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Author Topic: Engine Break in?  (Read 4560 times)

Offline frank mccune

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Engine Break in?
« on: February 27, 2021, 02:55:03 PM »
      Hi All:

      How does one know when an engine is broken in?

      Tia,

      Frank

Offline frank mccune

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Re: Engine Break in?
« Reply #1 on: February 27, 2021, 04:18:15 PM »
     Hello Walter:

      What determines when an engine is overheating?

       I am attempting to break in a McCoy .40 RH that appears to be very tight.  I mixed a liter of fuel containing 30% caster oil and 70% alky.  I have been running it in a very wet four cycle and tip the engine to 90 degrees to get it t run in a faster wet four cycle for 15 seconds then back to the very wet four cycle.  I have used two three oz. tanks thus far.  I am using a wooden 10-4 prop.  The piston and cylinder appear to be quite tight with no leakage.

       I do not want to destroy this engine by poor break in procedure!

       I have a McCoy .35 RH that was set up by a pro, and it is a joy to use.  I hope that the .40 is more of the same.

      Thanks for the reply.

      Frank

Online Brett Buck

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Re: Engine Break in?
« Reply #2 on: February 27, 2021, 04:47:35 PM »
What determines when an engine is overheating?

       If it won't hold the setting without sagging off after a few seconds to tens of seconds.

Quote

       I am attempting to break in a McCoy .40 RH that appears to be very tight.  I mixed a liter of fuel containing 30% caster oil and 70% alky.  I have been running it in a very wet four cycle and tip the engine to 90 degrees to get it t run in a faster wet four cycle for 15 seconds then back to the very wet four cycle.  I have used two three oz. tanks thus far.  I am using a wooden 10-4 prop.  The piston and cylinder appear to be quite tight with no leakage

      I am sure you know that this is not *nearly enough time*, or nearly hard enough running. You are doing the right thing to start with but you will want to run it in a 2-stroke, slowly working up to it.

     Brett

   p.s. figure that the total running time in break-in will need to be at least an hour, maybe two hours if it is tight. You probably have about 5 minutes so far.
« Last Edit: February 27, 2021, 08:06:26 PM by Brett Buck »

Offline Air Ministry .

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Re: Engine Break in?
« Reply #3 on: February 27, 2021, 07:20:12 PM »
SHEESHEZ .

( stolen from Martin Quartim , in the ENYA thingo currently on the primo thingo ) .

===================================================

The complain No 1 about Enya Engines is because they are hard to start and break in when new. That is true for the Iron Engines like the Enya 15III,  Enya 19, Enya 35III  and some of the Schnuerle ones like the Enya SS25/30 and 40.

However if you apply the steps below you will have a strong, 1st flip, reliable and long lasting engine in no time!

When the engine is new and it comes extra tight from Enya it will be harder to start (to much resistance to turn) but the harder to get started the better compression and power it will have.

These are the steps I do to break in Enya Iron Engines that has been working very very well for me .  All it takes is about an hour and a half of running time.

First Phase – Thermal Treating
I do 10 short runs of 1min with the needle set so the engine  burbling between 4/2, letting the engine totally cool between runs. Then 8 short runs of 2 min and 6 of 3min (perhaps the 6x3min is not necessary but I do it anyway)

Second Phase - Unleashing the Power
3 runs of 6 minutes with the same needle setting as in phase 1. Depending on how tight the engine is it may require more runs the same way.  Never had to do more then 5 times. I pinch the fuel line with care to make the engine keep at peak rpm for 8 to 10 seconds, then I release the fuel line, wait for about 25s and repeat the process until the end. The top rpm improves significantly in this stage. I call the engine ready to fly when I see that there is no more gain in the peak rpm. At this point as soon as I release the fuel line the rpm returns back immediately to the set rpm.

If you break in just letting the engine run rich and don't peak it out, it will never break-in and develop good power. You will mistakenly think it is a lame engine!

Of course these steps are not for Ring, ABC or AAC Enya Engines, only for those with Iron P/L.

==========================================================

Theres other info at THE TOP of this here engine page .

Offline frank mccune

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Re: Engine Break in?
« Reply #4 on: February 28, 2021, 03:10:16 PM »
     Hello:

     Thanks for all of the replies.

     After giving this break in a rest due to rain, I have more thoughts and questions.

     I am ready to go to phase two with leaner runs.  I installed a Fox muffler but the question that I have, should I remove  the muffler for the additional break in procedure.  I have no idea as to how much heat the muffler adds to the engine.  At present, the engine appears quite hot to the touch while running.  I hate mufflers! The engine is becoming easier to flip over by hand, but is still too tight to hand start.  It also has a great piston to cylinder fit that I am attempting to preserve.

