News:


  • April 24, 2024, 07:12:28 PM

Login with username, password and session length

« previous next »
Pages: [1]   Go Down

Author Topic: Engine Worn Out?  (Read 1666 times)

Offline Dave Moritz

  • 24 supporter
  • Trade Count: (0)
  • Captain
  • *
  • Posts: 405
Engine Worn Out?
« on: March 23, 2019, 04:10:13 PM »
Hello All:

How do you know when an engine is just too old and needs to be rebuilt or put out to pasture? The case in point here is an OS 20FP, probably an early version with Enya needle valve. It came with R/C carb, so was likely run that way. I have a nicer one of these with the same needle valve that starts much better.

I just spent 45 minutes propping this pup and finally got it running. After endless combinations of needle valve, primer amount, and even tank height adjustments, my poor arm is done for the day. But it does run.

I'd hoped to mount this on a crashworthy model, but not if it is a hard starter. Thoughts? I don't have much invested in this.

Dave Mo...

Logged
It’s a very strange world we live in, Master Jack.” (4 Jacks and a Jill)

Offline Joe Ed Pederson

  • 23 supporter
  • Trade Count: (0)
  • Captain
  • *
  • Posts: 472
Re: Engine Worn Out?
« Reply #1 on: March 23, 2019, 07:04:36 PM »
Quote from: Dave Moritz on March 23, 2019, 04:10:13 PM
Hello All:

I just spent 45 minutes propping this pup and finally got it running.
 
Dave Mo...

Dave,

I hope your shoulder is OK tomorrow.  Last year in May (age 64) I spent too much time flipping a prop and my shoulder didn't properly recover for 6 months. 

I don't know how old you are but there will probably come a day when flipping a prop for more than a few minutes will be unwise.

I don't have that much experience with glow plug motors, but I have learned this so far: if it doesn't start in a reasonable number of flips, try a different glow plug.   Just today I was bench running an old steel fin Fox .15 for the first time since I got it.  The first glow plug didn't get her going.  Changed the glow plug and problem solved.

Joe Ed Pederson
Cuba, MO
Logged

Offline Dave Moritz

  • 24 supporter
  • Trade Count: (0)
  • Captain
  • *
  • Posts: 405
Re: Engine Worn Out?
« Reply #2 on: March 23, 2019, 08:33:05 PM »
Some good points to ponder from Ty and Joe Ed.

Ty: Prop is APC 9x4; fresh fuel is 8% nitro & 25% castor; unknown glow plug that lights up nicely.
Compression seems a bit light to me. No unusual crank motion so bearing feels good. Piston top is dark gray, piston side is dark gray also. No scoring that I can see. Cylinder inside looks shiny.

As mentioned, I finally got it to run so I recorded the needle setting and the fact that it needed no prime to start. Will probably give it another try tomorrow before I have to head out of town.

Joe Ed: You and I are close to the same vintage. I'll be careful as the thought of a six-month recovery period sounds daunting. If I don't get results tomorrow with much less flipping, I'll try a different plug and see if that is the ticket. In the mean time, Ibuprofen for my shoulder.

Thanks, gents!

Dave Mo...
Logged
It’s a very strange world we live in, Master Jack.” (4 Jacks and a Jill)

Offline Fredvon4

  • 23 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 2099
  • Central Texas
Re: Engine Worn Out?
« Reply #3 on: March 24, 2019, 09:35:32 AM »
electrikery finger....no more sore wrist/shoulder/achy elbow
Logged
"A good scare teaches more than good advice"

Fred von Gortler IV

Online Dan McEntee

  • 23 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 6866
Re: Engine Worn Out?
« Reply #4 on: March 24, 2019, 10:00:23 AM »
   If an engine is truely worn out, it will not run at all if it doesn't have sufficient compression. I have experienced this with both slug type and ringed engines. I had a ST.46 in a Chipmunk, that was running just great! Put in a flight, landed, waited my turn on the circle, and even with electric fingers it would not start. Gary Hajek was there and said the ring wore out, right on that last flight. I bought a ring from him, called Tom Lay and pleaded with him to tell me how to service the ST.46 so I could fly the Chipmunk at the SIG contest the following weekend, and he relented and told me. I gapped the ring, installed it, put in 5 or six ground runs to seat it and all was well after that!
  Type at you later,
   Dan McEntee
« Last Edit: March 24, 2019, 07:30:10 PM by Dan McEntee »
Logged
AMA 28784
EAA  1038824
AMA 480405 (American Motorcyclist Association)

Offline Dave Moritz

  • 24 supporter
  • Trade Count: (0)
  • Captain
  • *
  • Posts: 405
Re: Engine Worn Out?
« Reply #5 on: March 24, 2019, 10:14:56 AM »
Thanks a bunch, Dan, for the tip on how to judge a worn out engine. Now I know!

