Os.46fx
05-13-2003 | 07:17 AM
#1
Thread Starter
Senior Member
Os.46fx
Hello Bill Baxter,
I may have started this hype about the OS break-in procedure being incorrect.
I started the thread about: "Break-in in tapered bore engines",
http://www.rcuniverse.com/showthread...59&forumid=145
I have my own 46FX, which has been broken-in by the vendor who sold me a pre-built WM T-34 ARF. It was clean and I believe, not used. I don't know what break-in method was used. The muffler baffle was removed by the vendor.
I have only used commercially available, 5% nitro, Model Technics, Morgan Omega and Byron Sport fuels, to which I added Castor oil to a total of 20% lubricant (I use the same fuel also for my MVVS engines, who specify 20% oil).
The props I use are MA 11x6 and Bolly 11.5x6 (and for a short time a 10.5x8). Reliability has been exemplary; never did I have to land with the engine off, unless I intentionally shut it down in the air. It never had a lean run either. It went through two glow plugs, which needed replacement because the element became scaled. I am on my 3rd OS No.8.
The engine, although about two years old, has a total of only 30-40 hours on it, on paved runways (no sandy environment) and lately has been performing less than satisfactorily.
Although idle and starting are OK, warm compression is low and power is low as well. I can only get about 11,400 RPM on the Bolly 11.5x6, and maybe a little over 12K with the 11x6 MA.
The Bolly 10.5x8 used to show 12,300 RPM, but I haven't tached it with it lately.
I removed the head and found no trace of peeling on the liner (a problem, from which a .40 FP I had did suffer. I conversed with Mr.Clarence Lee of RCM about it), although it seems to be shiny black, instead of being chrome like shiny.
Could my engine be worn out after so little running time?
You can reply to my E-mail: [email protected]
Please give my regards to Ms. Anne-Marie Cross, although I disagreed with her, about a problem I still have with my 6XAs... It is very usable non-the-less.
Sincerely,,
I may have started this hype about the OS break-in procedure being incorrect.
I started the thread about: "Break-in in tapered bore engines",
http://www.rcuniverse.com/showthread...59&forumid=145
I have my own 46FX, which has been broken-in by the vendor who sold me a pre-built WM T-34 ARF. It was clean and I believe, not used. I don't know what break-in method was used. The muffler baffle was removed by the vendor.
I have only used commercially available, 5% nitro, Model Technics, Morgan Omega and Byron Sport fuels, to which I added Castor oil to a total of 20% lubricant (I use the same fuel also for my MVVS engines, who specify 20% oil).
The props I use are MA 11x6 and Bolly 11.5x6 (and for a short time a 10.5x8). Reliability has been exemplary; never did I have to land with the engine off, unless I intentionally shut it down in the air. It never had a lean run either. It went through two glow plugs, which needed replacement because the element became scaled. I am on my 3rd OS No.8.
The engine, although about two years old, has a total of only 30-40 hours on it, on paved runways (no sandy environment) and lately has been performing less than satisfactorily.
Although idle and starting are OK, warm compression is low and power is low as well. I can only get about 11,400 RPM on the Bolly 11.5x6, and maybe a little over 12K with the 11x6 MA.
The Bolly 10.5x8 used to show 12,300 RPM, but I haven't tached it with it lately.
I removed the head and found no trace of peeling on the liner (a problem, from which a .40 FP I had did suffer. I conversed with Mr.Clarence Lee of RCM about it), although it seems to be shiny black, instead of being chrome like shiny.
Could my engine be worn out after so little running time?
You can reply to my E-mail: [email protected]
Please give my regards to Ms. Anne-Marie Cross, although I disagreed with her, about a problem I still have with my 6XAs... It is very usable non-the-less.
Sincerely,,
05-13-2003 | 01:43 PM
#2
My Feedback: (11)
Os.46fx
Your engine may or may not be OK. The low compression you feel may be the result of improper breakin, or it could be from some other source. How it runs is the determining factor.
The RPM measured is very dependent upon the propeller and fuel. We can only state what we use to give a comparison. As soon as the brand of propeller is changes, performance numbers will change, sometimes dramatically.
We've never used a Bolly prop, so we have absolutely no idea how they should perform. In all of our testing, we us APC because they give us very consistent results when we make replacements.
An 11 x 6 APC will turn in the high 12,000's, and a 10 x 7 APC will usually turn in the mid-12,000's. That's using the stock muffler and Omega 10% nitro fuel.
Your engine may be running just fine with the props you're using. Blade profile and thickness can make tremendous differences in the resulting RPM. However, if your engine is performing low, then you may need to replace the piston/cylinder assembly and re-breakin your engine.
The RPM measured is very dependent upon the propeller and fuel. We can only state what we use to give a comparison. As soon as the brand of propeller is changes, performance numbers will change, sometimes dramatically.
We've never used a Bolly prop, so we have absolutely no idea how they should perform. In all of our testing, we us APC because they give us very consistent results when we make replacements.
An 11 x 6 APC will turn in the high 12,000's, and a 10 x 7 APC will usually turn in the mid-12,000's. That's using the stock muffler and Omega 10% nitro fuel.
Your engine may be running just fine with the props you're using. Blade profile and thickness can make tremendous differences in the resulting RPM. However, if your engine is performing low, then you may need to replace the piston/cylinder assembly and re-breakin your engine.
05-13-2003 | 02:26 PM
#3
Thread Starter
Senior Member
46FX
Hello Bill,
Thank you for your prompt reply.
From my description of the inside of the sleeve; Shiny, smooth, dark surface, not the silvery shine I expected to see. No "step" above the piston travel, no scratches, no peeling nickel; can you conclude something?
Is it not supposed to have a metallic shine?
This is my only ABN engine, so I don't know how to identify when it is worn. In ringed engines there is a definite "step" above the ring travel and I never had an ABC engine wear out on me.
So please tell me what I am supposed to sense, when my 46FX's piston/sleeve set needs replacement.
I was told it would not idle, would not accelerate, would give low power, low compression... Now compression is low only when the engine is hot, but even then it is still enough to hand start.
Sincerely,
Thank you for your prompt reply.
From my description of the inside of the sleeve; Shiny, smooth, dark surface, not the silvery shine I expected to see. No "step" above the piston travel, no scratches, no peeling nickel; can you conclude something?
Is it not supposed to have a metallic shine?
This is my only ABN engine, so I don't know how to identify when it is worn. In ringed engines there is a definite "step" above the ring travel and I never had an ABC engine wear out on me.
So please tell me what I am supposed to sense, when my 46FX's piston/sleeve set needs replacement.
I was told it would not idle, would not accelerate, would give low power, low compression... Now compression is low only when the engine is hot, but even then it is still enough to hand start.
Sincerely,
