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Ideal Spark Plugs for 4.0 ?

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Old Nov 5, 2010 | 11:32 AM
  #1  
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From: AnkaraTurkey
Year: 1997
Model: Grand Cherokee
Engine: 4.0
Default Ideal Spark Plugs for 4.0 ?

I am using stock plugs which are stated on users manual but problem is, i am using LPG instead of Gasoline and this requires the tighter gap at tip. Any information? LPG has higher octane rating when compared to gasoline(actually it is not called octane for LPG but it is not important)

What is stock gap for gasoline? Which alternative brands can be used with 4.0 engine? it is 97 ZJ 4.0.
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Old Nov 5, 2010 | 11:39 AM
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I wish I could help, but I can't.

I'm curious, though, did you do the conversion yourself?
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Old Nov 5, 2010 | 11:42 AM
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mite be stupid but whats LPG?
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Old Nov 5, 2010 | 11:56 AM
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stock gap is .035.

There are special plugs you can buy for the petrol/LPG combination - do a search online, pretty sure they are manufacturer specific (non-standard)
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Old Nov 5, 2010 | 12:03 PM
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Originally Posted by shadowlm15
mite be stupid but whats LPG?
Natural gas or propane.
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Old Nov 7, 2010 | 02:26 AM
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From: AnkaraTurkey
Year: 1997
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Engine: 4.0
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LPG is liquid petrolium gas(actually liquid propane gas). my 4.0 operates on LPG. it is cheaper than gasoline.

if it is 0.035 which makes almost 0.9 mm, i need to find different spark plugs.

another question, do 4.0 have knock sensors for each cylinders?
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Old Nov 7, 2010 | 04:47 AM
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no on the knock sensors
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Old Nov 7, 2010 | 04:36 PM
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Originally Posted by gmv93
LPG is liquid petrolium gas(actually liquid propane gas). my 4.0 operates on LPG. it is cheaper than gasoline.

if it is 0.035 which makes almost 0.9 mm, i need to find different spark plugs.

another question, do 4.0 have knock sensors for each cylinders?
I think only the Renix 4.0's have knock sensors and theres only one under the intake/ exhaust manifolds on the drivers side. It uses a pezo crystal to create a pulse when detonation occurs.

Your running LP!? could you take a look at my thread and maybe give your 2 cents? I'm looking at doing a petrol/LP setup and could use some input..

https://www.cherokeeforum.com/f2/run...00-carb-64773/
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Old Nov 7, 2010 | 04:45 PM
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yea i wanna see this!
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Old Nov 7, 2010 | 04:48 PM
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From: gloucester va
Year: 1990
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i want to know the lpg conversion more like how you did it and how expensive was it i have a "90 renix motor and was tossing the idea of lpg around but dont know anything about it
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Old Nov 7, 2010 | 04:58 PM
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I too need more info. I have always wanted to run LP. More power less cost less moving parts and can be used at more extream angles. Haven't looked into it yet but now you make me want to. I have 2, 4.0 H.O.s a 95 and 99 please do a write up and give me a link. I'm tearing down the 95 soon and would love to add this to the list of mods.
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Old Nov 7, 2010 | 06:23 PM
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http://start.toshiba.com/search/inde...ane+conversion

Lots of reading/info.
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Old Nov 7, 2010 | 06:36 PM
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From: gloucester va
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can you post pics of your set up please
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Old Nov 8, 2010 | 04:42 AM
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From: AnkaraTurkey
Year: 1997
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dear friends, i will take photos and try to introduce you a LPG system.
It is better to open a new topic for that.

Originally Posted by EVcherokee
I think only the Renix 4.0's have knock sensors and theres only one under the intake/ exhaust manifolds on the drivers side. It uses a pezo crystal to create a pulse when detonation occurs.

Your running LP!? could you take a look at my thread and maybe give your 2 cents? I'm looking at doing a petrol/LP setup and could use some input..

https://www.cherokeeforum.com/f2/run...00-carb-64773/
thanks for answer. i will check your thread.
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Old Nov 8, 2010 | 12:44 PM
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Still wondering if you did the conversion yourself...

If you do start another thread please post a link here so its easier for others to follow!!
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