Spark plug reach?????

[anthonygubbin]

Hi Guys after some searching nothing answers my question. I have bought some plugs but the reach is different to the ones in it. There are 3 different NGK plugs listed and no specs available. The ones in it are Bosch but dont match the correct part #. I just got some Autolites double platinum but they are longer. Also unless the book is wrong they are the right reach, even though they are longer. Can no one sell me the right plugs for my XJ?
I want different plugs to the RC12LYC's listed under the bonnet. If I use the longer reach am I likely to hit a piston or something. Someone else on here was told to use longer plugs by whom I do not know.
Please help, cause this is driving me crazy.

regards A

[Deezelweazel]

There are a couple of plugs and depending on model and age they have to insert different plugs.

eg.: all Bosch numbers:
88-90: FR 7 DC+
until 93: FR 8 HC
00-01: FR7 HC+

so you need engine and built age
F is M14 x 1,25
R is special application
7 is hotter than number 8
D is thread length 19mm
H is also 19mm, but longer inner insulator of 7mm instead of 3mm
C is copper

[Doctor W]

There are a couple of plugs and depending on model and age they have to insert different plugs.

eg.: all Bosch numbers:
88-90: FR 7 DC+
until 93: FR 8 HC
00-01: FR7 HC+



So what Bosch plug is used for 1993 till 2000?

Also, I've found that no one seems to make a direct OEM replacment for the Champions......

I've also read in a few places that Platinum and Double Platinum and Iridium plugs are either not suitable or unnecessary for the 4.0.......

I know you are a professional military mechanic as well as a Jeep nut and even though your specialty is diesels, I would be very interested in your thoughts/opinions on sparkplugs for the 4.0 (of different years - although here in Oz we only got the '94 and later versions.

What opinions on Platinum, Double Platinums and Iridiums as opposed to the standard Cu plugs recommended by Jeep????

[anthonygubbin]

So mine is the 9/98 build with a 4.0 the what plugs can I use, besides Champion?

Regards A

[anthonygubbin]

So mine is the 9/98 build with a 4.0 the what plugs can I use, besides Champion?

Regards A

Looks like I only have a choice of standard plugs as nothing will cross reference by the looks of it. So I reckon I am getting the ZFR5N NGK's.

regards A

[Deezelweazel]

So the truth is: Bosch does not fabricate any spark plugs for the XJ between 93 and 2000.
You have to use the Beru numbers:
Z248 or 14FR8HUT

if you are using LPG you need different plugs:
Z225 or 14FR7HUX


I do share the standard opinion that those fancy Bosch platinums and the Split fire or Iridiums (they are very good for VW 's and other high compression vehicles like the Honda V-TEC's) are not that ideal for the XJ.

Standard copper electrodes are absolute ok. No need to go overboard and to throw money out of the window. In the US it might be ok to buy platinum because they have a competive price, but everywhere else they are expensive and simply overkill. You need a spark and you get it- that's it.

[tazwegion]

Hi Guys after some searching nothing answers my question. I have bought some plugs but the reach is different to the ones in it. There are 3 different NGK plugs listed and no specs available. The ones in it are Bosch but dont match the correct part #. I just got some Autolites double platinum but they are longer. Also unless the book is wrong they are the right reach, even though they are longer. Can no one sell me the right plugs for my XJ?

I though you were happy with the Platinums (http://www.ausjeepoffroad.com/forum/showpost.php?p=1160071&postcount=17) in your XJ (and their performance), if you don't mind me asking what changed your mind? :confused:



So the truth is: Bosch does not fabricate any spark plugs for the XJ between 93 and 2000.

According to Bosch Australia's PDF product chart seen HERE (http://www.bosch.com.au/content/language1/downloads/Spark_Plug_Australia_Web.pdf), their FR9HC (standard) & FR8HP (premium) are specified for the 4.0L Cherokee 1990~2004 (pre-KJ) :mrgreen:

[Deezelweazel]

Maybe I should have added : for the german market:rolleyes:

Interesting- why does Bosch (german company) split the german market into models and years and does not deliver the years in between??
Think about it....

[anthonygubbin]

I though you were happy with the Platinums (http://www.ausjeepoffroad.com/forum/showpost.php?p=1160071&postcount=17) in your XJ (and their performance), if you don't mind me asking what changed your mind? :confused:





According to Bosch Australia's PDF product chart seen HERE (http://www.bosch.com.au/content/language1/downloads/Spark_Plug_Australia_Web.pdf), their FR9HC (standard) & FR8HP (premium) are specified for the 4.0L Cherokee 1990~2004 (pre-KJ) :mrgreen:

It was time to change the plugs and a guys was trying to sell me some different ones, which has me all over the shop. I was sure that the Bosch ones I got 2 year ago were right now I am not sure. It was running alright but the gas installer suggested I change them. For now they can stay in, I got other bigger problems.

A

[tazwegion]

Maybe I should have added : for the german market:rolleyes:

Interesting- why does Bosch (german company) split the german market into models and years and does not deliver the years in between??
Think about it....


I don't know... I never shop in the German marketplace (not even on eBay), perhaps you'd like to enlighten us all on what you were alluding to? :confused:


It was time to change the plugs and a guys was trying to sell me some different ones, which has me all over the shop. I was sure that the Bosch ones I got 2 year ago were right now I am not sure. It was running alright but the gas installer suggested I change them. For now they can stay in, I got other bigger problems.


Worn plugs will lead to ignition break down and back firing (boom goes your airbox) not nice :(

[anthonygubbin]

I don't know... I never shop in the German marketplace (not even on eBay), perhaps you'd like to enlighten us all on what you were alluding to? :confused:





Worn plugs will lead to ignition break down and back firing (boom goes your airbox) not nice :(

Yerr will get them in two weeks my HB has gone.

regards A

[tazwegion]

Cheap? the last set of NGK FR5-1's I got for my XJ (from Supercheap Auto) were a couple of dollars each IIRC, the V-groove core tip provides increased surface area (for the spark) :mrgreen: