ok yesterday i was trying some new fuel i normally use PowerMaster but i tried some ritchs brew the engine ran great, but after i let it cool down the compression was alot less than normal. i need to know if it is just the fuel the engine resetting or is my engine trashed. please help it is a TT pro .46 it is about 5 months old and is very well taken care of i run it rich and use after run if im going to put it away for 2 weeks or more. so come on experts tell me what to do

What type of fuel did you use ? Was it pure synthetic ?
If you run a non-ringed engine on straight synthetic oil
and run it too lean...or have a cowled engine that doesn't
have enough cooling....you can damage it....in a very
short time....

i used 10% nitro 20% castor synthetic mix and the engine is almost brand new never been run lean at all. engine is completly open its on a big stik with no cowl what so ever and the prop is a 11 x 6 so i gets plenty of cooling. it is also ringed fuel is ritchs brew so there is the info.

the only way to tell if the engine is trashed is to run it if it has the same amount of power as before it is not trashed otherwise it is trashed if it is is trashed you will need a new piston and cylinder liner which are cheaper than a new engine and easy to change yourself fuel is fuel so unless you ran soft scrub tub and tile cleaner through the engine instead of fuel one tank should not cause the engine to wear out it may be that your engine is getting broken in then again you may have had a lean run you said you had to let it cool down was it really hot if it was really hot then you had a lean run even though you said you never ran it lean that doesnt mean that it didnt go lean in the air did it start to lose power toward the end of the flight if so this is also a sign that it was lean anyway good luck with your engine

well the engine has MORE power and it got extremly hot so i richend her up some, ran another tank still had more power about 1k more unless my friends tac is bad but i did try 15% instead of 10% nitro so what ever. lol becarfule with pulling the head of a TT after it is seated in cuz its a tight fit you will pull the sleeve out. lol it happend to me so while i had it out i inspected it, looked great was nice and slick piston was oil tinted like it should be so i figured it is ok. i will know next time i fly if it flames out on me but she will be aircooled so i dont think its going to be a problem, after all how could the beauty of a engine that TT.46 cough on me. lol thanks for the advice and comments guys. BTW mk it was ground tested and it gains plenty of power in the air it leans out to peak at about 150 ft so its tuning is fine or was fine with the other fuel she smokes alot so its rich enough

try tightening your glow plug a bit, it is possible it is loose. also, make sure your head is tight. if you have a four stroke, it is possible that your valves need to be cleaned

whenever you bump up on nitro you have to open the needle valve. as nitro brings more oxygen. also sometimes the glowplug needs to be slightly cooler to retard ignition timing.

that's all well and good, buit it has nothing to do with compression loss

Actually it does, running lean or even a too hot plug can cause an engine to overheat and lose compression. It usually returns when it cools down. A hot run also means there will be less oil film in the cylinder, this will mean less compression till new oil can saturate the pores. Of course a lean run, especially with high nitro, could mean you cooked the engine and it is now worn out, or nearly so. But a TT is usuall tough enough to take a few lean runs.

but overheating is also associated with other symptoms like pre-ignition especially on high nitro contents.

You state that the engine is ringed. Could it have a free floating Dykes ring that has rotated to have the end gap on the intake side? If so the engine will have almost no compression when turned forward, but will have the same old compression when turned backwards. If it is conventional ringed, one hot (lean) run can take the temper out of the ring causing compression loss. If that is the case a new ring is in order along with another long rich break in.

Mr. Motor:

Are you posting on the wrong thread? He stated the engine make, and said nothing of rings.

Sorry
I didnt catch it was a pro 46 and not ringed like post 3 said.

That post #3 caught my eye too...I was starting to wonder if they'd brought out an optional setup.