Time to replace the spark plugs, any recommondations on brands

Hi,
I am the Tech manager for Autolite. We make the motorcraft plugs that are OE in your vehicle. We have even better plugs available for you car, the XP Iridium fine wire plug. Why are they better? They take less voltage to fire and produce a bigger flame kernal in the combustion chamber. I am willing to send you a set for free if you post your results on this forum. If your interested, please email me at Jay.Buckley@Honeywell.com. Before I am deluged, I can only send a few sets out so first come first served.
PS- you should buy coil on plug boots and replace them when you do the plugs. They live in a harsh enviorment and will often crack when removed. The Autolite part number for the plugs is XP104, boots are 50034.:beer:

I hate to say this, but those are the exact plugs that cost my particular engine 50HP in the mid range, dyno verified, at Kaufmann's Motorsports in Dillsburg, PA. I cannot explain why, or could they, but it was a fact. Nothing else was changed. I had $300 spark plugs listed in my signature for a long time just for that reason. The cost of the dyno time to track down the HP loss :mad2:
 
I hate to say this, but those are the exact plugs that cost my particular engine 50HP in the mid range, dyno verified, at Kaufmann's Motorsports in Dillsburg, PA. I cannot explain why, or could they, but it was a fact. Nothing else was changed. I had $300 spark plugs listed in my signature for a long time just for that reason. The cost of the dyno time to track down the HP loss :mad2:
With all due respect, the spark plug did not cause your engine to loose 50hp. If your shop is any good at looking at the engine calibration, they would in no uncertan terms be able to tell you what parameters where out of whack to cause the power loss. Just shrugging their shoulders and blaming the plugs is total BS, with no basis in calibration engineering.
There may have been misfires due to a cracked plug or plug boot, there may have been misfiring due to excessive plug gap that they may have cut down when the next set of plugs where installed. our experience with boosted ford engines is they will misfire when running the stock plug gap.

Our plugs have been tested at Livernois Motorsprots and Thompson Racing engines and have never contributed to a "power loss' just because there are Autolite plugs in the engine. Our plugs are used in over 80% of all the top fuel cars in NHRA, they wouldnt use them if they caused a power loss over competitors plugs.

I strongly encourage the four guys I am sending plugs to please post your results so we can all see the truth.:eek:
 
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With all due respect, the spark plug did not cause your engine to loose 50hp. If your shop is any good at looking at the engine calibration, they would in no uncertan terms be able to tell you what parameters where out of whack to cause the power loss. Just shrugging their shoulders and blaming the plugs is total BS, with no basis in calibration engineering.
There may have been misfires due to a cracked plug or plug boot, there may have been misfiring due to excessive plug gap that they may have cut down when the next set of plugs where installed. our experience with boosted ford engines is they will misfire when running the stock plug gap.

Our plugs have been tested at Livernois Motorsprots and Thompson Racing engines and have never contributed to a "power loss' just because there are Autolite plugs in the engine. Our plugs are used in over 80% of all the top fuel cars in NHRA, they wouldnt use them if they caused a power loss over competitors plugs.

I strongly encourage the four guys I am sending plugs to please post your results so we can all see the truth.:eek:


My engine is not boosted. With all due respect it was the plugs. That was the only change made.
 
My engine is not boosted. With all due respect it was the plugs. That was the only change made.
What your saying does not make sense unless two of the plugs or boots were damaged during installation. Lets see the datalog for the dyno run. You can send me the plugs and I will have them checked in our engineering lab. I hear things like this from mechanics all the time, it usually goes, I installed Autolite and the car misfired, I took them out and installed Motorcraft and it ran great. There is no difference between Autolite and Motorcraft other than the paint job on the insulater. There is more to this stroy than what you or your tuner are revealing. Lets see the datalog?
 
What your saying does not make sense unless two of the plugs or boots were damaged during installation. Lets see the datalog for the dyno run. You can send me the plugs and I will have them checked in our engineering lab. I hear things like this from mechanics all the time, it usually goes, I installed Autolite and the car misfired, I took them out and installed Motorcraft and it ran great. There is no difference between Autolite and Motorcraft other than the paint job on the insulater. There is more to this stroy than what you or your tuner are revealing. Lets see the datalog?

