is AC Delco plugs. but whats the gap norm? i know .50 is norm but for msd should i gap mine at about .45? i got a gm crate 350...

 

[4X4HIGH]

I use NGK V-power plugs and change them every 2 years or so. The thing that usually makes them go bad are a high resistance from a bad plug wire. They can also go bad from an engine that burns oil, or is running too lean or too rich.

 

[littlejimmythatcould]

I change mine about every 6-8 months or so (I haven't changed mine in a while though). When I first got it running I went through a set every 2 weeks it seemed until I got my timing and carb set where the truck was happy. I think I gap mine at 35 thousandths, but by reading this thread I could probably go bigger now that I have HEI instead of points.

 

[big dan]

I change mine once a year also. even if there is nothing wrong with them. I know its not needed but after my first motor I like to make sure my plugs are good, it sucks when you only have half your cylinder firing.

when I had my "quart of oil every trip" motor that smoked like a freight train I was pulling the plugs to clean them twice a week and changing them once a month. I went through enough plugs in that one year to buy a new motor.

 

[diesel4me]

Huh?...

Heres a little food for thought. Most plugs are not desgned to burn oil so consiquently the fouling of the plugs. The little trick we use is in our older race car motors we put in lawn mower plugs, alot of these are designed to run or burn a gas/oil mix. Cuts down on plug fouling. Now I know someone is going to say its a dumb idea, but it works. You just need to get a plug that has the right length threads, right heat range, your parts people can help with this. Example-- In the older chevy heads we used a champion J8C, or a J6C plug.

I doubt that would help,but if it worked for you,more power to you!..as far as I know those plugs are not "special" because they can be used in 2 stroke motors,and are no different than automotive plugs..(My brothers '41 Stude uses J-8 plugs as OEM equipment!)..Champions foul faster, and wont recover from fouling ,more than any other brand,IMO--once they stop firing,they are done!..(OK,except maybe the Bosch Platinum ones,they wont fire right out of the box sometimes!).. fouled AC plugs will "clean" themselves after awhile,but Champions are dead forever once they foul..

I hate Champion spark plugs..I repaired small engines for most of my adult life,and many of them only needed the Champion plug tossed in the trash ,and a new plug of some other brand installed to get them running!..when you have only ONE plug,it needs to be a GOOD one!..

They sell "Aldor" brand spark plugs at an auto discount store here,that claims to "fire in oil",and are reccomended for old engines that guzzle oil and foul the plugs..I have tried them,they DO work!...I never had to change the one I put in a smokey straight six I had,that would foul "normal" plugs in a week or so..they sell several different ones,for whatever kind of engine you have..

Also,you can buy "non foulers" at parts stores that screw in the head and the plug goes in them,they increase the heat range and sheild the electrodes from oil and extend plug life..but they will reduce power a bit..they say to use them only on the cylinders that foul the plugs,and not more than half of the plugs (4 out of 8 on a V8 as an example)...I've had many old Chevy's that needed them!..

I used to swap a fouled plug into another cylinder that didn't foul the plugs,and put the "good" plug in the "fouled" cylinder..the heat from the "good" cylinder will eventually clean the fouled plug,and you can avoid having to replace them so often this way..


Adding stuff like "Lucas" motor treatment or STP Oil Treatment,"Motor Medic"and similar oil thickening agents will help reduce fouling and oil burning..but I'd wait until warm weather before adding that type of stuff,in cold weather it could lead to hard starts or engine damage from the oil being too thick to pump quickly when first started..