     Perhaps in the past, I may have not broken in my engines well enough for longevity.  This time, there will be at least an hour of break li on this engine before flying.  I bought it used and since it is has no signs of being mounted, I am regarding it as a new engine.

     Brett, I must confess that I did remove the backplate to determine why the crankshaft would not move.  I cleaned and lubed the engine sans the backplate.  Then took a 3/16” dowel inserted through the glow plug hole and with a very light tap with a hammer, the piston moved.  Everything appears to be very free moving.

     I am curious to see how well this engine pulls a Nobler or Magician this Summer!

     Stay well,

     Frank


Online Brett Buck

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Re: Engine Break in?
« Reply #5 on: February 28, 2021, 06:00:56 PM »
     Brett, I must confess that I did remove the backplate to determine why the crankshaft would not move.  I cleaned and lubed the engine sans the backplate.  Then took a 3/16” dowel inserted through the glow plug hole and with a very light tap with a hammer, the piston moved.  Everything appears to be very free moving.

     You don't have to apologize to me for anything, and in particular, taking a McCoy apart. The idea of "disassemble/clean/lube" was invented in the era when Fox and McCoy were around, because there was a very good chance that there was some debris left inside that would chew it up in one run. Its completely different than something like a reasonably modern OS, SuperTigre, HP, HB, K&B, or semi-customs like PA, RO-Jett, etc. where there is very little chance that this could happen. 

    The McCoy 35 Redhead used to be sold for <$10 on a bubble pack, they didn't make that profitable by carefully inspecting each one with loving care.

    Idly disassembling things as a ritual, for no reason, can only cause problems. Disassembling it for a good reason is an entirely different proposition, if something it wrong, or reasonably likely have a problem, you have to. It might cause a *new* problem (as has happened over and over and over again with Cox, OS, PA, RO-Jetts) because most people have no idea how to do it safely - to the point that I briefly considered putting together a post about *how to use a screwdriver* - but it's not rocket science, and lots of them have been disassembled and reassembled with no problems.

   If I had a brand new Fox or McCoy, or an engine from most engine reworkers except for Randy and Dub Jett, I would certainly at least take off the backplate and try to flush it, because there is a very good chance that you will find something that would screw you up.

  Note that merely taking it apart to clean it out or diagnose a real problem is a different thing than "modify before testing" or "modify it to tribal knowledge" ideas.

     Brett

Offline frank mccune

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Re: Engine Break in?
« Reply #6 on: March 05, 2021, 12:53:27 PM »
     Hello all:

     How much more running must I do to get this McCoy .40 RH Stunt to loosen up enough to put it into an airplane?  I have run a litre of fuel through it but it still very low on power.  With a a 10-4 wooden prop, it is turning at 8900 rpm in wet 2 cycle and 9400 rpm leaned out.  I Have been running it at those two rpms for 30 seconds each on a 3 ounce tank.  I permit the engine to cool and repeat for another tankful.  Will this engine ever be able to produce enough power to fly a Magician or Nobler or am I wasting my and time and money by living in the past?  Some of the old engine reviews reported that the test engines were run  for an hour or two prior to being tested.  I do not think that I am willing to spend that much time on this engine when I have great running OS .35 Stunt engines looking for a plane.  I also have a great running McCoy .35 RH Stunt that is also looking for a home.

      It appears to becoming a bit more loose, but not enough to be hand started.  It starts instantly when touched by an electric starter.

      Thoughts/suggestions ?

      Stay well,

      Frank

     

Offline john e. holliday

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Re: Engine Break in?
« Reply #7 on: March 05, 2021, 01:51:19 PM »
30 seconds is not long enough.  Once I have an engine that will hold a setting that will fly the plane it goes in the air.  On bench running I use about 2 ounces of fuel which gets the engine up to operating temps.  Remember first flights a little rich and go in with needle each flight until you are happy with it.  2 ounc tamk also until you are happy with setting.  I had one Fox that took almost all summer before it was ready and others that came in quite early and are still being used. D>K
John E. "DOC" Holliday
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Offline frank mccune

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Re: Engine Break in?
« Reply #8 on: March 05, 2021, 03:31:11 PM »
     Hello John:

     Thanks for the reply.

     Am I doing this all wrong?  I run the engine as fast as it will go before it sags for 30 seconds and then run it in a fast 4 cycle for 30 seconds to cool the engine ,cycle, it and repeat this until the tank is empty.  I then fill the tank while permitting the engine cool.  Repeat again and again until 1 litre of fuel is used.  Are you suggesting that I lean out the engine in a 2 cycle and run it for another hour on a test stand?  As it is now, it does not have enough power to fly anything save a small .09-.19 sized airplane.  Perhaps a Ringmaster Jr. or Ringmaster Flash.

       I have heard that the McCoy .40 was a great Stunt-Sport engine with an 11-4 prop installed.  This engine struggles to turn a 10-4 prop at 9400 rpm.  Perhaps a bit of nitro may improve the performance to a point where the engine may be useful.  I doubt it though!

