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Plug Change

90K views 180 replies 65 participants last post by  digisky 
#1 · (Edited)
Do not let your dealer charge you for dropping the motor to change your spark plugs when the time comes at 30,000 miles

I was able to remove and re install the center plug in less then 10 minutes including taking several photos (click for larger version)




First push DOWN on the "T" shaped release and remove the electrical connector from the COP assy




The using a 10MM open or boxed end wrench loosen (counter clockwise) the bolt on the right holding the COP to the cylinder head. Be careful to not drop the bolt as it is a bugger to find..(ask me how I know...grin)

The COP has a Long boot that is about 5.5" long below it attaching to the plug. Lift it up and as you remove it angle to your right and come up below the back lip of the engine compartment to the rear. It will not come out of the hole angled up and toward the front of the car.

Using a 3/8ths drive Locking ratchet, a 3 inch long 3/8ths drive extension and a 3/8ths drive 5/8ths PLUG socket with plug holding rubber insert break the torque counter clockwise.

I needed about another half turn loose to then remove the ratchet and finger loosen the plug all the way out of it's hole.

The plug, socket, and extension is removed the same up/right/and below rear lip route as the COP.

Two cautions inserting a Plug....

do NOT drop the plug/socket/and extension down in the hole...you will crush the electrode gap or break the ceramic insulator...most crush washer plugs are tightened 1/4 turn after bottoming

The COP boot is spring loaded. When you put the COP back on it will not want to seat and stay there... once in ...carefully insert the retaining bolt and get it started in it's hole a few turns...now push down the COP all the way over the plug and finger tighten the bolt with other hand. Using 10mm wrench snug up tight but do NOT crank down on it...this is a low torque 168 inch pound (14Ftlb) bolt and there is not real good room to use a torque wrench
 
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#9 ·
digital Photos and my poor white balance control do not translate well on a monitor... By eye, in bright sunlight, the plug has more carbon and burnt oil on it then I see on my other low mile motors

There was zero White / Grey ash any where in/on this plug

Denso XU22HDR9.... on insulator ceramic
1822A009 .... Mitsubishi Motor Part Number
A 132 159 00 03.... Smart Part Number ($19.99 each from my dealer)
Denso Japan EJ + + + + +..... around the base metal ring above washer

In my opinion the motor is running slightly rich...and like a few others noticed on the early oil change.....my factory oil had a rather strong gasoline smell even with less then 50 miles on the motor

All three are same basic location and access... I did the center because it seemed to be hardest from a visual and hand/fingers point of view..I think the outer two will be slightly easier

My intent was not to inspect the plug but to prove a theory I had from eyeball

My Master Tech claimed the motor had to be dropped because the COP and plugs were to long to come out with out damage...

I am betting in the few short weeks they have been in business he has not had to do any yet... thus I assume he was taught that BS by the training teams

I wonder how may other shop hour enhancing maintenance areas are taught the LONG way...
 
#12 ·
That's the shortest plug change interval I have seen in modern cars.

A little research on the web results in this cross-reference page:
DENSO SPARK PLUGS

It appears that the car comes with the low end basic plug from Denso (not surprised). When it comes time to change mine, it appears moving up to the IXU22, their Iridium Power line, or VXU22 - their Tough line. They can yield minimal performance and fuel econ improvement, but most importantly, longer plug life (5x normal plug) in the case of the Tough line.
DENSO SPARK PLUGS - Basic Knowledge

The IXU22 seems to be $12 a piece. VXU22 is hard to find, the only place I found in Japan is about $16 a piece.

Perhaps someone will know a better place to find Denso plugs. JCWhitney is a dealer, but their Denso catalog does not list smart in it.
 
#24 ·
No cross reference

That's the shortest plug change interval I have seen in modern cars.

