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How long do your plugs last?

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Old 02-09-2016, 02:34 PM
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Default How long do your plugs last?

Seems around 1000 miles my BR7EF's start to break-up under boost. Gaps are .022, but may go smaller. My idle AFR is 13.2, any leaner and the idle gets rougher. Also running MSD wires. I pulled the plugs out and they don't look bad at all in terms of soot or anything. Wondering what else I can do to extend the life. Not too worried about the 20.00 for new plugs, just wondering is something is off. Maybe try stock wires? Running truck coils FWIW.
Old 02-09-2016, 03:07 PM
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Originally Posted by 69-chvl
Seems around 1000 miles my BR7EF's start to break-up under boost. Gaps are .022, but may go smaller. My idle AFR is 13.2, any leaner and the idle gets rougher. Also running MSD wires. I pulled the plugs out and they don't look bad at all in terms of soot or anything. Wondering what else I can do to extend the life. Not too worried about the 20.00 for new plugs, just wondering is something is off. Maybe try stock wires? Running truck coils FWIW.
What size cam? Should be able to get it leaner than 13.2. You have any vacuum or exhaust leaks? Usually cam's I've tuned idle better with a lean idle. Have you played with idle timing?
Old 02-09-2016, 03:27 PM
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Originally Posted by ddnspider
What size cam? Should be able to get it leaner than 13.2. You have any vacuum or exhaust leaks? Usually cam's I've tuned idle better with a lean idle. Have you played with idle timing?
218/223, 112lsa. Don't think I have any leaks, care runs really good otherwise. I idle with 22*, any less it gets a little rougher and anymore no real change.

One thing I wanted to mention is that I only run 11* of timing at max boost (14psi-17psi). Don't really want to run more till I get on a dyno. Wondering if this could be an issue. 93 octane, 11.5 AFR wot. Spraying a bit of 50/50 too, which I think I'm going to take off.
Old 02-09-2016, 05:45 PM
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Everything you have mentioned sounds fine. Don't see why this would be hard on plugs. I run Brisk plugs... equal in heat range to NGK 7, and they last forever. The last time I changed them was just because I was doing some upgrades. The first set looked fine after 2 full seasons on them.
Has to be something going on.. maybe bad coil or wires.
Old 02-09-2016, 06:32 PM
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Originally Posted by 69-chvl
218/223, 112lsa. Don't think I have any leaks, care runs really good otherwise. I idle with 22*, any less it gets a little rougher and anymore no real change.

One thing I wanted to mention is that I only run 11* of timing at max boost (14psi-17psi). Don't really want to run more till I get on a dyno. Wondering if this could be an issue. 93 octane, 11.5 AFR wot. Spraying a bit of 50/50 too, which I think I'm going to take off.
That timing isn't unreasonable with that boost level and AFR, remember you idle and cruise much more than you're in boost so I tend to lean on the rich idle AFR as to why your plugs foul pretty quick.
Old 02-09-2016, 07:39 PM
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I run 28* at idle with a 14.4ish AFR using a Brute Speed Blower cam. Your cam is smaller than that so it shouldn't have any issues running leaner at idle.
Old 02-10-2016, 03:30 AM
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Vince,

I've had no luck with MSD wires on my vette.
You might try ohming them out. Frequently find one or more measuring 2k ohms instead of 40 ohms. It sucks, I've used msd all my life. But no more.

I just run the stock GM wires. They came on my engine from the bone yard. :-)

I run NGK R5724-8 plugs. Been in 2 years now. I didn't care for the BR7. I gap them at .028"

Brisk are nice, but not cheap! $8-$10 ea.

Ron
Old 02-10-2016, 06:17 AM
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I have not had a fouled plug in a long time, maybe luck, lol, but I ran the 7's all last year, and before that I ran them in my other car-I am switching back to 6's to try again, but the 7's were fine, a little dirty
I prefer a little wider gap, .028-.030
Old 02-10-2016, 06:18 AM
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Originally Posted by RonSSNova
Vince,

I've had no luck with MSD wires on my vette.
You might try ohming them out. Frequently find one or more measuring 2k ohms instead of 40 ohms. It sucks, I've used msd all my life. But no more.

