Shop Floor Talk  

Go Back   Shop Floor Talk > Welding and Metalworking Forums > Mechanical & Electrical

SFT Search:   
Thread Tools Display Modes
Old 06-12-2013, 11:50 AM
digger doug's Avatar
digger doug digger doug is offline
Join Date: Jan 2008
Location: NW Pa
Posts: 14,033
Default O.K. To run a N.G. genset on propane ?

I picked up an onan 30 kw (or so) genset with a 300-6 ford engine.

Set up for N.G.

I don't have enough gas to run it, but have a nice big propane
tank sitting idle (350 gallon or so).

Can I run it full power ? or would there be some timing/compression
changes made for N.G. that propane would damage the engine ?
Reply With Quote
Old 06-12-2013, 12:07 PM
Windy_Acres's Avatar
Windy_Acres Windy_Acres is offline
Chairman of the Headboard
Join Date: Jun 2012
Location: Northwest Illinois,.. the land of Fat Greasy Pancakes
Posts: 6,388

I think the propane has more BTUs, if that helps you work your way through the problem. Like 10% ish more, its not allot. I dont think any changes are required, other than watching the heat.

Im not a "genny" guy, but I do play with them. Doesnt Gerry know allot about them, I remember somebody here has genny experience.
Whiskey bottles, and brand new cars, Oak tree you're in my way....
Reply With Quote
Old 06-12-2013, 01:07 PM
RED caddy's Avatar
RED caddy RED caddy is offline

10-28-1951 to 4-19-2021
Da Chief
Join Date: Aug 2004
Location: Venice, Florida
Posts: 5,556

In my experience, if the engine is optimized for NG, it may well run lean on propane. (higher engine temp, lean popping/hunting at idle) Propane has more BTU's available (by volume) than NG, but will make up a good bit of the difference with gasoline, if the compression ratio is raised and the timing is advanced to take advantage of the higher octane rating (115 to 135 RON) of propane.

There are a couple different way's to run an engine on LNG and LP, depending on how your's is setup, it could be as easy as a jet change or a pressure/flow adjustment to the gas generator/atomizer. (assuming your's is not a dual fuel rig)

The tech at your local propane dealer might well be a good source if advice, most of those guys I have dealt with have a wide experience base and at least some knowledge of automotive applications. (like yours)

A 160 MPH drive, down a 2 lane blacktop, all by yourself, is NOT anti-social behaviour... I drag race because football, baseball, and golf only need ONE ball. Paul.

What I really need to know is, WHEN DOES THE SHOOTING START?

Last edited by RED caddy; 06-12-2013 at 03:42 PM. Reason: I'm soooo confused...
Reply With Quote
Old 06-12-2013, 02:28 PM
Ironman's Avatar
Ironman Ironman is offline
Iron Modification Investigator
Join Date: Feb 2008
Location: Warburg, Alberta, Canada
Posts: 16,697

The NG regulator is probably a Garret or Impco, and they have springs to change for NG or Propane.
Propane contains 2.77 times more energy than NG or 1 cubic foot of propane contains 2,516 BTU and 1 cubic foot of natural gas contains 1,030 BTU. So the orifice in a furnace must be larger for NG than propane and the pressure is a little higher in pane. In the generator engine application there are no orifices, but the regulator must flow the right amount or you will run lean if at all, like RED said.
You got freedom of speech, if you don't say too much.
Aaron Neville.

When a liberal screams racism, you can bet they were also born with white skin.

The countries whom the gods would destroy they first make green. Rex Murphy
Reply With Quote
Old 06-12-2013, 02:41 PM
moe1942's Avatar
moe1942 moe1942 is offline
Voice of Experience
Join Date: Jun 2004
Location: Alexandria, Louisiana
Posts: 11,236

Different jet generac came with both jets..more BTU's in propane.
Don't pick a fight with an old man. If he is too old to fight, he'll just kill you... John Steinbeck

"If we ever forget that we're one nation under God, then we will
be a nation gone under". ~Ronald Reagan

We should have picked our own cotton...

I love my women hot and my beer ice cold..
Reply With Quote
Old 06-13-2013, 06:04 AM
digger doug's Avatar
digger doug digger doug is offline
Join Date: Jan 2008
Location: NW Pa
Posts: 14,033

Thank you everyone for all the info. yes it's an impco regulator.

My concern was that maybe the compression ratio was upped
for the lower fuel value N.g. and when I would run propane,
I would have major kocking problems.

I assume setting lean/rich is just the same as with gasoline ?
Lean out till stumble, crank open till rich stumble, set in middle ?
Reply With Quote
Old 06-13-2013, 09:04 AM
Bolt Bolt is offline
Elite Member
Join Date: Oct 2004
Location: Texas
Posts: 1,267

I've done this on a genset powered by a 350 chevy. We put on a impco vaporizer, which draws liquid from bottom of tank and runs it through water from the water pump and vaporizes the liquid. I don't recall rejetting. It has since been swapped back to natural gas, with no problems.
Reply With Quote
Old 06-14-2013, 07:46 AM
Bender's Avatar
Bender Bender is offline
One Lone Sub
Join Date: Nov 2006
Location: Nampa, ID
Posts: 5,068

Originally Posted by Ironman View Post
Propane contains 2.77 times more energy than NG or 1 cubic foot of propane contains 2,516 BTU and 1 cubic foot of natural gas contains 1,030 BTU.
Wow I knew there was a difference but I didn't realize how much.
Boise Paint Contractor
How fortunate we are!
Reply With Quote
Old 06-14-2013, 07:28 PM
wtom24 wtom24 is offline
Junior Member
Join Date: Dec 2006
Location: Western Tn. Martin
Posts: 14
Default Impco

The Impco mixers are set up to deliver the proper air/fuel ratio with natural gas at atmospheric pressure or propane at minus 1.5 inches of water. Dual fuel engines have 2 primary regulators-one for each gas. No other changes should be needed. A 350 gallon tank should have enough surface area for vapor withdrawal if the outdoor temperature is not too cold.
Reply With Quote
Old 06-15-2013, 07:24 AM
tnmike's Avatar
tnmike tnmike is offline
Sultan of Scrounge
Join Date: Feb 2009
Location: NE TN
Posts: 4,101

I did not realize there was such.a difference in BTU's either. I learn something every day on this site.
Buy it cheap and stack it deep
Klaatu barada nikto
Reply With Quote

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

Forum Jump

Web Search:

All times are GMT -5. The time now is 05:00 AM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2022, vBulletin Solutions Inc.