       Stay well,

       Frank

Online Dan McEntee

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Re: Engine Break in?
« Reply #9 on: March 05, 2021, 03:39:32 PM »
  You are only talking about a little more than a quart of fuel through it !!!! You are no way hear where you need to be. You may need to put a gallon though it if it needs to. No muffler, correct? Do not put a muffler on it for break in. Proper amount of castor in the fuel? What does the exhaust residue look like? Is it clear or have a dark tint to it? When it's getting close to being broken in, the exhaust will clear up. A single liter of fuel ain't enough.
  Type at you later,
  Dan McEntee
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Offline frank mccune

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Re: Engine Break in?
« Reply #10 on: March 05, 2021, 06:57:59 PM »
      Hello Dan:

     Thanks for the reply!

     Yes, it does have a muffler attached.  That is why I am using 30% castor oil and no nitro.  I could remove the muffler and place a baffle behind the engine to help appease the neighbours.  I hate mufflers anyway!

     How does this sound for a solution?  Run the engine in a fast but safe 2 cycle for about 2-3 minutes and then stop and allow it to cool to room temp.  I am expecting about 11000 rpm on this 10-4 prop when broken in.  I hope that this is realistic if not, into the junk drawer it goes!  I have a couple of Fox .35 Stunts ,ugh, that I could use in lieu of this McCoy.  They are left over from  my Foxberg racing days and should be broken in. Lol  Perhaps it is time to revert to the old OS .35 Stunt engines!!!

      The longer the break in time is on this engine, the less I am interested in using it as a Sport engine! I have other engines that handle perfectly but are a bit heavy and much too powerful for what I want to fly. 

     Stay well,

     Frank

Online Dan McEntee

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Re: Engine Break in?
« Reply #11 on: March 05, 2021, 08:07:28 PM »
  Well, the muffler is part of the problem.  Take the test stand to the flying field, with a gallon of fuel, and spend the day running it in.  N neighbors t wrry about out there , is there. If you get tired of it I'll take it off your hands!
   Type at you later,
   Dan McEntee
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Offline C.T. Schaefer

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Re: Engine Break in?
« Reply #12 on: March 06, 2021, 05:10:13 AM »
Frank, I have a McCoy .40 in an ARF Nobler and here is my story.  I used a muffler that worked well on several other motors and the Mac did not like it. Ended up with a tongue muffler with bigger holes. It is mainly a deflector.  Don't have rpm but, as for props, a 4 pitch is not good on these.  Best for me  APC  10.5x6, Bolly  10.5x5, and Master scimitar  11x6.  VP  10/22.   Lap times  4.5 - 4.8     TS
   PS    If you are using a strap on, maybe distorting the cyl. some?

Online Brett Buck

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Re: Engine Break in?
« Reply #13 on: March 06, 2021, 10:25:27 AM »
     How does this sound for a solution?  Run the engine in a fast but safe 2 cycle for about 2-3 minutes and then stop and allow it to cool to room temp.  I am expecting about 11000 rpm on this 10-4 prop when broken in.  I hope that this is realistic if not, into the junk drawer it goes!  I have a couple of Fox .35 Stunts ,ugh, that I could use in lieu of this McCoy.  They are left over from  my Foxberg racing days and should be broken in. Lol  Perhaps it is time to revert to the old OS .35 Stunt engines!!!

   Neither of them is going to work very well with 4" of pitch, they don't have enough power. 4" of pitch and they are gutted out, in-flight, you might get them fast enough to make a decent level flight speed, but it will give you no variation in the maneuvers and will feel *dead as a doornail* in the maneuvers. Even 5" of pitch puts them at a disadvantage, although you might be OK in some conditions. Same thing with an OS35 (any version with a baffle piston - the 35FP is pretty good with a 10-4 or 11-4).

     People figured out a very long time ago that these sorts of engines went best with a 10-6 and on the McCoy 40, maybe an 11-6. That puts them at a much lower in-flight RPM, which will suit maneuvering much better. Of course you can experiment with it, and find out for yourself, but lots of other people already have done this experiment (60+ years ago...).

    Brett

   

Offline frank mccune

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Re: Engine Break in?
« Reply #14 on: March 06, 2021, 11:19:27 AM »
     Hi Guys:

     Thanks for the replies!

      The strap on muffler may indeed be the culprit.  As soon as it stops snowing, I will run the engine sans the muffler to determine if there was any negative effect. 

       As far as of the choice of prop, OS and Fox recommended an 11-6 prop to be used on their 40 Stunt engines.  An engine tuner suggested an 11-4 to be the prop for the McCoy .40 Red Head.  In any case, I will have something to act as a starting point for testing.

