Can/cannot reuse fouled spark plugs?

[talon2gbuyer]

hey all, stupid question. I've read in some places that once you foul spark plugs that they are un-usable, now I've always taken fouled plugs and sprayed them with brake cleaner or something similar, air dried them and then re-installed. I guess my question is, is this a good practice or not? also if that's the case, why is it when plugs foul they cannot be used again? What actually happens that ruins the plugs?

 

[2gnt99]

http://www.ngksparkplugs.com/techinfo/spark_plugs/faq/faqfouled.asp?nav=31200&country=US

When a plug is fouled it gets coated in some substance like oil or carbon. This prevents the plug from sparking correctly.

A spark plug can be cleaned and reused, but it more than likely won't run at or near the same efficiency as before it was fouled.

Given that NGK copper plugs are only a few dollars, it really doesn't hurt to replace a fouled plug.

 

[JusMX141]

Once the plug is fouled to the point that it grounds through the porcelain, it's junk no matter how clean you get it.

Plugs are $2 a piece- don't be a cheap-ass.



Edit- I lose the race.

 

[talon2gbuyer]

I know they are cheap, but i've spent better than $60 on over 4 sets of new plugs (first few sets were NGK irridum plugs $4 a piece ) but I was always curious as to why they are not really more durable.

 

[scissorman77]

Just by the new plugs.I always tried to save them and she never ran the way she should

 

[JusMX141]

I was always curious as to why they are not really more durable.

Smaller electrode. If your tune is shitty, the electrode has less surface area to keep it firing under rich conditions. Use standard copper plugs until you get your tune spot-on.

I went through this all the time tuning 2-stroke race bikes back in the day. It always seemed like Yamahas would cold-foul those special "racing" plugs every damn time until the engine warmed up. You had to use a standard BR8ES in those bikes to keep them running until the engine got warm enough to burn the oil off the plug.

 

[miloolim]

The way I personally look at it at my work is if the plug has been in the machine for over a year and it is fouled out (untuned or dirty carb what ever) then I replace it. If it has been over a week and it is something like a bad spark plug wire thats making it foul then ill just clean and reuse the plug.

 

[curt-s]

I know they are cheap, but i've spent better than $60 on over 4 sets of new plugs (first few sets were NGK irridum plugs $4 a piece ) but I was always curious as to why they are not really more durable.

Why Iridium?

Anyway, $8 < $60. I'd personally rather have the $8 insurance against miss or misfire.

 

[snowborder714]

That's what they told him were OEM plugs and he didn't search on here for what plugs were recommended

 

[bastarddsm]

turbo stuff is finiky with plugs. They can foul for no reason sometimes. I've had ones where I had the tune off, and it'll miss, and the plugs are junk. Can't see anything wrong with them but they won't run under boost. I run BR8ES, so I was saving em for snomobile use, I got piles of em .

 

[talon2gbuyer]

hm.. ok. If the BPR7ES plugs I have foul again (i have 2 full sets of em) should I upgrade to BPR8's?

 

[talon2gbuyer]

That's what they told him were OEM plugs and he didn't search on here for what plugs were recommended

Yea, i later learned from Bri that those ARE in fact OEM plugs... for the 420a motor.

 

[snowborder714]

hm.. ok. If the BPR7ES plugs I have foul again (i have 2 full sets of em) should I upgrade to BPR8's?

No. The heat level of the plugs is not what's fouling them out. It's another issue, and a fairly big one at that. Off hand I don't know what would cause this, but I'm thinking something somewhat big. Is it oil that is on the plugs?

I'd follow Craig's advice (from your other thread) and do a leakdown test and verify mechanical timing (pull cover and line up marks by rotating engine clockwise by hand). No sense in throwing more plugs at it when you know they're just going to foul out.

 

[talon2gbuyer]

Yea i'll have to see about doing a leak-down test then. I'll look into that tomorrow or this weekend possibly

 

[AM2SS]

http://www.ngksparkplugs.com/techinfo/spark_plugs/faq/faqfouled.asp?nav=31200&country=US

When a plug is fouled it gets coated in some substance like oil or carbon. This prevents the plug from sparking correctly.

A spark plug can be cleaned and reused, but it more than likely won't run at or near the same efficiency as before it was fouled.

Given that NGK copper plugs are only a few dollars, it really doesn't hurt to replace a fouled plug.

How about this...... My 99 Eclipse NT started misfireing and I cleaned the new NGK copper plugs and great it worked. It did it again and no joy the second time. Scanned it and the OB2 said misfire #4. Moved plugs around and no change. Put on a new coil pk, wires, throttle position sensor, cam shaft position sensor, injectors, fuel filter and the #1 O2 sensor and it could just need new plugs after only being 2 months old??

 

[curt-s]

Something else. I'd start inspecting your wiring first for broken/barely hanging on wires, cracks causing groundnuts, and ignition connectors.
Then I'd move inwards towards the ecu itself.

 

[AM2SS]

Something else. I'd start inspecting your wiring first for broken/barely hanging on wires, cracks causing groundnuts, and ignition connectors.
Then I'd move inwards towards the ecu itself.

Well good news the fuel pressure is good, the compression test was good except cylinder 4 it has 0 compression. So.....

 

[curt-s]

Oof. But perhaps it's something else..
I had like 60-70psi compression and when I tore the head off I found carbon chunks actually stuck on the valve seat. They would have blown off eventually but not before I removed the head

So I upgraded the springs whilst I had it off..

Maybe hold out some hope?

 

[Bud92gsx]

You should always have multiple sets of ngks on hand..
I have tho wire brushed,and maybe sand papered the spark plugs and reinstalled them. Especially on my lawn mower. But have done it to the dsm. But changed them out ASAP.

I say get a few extra sets.