hsukaria

That describes my engine, has good power and idle. I just wasn't sure what is used to determine compression loss. Just when power loss occurs?

1QwkSport2.5r

I guess technically the ring starts wearing out from break-in on, albeit very slowly. If there's a question as to whether your engine has lost power, take some tach readings of your engine and compare in the Tachometer forum. It sounds as if its common among the G51's. I have a G51 made in Italy that has a Frank Bowman ring in it and its flipping compression seems soft to me as does my S.29, but my S90 has heaps of compression - so much it needs a prop on it to turn it over. I think it depends on the engine. The .29 and .51 I have seem to have a lot of leakage past the ring, but they run really good. The long standing rule among the car guys is when the idle starts to suck, its probably getting to be time for a new ring or piston/liner set.

downunder

Knowing what's acceptable for a ringed engine is a matter of feel. The primary thing (which applies to all types of engines) is how easily it hand starts because an electric starter can mask a world of problems. Ringed engines can have all sorts of feel when turned over slowly ranging from massive leakage with a Dykes ring to feeling almost like an ABC but when flicked over fast there shouldn't be any noticeable softness (except with a Dykes ring) and should definitely flick well past the exhaust port opening with a little bounce back as the piston starts to go back slightly into compression again.

My most used ringed engine (Enya 45) had several hundred hours on it before it was no longer giving reliable one flick starts but once running was just as good as ever. I re-ringed it because I needed the one flick starts for CL stunt where there's a time limit on getting into the air. My Italian G51 though only has about 40 hours on it but is still a one flick starter. Both of these engines have only been run with 25% all castor.

I guess to sum up, if you have a ringed engine that starts easily, idles well and has good power then there's nothing to worry about.

hsukaria

Thanks for the help guys. I was just wondering because some of my ringed engines have very strong compression when hand flipping the prop and some don't, like my G51. My old GS40 had a lot of compression feel when hand flipping the prop. That's what got me asking.

hsukaria

I ran my G51 in a new airplane today. For the past few years it has been working great in an Escapade. But now I installed it semi-inverted in a Great Planes Reactor 46 with a 12.25x3.75 APC prop. Suddenly, the engine does work properly at all. I had the low speed needle open between 8-9 turns to just get the engine started. I could not get much power at WOT, and it dead-sticked everytime. We cleaned the carb jets but to no avail. I will take the engine out of the plane tomorrow and bench run it. I don't know if something messed up the carb or like I suspected a compression loss.

Any ideas?

Scrubmonkey

id say fuel tank setup....

1QwkSport2.5r

+1. The engine ran fine in the escapade and subsequently ran like crap in the reactor. Fuel system is first to check. Do this before bothering with a bench run.

hsukaria

I will take the fuel tank out and inspect it. It may be bad to start with since I bought the plane used. I have a few spare tanks that will do the job.

hsukaria

Can somebody tell me how many turns to open the low speed needle on a G51?

1QwkSport2.5r

It's easiest set with the carb off the engine, screw the idle mixture needle in/out to be in the center of the cats eye or a little past. How many turns, I have no idea. You could try 3 turns and see what that gets you.

hsukaria

Ok, thanks, I remember doing that in the past. I think it translated to several turns, like 7 or 8. But I wasn't sure. I will re-do it.

Scrubmonkey

http://www.lymanslack.com/Articles&Archives/st.htm


got mine running great with this method and needed no adjusting afterwrds

hsukaria

That is a good guideline.

I ran my G51 engine on the bench this evening. I ran it on 5% nitro, 12.25x3.75 prop and an older OS muffler. It actually ran well with good throttle transition despite the big prop. I did notice a very faint rattle that I suspect is from the bearing(s). I had not noticed that before because I was running a smaller 11x6 prop and a louder MACs one-piece muffler compared to the quiet OS stock muffler.

So, that proves that the problem I was having is related to the fuel system, which I am going to tackle next. I also realize that the engine is going to need bearings in the not-too-distant future. So, while I replace the bearings, I will also replace the piston ring. But for now, I will moth-ball this engine and use a 4-stroke engine on this 3D plane.