I just run the stock GM wires. They came on my engine from the bone yard. :-)

I run NGK plugs R5724-8. Been in 2 years now. I didn't care for the BR7. I gap them at .028"

Brisk are nice, but not cheap! $8-$10 ea.

Ron
Ron I just measured 7 out of the 8 wires and they were all between 35-52. I have to take the downpipe off to get to the last one. I always wondering about these wires to be honest vs stock...I may change them anyway.

What was your experience with the BR7's? The ones I'm running have the "V Groove" which I'm wondering is part of the issue as the bottom of the V is far away from the grd strap than the rest of the electrode. I just ordered some BR7EFS which is the standard electrode from what I gather. Perhaps I should try a projected plug? My car sees ALOT of idle time...I mean, most of the time it IS idling. Not sure if I can run a non-resis plug like yours with the Holley or not.
Old 02-10-2016, 06:20 AM
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Originally Posted by forcd ind
I have not had a fouled plug in a long time, maybe luck, lol, but I ran the 7's all last year, and before that I ran them in my other car-I am switching back to 6's to try again, but the 7's were fine, a little dirty
I prefer a little wider gap, .028-.030

Any wider than .022 and I break-up even with low boost...wondering if this is an indicator of an underlying issue
Old 02-10-2016, 06:46 AM
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Originally Posted by 69-chvl
Ron I just measured 7 out of the 8 wires and they were all between 35-52. I have to take the downpipe off to get to the last one. I always wondering about these wires to be honest vs stock...I may change them anyway.

What was your experience with the BR7's? The ones I'm running have the "V Groove" which I'm wondering is part of the issue as the bottom of the V is far away from the grd strap than the rest of the electrode. I just ordered some BR7EFS which is the standard electrode from what I gather. Perhaps I should try a projected plug? My car sees ALOT of idle time...I mean, most of the time it IS idling. Not sure if I can run a non-resis plug like yours with the Holley or not.
I would rather change the plugs every 1000 miles than run a projected tip plug on a boosted car and risk hurting something.
Old 02-10-2016, 07:25 AM
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Has anybody ever seen a failure that can attributed to a projected plug? The design of a projected plug is interesting in the sense that its designed to run hotter at idle but the projected tip is cooled by the incoming fuel charge. I also read that iridium plugs shouldn't be used, but a lot of Vette/CTSV guys ARE using them and making huge power. Who's to say??
Old 02-10-2016, 09:14 AM
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Originally Posted by RonSSNova
Vince,

I've had no luck with MSD wires on my vette.
You might try ohming them out. Frequently find one or more measuring 2k ohms instead of 40 ohms. It sucks, I've used msd all my life. But no more.

I just run the stock GM wires. They came on my engine from the bone yard. :-)

I run NGK R5724-8 plugs. Been in 2 years now. I didn't care for the BR7. I gap them at .028"

Brisk are nice, but not cheap! $8-$10 ea.

Ron
Ron, one of my wires measured 2.6-3.0k :eek. I guess this could be a problem
Old 02-10-2016, 09:19 AM
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What coils are you running-the early Holley HP's had a problem with some of the coils, there was a break in the HP serial #'s that they fixed the problem, prob 3-4 years ago
What boost does it start to break up with wider gaps-there may be another problem, maybe grounding or something
I think I have the MSD wires, never ck'ed the ohm's, but they ran fine-some of the problems were people were not getting the plug all the way in the coils, where you heard the click, and they were coming loose
Old 02-10-2016, 09:24 AM
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Originally Posted by forcd ind
What coils are you running-the early Holley HP's had a problem with some of the coils, there was a break in the HP serial #'s that they fixed the problem, prob 3-4 years ago
What boost does it start to break up with wider gaps-there may be another problem, maybe grounding or something
I think I have the MSD wires, never ck'ed the ohm's, but they ran fine-some of the problems were people were not getting the plug all the way in the coils, where you heard the click, and they were coming loose
Late-model ECU, truck coils w/heat-sink, additional grd wires run to each coil pack. Usually with ~.022 gaps it doesn't break-up under boost at all until about 1k miles on the plugs. Any wider gap it breaks-up immediately even with very low boost.

