Just how long do spark plus last

junkyardjeff · April 27, 2011, 11:04:04 PM

I know that they are advertised on the new vehicles to last 100,000 miles but just how long do the plugs from the parts stores last now,I put my 65 custom 500 togather 5 years ago and have 20,000 on the plugs and they still seem like they have plenty of life left on them. Years ago it was about every 15,000 that a motor got a tune up so its past that now,it had a points distributor most of the time but I just installed the duraspark ignition again so I will run it untill it gets a miss and change them then.

DRD57 · April 27, 2011, 11:46:47 PM

I dunno. My '03 dodge Ram has 144,000+ miles on it and I don't even know where the spark plugs are. As long as it knocks down 18 mpg I'm not going to worry about it.

GPster · April 28, 2011, 07:59:36 AM

Some information I picked up somewhere Probably from spark plug manufacturers) is that the newer HEI igmition systems have a spark with such high energy that it will jump a .060" gap. Now with some engines starting with a .040" gap they could burn a lot of electrod off and still jump the gap. Maybe it's got something to do with no lead in the gas too. GPster

wayne petty · April 28, 2011, 12:35:08 PM

how long they last depends upon the brand and model of the spark plug..

some i have seen .. conventional NON platinum.. go over 100K.. but the gap go so excessive that the secondary build up of voltage needed to jump both gaps (rotor tip to cap and spark plug) caused the coil windings to leak to the frame of the coil.. this has been an ongoing problem.

this is more of a problem than spark plugs wearing out lately..

investing in a 8 buck coil output voltage tester is one of the ways to verify that the coil is creating enough high voltage to jump the gaps and light the fuel mixture with enough energy to really set it off..

there are a few trucks and vans that are really really hard to get at the spark plugs.. and special spark plugs were made for them.. the 18 mm champion F10 y.. with the double thick center and side electrodes. and the ac delco CR43TS and CR44TS are conventional small block chevy shaped spark plugs. but with a massive center and side electrode.. used mostly in van applications so they don't wear away as fast..

while on this subject.. owners of trucks with ford triton engines.. might want to think about carefully changing spark plugs long before 100 K... as they have had terrible problems with them sticking in the hole.. there have been people who say to pull the coils.. loosen the spark plugs all 1/4 turn.. put the coils back in.. start and run it for a minute to clear any loose carbon from the extended tip of the plug.. then take it all back apart and remove the spark plugs.. warning.. if the plugs break off.. it can cost thousands.. if they strip out. same thing.. there are ONE piece shell spark plugs for these beasts now.. there are tools designed to get out broken plugs and to install new solid threaded inserts.. as heli coils are not going to work on this one..

anti seize on the spark plug threads...

dielectric tune up grease on the inside of the boots.. but not on the terminals.. wiped on.. not packed in..

Arnold · April 28, 2011, 01:05:09 PM

What Wayne said..plus..leaving plugs in too long in aluminum heads(whether they are good or not) can really,really make you wish that you changed them. Not just aluminum heads..there are now waay too many engines that have too much stuff to be removed that is/and the fasteners subject to heat/cold/moisture rust etc. Change the plugs in something nasty with iron heads that have not been changed in forever and you will curse. I give plugs about 50,000 and out they come.

UGLY OLDS · April 28, 2011, 06:12:58 PM

Gee Wayne ... The nice thing about Ford plugs is that if left in too long , they tend to exit all by themselves ....

ALWAYS breaking the coil in the process .....

We have some REAL problems in this area ....And you are correct ....SERIOUS dollars to repair properly ....

Bob....

wayne petty · April 29, 2011, 02:45:34 AM

i know there are going to be more rodders reading this thread..

here are some articles on how to do the job right... so you don't end up emptying ones wallet...

http://www.enginebuildermag.com/Article/5195/this_super_duty_was_a_super_headache.aspx

http://www.enginebuildermag.com/Article/38150/tech_tips_for_2004_and_up_ford_f150_engines.aspx

take a few minutes to add to your knowledge base... just in case....

UGLY OLDS · April 29, 2011, 06:35:05 PM

Thank You Wayne ... I will be able to use those sites for some of our guy's to do some "learnin'" ...

Bob.......

enjenjo · April 29, 2011, 08:54:35 PM

I just had the ones on my Excape replaced, one of the coils went bad, so while he was in there he replaced the plugs. It has 105,000 miles on it. It still had the original plugs, even though my son paid a Ford dealer to replace them 45,000 miles ago.

butch27 · April 29, 2011, 11:22:05 PM

Frank: That sounds like a normal dealership rip-off.

river1 · April 29, 2011, 11:44:12 PM

how do you know they are the originals?

i'm assuming that the dealer would put OEM plugs back in it.

later jim

enjenjo · April 30, 2011, 12:26:56 AM

Quote from: "river1"how do you know they are the originals?

i'm assuming that the dealer would put OEM plugs back in it.

later jim

For some reason, Ford paints a blue dot on the top of the spark plugs at the factory. None of the replacement plugs have the blue dot on them. These plugs all had a blue dot.

river1 · April 30, 2011, 03:26:21 AM

Quote from: "enjenjo"
Quote from: "river1"how do you know they are the originals?

i'm assuming that the dealer would put OEM plugs back in it.

later jim

For some reason, Ford paints a blue dot on the top of the spark plugs at the factory. None of the replacement plugs have the blue dot on them. These plugs all had a blue dot.

interesting, i never knew that.

thanks jim

UGLY OLDS · April 30, 2011, 08:30:50 AM

Quote
Quote from: "enjenjo"I just had the ones on my Excape replaced, one of the coils went bad, so while he was in there he replaced the plugs. It has 105,000 miles on it. It still had the original plugs, even though my son paid a Ford dealer to replace them 45,000 miles ago.

This is sad .....

BUT it is something we see VERY often :x

Especially with Ford products that have spark plug "issues" ...

Some dealers will not replace plugs without doing the insert repair as "part of the package" ....

Another common repair procedure is refusing to replace one spark plug insert when a plug blows out ...They will replace ALL the inserts or none .... :?:

Some refuse to do insert repairs at all & INSIST on replacing cylinder heads ...... :?:

Bob...

jaybee · April 30, 2011, 09:30:21 PM

Man, someone oughta be FIRED over that design.