And OS isn’t even true ABC! True ABC - if done properly - can easily out-power a ringed engine simply due to superior piston sealing if all else is equal. True, a piston ring will freshen up a ringed engine, but a simple liner pinch can bring an ABC engine back to life if you cannot machine a new piston (what really wears out in an ABC engine).

My favorite engine constructions in order of greatness in my book:
Ferrous Iron/Steel, AAC, ABC, Thunder Tiger ABN, Dykes ringed, and lastly traditionally ringed.

I sold many of my ringed engines, and the ones I have that could be converted to ABC were. I have a few ringed engines that I’ll keep as they are because they’re so stupidly reliable (they all have Bowman rings installed and a spare Bowman ring for each.. I’m a hoarder. )

Yeah, it’s hard with some of the bigger engines. I found out a piston and liner from a Tiger Shark .52 fits in a Super Tigre G51 flawlessly. The ports just need a little work to line up correctly, but the engine runs just as well as the original ringed version did despite being a true .46 now instead of a .51 or .52. It just takes some messing around with parts from a few engines to find something that could work.

Here’s some pics of my G51 ABC conversion.

The Tiger Shark engine has some parts that seem to be machined from Butter or possibly Lard. When I received it (in a box of 20 some engines), the big end was egged out so badly, you could have drilled it square and pressed a new bushing in. The crazy thing is, the engine had only run maybe a tank or two.

So I took another parts engine apart and stole a rod from it (46FX with peeled liner) to put in the TS .52. I ran the TS once and found the bearings to be bad, so I set it aside until I messed around with the G51 and found the parts fit. So the G51 is mostly Italian, a little China, and a dash of Japan.

I am getting rid of anything OS other than the FP .10 I have that’s getting a Duratrax ABC piston and cylinder intended for a OS .15 car engine. It’ll basically make the FP a .12 with true ABC. Then I can grind the OS off and stamp it something better.

I don’t like ringed engines. I have the original parts should the Chinese/Japanese crap fail, though.

And really - the G51 isn’t anything special. The GS45 is a stronger engine in every sense - which I have a few of as well. If I had to choose one engine between a G51 and a GS45, I’d take the GS45. Then there’s the Como .51 ABC SCH which I have one of. I haven’t run it yet, but initial evaluations say it should be a good and strong runner as well. A little summertime nitro burn-off is in order I suspect.

Preference is preference. That’s all.

Since OS does such a poor job of supporting their older engines many folks have been using Magnum replacement parts. Readily available and priced well below an OS mortgage, the Magnum parts usually work well, at times even better than OS OEM.