ORIGINAL: Ttowntoolman
Herrsavage, I agree, nothing wrong with SH engines. I also agree they like a richer tune than say an OS. I would like to ask you though, how do you check to see if an engine is used up or still good without tearing it down, short of a compression test? I simply roll the flywheel around with the glow plug in to see if there is a mechanical pinch left, or at minumum compression left. I would venture to guess that the OP can spin his flywheel all the way around with little to know resistance what so ever. Almost as if it had no glow plug left in it.
I understand your theory of lesser pinch equates to less stress on the conrod, makes good sense. I dont think the OP has anything wrong with his conrod, sounds like it has little to no pinch left.
I dont really see a difference at the end of the day.......you spend $150 on an SH based engine and it lasts 6/8 gallons. You spend $300 on an OS engine and it lasts 14/16 gallons. I dont think you could be wrong with either choice, it's a wash.
I can't imagine any engine lasting 14-16 gallons without a new rod, bearings, etc.. Again, new for new, with equal maintenance, I don't think an OS is going to last longer than an SH.. Just my opinion though. In fact, I hear pretty often that OS - great engines that they are - require quite a bit in the conrod, rebuild, bearings, etc.. dept.. to last..
As for how I check, I just run them til they don't run well anymore.. Never really had any die.. A couple Sportwerks .26's got difficult, so I just sold them for spares(they each got a good six though I would say...) But three Machs, an LRP Spec 3, and a Dynamite Big Red 28 all got about eight-ten gallons on them with no issues.. Also currently running a Losi 454 and LRP 30X now, and they run great..