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-   -   60LX tightness? (http://www.rcuniverse.com/forum/dub-jett-engines-support-115/8957753-60lx-tightness.html)

learjet45xp 07-23-2009 12:11 PM

60LX tightness?
 
Hi Bob,

I have a slightly used 60LX that was purchased used. It appears to be in great shape and looking through the exhuast port the cylinder looks to be in great shape. It is however very hard to turn over when its cold. I need a high torque starter to turn it over. It runs great once its in the air and has no problem getting over 17k with a 9x8 prop. It is just so darn hard to turn over. It doesn't feel like its compression that im fighting against either. Any ideas?

bob27s 07-23-2009 02:58 PM

RE: 60LX tightness?
 
Sounds like there is no problem. That is the way a GOOD ABC engine should feel.

There is a slight interference fit between the piston and sleeve at the top of the stroke. When the engine is wet with fuel and/or oil, that can feel a bit more tight. If you take the glow plug out, you will feel the same "pinch" even with zero compresison.

The engine will loosen up a very little bit with time. If that seal goes away, that means a worn/damages/burnt up engine (metal has actually be compromised).

Give it some flight time, and if you can fly it with a 9x7 for a while ..... let it spin up a bit for a few flights. Find peak rpm on the ground, back down from that about 800-1000 rpm from there ... and that is where you want to launch it.

Bob


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