Question: I think the piston and sleeve in my engine is worn out or damaged. Are they worth replacing?

Answer: Well it comes down to cost and HOW you replace them.

Consider this:

1) KNOWLEDGE and TOOLS. To actually replace the piston and sleeve you have to disassemble your engine in order to take them out. We recommend replacing the piston and sleeve together in any ABC engine and in many cases it is prudent to so in a ringed engine as well. The conrod and wrist pin and wrist pin retainer should also be replaced at the same time. To get these parts out of your crankcase you have to know what you are doing and most importantly to put the new components in you have to be careful not to damage them during installation and you must align the ports correctly. Removing and installing pistons and sleeves requires some knowledge and a few small special tools to do the job right. In our experience most modelers have some difficulty with this and may damage the sleeve and/or conrod bottom end.

2) WORK/EFFORT/TIME. Do you have the time? It takes about 30-60 minutes to do a good job IF you have the tools and knowledge to change these components effectively.

3) COSTS. The cost of a piston, sleeve, conrod, wrist pin and retainer can vary widely from engine to engine and source to source. They are the most precise parts in the engine and in no case are they cheap. The price for a piston, sleeve, conrod and wrist pin set for the VMAX 46PRO and 52PRO is about $40 as of 20050228. This may have increased since then.

Question: So what to do when you have neither the knowledge, the tools, the time or money to burn? Is there another way short of dumping the engine?

Answer: Yes there is! If your carburetor and muffler are working well... ask us for a "short block". A short block is the entire engine ready to go except for carburetor, carburetor cinch bolt,  muffler, muffler screws, prop nut and washer.  Just remove your prop nut, washer, carb, muffler and retaining bolts for both, re-install them on the short block and you are ready to go with just about an entirely brand new engine! As of 20050228, the price for a short block for the VMAX 46PRO and 52PRO was just $5-10 more than  the cost of the piston, sleeve, conrod, wrist pin and retainer set. So for a few bucks more you can do less work, have a much better chance of a satisfactory outcome and get the job done quickly so you can get back to flying!

Conclusion: On a VMAX engine we recommend going with a short block replacement rather than changing the piston and sleeve. It will cost just a few dollars more than the parts but has an almost 100% chance of producing a satisfactory outcome with much much less work.