Hobbsy

My Feedback: (102)

I decided to finish breaking in a Super Tigre 2300 I bought in 2010, I mounted an 18x6 Master Airscrew Classic, the only fuel I have is WildCat 15% Premium Extra

Super Tigre 2300
Prop==Classic 18x6
Fuel WildCat 15% with 18% 80/20 syn/castor blend
Muffler==stock
Carb==stock
Max rpm===8,300
Idle, a very nice slightly burbly 1,800
Plug===stock plug.

5% fuel would be better as it is a little rattly, it has that secondary egg frying sound as Mr. Davis calls it that lets you know when a Diesel is over compressed.

hsukaria

Thanks Hobbsy for the info. Any plans to put in an airplane? I have read that the bigger ST require less nitro and less oil as well. That would translate to some $aving$.

hsukaria

Well, I'm embarassed at myself. I checked the engine on the stand and it ran great. I took out the fuel tank and noticed that the clunk tube was too long and the clunk would get stuck against the back of the tank. DUH!!!!
I shortened the clunk tube, and test flew it last Saturday. Flew real nice. It is also very quiet with the 12.25X3.75 3D APC prop. and an OS muffler. But still, I think this engine would do better in a faster plane and I will put a 4-stroke in this 3D plane.

aileronmodelismo

Hello Sirs;

I am need a SUPER TIGRE G71 cilynder head!!! Anyone know who have this piece to sell?

Thanks;

Alexandre - BRAZIL

Bax

My Feedback: (11)

The SuperTigre G2300 requires AT LEAST 18% oil content in the fuel. That's different from the other large SuperTigre engines.

hsukaria

Thanks Bax, that's good to know.

gianfry2866

hi guys

for my supertigre 46 bull ring I need to replace the backplate...

pls someone can confirm that I can use the back plate of the actual supertigre g45


tks a lot

Hobbsy

My Feedback: (102)

HS, I plan to put the ST 2300 in an ACE 4-120 as a Diesel conversion.
One thing I didn't see in this discussion is that a ringed engine has a far longer stable period between break in and being worn out. ABC engines break in quicker, (hence their popularity), in this day and age. They also won't last near the hours of a ringed engine. Plus, the ringed engine normally only needs a new ring to last another long time.

hsukaria

That's got me thinking too. I have 2 Irvine ABC 40 engines that are awesome. I doubt that I will be able to find the piston/liner set for them when they wear out. These engines are incredible in my opinion, easy to tune and great power.

Not to put down the Super Tigres, but all these engines, especially the ABC/ABN/ABL will especially be hard to keep going in the future whenever the piston/liner sets for them are no longer available.

blw

My Feedback: (3)

Go to Just Engines in the UK: http://www.justengines.co.uk/acatalo...ke_Spares.html

Your piston and liner set conversion to dollars is $61 and change. I recently ordered Saito parts from another company and postage was cheaper than the fixed rates here. It took longer to get here, but I'm happy with ordering from the England when I need to. Just Engines has an excellent reputation too.

hsukaria

Thanks BLW. I knew about them, but forgot. My Irvine 40's are the old 2-piece crankcase. So, I would have to call them to verify that the p/l are the same as the newer Mark III/IV versions. I don't need the P/L now, but it would be good to be ready for the future.

On the other hand, my ST G51 is ringed and finding a ring for it should not be a problem. I could get a couple of Frank Bowman rings for it and be set for a long time.

Does anybody have experience with both the G51 ringed vs. the G45 ABC? How do they compare in power/torque, etc...? Tower Hobbies still sells the G45 ABC, but not the G51.

Hobbsy

My Feedback: (102)

I don't know what you might gather from this but these are the Diesel numbers for the two engines.

SuperTigre .45 ABC Gr.-12x7 DDD ABC mix===9,800
SuperTigre .51 Graupner 12x7 DDD ABC mix===9,650