A little research on the web results in this cross-reference page:
DENSO SPARK PLUGS

It appears that the car comes with the low end basic plug from Denso (not surprised). When it comes time to change mine, it appears moving up to the IXU22, their Iridium Power line, or VXU22 - their Tough line. They can yield minimal performance and fuel econ improvement, but most importantly, longer plug life (5x normal plug) in the case of the Tough line.
DENSO SPARK PLUGS - Basic Knowledge

The IXU22 seems to be $12 a piece. VXU22 is hard to find, the only place I found in Japan is about $16 a piece.

Perhaps someone will know a better place to find Denso plugs. JCWhitney is a dealer, but their Denso catalog does not list smart in it.


JRyan, you need to double check your cross reference, Denso does not currenetly show an Iridium cross for the XU22HDR9 plug the smart uses. If you check the specs, the IXU22 and VXU22 are both 7.5mm shorter reach(19mm vs. 26.5mm). If you install them is a smart, the exposed threads are going to act like glow plugs, and your going to have major detonation issues. Good try, and they are close, but I just didn't want anyone buying $40 worth of plugs they can't use.
 
#13 · (Edited)
Caution slight side trail:

Old Smart and saskdiesel

Since I know both you guys let me get in this

I build a both motorcycle and small block ford and chevy racing motors as a side (cash producing) hobby. And while not a NASCAR or F-1 level tech I do have a world of practical experience... and a waiting list each season for one of my motors.

Both you guys are correct from a different perspective and I hate to see us argue the Process....

The real point is there are ways to "Read" a plug and make educated guesses about the fuel trim and cylinder health relating to rings and valve guide seals, in some cases we can see evidence of leaking intake air filtration, or a too heavily oiled gauze filter, or faulty Exhaust Gas Recirculation system

The various techniques to use the plug condition to diagnose something vary by what you are trying to detect...

When I simply want to use plug deposit color and density to tell me about fuel trim:
We start with a fully broken In motor. ON the test stand, or in a vehicle, first run is to get to full operating temp... then we insert new plugs.... 5 minutes of idle time to get plugs in their heat range soak.... then a run through all torque-loaded gear shifts up to 15~30 second duration in top gear loaded torque ( no free reving)...CUT motor and stop... then pull and mark each plug

These brand new plugs will have sufficient deposits to visually see (usually with a 3x~4X lighted mag) what we need to see to tune the ignition and fuel delivery systems....

In our quest for power (LATER) we still use the plug condition to determine if the headers, air filter, crank case breather or EGR systems are doing their thing properly...

Exhaust headers are always a compromise and many of our projects are one off adaptations to fit a vehicle... if you have all the plugs running Grey/deposit free with the test set up and the new set makes one (or more) plug soot up or (rarely) evidence of electrode erosion, then we can tell the primary tube for that cylinder is restricting flow... or (rarely) the scavenging effect from other tubes has that one sucking too hard leaning out and super-heating the exhaust valve and plug

Actually it is much More complicated because we have to consider valve lift, duration, and many other factors

Some of this is pure physics and science and much of it is ART or historical wisdom...

The bottom line is; Plug condition can tell you a lot and there are various techniques to prepare to use that information.
 
#14 ·
OK, no more.
And your right about the headers Fred.
I remember the first set I welded up when was a teenager.
That old GS motor never knew complications until I started screwing with it. To this day I only use proven exhausts as dyno runs have shown that lots are all show and no go. Well, maybe "go" if money flying out of my wallet is the only performance result.
All this is a moot point however as I am going to be buying a Smart that has no spark plugs!
 
#15 ·
Sure wish I did not have a day job some times... I would love to own a motor and chassis dyno...currently we borrow or pay for time on a local one....

Back to plugs.... there is a Brit tuner claiming some exceptional gains just in a plug change on this motor...so far Big Performance is being real coy on what plug they used and the few folks who got the mod are being equally tight lipped...

