6.8 V10 Spark Plugs for LPG & Vac Lines - Ford Truck Enthusiasts Forums



Modular V10 (6.8l)  
Sponsored by:
Sponsored by:

6.8 V10 Spark Plugs for LPG & Vac Lines

Reply
 
 
 
Thread Tools Search this Thread
  #1  
Old 01-05-2018, 06:57 PM
dwarfy dwarfy is offline
New User
Thread Starter
 
Join Date: Mar 2017
Posts: 2
dwarfy is starting off with a positive reputation.
6.8 V10 Spark Plugs for LPG & Vac Lines

Going to change the plugs and COP on our 1999 E450 RV which also has an LPG conversion due to the high gas prices here in the UK. It has only done 75k miles but it has had a minor intermittent misfire lately an being an RV I dont want it spoiling family holidays so would rather get it sorted. The help I need is:

1. Are standard plugs fine for running with LPG?
2. What parts will I need other than the plugs and COP's, if any?
3. Will I need anything other than standard tools to get to the awkward plugs?
4. What is the correct torque for the plugs? I have read previous threads and there seems to be some contradiction.
5. Last time out we had a vac leak but fortunately it was at the end of a line so I was able to cut it back and refit. Looking at the rest of them they are all starting to crack so need changing. Is there a diagram anywhere with sizes to save me measuring them?

Being UK based I need to get the parts imported so would prefer to put a shopping list together and have everything here before I start so any help would be much appreciated.

Oh and what is the easiest way to access the engine? Just climb up and lie across it?!!
Reply With Quote
  #2  
Old 01-06-2018, 09:58 AM
maticuno's Avatar
maticuno maticuno is offline
Posting Guru
 
Join Date: Nov 2003
Location: California Desert
Posts: 1,892
maticuno is gaining momentum as a positive member of FTE.
I don't know anything about the LP specific parts, but it is recommended to replace the plug boots as well. Order the Denso COPs as they are the OEM manufacturer and are much cheaper than the Motorcraft branded part.

Mid 20 ft/lbs is the recommended torque around here, with the big debate being whether to use anti-seize or not.
Reply With Quote
  #3  
Old 01-06-2018, 11:40 AM
Krewat's Avatar
Krewat Krewat is offline
Super Moderator
 
Join Date: Jul 2002
Location: Long Island USA
Posts: 38,112
Krewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputation
When you say lay on the engine, if it's an E450, doesn't it have a "dog house" that you remove from inside the cab?

1) Unknown. LPG burns hotter than petrol, and may or may not require a "colder" plug usually one step down. What I would do is, pull a plug NOW, post a picture of it, and we'll decide if it's been running too hot. The misfire could be a spark plug that's been overheated. This will also tell us what plugs are in it now.
2) Make sure the COPs come with the boot and spring, and if not, get them. Don't reuse the old ones.
3) Not really. Standard extensions should be fine.
4) Go to 21ft/lbs with nickel-based anti-seize.
5) There should be a decal under the hood with the vacuum diagram, but there will be no sizes. You should have standard sizes of rubber lines in the UK.

Out of curiosity, the LPG conversion is basically a bolted-on throttle body conversion?
Reply With Quote
  #4  
Old 01-06-2018, 11:44 AM
Krewat's Avatar
Krewat Krewat is offline
Super Moderator
 
Join Date: Jul 2002
Location: Long Island USA
Posts: 38,112
Krewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputation
By the way, Ford actually did offer LPG and Natural Gas "bi-fuel" options around 2000-2001 - my service manual for 2001 has all the maintenance procedures in it.

There is no specific spark plug for LPG or Natural Gas, it's the same one for gasoline (petrol). So the V10 running LPG seems to be OK with the standard plugs. I'd still like to take a look at one before going any further.
Reply With Quote
  #5  
Old 01-07-2018, 03:22 PM
dwarfy dwarfy is offline
New User
Thread Starter
 
Join Date: Mar 2017
Posts: 2
dwarfy is starting off with a positive reputation.
Ok so vac lines I will figure out. Yes we have standard sizes over here so once I have measured them I will replace them all with silicone like I have done on our cars.

Having read up some more I agree with you that standard plugs will be fine for running LPG. NGK do specific LPG plugs which are iridium as they apparently cope with the additional heat better. These plugs are mega bucks so probably just go with the standard iridiums from NGK which I know will be readily available over here.

Time and weather permitting I will pull a plug to check and post a pic on here.

Thanks for your help.
Reply With Quote
  #6  
Old 01-07-2018, 05:28 PM
Krewat's Avatar
Krewat Krewat is offline
Super Moderator
 
Join Date: Jul 2002
Location: Long Island USA
Posts: 38,112
Krewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputation
I used a set of Bosch plugs in my V10, because they were given to me to do a review - they've been flawless. Your Mileage May Vary
Reply With Quote
  #7  
Old 01-08-2018, 10:16 AM
rock2610d's Avatar
rock2610d rock2610d is offline
Elder User
 
Join Date: Mar 2013
Location: Wyoming
Posts: 911
rock2610d has a great reputation on FTE.rock2610d has a great reputation on FTE.rock2610d has a great reputation on FTE.rock2610d has a great reputation on FTE.rock2610d has a great reputation on FTE.rock2610d has a great reputation on FTE.
If I recall the lp motors that ford produces have harden valve seats in the heads.

the non-lp motors do not.

I assume softer seats will erode, and cause issues.

​​​I would never suggest new plugs and COPS are not a good starting point but wanted the OP to be aware of LP issues with non-harded valve seats.
Reply With Quote
  #8  
Old 01-08-2018, 11:49 AM
Krewat's Avatar
Krewat Krewat is offline
Super Moderator
 
Join Date: Jul 2002
Location: Long Island USA
Posts: 38,112
Krewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputation
It's an aluminum head, and no-lead gas, so they all have hardened seats. But there might be something different in the valves themselves. But good point
Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Running cars on LPG (propane) in the U.S.? Lauda 1997-2006 Expedition & Navigator 3 08-01-2017 10:25 PM
1999 V10 6.8L Power Issue Need Help fluffyboxerfan Modular V10 (6.8l) 4 06-27-2017 08:58 AM
Ford van Econoline E series CNG all parts free swap for gasoline parts, (Expedition, F150?) GreenMM Ford Truck Parts for Sale 13 01-07-2017 09:49 AM
Ford Escape 2001: Error Code P0401 on Petrol, but Not on LPG Gas Stu Murphy Escape & Escape Hybrid 1 04-20-2016 10:16 AM
460 loss of power gaz2313 1968-2013 Full Size Vans 4 03-14-2016 04:24 PM


Go Back   Ford Truck Enthusiasts Forums >

Thread Tools Search this Thread
Search this Thread:

Advanced Search

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

Forum Jump


All times are GMT -5. The time now is 04:54 AM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.