Denso Iridium TT has an iridium center electrode where it counts. Its ground electrode is of Titanium-enhanced alloy... Titanium is arguably the most beautiful metal on the face of this planet, and of the most resilient as used to build interstellar spacecrafts! It is after all made in JapanScroll down further at rockauto.com:
BOSCH 9600 OE Fine Wire Double Iridium; Iridium; 0.043" Gap (Pre-gapped). @ $4.92 each.
Denso (or anybody else) does not offer a DOUBLE- IRIDIUM spark plug.
Just sayin' ;>)
Standard Pressed Steel (Jenkintown, Pennsylvania) was producing titanium aircraft fasteners as early as the late 1960s in their "HI-TI" division.Denso Iridium TT has an iridium center electrode where it counts. Its ground electrode is of Titanium-enhanced alloy... Titanium is arguably the most beautiful metal on the face of this planet, and of the most resilient as used to build interstellar spacecrafts! It is after all made in Japan
Beats me how ANY spark plug knows what country the engine came from.
I'm thinking that the person installing the plugs selected the wrong plug for his/her particular engine.
Experienced mechanics know that there is ALWAYS some monkey that wants to experiment with different heat ranges and/or plug reaches, thinking that they will improve performance -- then when it all goes to hell, they blame the plug manufacturer.
A couple of years ago, I was travelling in Idaho (speed limit=80) and got a "Check Engine" light.
My Actron OBD II scanner showed a misfire in #7 cylinder.
Pulled the plugs (Bosch), and they looked "bad" after only 40,000 miles. I had expected 100,000 miles, so I was pretty jacked at the plug failure !!
The mechanic was a young fellow, who said he had a lot of trouble with Bosch plugs in the same 4.6 liter FOMOCO engine.
He installed a set of Densos (at $7.60 each), which got me another 1,200 miles to get back home.
After arriving back home and investigating the situation, I discovered that I had ordered the WRONG part number for my application !!
Stupid mistake on MY part -- not a reflection on the Bosch plugs at all !
I yanked the Densos, and replaced 'em with Bosch plugs of the correct type and part number (Bosch 9605, Double Iridium). No more problems !!
Kept the Densos for spares -- ya never know !:>)
I don't have anything against Densos or NGKs, but I run a lot of Bosch parts on my '95 Mercury Grand Marquis Restoration -- Fuel Pump, In-Tank-Screen, Fuel Injectors, Plugs, Ignition Wires, Alternator, and Starter.
I use the Bosch fuel and ignition parts on the FOMOCO engine because FOMOCO uses an ignition/fuel-management system that was designed by Bosch -- similar to that used on Porche and Audi, and shared with a couple of million Ford Crown Vics, Mercury Grand Marquis, and Lincoln Town Cars.
The Bosch Fuel/Ignition system has proven to be extremely reliable over the decades, for domestic cars and Ford trucks used in fleet and police vehicles.
I don't tell others what they should buy or do -- I just tell 'em WHAT I DO, and WHY.
If employees get to fill up with 91 for the price of 87, why the hell not >You talk like there's a difference between Denso & NGK. There really is no difference. As far as running 91 over 87, 91 has much better/more cleaning additives.
At least where I've worked, Chevron Richmond refinery.:smile:
I did not get a chance to remove a spark plug to examine condition and make & model of spark plug. From all of the reading I used to do for over 10 years on Toyota 4-Runner/pickup dedicated discussion sites (Toyota Nation and about 4 others) I learned that for a Toyota vehicle Denso and NGK were the best tune up parts specially spark plugs. So if or when I need spark plugs I will buy Denso and probably the Iridium TT which as people have stated here they are the exact ones in my car (1ZZFE engine).I wonder what Sydney decided to buy?.... Hopefully not Bosch!
So the 4701 is in spec, at the smaller end, which means as they wear away they'll still be in tolerance. I bet you could leave them in for 200,000 miles and when they come out they'd be in spec under 0.051 gap but pretty worn out looking. I know on my 2ZZ I noted a HUGE difference from 30K mile Iridium IX plugs and the Denso Iridium TT plugs, the idle was incredibly smooth with the new plugs and the engine felt a good deal smoother over all when driving.Gap 1.0 - 1.3 mm (0.039 - 0.051 in)