       I am planning to use the McCoy .40 in a Nobler ARF.  If all else fails. I can always put an OS .40 or .46 into the Nobler and stop mucking about! Lol

      Off the subject, I looked up old Engine Tests for these older engines and the time prior run time before testing, was often no less than one hour and many times three hours.  One engine had ten hours prior to testing! Does a McCoy RH engine have ten hours of life before wearing out in it?

     Perhaps I should start my break in tests with a NEW engine and determine that my problems are related to the misuse the engine was subjected to prior to my possession.  I do not think that I have ever run a NEW engine!  The only NEW engine that I own is a K&B 5.8 Control line engine that I bought in 1980 to be used as a Combat engine.  I just remember that I also have a S.T.  S.36 that has the same history.  Never started as I went to the Fox CS .36 for Combat.  Both of the above engines are much heavier than the Fox.  I do not think that anybody used them for Combat in those days.

      Perhaps what I am looking for is a NIB engine from the 50's-60's to break in and use for Sport flying.  But as Brett would say, "Why?"  I have a collection of about seven O.S. LA .40 and .46 engines to use.  Stop living in the Past Frank and get on with it! LOL

     Is there anybody else stuck in the Past?

     Stay well,

     Frank










Online Brett Buck

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Re: Engine Break in?
« Reply #15 on: March 06, 2021, 05:39:25 PM »

      Perhaps what I am looking for is a NIB engine from the 50's-60's to break in and use for Sport flying.  But as Brett would say, "Why?"  I have a collection of about seven O.S. LA .40 and .46 engines to use.  Stop living in the Past Frank and get on with it! LOL

    I am sorry if it comes across that way. I am trying to give you the best advice I can - first and foremost that you have to run the engines the way they work best, not get different ideas from a bunch of different places and try to average them out. It is absolutely no mystery how a McCoy 40 works best for stunt. At least *start* with a known-to-work system. Then if yours doesn't work, you know it is not a matter of swapping props, venturis, fuel, etc. but something about your particular configuration.

     This is a setup to start with (once you get it broken in) - 10-6, 15% nitro with 25% castor/synthetic blend, set on the ground so it is just *barely* in a 2-stroke, as rich as it will go and still be two-stroking. When you release the airplane, it *should* go into a constant 4-stroke in level flight, just "rich" enough to stay in a 4 all the time. in the maneuvers, say, a round loop, it should go about 1/4 of the way around, then break into a 2-stroke, stay until it is about 3/4 of the way around, and then go back into a 4 at the bottom. That ought to repeat in consecutive loops. Same thing on outside loops. It should return to a 4-stroke exactly as it was within 1/4 lap, if it takes a lot longer, like an entire lap, then it needs more run time.

   If, when you release it, it stays in a 2-stroke or gets leaner, then, there is something wrong with it, or you have to big a prop. If, when you release it, it slows down to blubbery rich, there is something wrong with it, or you have to large a prop.

     Brett

Online Dan McEntee

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Re: Engine Break in?
« Reply #16 on: March 06, 2021, 06:42:52 PM »
  I'll swap you a decent used LA.40 for it if it is keeping you awake at night. I have a couple of Sterling Skylark "builders kits" that I would like to have a nice McCoy .40 Red Head to put in it.  As long as this one hasn't been too abused already and is still a viable engine.
  I'm not stuck in the past but do spend quite a bity of time there!
   Type at you later,
   Dan McEntee

   
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Offline kenneth cook

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Re: Engine Break in?
« Reply #17 on: March 07, 2021, 05:59:33 AM »
             I can't comment on the .40 but when you say the engine is tight and won't hand start, it had me thinking. I've seen many of the .35's with the wrist pin not square to the piston. This causes the rod to jump back and forth . This really eggs the rod out and also opens the wrist pin bosses. It makes the engine tight and it gives you the illusion that the compression is too much. Taking out the plug and turning the engine over slowly checking for tightness through the rotation is a start. Then do it with the backplate off checking again. It seems a bit strange to me that you can't hand start the engine and the rpm's are down. Not saying that not being broken in isn't plausible. It would just alert me due to the fact you were running a light pitch prop and it was sagging.

Offline BillP

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Re: Engine Break in?
« Reply #18 on: March 07, 2021, 11:34:34 AM »
The 40 RH is perfect for a Magician. I fly one on a Magician (11X4.5 TT prop) and before that it had a 35 RH (10x6 SuperM). The 35 was enough but the 40 gives a tad more overhead tension.