Based on recommendations here I went from the OEM plugs to AutoLite Iridium. For whatever reason they did not work in my particular engine. That was atleast three years ago. I was so PO'd I threw out all the associated paper work and have not gone back to that shop since. The shop is 4.5 hrs from my house and my car is currently in storage.
I too could not believe that something as simple as switching plugs made that big of change in my engine's performance. Maybe I had a bad set of AutoLites, maybe they were mismarked.
FWIW, I had a similiar problem with a VW we used to own. I put brand X in it and the car threw a CEL. I put the OEM plugs back in and NO CEL. Go figure :rolleyes:
I know you make a good product. I just does not work in my Marauder. I do not wish to spend another $300 to prove this again.
 
Can someone give me a list (brand names included) for what I need in changing my spark plugs, wires, etc. What else would I need?!?! and what is this "gap" you guys speak of?!?! I'm learning fast ask first before a buy or install!
 
Can someone give me a list (brand names included) for what I need in changing my spark plugs, wires, etc. What else would I need?!?! and what is this "gap" you guys speak of?!?! I'm learning fast ask first before a buy or install!
At the risk of sounding rude, if you do not know what spark plug gap is, you may just want to have your friendly neighborhood Ford dealer/repair center work on it.
 
At the risk of sounding rude, if you do not know what spark plug gap is, you may just want to have your friendly neighborhood Ford dealer/repair center work on it.



^^That's why I'm asking my fellow Marauder bredren but it's cool....when I don't know I get started on my research!!
 
Use a tool called a feeler gauge or spark plug gapper to set the distance between the positive and negative electrodes to the manufacturer's specifications. Lots of spark plugs come from the store pre-gapped, but sometimes they can be bumped in shipping or handling.
 
Use a tool called a feeler gauge or spark plug gapper to set the distance between the positive and negative electrodes to the manufacturer's specifications. Lots of spark plugs come from the store pre-gapped, but sometimes they can be bumped in shipping or handling.




^^AHAHA ok gotcha!! just checked a couple of websites...."gap" ok, learn something new everytime I log on. Now I just need to save up for the XP iridium plugs, thank you sir!!
 
Now I just need to save up for the XP iridium plugs
With all due respect to the Autolite guy (and I mean that; I have nothing at all against Autolite plugs), iridium plugs are of minimal value in an N/A car. SergntMac did actual dyno tests between the once-popular Denso Iridiums and plain old Motorcraft coppers and found the iridium plugs were worth only about 4 HP...and even that wasn't consistent. For the large difference in cost, they just aren't worth it. Use the plain copper Autolites and buy your wife/girlfriend/dominatrix something nice with the rest of the money.
 
Hi,
I am the Tech manager for Autolite. We make the motorcraft plugs that are OE in your vehicle. We have even better plugs available for you car, the XP Iridium fine wire plug. Why are they better? They take less voltage to fire and produce a bigger flame kernal in the combustion chamber. I am willing to send you a set for free if you post your results on this forum. If your interested, please email me at Jay.Buckley@Honeywell.com. Before I am deluged, I can only send a few sets out so first come first served.
PS- you should buy coil on plug boots and replace them when you do the plugs. They live in a harsh enviorment and will often crack when removed. The Autolite part number for the plugs is XP104, boots are 50034.:beer:

The problems of being in the military is ever constant...I start this thread about what spark plugs to use, go away for a few days due to work, and miss out on an offer to try out new spark plugs. I am glad however that this is a great community that has guys who do help out and give good advice. Let me know how the plugs work as I still haven't had the time to get new plugs.:shake:
 
I just recieved an email from Motorking, and he had a set of plugs set aside for me. Thank you for the plugs! I greatly appreciate it and will post my results. I will also buy new boots as you recommended. I won't return home until next weekend, but I will definitely go play in the garage next Sunday. Thanks again..This web site is awesome.:beer:
 
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