Difference in Spark plugs?

[SHO87]

I recently bought a 91 sho that has bosch platinum 4 spark plugs in it. I have used these plugs on a Gen III I had and they worked fine, but I was reading up on sho shop and they said you want to use only the Motorcraft Double Platinum Plug and never use anything else. I was just wondering if there is really that big of a difference in them? I am sure this guy knows what he is talking about, but I am just curious. Thanks

 

[rubydist]

the SHO motor and the platinum 4 plugs are not a good match, and do not play well together.

 

[beaudeen]

When I first purchased my SHO, it developed a little miss at WOT so I thought plugs or wires. Having not found this site at the time, swapped out the plugs with guess what....Bosch platinum 4's...that was back in June of 2003 and nearly 100km(65k miles) ago and still running original plug wires..The valve covers have a slow leak and I clean out the plug wells every second year. I haven't removed the intake as of yet, but I have a spare set of valve covers with new seals ready to go in...maybe this year..lol
Now would I recommend using the platinum 4"s...NO...use what these guys tell you to use as they've got the experience...BUT...when those covers come off and the plugs are pulled, I'll be using what my engine seems to like..Bosch Platinum 4"s.

 

[turbosho]

platinum+2 or 4 or 6 or anything, will not help your car in any shape or form. Electricity flows only to the path of least resistance, and will repeatedly do that. thus the other 3 electrodes will become covered in carbon, making the path of least resistance the only path now.

so all you have left is a tiny little electrode and a tiny little spark, a gap you can not adjust, and a car that runs less than optimal.

 

[beaudeen]

I'm in NO WAY endorsing the Bosch Platinum plugs..The guy just asked if they were a problem..had I known what the correct plug was at the time, I surely would have gone with the recommended plug of choice..my 95 runs just fine with them for the past 7+ years and have been averaging 27 mpg highway...I'll post a pic of the plugs when I get around to replacing them..I may change my mind on using them in the future though...Just my 2 cents

 

[220ksho]

after 100k miles, what do you have to compare them to?

Stick with OE IMO

 

[notbange]

Just replaced a set of platinum +4 in a Hyundai Tibouron v6 that had the plugs and wires replaced probably 10k miles before I was replacing them. Customer was complaining of a slight miss under load, and didn't want any diagnostic, just to replace the plugs and wires again. I thought that was a little suspect because the car only had 60k on it and already had new wires and plugs, but then I started pulling out those Bosch +4 plugs and it made more sense. Bosch plugs don't belong in anything but what requires them (volkswagens maybe?)

 

[SHO87]

I appreciate the help guys! I was on here lookin for the gap setting on the double plat. spark plug and cant find in any forums. Any ideas? Thanks

 

[rubydist]

stock gap is .044" iirc.

 

[luigisho]

You can get away from the double plats and go with the oem replacement finewires. Those run well. gap is .044

 

[AREA 91]

Motorcraft part #'s AGSP32PP (double platinum)
AGSP32FM (platinum fine wire)

Autolite part # APP3924 (double platinum)

:wave:

 

[frosho]

+1 for the Motorcrafts. I learned the hard way. Aftermarket replacement plugs are slightly longer than OE Motorcrafts. Because they are slightly long, the plug wires won't seal correctly against the valve cover, and water and other debris will find its way into the plug wells and cause a misfire. Motorcraft is the ONLY option for plugs, IMO.

 

[SHOtime2511]

I've never seem Bosch +4 work worth a damn in any application.
Autolite or Motorcraft.

 

[beaudeen]

You guys are hurting my feelings..lol
Like I said earlier..Ive had good luck with these incorrect plugs and they've been in there for over 7 years..If it ain't broke...But I promise to replace them with the correct plug when I do change them out...so there...LOL

 

[turbo79]

+1 for the Motorcrafts. I learned the hard way. Aftermarket replacement plugs are slightly longer than OE Motorcrafts. Because they are slightly long, the plug wires won't seal correctly against the valve cover, and water and other debris will find its way into the plug wells and cause a misfire. Motorcraft is the ONLY option for plugs, IMO.

There's a Denso plug that works, probably because Denso also makes the Motorcraft OEM plugs. It is the correct length.

From SHOTimes:

The Motorcraft AGSP32PP spark plug was designed to the ISO specifications, not the SAE design which makes it's over all size approximately 2.3mm shorter from the gasket to the top of the contact. This is why most name brand spark plugs designed to the SAE specifications do not work in the SHO motor. <snip> In fact the Motorcraft AGSP32PP spark plug was not designed or manufactured by Autolite (that's why the APP3924 plugs don't fit), it was supplied by Denso, formally known as Nippondenso.

Denso p/n is PK16PR-L11

 

[chrism3784]

I use the correct autolite iridium, gaped correctly, and works great. I can cruise and remain at 7,500 rpm for any length of time, and ignites everytime, no problem, no misfire ever. Denso plug same thing, worked great. Any "platnium" plug I ever used fouls out at 4,000 rpm and unable to bring the engine at all past 4,500.

I even use the correct iridium plugs on my 95 3.8 sable wagon with very satisfactory results. I get 28-30mpg cruising on flat ground in calm winds at 65 mph. My manual sho doesn't even get those milage ratings. I get abt 24 at 65 just cruising. Seems to get better the warmer the air.

 

[Sholovenothate]

Always Motorcraft for me.

 

[sho4life]

I have bosch +4 and my car is running like crap under a load now. I checked a plug and they look fine but I will listen to the experts and get motocrafts. They only had 8k before they started acting up.

 

[Ex3Cutioner8]

i have been running E3 they work great.

 

[wjayg]

Motorcraft

I bought my first MTX SHO on 9/8/2009 w/ 95537 miles, did the struts, oil and tranny, changed the fuel filter and took her on a 1200 miles trip to Mt Rainer. She purred like a kitten but when I got back I pulled a spark plug and the oil was filled up to the resisitor on ever plug. 20 year old plugs and 20 year old spark plug wires. I bought (6) new AGSP32PP and a ford service manual from Don Donelson, did the upper 60k and replaced the spark plug wires. I figured if the original set went almost 100K and the car ran perfectly w/ oil filled in the spark plugs I should go back with AGSP32PP