If you were to rebuild an engine and had the choice what woudl you take and why?

Steven

(25$ more for the aac)

If engine weight is a consideration, then AAC.

Im more intrested in max rpm performance and durability than mass

Steven

Definitely go ABC then, that's what all the surface nitro motors use and they see alot more abuse than airplane engines. I should know, check out my signature!

Given the choice it's AAC all the way. However there are very few manufacturer's doing AAC, Enya have it with a couple (I have the AAC Enya 60X) and Jett have it as a high performance option on some of their engines (as if they aren't high performance enough already ).

One of the benefits of AAC is that the liner doesn't stretch at the top as ABC liners do after some time so they keep their clearances (last longer).

Iv always wondered how much more abuse they really take, sure they get that 40k rpm but it only holds it for what max 5 seconds? than your back down to idle pylon engines turn 30krpm for 5 minutes thats probably alot more revolutions in one minute.....

Steven

A few years back the Nelson N40 (Q500) engine was avaliable with your choice of AAC or ABC liners. This seemed to only last a few years before no one was buying the ABC version. Not about to speculate on the reasons but having had at that point both and the AAC did seem to outperform the ABC.

Now the new Nelson LS seems to be AAC only. Its certainly not about money since we are talking about $400 forty size engines here.

Several of our locals involved in our RC Pro warbird racing are using OS 50's with Nelson AAC piston sleeve sets sold by Dave at Performance Specialties and the performance is dramatic but agine would not want to speculate on how much of that is attributable to the timing changes and the metalurgy.

John

It's not so much the time spent at high rpms, but the load placed on the engine. Take my 13lb. Savage for example, the .28 in it is constantly accelerating from idle to top speed, and take hard landings. The acceleration under the load of a vehicle is definitely more stress than simply turning a prop and having a constant supply of cooling air.