Running Propane - Help with Timing

Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic

   Hi all,A bit of background:

I'm running a 360 in my 1991 Jeep Grand Wagoneer. It's just had a full rebuild after cam bearing failure and other issues. It has been bored 0.030" over and everything is stock except a Melling MTA-1 "RV-style" cam. 

I'm running the original Motorcraft 2150 carb with an unknown propane mixer bolted on top.
The distributor is the original Ford Motorcraft one, currently set to 10 degrees base timing. 

Now that it's back and running, I'm concerned that in might be pinging whilst running on propane. 
It runs and idles great, and 99% of the time it's fine. 
Occasionally it will make a rattling noise when it hits a certain engine speed whilst accelerating reasonably hard up a hill in 1st gear. The noise continues until I back off or it shifts into 2nd. 

It doesn't do this if revved when parked, and it doesn't do it in any other driving conditions. 

I guess I have two questions:
-Is the noise I'm hearing likely to be pinging?
-What should I be setting my timing to to run on propane?

Author	Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic
Brynjaminjones Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Apprentice Joined: Sep/27/2017 Location: Derbyshire, UK Status: Offline Points: 55	Post Options Post Reply Quote Brynjaminjones Report Post Thanks(0) Quote Reply Topic: Running Propane - Help with Timing Posted: Jun/20/2019 at 3:44am
	Hi all, A bit of background: I'm running a 360 in my 1991 Jeep Grand Wagoneer. It's just had a full rebuild after cam bearing failure and other issues. It has been bored 0.030" over and everything is stock except a Melling MTA-1 "RV-style" cam. I'm running the original Motorcraft 2150 carb with an unknown propane mixer bolted on top. The distributor is the original Ford Motorcraft one, currently set to 10 degrees base timing. Now that it's back and running, I'm concerned that in might be pinging whilst running on propane. It runs and idles great, and 99% of the time it's fine. Occasionally it will make a rattling noise when it hits a certain engine speed whilst accelerating reasonably hard up a hill in 1st gear. The noise continues until I back off or it shifts into 2nd. It doesn't do this if revved when parked, and it doesn't do it in any other driving conditions. I guess I have two questions: -Is the noise I'm hearing likely to be pinging? -What should I be setting my timing to to run on propane?

Trader Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: May/15/2018 Location: Ontario Status: Offline Points: 6913	Post Options Post Reply Quote Trader Report Post Thanks(0) Quote Reply Posted: Jun/20/2019 at 7:24am
	Likely going to have to find the mixer information. The forklifts that we had were a simple 14 degrees initial, 14 degrees mechanical and 14 degrees vacuum. All in at 2500 or 2600 RPM. But these were fork lifts, low revving engines, and I don't remember any more the mixer they used. There were screws on the mixer for setting the vacuum to propane air fuel flow. Vacuum advance was closer to what you would call ported on a carburetor. Everything was set using a vacuum gauge. Don't know if this would help you or not?

Brynjaminjones Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Apprentice Joined: Sep/27/2017 Location: Derbyshire, UK Status: Offline Points: 55	Post Options Post Reply Quote Brynjaminjones Report Post Thanks(0) Quote Reply Posted: Jun/25/2019 at 4:09am
	Thank you Trader, that sounds similar to the kind of information I've been reading. A fairly high initial, with a lower total (mechanical) and coming in earlier than on gas. I'll be working on it towards the end of the week and will report back for reference.