I just ordered a new Tower Hobbies .75 . I would like to know the correct procedure to Break In this engine. I have read some posts around here, where some people claim that the procedure on the manual is not the correct one, or that there is a better way. I have also read that you can ruin the engine if you mess up the break in. I am relatively new to the hobby, this will be my second engine, to be installed on my second plane (a new GP Extra 300 40 ARF ). I sure don't want to mess it up. I would appreciate any help you can give. Thanks!

Follow the manual. The internet isn't exactly the most credible source of information these days. Besides if you follow the manufacturer's suggested procedure and have problems then they will warranty the engine.

Sorry... A little additional information to qualify my opinion:

I own a Tower .75. I followed the recommended break in and was flying by the second tank. I have flown the plane for a year and the engine has performed flawlessly.

mayday421p....

....the instructions that come with the Tower .75 are spot on.
Follow them exactly. When you get the engine it will be really
SUPER TIGHT...!!! Don't be tempted to keep flipping the motor
through compression.....you can scuff the piston and the bore,
and prolong the break-in. Squirt a little oil into the top of the bore
on your final assy, before you put the muffler on. When you first start
the motor, it might "knock" for a few seconds....they are extremely tight.
...you can avoid this knocking, and the strain it puts on the rod....by
preheating the head with a heat gun, before the first start-up.

Make sure you have some castor in the blend....as per the instructions.
Put a block of wood over the carb, and tap the carb down tight against
the o-ring before you tighten that nut. If it is not tight against the o-ring,
you might have trouble shutting the engine off.

Don't use the muffler gasket....put the muffler on without it. The soft
aluminum gasket will compress a bit, and loosen....and bang up the
surfaces on the engine, and on the muffler. It is better to not let that
happen....and install it straight-on....while the surfaces are perfect. Take the
muffler apart and Lock-Tite it front and back before you run the engine. If you
don't....it will probably come loose. After the threads get oily, it is difficult to get
them really clean....especially the front threads in the muffler....to get a good
Lock-Tite job....so it's better to do it beforehand.

You can remove the cap off the side of the carb, and install the guts out of
the remote needle valve into the carb....for a conventional front needle
(and more precise) set-up. Or you can leave it in the back. I prefer the front
needle myself, because the give a quicker and better adjustment....and the
rear needles can sometimes cause problems, however the Tower remote
needles are top quality.

The prop, plug, and fuel are a matter of personal preference. I use a MAS
11-8 prop, a Fox Miracle plug, and 15% PowerMaster fuel. Just don't over
prop the motor....let it turn....you will Love that motor....

Dave.

Thanks ksechler and Flyboy Dave for the words of advice. I will follow the instructions and your assembly advice as well. I have read some of your posts Flyboy. You seem to have a lot of experience with the Tower engines. Actually your posts had a big influence in my decision to go with Tower. Thanks again! I can't wait for the engine to get here. Since I live in Panama it takes a little longer [&o]

Yeah, Ol' FlyBoy knows his stuff.....but shhhhhhhh, I don't want him to know I know....

Gary

Dave,

Did ya notice much differance between using the MAS 11 x 8 versus a 12 x 7?

mayday:

I followed Dave's instructions when I was breaking in my Tower 75 and it went very smooth. Very good advise on pre-heating a cylinder head with a heat gun it worked great for me. I needed to adjust a "low" or carb needle to “stabilize� my idle a little (it is my understanding that factory settings seemed to be on a reach side… Because as far as I know “low� needle on this engine works opposed to high one – more in (clockwise) = reach, more out (CCW) = lean… Dave, am I correct on this one? ).

After all, engine runs quite nice – you’ll love it.

Good luck,
EK

Gary, Dave... Any connection between Tower engines and "Revver's Brotherhood" we should know about...[sm=lol.gif]

ekrcflyer,

There is no connection Tower/Brotherhood, however, stick that 75 in a .30 P-51 and we'll let ya right in! LOL

Who is the actual manufacturer of the Tower line of engines? I know Tower doesn't actually make them?

ekrcflyer ....

....no,....the low speed works just like the high-speed....In (clockwise)
for lean....Out....for richer.

Ed...."Did ya notice much differance between using the MAS 11 x 8
versus a 12 x 7?"

I started out with a 12-7 APC....it was a DOG !!! []....I went to the
11 7-1/2 MAS, and it came to life....the 11-8 is the best all around prop.

Mayday,

You must remember that your new engine is not a ringed engine.
It must not be broken-in cold, but at working temperature, that will cause the sleeve to expand.

It must be run rich, with plenty of Castor oil in the fuel (I recommend 21-22% total oil for break-in), but not rich enough to cause it to four-cycle. About 1/2-3/4 of a turn richer than peak is OK and finding this peak, in an ABC/ABN engine, will not cause any damage. Don't bother to touch the idle needle, before completing the break-in and running these 15-30 minutes on a test stand will be much better for the engine, for you and for the plane.

Starting after 15 minutes, peak the engine and listen if it can hold peak without ANY speed reduction, for 60 seconds.
If it can, you are done. If not, richen it immediately and continue the break-in for 5 more minutes and try this again.

Running it in four-cycling and cold will potentially damage it permanently.

Please go to the OS support forum and see what Bill Baxter has to say about break-in of this type of engines.

An 11x7.5, or an 11x8 prop, will give it a light load and plenty of cooling air.

Again, thank you all for the help. This place is great.

The manual suggests a 12 X 6 prop for break in. I take it that the props you guys are suggesting are for after break in? What prop should I use for break in?

I can't wait to take that Extra in the air. I will have to fly my cousin's Superstar this weekend, since the engine won't be here in time, and my Avistar is in no condition to fly. [] I'll still fly though

MayDay,

I suggested using an 11x8, because it offers an approximately equal load to a 12x6, but at the same time its higher pitch sends more cooling air to the engine.

A larger, higher inertia prop, like the suggested 12x6, could make the starting easier, but only if you intend to hand start.

I would still prefer the 11x8 size for break-in, even if hand starting.