I think something is wrong with your engine or setup, it should turn more revs with a 10x4 regardless of break in. I'd say the 10x4 isn't loading the engine enough for break in either but to each their own. If the engine is in good mech shape I'd look at the muff as a check. I fly mine with a Big Art tongue muff and it has no issues...5/25 all castor Sig. You don't need hours of break in before flying to get long life. My 40RH was nib and I started with a 10x5 wood on the stand. Did that for a few 2 oz runs at blubbering rich. Then changed to a 10x6 wood SuperM for a few more tanks of rich and short leaner run cycles. Maybe a total of 25-30 oz of fuel before taking to the air.  Flew it totally rich for a dozen or so flights with the 10x6 wood. Then  started with 11x4, 11x5, 11x6, 12x3 APC in a 4/2 setting. The APC was too much and taken off after the first flight. I've settled on the TT 11x4.5. The engine now has maybe 40-50 flights between a T Bird and the Magician (which is many yrs for me between flying other planes). Its a couple flip starter with plenty of compression. If I followed everything I hear bad about McCoys this engine would have been totally trashed by now. I needle for take off in 4 stroke and point the nose up to make it 2 stroke. I never fly McCoys with mixture set at 2 stroke for takeoff or anything else...using a standard Perfect #11 tank, no uniflo.
Bill P.

Offline frank mccune

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Re: Engine Break in?
« Reply #19 on: March 07, 2021, 05:01:14 PM »
      Hello Again:

     Just a few comments re. getting the McCoy .40 RH to run up to expectations.  Perhaps things are not as bad as I have thought.

      I noticed a venturi restrictor that had an opening of 1/4 " installed in the engine.  I removed it and  now the venturi  has a diameter of 5/16".  This may give me what I have been looking for in performance.  Also, the temps were in the 30's so starting was a bit more difficult.  My fuel was also at that temp.  Perhaps these two things contribute to difficult starting.  It was also suggested that I NOT use an idle bar plug in this engine. 

     Warm weather is not too far away so I will again try these changes and hope that things improve.

     Again, thanks for all of the replies!

     Stay well,

     Frank

       

     

Online Dan McEntee

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Re: Engine Break in?
« Reply #20 on: March 07, 2021, 06:00:44 PM »
  If that restrictor was put there by the factory, I would not take it out. A 5/16" opening is HUGE and equals .312". I think trying to run it like that will certainly ruin the engine by not being able to run rich enough, especially in cold temps with that much dense air, if you were able to get it to draw any fuel at all. Put the restrictor back in PLEASE!!  Why are you so hung up on RPM?
   Wait for warmer weather and follow the advice you have been given. The swap I offered for a decent used LA.40 still stands.
  Type at you later,
   Dan McEntee
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Online Brett Buck

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Re: Engine Break in?
« Reply #21 on: March 07, 2021, 07:32:12 PM »

      I noticed a venturi restrictor that had an opening of 1/4 " installed in the engine.  I removed it and  now the venturi  has a diameter of 5/16".  This may give me what I have been looking for in performance.
   

   Please put it back in!  .3125 is, again, *far too large* for a very mild baffle-piston 40, at least on suction.   That's much too big for an ST60 (assuming the stock McCoy spraybar) much less a 40. And jumping from .250 to .3125 is a MASSIVE change, 13 of my standard "steps".

    Nothing you can do in a practical sense is going to make this engine into some powerhouse. A Fox 35 is a stronger engine. If you absolutely *must* get more power out of it, then, *nitro* is a much better path than completely unworkable venturis. If you want to run the unrestricted venturi, then, use a bladder tank and deal with the problems.

    Either way, if you pump it up sufficiently , no matter how, this will also destroy it in a tiny fraction of normal life, because it was never designed to handle much more power than it comes with stock.

  Again, as always, it is just advice, do as you wish. But I hate to see you have problem-after-problem-after-problem, all of the same nature, like this.

     Brett

 p.s. Might consider taking Dan up in his offer, too. An 40LA (which is also a very low-end sport motor - from 2000 instead of 1958) is *vastly more powerful* than anything you can manage with a McCoy 40, and you won't likely destroy it trying to pump it up - because it already greatly exceeds your standards, you can just leave it alone.

« Last Edit: March 07, 2021, 07:53:14 PM by Brett Buck »

Offline BillP

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Re: Engine Break in?
« Reply #22 on: March 08, 2021, 08:56:15 AM »
For what it's worth I fly the 40RH without the restrictor...and also fly McCoy 36 SuperStunts (one was also flown on a Magician) without restrictors. I removed them before first mounting so don't have a benchmark on what the difference is. Considering how well they run sans restrictors it's doubtful they will ever be used. I'm basically within a few feet of sea level with high humidity. 

If a 40RH isn't more powerful than a Fox 35 it has to be worn out or have other issues. My 40RH makes major more power than my stock and hemi/stuffer Fox 35s. Even 35 RHs are stronger by a few hundred rpms in every bench test I've done. The 40RH is notably stronger than the 35RH or 36 SuperStunt.
Bill P.

