Go Back   Jeep Garage - Jeep Forum > Modifications & Enhancements > Performance Modifications

Join Jeep Garage Today
Reply
 
Thread Tools Display Modes
 
  #1  
Old 12-16-2010, 05:44 AM
Member
My Jeep: 2007 5.7L WK
 
Join Date: Nov 2010
Location: Rome
Posts: 48
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 1375
Blutarsky is on a distinguished road
LPG modding & Valves Tearing?

Hi there guys, I'm running my HEMI 5.7 on LPG and little worried about the valve tearing risk.


Here in Italy there’s a kind of never-ending debate about using LPG as a propellant in HEMI 5.7 engines.



As you may know, LPG is being described as a non-liquid propellant, that apparently has only a unique drawback: valve lubrication.


That is, some engines may suffer from using LPG as a unique propellant, narrowing down valves and seats lifetime; some cases are reported here in Europe about some engines using LPG, tearing down valves after only 30.000 Km. Other engines are being reported to be fully functional after 400.000Km running uniquely on LPG.

Critical factors about using LPG as a propellant, seem to be:
- Global engine mileage
- Engine RPM, where high RPMs engines seem to suffer more
- Engine power, where weaker engines will suffer more
- Valves and seats alloy; tougher or weaker alloys may be crucial, due to exposure to higher temperatures

Having said so, we where wishing to hear from you about this particular propellant usage.


Great if someone could witness it's experience after a long-mid term usage on LPG...
__________________

__________________
Reply With Quote
  #2  
Old 12-16-2010, 07:53 AM
StoneCold's Avatar
Senior Member
My Jeep: 2000 4.7L WJ
 
Join Date: Feb 2010
Location: Bankfoot, Scotland
Posts: 3,204
Thanks: 8
Thanked 27 Times in 26 Posts
Rep Power: 153374
StoneCold has a reputation beyond reputeStoneCold has a reputation beyond reputeStoneCold has a reputation beyond reputeStoneCold has a reputation beyond reputeStoneCold has a reputation beyond reputeStoneCold has a reputation beyond reputeStoneCold has a reputation beyond reputeStoneCold has a reputation beyond reputeStoneCold has a reputation beyond reputeStoneCold has a reputation beyond reputeStoneCold has a reputation beyond repute
Garage
Re: LPG modding & Valves Tearing?

First I've heard of this. There are a number of high mileage Jeeps (usually XJ's and WJ's) over here that have been converted. I also know of a couple of Subaru Imprezas that have been done and none have had any issues.

I ran a converted XJ 4.0 about 6 years ago with no problems whatsoever. That said it could well be different story with the Hemi, but that said if the boxster engine in the Subaru copes fine (and it's quite a high RPM engine) I would imagine the Hemi would too.

The only drawback I've experienced is that it isn't as cheap to run a vehicle on LPG as it's made out. You can use upto 25% more LPG than petrol, even though it's around half the price at the pump, it takes at least two to three years to recoup your investment
__________________

__________________
Tinted tails - Custom intake with mushroom filter - Superchips performance tuned - 20" SRT reps - Alcantara headliner - Magnaflow exhaust - Roush performance tips - LED conversion - Carbon Fibre/Alcantara interior - 20% tint -Bright Jeep pedals - Matte black viper stripes - Gauge pod - Gen 3 halo projectors & HID's - Airbrushed engine bay - Mesh grille - Snakeskin green calipers and accents(inspired by DAVY27)

www.facebook.com/stonecoldpaintwerks
Reply With Quote
  #3  
Old 12-20-2010, 05:20 PM
Member
My Jeep: 2007 5.7L WK
 
Join Date: Nov 2010
Location: Rome
Posts: 48
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 1375
Blutarsky is on a distinguished road
Re: LPG modding & Valves Tearing?

There are many people converting this engine out there, however it is unknown what valve tear/recession risk is running on it...
__________________
Reply With Quote
  #4  
Old 12-20-2010, 06:08 PM
Member
My Jeep: 2002 4.7 HO WJ
 
Join Date: Nov 2010
Location: Wrexham, United Kingdom
Posts: 10
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 1352
NeilF is on a distinguished road
Re: LPG modding & Valves Tearing?

Hi,

I've not had any real direct experience of lpg on the Hemi, but it maybe worth looking into things like Flash Lube if you are worried about potential negative wear effects of running lpg.

Cheers,

Neil
__________________
Reply With Quote
  #5  
Old 12-20-2010, 06:58 PM
rvtifer's Avatar
Member
 
Join Date: Sep 2009
Location: Kosovo
Posts: 593
Thanks: 0
Thanked 2 Times in 2 Posts
Rep Power: 2398
rvtifer has a reputation beyond reputervtifer has a reputation beyond reputervtifer has a reputation beyond repute
Re: LPG modding & Valves Tearing?

There is indeed a risk of shortening the life of the valves using LPG. This is one of the reasons why the injection system always start the car on gasoline and no longer offer the option of a full time LPG like the older systems do. On some systems you also have the possibility to run on 95 % LPG and 5 % gasoline if that is a concern.

I am 34,000 on a 2006 WK HEMI (here) and have not experience a problem but I do go on gasoline once in a while.

What system are you running ?
__________________
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
4.7HO Modding questions speedyway Performance Modifications 13 04-10-2010 08:23 PM
Going to regular old valves good or bad move? 05quadratrac Grand Cherokee - WK 24 02-18-2010 10:09 AM
Modding the steering Dylans3960ccs Troubleshooting/Problems 39 12-18-2009 08:19 PM
LPG install on 5.7 Hemi / 06 Overland rvtifer Performance Modifications 14 10-21-2009 02:55 PM

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 08:21 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Copyright 2012 - JeepGarage.Org
The Jeep Grand Cherokee Owners Community