Flyer95

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Hi Guys,
I need some expert help here!! please.
My first piston/ liner peeled like those bad OS batches many people talk about. This engine is more than a year old so it is not made by the OS. Damages was covered by the warranty, and the piston, liner, conrod and the rear bearing was replaced.

About 3 gallons later I have found many deep scratches on the piston and liner of my excellent running Irvine 53 ABC engine[]. I was changing the bearings when I saw them. I use fuel filters to the tank and between the tank and the carburetor. There was some metallic particles at the top of the head and upper side of the piston which I have removed by now.The engine has always been running with no less than 20% oil, half of it being castor oil. Thanks for any suggestions.

j.duncker

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Any chance of grit or dust being sucked in with the air?

If you have a dusty field that will do it and ruin an engine in minutes.

The car boys run air filters for that reason.

Flyer95

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I have been flying this airplane only on grass field, which is not dusty at all, and the engine is in the upright position, but no cowling.

Hobbsy

My Feedback: (102)

The important thing is, how is the compression, I'll bet it's great. I have several ABC type engines that appear to have scratches, when looking in the exhaust port of my Webra .91 you would wonder how it can run and yet when you turn the prop driver there is no leakage.

Flyer95

My Feedback: (1)

The engine is on a tuned pipe and the power and compression is very good turning a APC 13x6 between 11500-12000rpm peaked. I just prime it and only one or two backflips is needed to get started[sm=thumbup.gif]. But there was some metallic particlec in the combustion area [] stucked on the top off the piston and in the head around the glowplug[:@], inside the engine is clean and shiny. What could have caused this "damages"?

RC-Captain

I am no expert, but have read allot here in RCU and what you are describing is exactly what caused my OS .40 to get damage in the same way . RICH RUNNING ! I am not yelling just wanted to make the words apparent to any one reading the post . GL


RCF esq.

downunder

It's not from rich running.

My guess is detonation. You're running at around peak torque which means highest combustion pressures, plus it's on a pipe so you have the supercharging affect which adds even more pressure. You don't state how much nitro or what plug but reducing nitro and/or a cooler plug would help. Or lowering the compression a little.

rmh

Also along with detonation - have you lost any plug elements? (this goes along with running too much compression/too lean and or both.)

RC-Captain

I guess this statement is written to contradict all of the information I have read on RCU , including the pic I put in a forum of my .40 engine's cylinder and piston which most agreed it was due to rich running not to mention I was running the engine 1 turn past the standard setting for normal running from the time I received the engine ?

You are a hard act to follow my friend.

MrMotor

You mentioned replacing the bearings. Could the metal pieces be from the OLD bearings losing part of their retainers? Otherwise I believe the engine is run overloaded with that much prop and pipe combo using too much nitro or too hot a plug. As stated earlier, could the parts be old plug elements that have gone through the engine into the pipe and stuffed back into the engine from the pipe when the engine comes on pipe?

Bodge

The Irvine 53 and well-tuned pipe will turn a 13 x 6 comfortably.

Flyer95

My Feedback: (1)

Hi,
Thanks for all the replys. I used 5% nitro in the fuel and the plugs I have used are McCoy55 and TowerPowerplug which is very similar to the OS8 plug I think. I think I also tried the the OS-F on this engine in the beginning when it was cold weather here.

I could not hear any detonation but it is very possible because after I had to change the bearings that fast I also got suspicious and lowered the compression by putting a thick shims 0,6mm instead of the original shims which was about 0,2mm. And to my surprise the idle and the top end power was just as good as before.

Old plug elements also is one possibility, or the old bearing losing parts from the retainer. The bearings also lasted for only 5-6months and 3 gallons of fuel which is less than any other engine I have ever owned.
I think however you guys got me on the right track now.

blw

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RCFiend,

You sound a little rough on downunder. Why were you running an engine one full turn past what the manufacturer specified? Maybe you can clear up some questions here....

RC-Captain

LOL , rough ? Naw, just trying to get a point across that was over looked when I was a nooby. I received some info on here about 1 year and a half ago and I also down loaded the manual for the OS .40 LA . Long story short, I read the wrong specs for this engine as you know OS puts high and low speed settings for more than one engine in one manual and also I listened to the wrong info. for setting the high speed needle.

It's funny though, I clearly remember a guy walking up to me and he mentioned I should be getting more power out of the OS .40 LA . now I know why ... go figure.

downunder

No, not really. It's written from 40+ years of running engines very rich (my main area is C/L stunt) plus all the other thousands of C/L stunt fliers who run their engines the same way and no one has ever had any problems. You should hear my OS 40VF (ABN) running in a 4 stroke on its pipe...as Cartman would say, "sweeeeeet"

As for the OS peeling issue, George Aldrich put it down to the fact that their nickel plating only held up if a lot more oil than is found in normal RC fuel was used. His recommendation was for 22% oil.

