Conference vmszoo::rc

    Hi Steve,
    
    We need a little more information on the engine before suggesting
    solutions. It really depends on what model .40 you got. An ABC engine
    will be a lot tighter than a ringed version. Most engines are
    intentionally tighter at TDC for the compression. This will get better
    as the engine breaks in. Were you cranking the engine over with a prop
    on it? The engine load will pull the crankshaft forward in normal
    running. The electric starter is the only thing that will put
    significant pressure back on the crankshaft unless it's set up as a
    pusher.
    
    

I had the same problem with my early-model K&B .20.  It was very
tight, and I even distinctly remember it squeaking a little.

Its intentional, and is frequently done with ABC engines from
what I understand.  Worthy of note is that when I sent it back
for rework, the new piston and cylinder they put in was a good
deal looser, something that they've done to all their engines
since then.

The common advice with ABCs is to break them in slightly leaner
than you would normally set it for a lapped or ringed piston
engine.  The heat and friction is needed to get a good seal up
there.

Personally, my experience has been to keep the ABC quite rich, as
the increased compression and heat from the tight seal causes the
glow plug to blow when its a little lean -- actually the glow
plug doesn't blow, it just will not stay lit for a whole run.

Then you go nuts trying to figure out the problem because it
looks like a fuel flow problem to the local wags.  They'll tell
you to raise the tank or buy new fuel with higher nitro.   Put in
a new K&B plug and you've got it.  Seek field advice only at the
last resort!

Anyway, be prepared to let it run for at least 2 hours, probably
more until it gets up to full power.  Mine was going on 5 hours
before it came to life.  It pulls like a horse when its done, and
the pain is worth it.

Now, I'm going to contradict my advice a little.  While the
tightness was not a problem with the K&B, it could be a problem
with the OS since my OS .40 FP ABC was not tight at all.  Might
be a good idea to get someone who knows about such things to take
a look at it.  Possibly a phone call to the OS service center
would be all that's needed to get a little peace of mind before
you fire it up.

re .1

It's just the cheap version... RS I think.  Tower sells it for $69.

Remember, it's not a compression problem... it gets hard to turn even when 
the cylinder head and the crank cover are removed. 

Thanks,
Steve

    Right. The binding is between the piston and cylinder liner. The point
    is that it might be desired. I still think that it just needs to be
    broken in (If it will start, it's probably all right)

    
    	If the engine is an ABC construction then count yourself
    luck that it's that tight and pray you haven't damaged it.
    
    	ABC ENGINES CAN BE DAMAGED IF NOT LUBRICATED.  YOU COULD
    SCRATCH THE PISTON OR CYLINDER WALL.  Pray you haven't done this.
    
    
    
    	1) check the documentation that came with the engine. If it's
    an ABC engine stop playing with it until you get some oil into the
    engine and even after that.
    
    
    Tom

    
    The piston and cylinder walls came pre-lubed.  I'm sure I haven't
    scratched the walls.
    
    Steve
    

    
       All FP-40 engines are ABC construction ( at least the ones made now
    are), so the ABC advice is relevent.
    
    

    
    
    Just as an observation...  be extremely careful these day with most
    "ABC" engines purchased.   The fact of the matter is that they ARE 
    NOT  "ABC".  Rather they are ABN.  The N standing for nickle.  A
    cheaped, softer,thinner plating of the brass sleeve.  I've seen
    a few engines from different makes with places where the nickle
    peeled off due to excessive heat.
    
    
    Tom

I think I have mentioned this before but ABC's should be tight. It is essential
that you wash engines thoroughly before running a new engine for the first
time. 

Depending on you confidence/competence as a mechanic determines the way this
should be done. The best method is to dismantle the engine completely, wash in
petrol (ie: gas) to remove all deposits including oil and metal dust, then lay
them out on a clean dry surface covered with a CLEAN dry piece of cloth. The
engine should then be reassembled and lightly oiled. The risk of this process
is reassembling the engine incorrectly, reading through this notes file will
prove the point by the number of problems created by incorrect reassemble. 

The next best is to remove the plug and the back plate noting the rotation of
the back plate, and submerse the engine in petrol/gas then turn it over for a
few minutes in both directions. Again lightly oil the engine and restore the
bachplate. 

The biggest risk with a new ABC engine is heat. For the first few runs don't
run a big prop as that generates more heat from the load. My thoughts go
against the old school of running on the bench for 4-5 tanks of fuel, that may
be OK for a ringed motor but ABC's need to be run hard. 

My recommendation is to put the engine in a model with a prop on the small side
of the manufacturers recommendation.  For a 40 I would use a 9 3/4" X 6"
balanced. Start the engine and allow it to run at about 3/4 throttle very rich
for a few minutes. Then bring it up to full throttle and adjust the mixture
till it is just off song rich, crackling but still reliably running. Take off
and gain height and then alternate between about 3/4 throttle for 1 min, then
full throttle for 15 sec. For the next 5-6 flight progressively more time at
full throttle and start peaking the engine. 

The main advantage of this process is cool air and minimum dust and grit. On a
bench or stand you are close to the ground with the highest level of dust
contamination, 50-100' up it is cleaner and cooler. 

A properly bedded ABC engine will have the top 1/16" of the piston shiny and a
different finish to the rest of the piston. This is that tightness you feel
bedding in. 

ABC's should always have a nippy top end at room temp, this disappears at
operating temp, but after a flight it will be smooth. Turning an ABC over at
room temp should be avoided where possible, it reduces the life and performance
of the engine. 

John 

    
    I started it running last night and ran about 18 oz of fuel through
    it... it really took off after about 8 oz.
    
    Thanks for the help y'all!
    
    Later...
    Steve