Breaking in engine.... awww... c'mon guys, help!

LAST EDITED ON Dec-14-03 AT 09:08 AM (CST)
 
Well guys, I built a McCoy 40 RH Lighting Bolt from parts. A brand new piston was a very tight fit in the sleeve, and I have begun to run it in. I have been using Sig 25% all castor w/ added castor. I have put 30 min. on it with 4-5 min runs in a 4 cycle. I let it cool completely between runs.(air temp mid-upper 40's) Last two runs were a "good" 4 cycle. It is getting "free" now, and has excellent compression.
I noticed a drop of fuel falling from the front bushing about every minute. There is no play in the bushing, side to side, etc., but being that this is my first Mac RH 40, is that usual? Also, should I put about another 30 min on it? I guess I should treat it like I would a Fox 35 ??
Thanks
Bill

LAST EDITED ON Dec-14-03 AT 09:22 AM (CST)
 
The single drop of fuel from the front of the shaft every minute is very good (in my opinion). That is a bushed main bearing and needs "some" cooling and lubricant up there. I would think that some more wouldn't be unusual nor bad. As for break in, Treating it as you would a Fox is ok. I would use a mite more oil (all Castor) say 28 to 29 %. and avoid over lean runs at all costs.
Sounds like you got a good one.

Bigiron

Thanks, Marvin!
I added some more castor, about 3oz., to a partial gallon of Sig 25% all castor. (about 8 oz. were missing)
I had just not noticed the "drop" before when running on the stand with other engines. Been a while since I had to run in a steel/iron set up.
Thanks, again!
Bill <><

THE PROP, What about the PROP? Are you taching the engine? Are you cycling the engine run. Pinching the fuel line and then let it go so the engine rev's up and then back to 4 stroking. Running it at 4s will take forever to break it in.

Scott(Took two gallons before mine was ready to go)Riese

Hi Scott,
I am using a 10 X 31/2 Top Flite nylon prop that Big Art suggested about 10 years ago. Turning about 7000-7500 rpm. I do squeeze the line a few times each run. Haven't tried to see if it will hold a 2 cycle run yet. Have 30 min on it now.
I will just keep on! (for da dirt)
Anything else?
Thanks
Bill <><

Get your RPM'S up, put on a 10X5, it's time.

Will do. Tuesday, barring the weather, it will get the 10 X 5 and up go the rpm.
Thanks!
Bill <><

P.S. Did you get my email?

I'm confused. How will going to a 10x5 from a 10x3.5 increase the RPM? Increasing the pitch should put more load on the engine. I would opt for the 9x6 and see if the engine frees up a little. 7800 is pretty low RPM for that engine. I would hope to use a 10x5 after it's broken in.

It sounds like you have plenty of oil and you definitely want to see some weeping from the front end. That's the only way the crank gets lubed.

My two cents. Have fun and I hope it works out for you.

Ron King

Hi Ron,
I was hoping to use a 10 1/2 to 11 inch 5 pitch when I use it.
Actually I have now decided to use the 10 X 6 3 bld. black tornado (last one I have) on my rebuilt P-47.
We will see.
As for increasing the rpm, I'll have to go in on the needle if I go to the 10 X 5 for the rest of the break in.
Bill <><

>I'm confused. How will going to a 10x5 from a 10x3.5
>increase the RPM? Increasing the pitch should put more load
>on the engine. I would opt for the 9x6 and see if the engine
>frees up a little. 7800 is pretty low RPM for that engine. I
>would hope to use a 10x5 after it's broken in.
>
>It sounds like you have plenty of oil and you definitely
>want to see some weeping from the front end. That's the only
>way the crank gets lubed.
>
>My two cents. Have fun and I hope it works out for you.

Well you turn in the needle. PUT some load on the engine.

Running it with a 3.5 is not enough pitch. FOR THE FIRST FEW RUNS it a good choise.

LAST EDITED ON Dec-15-03 AT 08:12 AM (CST)
 
Scott,

Maybe we are talking about the same things, but in a different language. Turning in the needle valve will lean out the mixture and the increased RPM will add more load.

Changing to a 10x5 prop will definitely increase the load. Changing the prop and leaning the mixture will increase the load and the rpm - but will also increase the heat.

Since we never got any info on cylinder head temperature, I'm not sure which way we should go. The engine definitely needs a certain heat range to break in properly. If changing to a 10x5 and leaning it out gets it to that good range, I agree with you.

I have always stayed with the lower pitch props for break in because I had more room for error with my needle valve setting. 7800 RPM seems too slow for a 3.5 inch pitch and would lead me to believe the engine was too rich (and cold). But since I didn't have my hand around the cylinder head I cannot say for sure.

Two more cents.

Ron King

RON...same answer, better put.

HEAT IS THE KEY to break in a engine

I got computor problems so I got to go &**%$#

In the instructions he sent with one of his tweaked Fox .35's, GMA recommended a 9×6 (down an inch from the "standard" diameter to decrease load while keeping the same pitch to maintain cooling while the engine is not moving through the air) for break in. I always used to use a 10×3½ or 10×4 (or even a very flat 11"--I liked the flywheel effect for new engines with whose operating characteristics I wasn't yet familiar) myself, but, when breaking in this engine, I'll follow George's recommendation. He broke in and ran a lot more of these than I'll ever run.

>Hi Scott,
>I am using a 10 X 31/2 Top Flite nylon prop that Big Art
>suggested about 10 years ago. Turning about 7000-7500 rpm.
>I do squeeze the line a few times each run. Haven't tried
>to see if it will hold a 2 cycle run yet. Have 30 min on it
>now.

Be-careful on running it to rich (sloppy Rich). It causes a lot of stress on the connecting rod and piston. The richer you run it the higher the cylinder pressure. Even on a Fox this is bad, I do the test runs on the Fox 35's with a 10X4 APC and I set them right around 10,000 RPM, they are in a four cycle at this speed. When I break them in I continue this for 8oz, two ounces at a time then I go to a (9X6), then to a 10X6 until they are ready for airtime. I've tried a lot of ways to break them in and they all work some ways are just faster then others. A fast four cycle is always best, my opinion and we all know what they say about opinions.

Larry

Thanks Larry!
I think I need to go to the 9X6 now, and turn in the needle some.
Will probably put another 30 min on it, finally going to a 10x6.
Bill <><

Fuel "weep" from the front end is not untypical of bushed engines, especially the McCoy and Fox engines. I have sen this since the 50's and thought it was normal. It is unusual to not see it. See my private secret message. Ha

Ty,
Did you get my message on the spinner? I have not received anything from you since Thursday. Email or call!
Bill <><

I just replied on the "secret" mail list on Stuka Forum. However I will call.

Hi Bill,

I am far from the expert, but I would have to agree with most on this thread....oil seeping out of the front bearing is probably okay. I had a McCoy 35 lightning that did it real bad, but it didn't seem to affect how it ran or anything else for that matter. I know some of the old style bushings were even cut with a spiral in them to encourage oil flow through the front bearing.

I use a Top Flite 9 x 6 Super M with Fox Super Fuel for most of the break-in running with the old style engines. What I read in several pieces of literature that George Aldrich sent with the engine he did for me indicated to run it rich for 3-4 minutes at a time and to let it cool off all the way in between runs to "season" the metal. I also pinch the fuel line for a second or two every now and then to keep the rpm variable.

I would think that if it is real tight to begin with, you should notice the engine loosening up a little after about the third or fourth run and I would think that the compresssion would get better, too.

Regards,