Hi guys, with regards to detonation what exactly would happen to an engine that has higher compression piston in it if you ran regular octane mogas in it?
The story: I have an RV4 with a O-320 E2D in it. This engine only has the low comp pistons in it (maybe) resulting in 150hp. The engine was rebuilt at sometime a few owners back but the paper work is sketchy at best. The last owner only ran avgas in it because he thought that maybe when the motor was redone they upped the pistons to the high comp ones. Again, this was just his theory.
I only have about 12 hours on the plane since i bought it and it has ran perfectly on avgas. Today on a whim, i added about 7 gallons of mogas (reg octane) to each tank to top them up. I was planning on running this plane on mogas (150hp) but thought i would ease into it to see how the engine reacted.
I'm not sure if it was my imagination or not but i thought i got around 100rpm less static rpm on takeoff although it was a little colder then normal and I have not established a solid base line for this. Also the engine seemed to have a slight miss at around the 2300 rpm setting in cruise, again not there before. It was fine at higher rpm's. Finally, i have a climb prop on it and in the past was always able to push the rpm beyond redline at max power, today i was lucky to achieve 2700 rpm.
Could all of these or some of these issues be a result of a roughly 50/50 mix of avgas and mogas in a high compression piston engine? Or again, just my imagination? what exactly does detonation sound like? Is there anyway of figuring what compression pistons your engine has? Again no paperwork.
Even in a low comp engine would you see these issues just because you ran car gas instead on Avgas?
So basically i'm after what i should be looking for or seeing if i'm indeed running regular octane car gas in a high compression O-320.
Cheers
Wade
The story: I have an RV4 with a O-320 E2D in it. This engine only has the low comp pistons in it (maybe) resulting in 150hp. The engine was rebuilt at sometime a few owners back but the paper work is sketchy at best. The last owner only ran avgas in it because he thought that maybe when the motor was redone they upped the pistons to the high comp ones. Again, this was just his theory.
I only have about 12 hours on the plane since i bought it and it has ran perfectly on avgas. Today on a whim, i added about 7 gallons of mogas (reg octane) to each tank to top them up. I was planning on running this plane on mogas (150hp) but thought i would ease into it to see how the engine reacted.
I'm not sure if it was my imagination or not but i thought i got around 100rpm less static rpm on takeoff although it was a little colder then normal and I have not established a solid base line for this. Also the engine seemed to have a slight miss at around the 2300 rpm setting in cruise, again not there before. It was fine at higher rpm's. Finally, i have a climb prop on it and in the past was always able to push the rpm beyond redline at max power, today i was lucky to achieve 2700 rpm.
Could all of these or some of these issues be a result of a roughly 50/50 mix of avgas and mogas in a high compression piston engine? Or again, just my imagination? what exactly does detonation sound like? Is there anyway of figuring what compression pistons your engine has? Again no paperwork.
Even in a low comp engine would you see these issues just because you ran car gas instead on Avgas?
So basically i'm after what i should be looking for or seeing if i'm indeed running regular octane car gas in a high compression O-320.
Cheers
Wade