Online Brett Buck

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Re: Engine Break in?
« Reply #23 on: March 08, 2021, 10:11:34 AM »
For what it's worth I fly the 40RH without the restrictor...and also fly McCoy 36 SuperStunts (one was also flown on a Magician) without restrictors. I removed them before first mounting so don't have a benchmark on what the difference is. Considering how well they run sans restrictors it's doubtful they will ever be used. I'm basically within a few feet of sea level with high humidity. 

  OK, well, I guess Frank got the answer he wanted, so problem "solved".

    Brett

Offline BillP

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Re: Engine Break in?
« Reply #24 on: March 08, 2021, 11:30:12 AM »
I don't know what the answer is but Dan and you are on a totally different page than me. I suspect density altitude may be part of it. That made me pull the old insert out and check it. The insert is approx .407 long x .255/.245 inside. The bottom is stepped after the nva for about 1/8" to .245. The engine venturi is .870 long x .321 inside.

Unfortunately I never tached the 40RH but these are what I got for others in order of max rpm...
9.7 rpm 10x6 MAS McCoy 29 SuperStunt well used
10.5           "         Fox 35 -
10.8           "         35 RH
11.2           "         36 SuperStunt

Here's some pics. It's ugly but shows the setup with perfect 4oz tank, Big Art Muff and open venturi.
Bill P.

Offline EddyR

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Re: Engine Break in?
« Reply #25 on: March 11, 2021, 08:19:37 AM »
 Frank you said this is not a new motor. Why are you breaking in a used motor, is this a motor that you put together from parts. Is it something you built from parts. You talked before about a 40 parts motor. The old mcCoy 40 never had a tight fit at the top. They had a brief history of use just before the ST 40-46  came out. Most of the ones used by top national flyers were not stock motors. They did not use mufflers but did use a stack to get the exhaust outside the body. I had a few for rc flying and they wore out very fast.
Ed
Locust NC 40 miles from the Huntersville field

Online Brett Buck

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Re: Engine Break in?
« Reply #26 on: March 11, 2021, 10:29:01 AM »
Frank you said this is not a new motor. Why are you breaking in a used motor, is this a motor that you put together from parts. Is it something you built from parts. You talked before about a 40 parts motor

   Agreed - if this engine is not new, then, there is no reason for it to be "tight". Or rather, there is a reason - it is damaged somehow. Breaking in a damaged engine will not fix it.

    On the other hand, it does make it irrelevant which venturi insert it uses.

   Frank - is this a *new* engine straight from the box?  Or is it built up from parts?

      Brett

Offline Chris Wilson

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Re: Engine Break in?
« Reply #27 on: March 11, 2021, 11:50:44 AM »
Used engine, tight piston fit, low on power - is the piston baffle around the right way?
MAAA AUS 73427

You have enemies? Good. That means you've stood up for something, sometime in your life.
 Nothing in life is so exhilarating as to be shot at without result.  It's not enough that we do our best; sometimes we have to do what's required

Online Gerald Arana

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Re: Engine Break in?
« Reply #28 on: March 11, 2021, 12:21:35 PM »
Check the liner to see if it is installed correctly. I had/have a Veco 29 that I bought on Dabay and the liner was in backwards. It ran but wouldn't peak out. I took it apart and voila , saw the problem immediately! Re assembled it and WOW (!) what a difference.

Cheers, Jerry

Offline Chris Wilson

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Re: Engine Break in?
« Reply #29 on: March 11, 2021, 12:52:15 PM »
Check the liner to see if it is installed correctly. I had/have a Veco 29 that I bought on Dabay and the liner was in backwards. It ran but wouldn't peak out. I took it apart and voila , saw the problem immediately! Re assembled it and WOW (!) what a difference.

Cheers, Jerry
Good point- or the liner.
Your cylinder fit is screwed either way.
MAAA AUS 73427

You have enemies? Good. That means you've stood up for something, sometime in your life.
 Nothing in life is so exhilarating as to be shot at without result.  It's not enough that we do our best; sometimes we have to do what's required

Offline frank mccune

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Re: Engine Break in?
« Reply #30 on: March 16, 2021, 01:28:55 PM »
      Hello All:
     
      I thought that I owe you people who helped me with my break in problem a  final thought.  The problem may be solved.

      After removing  the venturi restrictor, the engine turned 10,300 on a wide wooden 10-6 prop in a wet 2 cycle.  It appeared to draw fuel in a 90 degree attitude and started very easily and broke 4-2-4 vey well. The engine was fed 30% castor and no nitro.  The p&c still have a great seal.  Now, should I run another litre of fuel through it in short runs or is it ready to go into an airplane?  I will be flying with a muffler if that matters.

       Comments/Suggestions?

       Again a big thanks to all of those who responded!

       Frank


     

Offline Air Ministry .

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Re: Engine Break in?
« Reply #31 on: March 16, 2021, 05:21:23 PM »
You tend to see the top circumferance of the piston ' seat ' , get shiney . as it beds in .

