OT gen help(long, I know)

I bought a 30KW generator with a 3.0L GM engine on ebay. (no returns). Been running an aircooled on natural gas. I discovered that the gas company can not provide me with sufficient volume for the new one. I live in a small town and the gas company runs 4oz pressure in the whole town and I am on a 2 inch main with other customers.This is a new unit, never been run but surplus. After I learned that the gas company can't provide sufficient gas, I set out to convert it to LP (vapor)I was told that the spark needed to be retarded 6deg. I then discovered that the engine was dressed up in an EPA costume and that the timing was controlled by the ECM. I contacted the Engine outfitters ( I don't know the official designation) I was told that I would have to bring the engine in (to Oklahoma) and they would have to change the wiring harness and regulators as well as adding a vaporizer. I told them I didn;t need a vaporizer that I would be running it off vapor from the tank. They said the only certification that they had was for Liquid LP and they would have to build it to certification. I hooked it up on LP runs great, didn't set any codes on the Micky Mouse ECM. but I was told that it would possibly damage the engine if I didn't change the timing. I wasn't able to check under load . Any suggestions would be appreciated.

When working with LP engines years ago the Impco service book showed that LP engines need less TOTAL advance, but a bit more INITIAL advance. Used to have total advance limiting plates installed for this reason. Have not been around any newer LP engines, so not sure if you have a serious concern or not.

I wouldn't worry about the timing. Doubt the engine knows the difference. I worked for a MM dealer. We sold new lp and natural gas engines. Never changed the timing. But did have to open load screw for natural gas.

I don't think you will have a problem. There are systems out there that will switch fuel systems. If one system fails.They work just fine. I think that shop is just trying to talk you into spending money. All a vaporizer does is convert liquid to gas. Which you already have coming from the tank. What brand is the generator.

The generator head is a Mecc Alti. The engine is a GM 4cyl electronics ,Auto start etc. is Deep Sea. No housing. have it in a shed.

I doubt natural gas main pressure is 4 oz. They usually run at 50 lbs. Indoor pressure downstream of the regulator is 6". Way more than 4 oz.

Modern engine control systems monitor for spark knock, and pick up levels of detonation that are beyond hearing. Because of that, modern engines run the advance on the edge of pinging, because if the ECM senses it, it backs the timing down until it stops. In a constant load setup like a generator, doubt you will have an issue. Main concern from the company's point of view is it is not EPA certified to do what you are doing. Doesn't mean it won't be fine, just doesn't have the blessing of the EPA. You know, the same organization that dumps mine waste water into a rivers.

Since the timing is controlled by the ECM, the only way to change it is to reprogram the ECM. Good luck on that one.
However, there are a few other thing to take into account. First thing is that there may not be as much difference in the fuel as you think. Second is that timing may not be that critical. You only have it on hearsay that it should be changed. Knock sensors are an amazing thing. Third is that I also question the availability of the gas volume for the natural gas.
Two years ago, our local gas company came through and upgraded and lined all of the gas lines in my neighborhood. I had the opportunity to talk to the men doing the job. What I learned is that they run 50 to 60 psi in the 2-inch mains. This pressure is maintained all the way to the meter, where it is regulated before entering the meter. Since appliances that are designed to use natural gas seem to be universal, I would think that the gas pressure is set to a STANDARD, and is therefore compatible throughout the entire country. Likewise with appliances set up to use LP or propane.
I see very little potential for long term engine damage. My suggestion is to use it, enjoy it, and don't believe everything that you are told.

Mr. Pat, please read what Mr. jimg allentown wrote. He has it exactly right.

I posted my reply to Mr. Pat before I read all the comments. I agree with all answers. The knock sensor is going to handle any problem if there is in fact a problem. Liquified Petroleum Gas is about 105 octane. Or was forty five years ago. It's a little harder to make that knock than 89 octane gasoline and I doubt that the generator engine was designed and built for LPG. Steve Norwood Banner Ms.

Most mult-fuel generator manuals will plainly state that you will only get about 90% of rated output with natural gas, because there is less energy in a cubic foot of it than in a cubic foot of propane or of vaporized gasoline.

Timing is not an issue. Even if it was, there is enough wiggle room in the electronics to handle various grades of gasoline (at altitudes from 0 to over 6,000'), including the 'ethanol added' carp which reduces fuel energy density. The GM electronics will take care of timing, regardless. No worries.

You'll also find that engines run on propane have the cleanest spark plugs. It's amazing.

In regard to knock sensors and the ECM I'll add this. A few years ago I changed the timing belt on the wife's '02 PT Cruiser. I unknowingly managed to get the timing belt on 1 tooth off. The engine fired and ran just fine, and didn't show any problems except a slight knock at higher RPM's. When I finally got my FIL's scan tool and hooked it up to see what the problem was (before I knew the belt was off a tooth), it was showing the engine running with more than 20 degrees off. It amazed me that it the sensors would show that many degrees off, but the ECM had no problem compensating for it.

Run as is. LP has lots of octane. If the spark map is over advanced the signal from the knock sensor will make the ECM retard the spark. The genset will be operating at part load so detonation is a minor concern.

I would re-check the utility gas pressure. Usually it is measured in PSI on the utilities lines, and in inches of water column downstream of the regulator. Most appliances look for 7-10 inches WC
Pete

I agree with the others.... the ECM will compensate and adjust the timing as necessary. If it runs find and don't knock now... just run it.

Rod