Congrats Paul on the NIB AR purchase!! And the Summit III!! What a really nice combo that will be!! I know you'll love the engine, they are fantastic... [8D]

I like Will's suggestion of swapping to the Shadel kit now and keeping the original as a spare, that may be the way to go. I'm re-thinking my position for my engines too.

Unlike my OS Hanno liners, I trust the factory AR liners...but in both instances I trust the Shadel liners more...

Here is a link to a post I made about the liner swap in the AR engine:
[link=http://www.rcuniverse.com/forum/m_9054234/tm.htm]Note: Shadel/Nelson YS Piston & Liner Installation..[/link]

Not sure if you will run into that situation but wanted to give you the heads-up just in case...


My Opinion:
You mentioned your kit comes with bearings...good. I was going to recommend swapping the bearings out from the start because the YS factory bearings are...ummm...junk in my opinion. I've decided I'm not going to run any of my engines (OS or YS) with the factory bearings anymore. They are all getting swapped out for stainless/ceramics prior to use. I have already changed several engines but still have a more to go. The majority of my acquired engines have been used so changing bearings was sorta expected. However after running a NIB AR once, finding "mud" (rusty oil) in it the next day, I made the decision to change the bearings before running. I also had that same thing occur on a YS-60 short stroke and a standard .61 LS. This occurred while using Powermaster YS 20/20 fuel which is suppose to be good stuff. YS 20/20 is no longer available so I'm changing to Cool Power MVS. I haven't run many engines with that fuel so we'll see how that goes. It doesn't really matter because I'm now hooked on the stainless/ceramic bearings. They are soooo smooth and with such good tolerances. I have zero running time with any of the ceramic bearings engines thus far but expect them to be good. I'm almost ready to get an LA-2 in the air which has my old Pink Head Hanno in it which will be my first engine with the bearing mod put into service. Hopefully it will be good...