If you can ditch it if it leans of , in the airs ( maybe ) o.k. ,

Tockerkickally , it needs to hold a two stroke , on the bench , without ' tightening up ' thru getting hot cause its tightened up , cause its to tight . See Above '.

So in the airs good , IF you can stop it if it sags , squirms or whinges . So Wheelless & a nylon prop . On luxuriant grass , not dust & dirt . or sand .

Offline BillP

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Re: Engine Break in?
« Reply #32 on: March 16, 2021, 10:08:33 PM »
Sounds like you are making progress! Considering the rep that McCoys have for wearing out fast I have to think long break ins are wasting fuel. I flew mine at about the same break in period you are at and it had no issues. First flights were a solid 4 stroke and 2 stroke at the end of the tank. After a few flights leaned it for 2 stroke when the nose was held vertical and back to a 4 stroke when horizontal. I fly Fox Stunts and McCoys RHs the same way, 4 stroke flight with 2 stroke breaks. 
Bill P.

Offline Dave Hull

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Re: Engine Break in?
« Reply #33 on: March 17, 2021, 12:29:38 AM »
Were the bench runs with the muffler on? If not, better repeat a couple of bench runs with the muffler installed to be sure you are still getting what you want.

And if you're still happy, I'd go fly it.

The Divot

Offline frank mccune

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Re: Engine Break in?
« Reply #34 on: April 19, 2021, 11:02:47 AM »
      Hi All:

      Thanks to all who replied

       The McCoy .40 is now running very well.  I replaced the venturi insert as it would not run in a 4 cycle and I did not the need then power of a full time 2 cycle.  It is very easy to start and adjust.

        I think that I will do what Brett and others have  suggested and get rid of all of my old engines and just use modern engines that perform much better. 

        I was asked to why I breaking in an used engine.  I bought it used and it did not have any indication that it had been run in the past.  The p&c were very very tight so I thought that I would err on the side of caution and treat the engine as if it were new.  This produced a very good running RH .40.  Oh yes, it appears to really enjoy fuel containing 30% castor oil and 5% nitro! Perhaps a dash of synthetic oil may help to keep the engine clean.  My flying mate has run 25% castor, 5% nitro and 5% acetone for the last 5 decades in all of his engines and they run perfectly!

        Stay well,

        Frank

Offline Christopher Root

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Re: Engine Break in?
« Reply #35 on: April 19, 2021, 01:40:32 PM »
***************************************************
 "set on the ground so it is just *barely* in a 2-stroke, as rich as it will go and still be two-stroking. When you release the airplane, it *should* go into a constant 4-stroke in level flight, just "rich" enough to stay in a 4 all the time. in the maneuvers, say, a round loop, it should go about 1/4 of the way around, then break into a 2-stroke, stay until it is about 3/4 of the way around, and then go back into a 4 at the bottom. That ought to repeat in consecutive loops. Same thing on outside loops. It should return to a 4-stroke exactly as it was within 1/4 lap, if it takes a lot longer, like an entire lap, then it needs more run time.

   If, when you release it, it stays in a 2-stroke or gets leaner, then, there is something wrong with it, or you have to big a prop. If, when you release it, it slows down to blubbery rich, there is something wrong with it, or you have to large a prop.

     Brett"
*******************************************

Does this apply to smaller engines as well?  Say .15's to .35's?

Online Brett Buck

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Re: Engine Break in?
« Reply #36 on: April 20, 2021, 11:24:16 AM »
***************************************************
 "set on the ground so it is just *barely* in a 2-stroke, as rich as it will go and still be two-stroking. When you release the airplane, it *should* go into a constant 4-stroke in level flight, just "rich" enough to stay in a 4 all the time. in the maneuvers, say, a round loop, it should go about 1/4 of the way around, then break into a 2-stroke, stay until it is about 3/4 of the way around, and then go back into a 4 at the bottom. That ought to repeat in consecutive loops. Same thing on outside loops. It should return to a 4-stroke exactly as it was within 1/4 lap, if it takes a lot longer, like an entire lap, then it needs more run time.

   If, when you release it, it stays in a 2-stroke or gets leaner, then, there is something wrong with it, or you have to big a prop. If, when you release it, it slows down to blubbery rich, there is something wrong with it, or you have to large a prop.

     Brett"
*******************************************

Does this apply to smaller engines as well?  Say .15's to .35's?


  Frank was specifically asking about a McCoy 40, but it generally applies to 35-40 4-2 break baffle piston engines running 6" of pitch in stunt. That seems narrow but it covers a lot of the classic stunt engines.   

