spark plugs
Senior Member
Joined: Feb 2004
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Hello, I did google that, and came up with alot of conflicting info on what spark plugs to use for compressed natural gas and gasoline. Since there were 7 replies, none of which said you can use x spark plug for cng and gas, I figured I would have johny clarify what cng was. Worse come to worst, he could replace the plugs with whatever was in there originally. Sorry for trying to strike up a dialog on a forum. Peace, Dave.
)So - how 'bout this one - more amenable?
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Joined: Dec 2006
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From: Joplin MO
I understand you are an engineer - and from an engineering standpoint, you are totally correct in theory. However, in the real world, for some reason the 4.9 does not like platinum plugs. It's not the only engine out there that doesn't like them - I had a BMW 320i that absolutely hated Bosch platinums for some reason, I had to run NGK copper U-grooves in it. Go figure.
sorry for the late respond, its actually LPG, liquid petrolium gas, kinda the same as cng i thought you would be more familiar with cng then LPG,
spark plugs are acdelco now, but the electrode is kinda eaten off, so would like replacements,
question: is this 'eaten' thing caused by bad pre-ignition timing? or is it normal on worn, never had any plugs worn as far like this...
but engine runs good... since i'm not used on these kinda engines i don't know whether it lacks power or not. and because i'm not a speeder in my truck (only in small cars because the truck is far more comfortable
) i don't know how fast it goes or what the time should be to get 0-60 (if it even does 60 
)
spark plugs are acdelco now, but the electrode is kinda eaten off, so would like replacements,
question: is this 'eaten' thing caused by bad pre-ignition timing? or is it normal on worn, never had any plugs worn as far like this...
but engine runs good... since i'm not used on these kinda engines i don't know whether it lacks power or not. and because i'm not a speeder in my truck (only in small cars because the truck is far more comfortable
) i don't know how fast it goes or what the time should be to get 0-60 (if it even does 60 )
Senior Member
Joined: Dec 2011
Posts: 443
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From: Durham, NC
I understand you are an engineer - and from an engineering standpoint, you are totally correct in theory. However, in the real world, for some reason the 4.9 does not like platinum plugs. It's not the only engine out there that doesn't like them - I had a BMW 320i that absolutely hated Bosch platinums for some reason, I had to run NGK copper U-grooves in it. Go figure.
The Bosch single platinum has a lot of problems, the worst being the platinum slug will fall out of the insulator, and score the cylinder wall.
Last edited by Takeda; Jun 1, 2012 at 09:04 PM.
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Joined: Jul 2006
Posts: 117
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From: S. Jersey
Hey MGD, since there were none of those smiley emoticon thingies, I took it as a snarky comment. It's hard to show emotion on a monitor, I know. I apologize if I took it wrong. 
As far as your solution being more amenable, sorry lad, I'm more of a Druid. johny, I googled lpg spark plugs, and again came up with conflicting info on what to use. According to Bosch, (who just so happen to have the plug you need at a premium price) you have higher temps and pressures involved with lpg, so you need a higher spark voltage. (I really hate to ask it, but is your coil upgraded or stock?) But since you have less fouling with lpg, you can go 1 heat range cooler with your plug than with gas. These little factoids help wear out your plugs faster, which is probably what you're looking at now. Like glc said, they were probably in there too long. I would say go with what you had before, and change them more often. Peace, Dave.
As far as your solution being more amenable, sorry lad, I'm more of a Druid. johny, I googled lpg spark plugs, and again came up with conflicting info on what to use. According to Bosch, (who just so happen to have the plug you need at a premium price) you have higher temps and pressures involved with lpg, so you need a higher spark voltage. (I really hate to ask it, but is your coil upgraded or stock?) But since you have less fouling with lpg, you can go 1 heat range cooler with your plug than with gas. These little factoids help wear out your plugs faster, which is probably what you're looking at now. Like glc said, they were probably in there too long. I would say go with what you had before, and change them more often. Peace, Dave.
Last edited by terrapinflyer; Jun 1, 2012 at 11:46 PM. Reason: Forgot to add change them more often.
i normally change the plugs (and everything) very often but the car is only 10k miles with me now and prev owner said it has gotten a lot of new parts and a tune up. which i actually questioned after i had worn brake pads after 2weeks
I just changed out the plugs in my 302. I had no idea what was in it but it was running a little rough and my mileage wasn't all that great. After reading the great advice on this forum I bought some Motorcraft Copper plugs and my truck runs soooooo much better now. I took it for a test drive and when I stopped at a light I seriously wondered if y truck stalled. Nope, it was just running SMOOOOOOOTH. Can't wait to see what kind of MPGs I get now. Here is a pic of the Bosch Platinums I took out.
https://plus.google.com/photos/10237...CP-yyMPFt9OIeg
They look good but they ran like crap.
https://plus.google.com/photos/10237...CP-yyMPFt9OIeg
They look good but they ran like crap.