Propane Question... NEED HELP!

Mtn Goat

Mtn Goat

Active Member
Joined
Dec 5, 2005
Location
Ellenboro NC
I am going to switch my CJ7 over to propane an I was talking to some guys that I know that own and operate a fork lift shop that does sales, service and rentals and I was telling them about the swap on the CJ7 and one of the mechanics told me that propane would distroy the valve seats if the motor was meant to run unleaded gas. I asked why and he went on to explain to me that they have a Toyota fork lift in their shop that has a Vortec V6 and they could not get it to run very well so they pulled the heads and saw that two valves were sunk into the head about .060 and the seats were as well? They took the heads to the local engine shop to have a valve job done and the owner of the engine shop took one look at them and asked first thing if those heads came off a motor that ran LPG, because he has seen this alot? So my question is, has anyone out there heard of this and is it true that running LPG on a unleaded motor will distroy the valve train???
Thanks!
 
GM Vortec 4.3 V6's have had random problems with valve seats, it's nothing new, Running on LP had very little to do with it.

There is a larger chance that the intake gasket failed causing a lean condition on the effected cylinders and caused the valves to over heat and "tulip" also taking the seats with them.

How do I know this ? I have seen it happen on both gas and LP engines, GM intake gaskets are known to be trash, and cause vacuum leaks, it happens on the Vortec 350's, and the LSx engines if you continue driving when the check engine light illuminates for a lean/rich condition on OBD2 equiped vehicles. ( not until the last few years has there been a "check engine" light on industrial equipment, emissions requirements are getting tougher on everything, ALL LP and GAS forklifts since 2004 have had catalytic converters and since 2005 have had O2 sensors before the cats.)

I have seen this issue as both a GM dealership tech ( former) and currently I have seen it as a Toyota forklift tech, pisser is, not much has been done to fix the issue.

FYI, the 4.3 Vortec engines used in forklifts are INDUSTRIAL engines, it is not the same as one you would find in your S-10 or Mom's Blazer.
There very similar, but some of the casting and bolt locations are different. ( to keep you from using them in an automotive application, they are not EPA rated for highway use)

And Toyota is not the only ones using the engine, they are in Hyster, Yale, CAT/Mitubishi, and Clark lifts. MOST all of which run on propane, how much of a valve problem you think there is ?

:EDIT: 5.7 and 4.3 VOrtec engines are also used in ZAMBONI's, as are the LSx engines and still running propane.
 
Thanks for the information on this it makes alot of since because I told that guy at the forklift shop that so many people I have talked to are running LPG and have for a long time with no issues, but even though this guy is a good guy he is a die hard GM fan. Thanks again hope you have a good New Year!
 
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