I scour several sites every few weeks to see if some one spilled the beans or cracked the code

I have a sneaky suspicion that they did four things:

I assume they noticed this motor runs a tad rich

Used one range hotter plug
Used thin Iridium or platinum tipped plug
Opened the gap way up
Indexed the Plugs so ground electrode is not shrouding the tip
 
#16 · (Edited)
... Indexed the Plugs so ground electrode is not shrouding the tip
I "sort of" tried that once with a set of "Splitfire" plugs, but didn't feel anything noticibly better. My engine consultant in the UK, Roger King Engines, had no enthusiasm for their use. I have seen others file the ground electrode to a quite narrow blade, claiming some improvement. And still others tried twisting the electrode off-axis but with no claims of sucess. In the later case they may have been contorting the flame kernel off to one side and getting an inconsistant or asymmetric burn.

In the end I found it best to spend my time and money on lots of fresh, best NGKs. In the case of the NGK "R"s, the ground electrode approached the center electrode at an angle from the side but did not crossover the top and "blind" it. They wouldn't last long enough for passenger car use.

 
#17 ·
Looking forward to more info...

on what the hot plug to install will be. I am sure that there will be one other than the one shown by Fred. I have always gotten great performance, gas mileage and spark plug mileage from platinum tipped plugs or maybe even a more advanced type than that will be available by the time our smarties get 30K miles on them.

John
 
#18 ·
Indexing plugs or using the expensive multi spark pulsars can be seen on the dyno as a 2-5HP adder ...intresting that if you do both there is no added gain

Mostly we screw with these meager yield techniques simply as a way to optimize every system we can.. in the search to eek out every possible advantage or simply to keep on PAR with the other tuners

I have spent the time to do some of the techniques on my private car, motorcycles and trucks... no measurable gain at the BUTT or gas pump with any single mod but I can report that a combination of the correct intake, exhaust, fuel delivery, and spark control can all add up to 7~15 extra ponies and modest increase of MPG

Unfortunately these increases are all on 3L or larger motors...on my 1.3L motor cycle motor the gain is too minuscule to really tell

I am too new with the Mitsubishi design to know if there is really any factory inefficiencies that we can exploit... in my experience the last 7~12 years the factory guys are doing a great job of eking out max performance from the get go... the days of finding 20% or more out of a factory motor are mostly behind us

This of course is an observation from a mechanical engineering point of view... I am keenly aware that the world of computer mapping the various control curves has a lot of potential to optimize the power band

Also note... it is a good thing that at least one of the two O2 sensors is the Bosch Wide band version
 
#20 ·
The normal 02 sensor is a low tech and low cost device with a 0 to 1 volt range of change...and the individual points between 0 and 1 volt are few so it is a course calibrated device

Some years back Bosch developed a Wide Band sensor that out puts 0 to 5 volts and because there are more discrete steps from rich to lean it is a finer or closer calibrated unit

With more precise data, the ECU can be programed to have many more steps in it's mapping curve.. thus being more precise in it how it manages the ignition timing, valve phasing (we have variable intake valves), and fuel injector timing and pulse width

The motors, with the more expensive sensors can stay longer in the best optimum fuel air ratios to maximize power and fuel efficiency

The second "down stream" O2 sensor is ALWAYS part of the health check for the catalytic converter and almost always a narrow band lower cost sensor
 
#25 ·
I have a sneaky feeling that the Denso XU22HDR9 plug and the Mitsu 3B20/3B21 engines are unique to each other. BTW, the "22" heat spec of the XU22HDR9 is the third hottest in the range behind "16s" and "20s."

NGK does not make any plug for the 451 either, only plugs for the 450 gassers (LKR8A).
 
#26 ·
Old smart, I think your onto something, I've been doing a lot of research, and cannot find a cross for the Denso plug from any other manufacture. I did find what appears to be a cross from Denso to an Iridium plug, their P/N SXU22HDR8. Only difference is a .8mm gap vs. a .9mm gap, but that should be adjustable. I haven't tried to locate anyone who may have these yet, but the plug specs match. I would really like to locate either a platinum or Iridium plug for longer life.
 