     I would also note that there are two things going on here - "breaking in" an engine (which for some reason is being done to a engine that has already been run), and picking a venturi or prop. Frank was/is trying to use a large venturi to get a particular, probably unrealistic, RPM on a particular prop. I was trying to give him a way to determine whether it is excessive for practical use, after having one problem with grossly excessive venturis after another, on a wide variety of engines, while also having low power very consistently.

   There is some factor we are not seeing here. I very strongly suspect that a competent expert pilot could probably figure out the missing element, have an "A Ha!" moment and at least diagnose the issue in about 10 minutes. That's the problem with trying to figure out everything at once by yourself, no one knows this stuff naturally. What is going on here is a bunch of people trying to land an airplane over the radio like "Airport 75", with people yelling "give it up, give it down!" at Frank over the internet, while we attempt to put the peices together remotely as to what the real problem might be.

   The venturi sizes that will work are in a very narrow range, there is no real debate about what the range is, or what venturi needs to be on particular common engines. If you are just going to experimentally discover the right range, you need to evaluate what you see accurately, and make appropriate decisions. In general, when you take off, the engine should "go rich" - that is, sounds the same way it sounds if you opened the needle one click on the bench. In reality, the actual mixture might get richer or leaner depending on the tank setup, the effect is really due to a change in the load (it goes down...) but it will be universally be interpreted as "richer". Same in the maneuvers, it should "lean out" - that is, sound as if you closed the needle a click or two to "lean it out".

     Excessive version of these changes are probably due to too much prop or (in this case) excessive venturi choke area. If you are *way* over the top on either, the effect will go backwards to the above description, and a very excessive venturi will cause it to "go hard lean", i.e. the dreaded runaway.

  You are *much better off* if you do not fully grasp these effects *starting with a smaller venturi* and working up to larger ones. At least it will needle properly and you will begin to understand how various things are supposed to work. If, after a lot of experimentation, you are having to set it too lean to get adequate speed, *then*, you start trying to bump up the venturi *in small amounts*. .005" of diameter is a pretty good change. What usually happens, however, is that people start too big, and then start "diagnosing" the problem as too much compression or some other thing *that is best left alone*, and never work their way down because everyone know that You Can Never Have Too Much Power!(tm).

    Note that some of the effects can also be break-in effects, particularly, going lean in-flight (due to the engine tightening up when it gets hot and increasing the load, which tends to feed on itself) is a classic "I need more run time". If you don't know exactly what you are doing - or even if you do - it can be pretty easy to misinerpret the signs.

     This is also why I would suggest running engines *stock* first - because at least you know it was "right" in some sense. When you get modified engines from who-knows-where-random-local-expert, it may be pre-screwed-up because many of the local experts don't understand it any better than the customer, and have just enough knowledge to be dangerous.


     Brett

Offline frank mccune

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Re: Engine Break in?
« Reply #37 on: April 26, 2021, 09:36:15 AM »
     Hello Brett:

     Your final post makes sense.  I have been made a convert to the KISS method using model engines.

      It is “fun” to play with these engines but to improve them at home is a fool’s errand.” The designers did a great job of developing a great product.  The other thing that I can’t deny is that the modern engines are vastly better than what was produced in the 50’s and 60’s.  No more nostalgia for me! Lol.

        Thanks for all of the good advice.

         Frank McCune


Online Dan McEntee

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Re: Engine Break in?
« Reply #38 on: April 26, 2021, 11:16:37 AM »
     Hello Brett:

     Your final post makes sense.  I have been made a convert to the KISS method using model engines.

      It is “fun” to play with these engines but to improve them at home is a fool’s errand.” The designers did a great job of developing a great product.  The other thing that I can’t deny is that the modern engines are vastly better than what was produced in the 50’s and 60’s.  No more nostalgia for me! Lol.

        Thanks for all of the good advice.

         Frank McCune

      Well, my offer of a swap of a LA.40 for your McCoy .40 if you are so inclined still stands. Just PM me off list and we'll work it out.
     Type at you later,
  Dan McEntee
AMA 28784
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Offline Christopher Root

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Re: Engine Break in?
« Reply #39 on: April 27, 2021, 08:40:34 PM »
Just took a McCoy .19 off my Akromaster and replaced it with an Enya .15– couldn’t be happier! All those years fiddling with McCoys, trying to get them to run consistently. The Enya’s and OS’s just start right up!  Wish I had found this forum years earlier— thank you!

Offline bob whitney

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Re: Engine Break in?
« Reply #40 on: April 27, 2021, 09:33:07 PM »
  I'll swap you a decent used LA.40 for it if it is keeping you awake at night. I have a couple of Sterling Skylark "builders kits" that I would like to have a nice McCoy .40 Red Head to put in it.  As long as this one hasn't been too abused already and is still a viable engine.
  I'm not stuck in the past but do spend quite a bity of time there!
   Type at you later,
   Dan McEntee

   
Dan, how about a new Blue head 40
rad racer


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