Think I'll try new wires and plugs and see what happens.
Old 02-10-2016, 10:19 AM
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Originally Posted by 69-chvl
Has anybody ever seen a failure that can attributed to a projected plug? The design of a projected plug is interesting in the sense that its designed to run hotter at idle but the projected tip is cooled by the incoming fuel charge. I also read that iridium plugs shouldn't be used, but a lot of Vette/CTSV guys ARE using them and making huge power. Who's to say??
Do a search over on the nitrous forums, they turn into a glow plug when there is too much heat/combustion pressure.

Last edited by ddnspider; 02-10-2016 at 11:24 AM.
Old 02-10-2016, 11:18 AM
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I assure you I had my msd wires plugged in all the way. The ohm meter doesn't lie.
MSD quality has gone down hill. If folks don't believe that, just keep buying them.
I bought the third set hoping they wouldn't have issues.....they did.

Vince, I prob get away with non resistor plugs because the stock wires are 700 ohm.

As for the plugs I run, they are something between an extended tip and the BR7's. I've seen no issues running them at all.

Glad you checked the wires!
Old 02-10-2016, 12:00 PM
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Originally Posted by 69-chvl
Seems around 1000 miles my BR7EF's start to break-up under boost. Gaps are .022, but may go smaller. My idle AFR is 13.2, any leaner and the idle gets rougher. Also running MSD wires. I pulled the plugs out and they don't look bad at all in terms of soot or anything. Wondering what else I can do to extend the life. Not too worried about the 20.00 for new plugs, just wondering is something is off. Maybe try stock wires? Running truck coils FWIW.
I forget if you run e85 or not? E85 plugs should last a long time. I’ve always used the $28 autozone cheapie ign wires. They are also around 700ohm. I've yet to see a bad one.

Why do you think it's the plugs? If the electrode isn't worn excessively I don't know why a plug would suddenly lose spark strength after 1000 miles? There’s not much to them. Judging by the amount of water your injecting and the ign issues you’ve reported in the past, it sounds to me like you have had ignition issues for a while now. I’d look into a new set of D-585 delphi coils (not the cheapie parts store fakes) and Holley dwell settings as well when you replace the wires.

Something sounds off. With healthy bone stock system you should be able to fire off a .045 gap at low boost levels easy. I’ve seen the D585 fire off at .130 gaps happily at 5ms dwell. It’s a monster coil, sounds like your sparks is super weak.

Do you have full bat voltage going to the coil harness? Also How are these additional grounds you setup run? Have a picture?
Old 02-10-2016, 02:06 PM
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You guys have me curious now, so I spot ck'ed the ohms on 2 of the wires, they were 23 and 39-tomorrow I will do the rest just to be sure
Old 02-10-2016, 08:13 PM
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Originally Posted by Forcefed86
I forget if you run e85 or not? E85 plugs should last a long time. I’ve always used the $28 autozone cheapie ign wires. They are also around 700ohm. I've yet to see a bad one.

Why do you think it's the plugs? If the electrode isn't worn excessively I don't know why a plug would suddenly lose spark strength after 1000 miles? There’s not much to them. Judging by the amount of water your injecting and the ign issues you’ve reported in the past, it sounds to me like you have had ignition issues for a while now. I’d look into a new set of D-585 delphi coils (not the cheapie parts store fakes) and Holley dwell settings as well when you replace the wires.

Something sounds off. With healthy bone stock system you should be able to fire off a .045 gap at low boost levels easy. I’ve seen the D585 fire off at .130 gaps happily at 5ms dwell. It’s a monster coil, sounds like your sparks is super weak.

Do you have full bat voltage going to the coil harness? Also How are these additional grounds you setup run? Have a picture?
93 octane. When I change the plugs, engine runs clean again. The Holley provides the voltage and grds to the coils, never checked the voltage going to them. I have a grd wire to each coil pack frame and then to chassis grd.

I need to work on the tune a bit b/c on decel it goes way rich until closed loop kicks in and straightens it out. Could contribute to a fouling condition I guess.

I had a set of d581 coils which I then replaced with the 585's. I'll try opening them up again now that I have new wires and plugs coming in.


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