#28 ·
Looks awfully closed or shrouded to me, that's not a good design. The arc needs to be as much in the open as possible and should be as near to a straight line of sight open to the intake valves as can be. I'd bet these would actually produce less power and economy than the stock plugs.
 
#29 ·
Oil Change Interval feels wrong.

I am working on getting more information on the engine oil intervals etc. I am going directly to Mitsubishi using a Japanese contact. I will let everyone know what I learn.

So far I can tell you in their cars they recommend changing the oil every 7500 miles no more than that. In heavy stop and go they informed me they suggest no more than 5000 miles at most.

I find it curious that the smart has one of their smallest engines yet it is suggested by smart to do a 10,000 mile oil change... (I smell something fishy)

My gut is telling me to do oil changes every 5000 at most on the smart.

I will share if I learn anything new. Translation from Japanese to English and back can be a challenge. Something just doesn't feel right about the intervals that smart suggests.
 
#30 ·
oil

I am working on getting more information on the engine oil intervals etc. I am going directly to Mitsubishi using a Japanese contact. I will let everyone know what I learn.

So far I can tell you in their cars they recommend changing the oil every 7500 miles no more than that. In heavy stop and go they informed me they suggest no more than 5000 miles at most.

I find it curious that the smart has one of their smallest engines yet it is suggested by smart to do a 10,000 mile oil change... (I smell something fishy)

My gut is telling me to do oil changes every 5000 at most on the smart.

I will share if I learn anything new. Translation from Japanese to English and back can be a challenge. Something just doesn't feel right about the intervals that smart suggests.
That's the fleece filter and synthetic oil talking, 10000 miles. That is simply an MB thing.
 
#32 ·
I need to find data on the COPs

I personally think 0.035 gap is too narrow

I run 0.045 on my bikes and 0.052 on my V10 truck

BUT all that depends a LOT on hot much oomph the coil packs have

This is a 4 valve head with spark dead center and flat top pistons... a hemi if you will

I will be experimenting with indexing (thanks Mitsubishi for the flat seat plugs) and I will probably open the gap to 0.040 and see if it throws any misfire codes

I have searched every way I know how and sent contact us mails to several plug company searching for a replacement (I personally like MotorCraft and Autolite (same manufacturer))

Any one notice how the XU22HDR9 does not decode properly on the Denso site's Plug specification page?

XU=12mm (thread) x 16.0mm (hex socket)
22= heat range
H= Reach 19mm or 26.5mm???
D= Quadruple ground electrodes???
R= resistor?
9= 0.035 gap

DENSO SPARK PLUGS
 
#34 ·
oil changes more frequently are just a waste

Thats why we have an oil shortage... waste not want not....

I have never had a car that burned oil or failed prematurely. Conventional oil every 5000 and synthetic every 10,000. And I have had everything from gas to diesel, economy to luxery, sport to hot rod, van to suv....

Anything more often than that on changes is just simply waste. Amsoil even recommends 25,000 mile changes with their synthetic oil. Never tried theirs out of convenience or lack of convenience, due to their independent dealer network.

I'll be following the 10,000 mile recommendations.

:cool: :smartje.zw.zw:
 
#35 ·
oil

Thats why we have an oil shortage... waste not want not....

I have never had a car that burned oil or failed prematurely. Conventional oil every 5000 and synthetic every 10,000. And I have had everything from gas to diesel, economy to luxery, sport to hot rod, van to suv....

Anything more often than that on changes is just simply waste. Amsoil even recommends 25,000 mile changes with their synthetic oil. Never tried theirs out of convenience or lack of convenience, due to their independent dealer network.

I'll be following the 10,000 mile recommendations.

:cool: :smartje.zw.zw:
You and your wallet can certainly do as you please. I'lll bet Amsoil doesn't pay for blown tiny motors at 25000 miles. THERE IS NO OIL SHORTAGE.
Again, in my opinion. Enjoy.......
 
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