However, the rich running myth persists

RC-Captain

so be it , so far the other three OS engines I have don't have peeling problems ....[:-]

Harry Lagman

Grasshopper, you have much to learn...

With more experience in RC and more time hanging out on RCU, you will learn to identify, learn from and respect those who know what they're talking about. Here's a time saver: Downunder is one of those!

RC-Captain

If I only had a dollar...................

Downunder is very knowledgeable about RC engines at least the ones he has run in his planes and the ones he has physically seen in use , but as far as kissing the ground he walks on because he answers every question about engines which he doesn't have the full background on is just pure nonsense.

My father is a mechanic , he is 66 and retired down in Florida thanks to me driving him and my MOM there last week in a car that has 127000 + miles on the odometer. Now once again tell me how much knowledge I have about any kind of engine. I was born learning how engines operate and would never proclaim to know it all about an engine I have never seen heard or touched. GL and do as you will.

SST

My Feedback: (2)

Listen, kid. I've been swinging wrenches for 35 years. I was a mechanic in the Army. I've worked for Buick for 29 years. I spent several of those years on the line and machine floor in factory 36 building engines and their components. 127,000 miles? I drove a '78 Mercury Marquis 400 (not exactly an engine of legendary longevity) with 214,000 miles to work until it finally spun a rod bearing. I kept driving it to see just how much farther it would go, and that was an interesting week getting to work...And I listen to what Downunder has to say. Your 'expertise' has already alienated you from most of the SPAD forum guys. Do yourself a favor and pay attention to those who know what's what, and don't pontificate.

CCRC1

My Feedback: (13)

Maybe we should listen to some things he has to say...................[sm=tired.gif]

RCPAUL

My Feedback: (1)

First:

RC-FIEND stick to your guns. Running an RC in a rich mode will increase the wear significantly and you can do serious damage, including damaging the piston/liner and even, in a few cases, breaking the conrod.

True, UC folks do run ABC and ABN engines in a rich mode, and often with more oil in the fuel than RC people usually use. However, as most engine folks will know, this causes the engine to never get up to full temp and thus wears in to a much looser piston/sleeve fit than an RC run where the engine is at a higher temp resulting in a tighter fit. Many UC folks run their engines around 8500-9000 rpm usually - just between a two and a four stroke - and in a very narrow rpm band. Thus the engines run in a very constant temperature mode - these engines have a looser fit than a typical ABC RC engine. Other UC folks run them in a fast two stroke just as the RC guys do. (Ask me how I know!)

I object to people saying "I've run engines for 40+ years and thus must know what I'm talking about." Bull! By the way, only 40 years - you must be a newcomer!


Paul

RC-Captain

This is all bandwagon material and has nothing to do with the post so I refuse to respond.

Maybe I do , how do you know I don't ? or are you just part of the hate RC-Fiend clan. I can't believe you waste your time trying to convince me to think like you. Let's see, other then my first engine OS .40 , I haven't had any problems breaking in the other 3 OS engines I have. Now the MAG .28 , being a piece of junk IMHO, had to have something altered to get it to run properly. The OS .40 was a used engine and I didn't have a manual and you know the rest of the story.....

The reason I am not fond of Downunders comments is because if you really read his post and I mean really read them , he contradicts himself often. A man who can't admit he makes mistakes isn't a man, period.


So it can't be detonation, because all of my engines would have the same problem. The list above is standard engine equipment.

GL all and enjoy.


PS I don't really mind being alienated from the SPAD or any forum for that matter. I have a mind and I know how and where to find information if anyone refuses to help me in RCU. Get a grip, this is one forum out of thousands and quite frankly I am getting sick of the attacks from bone headed individuals that offer no help at all only demeaning words. REMEMBER, you reap what you sow.

Hobbsy

My Feedback: (102)

We need to bring this back to talking about RC Glow engines.

Sport_Pilot

Now, I'm not an expert or anything and I haven't used an Irvine, but many English engines are built for low nitro. That is that same engine may detonate with 10% nitro with a 11-5 prop in warm weather, or it may detonate with a 13-6 prop and 5% nitro in warm weather. Not saying it is, but I know my ASP red head .91 will detonate with a 14-8 and 5% nitro if it is real hot outside. I normally run it with a 13-6, 13-8, or 14-6. No problem with those props. He was using rather hot plugs also, which could also make a differance. However I suspect his problem is actually debris from a poor bearing.

Sport_Pilot

I have flown control line, and for a short time I observed a control line competition here in Marietta, Ga. this past weekend. Those planes must run in a two stroke mode for an extended period during repetitive manuevers such as three consecutive loops, then a half lap and another stunt. They seem to run well in that two stroke mode. I have a couple of R/C ABC engines that have very little pinch at the top. They run very well that way, better than a recently broken in ABC engine with plenty of pinch. But this has noting to do with pealed liners, that is a result of poor plating and lots of heat and wear, which doesn't happen with rich running. Unless you are flying in lots of dusty sandy air.