Joe Ed - you are the man! I replaced the glow plug and it fired up.

An electric starter is in my future, Fred.

All's well that ends well. Thanks to all for bearing with me on this.

Dave Mo...
Logged
It’s a very strange world we live in, Master Jack.” (4 Jacks and a Jill)

Online Dan McEntee

  • 23 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 6866
Re: Engine Worn Out?
« Reply #6 on: March 24, 2019, 01:36:50 PM »
   Hi Dave;
  One thing to remember also, is do not underestimate the ability of your glow plug to leak compression. They are made by machines run by humans and have the capacity to spit out a bad one now and then. Some brands are more prone to this than others. That may have been your only problem. Just because you checked it with a battery and it glowed, doesn't mean it's good! Ever have a Cox engine not want to start, then reach over and twist the glow plug and it turned with your fingers? Common occurrence with that breed.
   Type at you later,
  Dan McEntee
Logged
AMA 28784
EAA  1038824
AMA 480405 (American Motorcyclist Association)

Online Brett Buck

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 13737
Re: Engine Worn Out?
« Reply #7 on: March 24, 2019, 03:48:01 PM »
Quote from: Dave Moritz on March 23, 2019, 04:10:13 PM
How do you know when an engine is just too old and needs to be rebuilt or put out to pasture? The case in point here is an OS 20FP, probably an early version with Enya needle valve. It came with R/C carb, so was likely run that way. I have a nicer one of these with the same needle valve that starts much better.

   I don't think that any of them were delivered with an Enya needle valve, even the early ones.

     If this is an iron-liner version, my guess is that someone ran it on something like Omega or Cool Power in RC, and that wore it out. I have only run the ABC version, although the iron-liner versions seem to work pretty well as long as you have enough castor. My first engine is still in good shape, even though I ran it on gasoline and vegetable oil (with a little Powermaster to get it to fire). I haven't seen anyone wear out an ABC version when run as recommended.

    Brett
Logged

Offline Peter in Fairfax, VA

  • 23 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 1109
Re: Engine Worn Out?
« Reply #8 on: March 24, 2019, 06:21:01 PM »
A comment about electric starters.

There is a technique called "motoring" to break in an engine.  Some of the more complex multi-cylinder four stroke manufacturers use it, as do some car racers.  The idea is that you use a starter motor, or similar, to simulate an actual run.

My experience as a hobby shop employee is similar, if dated.  Beginners would report that they finished their model, but now can't start the engine.  I was dispatched with an electric starter.  Typically, I would pull the plug, then make sure that a starter run resulted in plenty of fuel being run through the engine.  After that, I would installed the plug loosely, then start the engine. 

Most engines will run with the plug loose, which makes the starter application easier.  Starting with a loose plug was locally popular for high compression boat engines.  Decompression starting is not unusual in the IC world.

With the engine warmed up and a little broken in, regular flip starts with a plug installed could then be demonstrated.  Customers would often respond by finding that an electric starter was essential.

Peter
Logged

Online Dan McEntee

  • 23 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 6866
Re: Engine Worn Out?
« Reply #9 on: March 24, 2019, 07:46:50 PM »
Quote from: Brett Buck on March 24, 2019, 03:48:01 PM
   I don't think that any of them were delivered with an Enya needle valve, even the early ones.

     If this is an iron-liner version, my guess is that someone ran it on something like Omega or Cool Power in RC, and that wore it out. I have only run the ABC version, although the iron-liner versions seem to work pretty well as long as you have enough castor. My first engine is still in good shape, even though I ran it on gasoline and vegetable oil (with a little Powermaster to get it to fire). I haven't seen anyone wear out an ABC version when run as recommended.

    Brett

   Just curious as to how common an iron liner version of the FP-20 might be? Iron piston also? I have heard this mentioned about early FP-.35 and .40's, but I don't think I have ever seen one of those either. I think I remember it was mentioned there is a slight difference in the bump on the case on the by pass port side? I have a couple of the steel fin OS.20 and .25 engines but I don't think they can be mistaken for FP versions.  I'm going to hit a swap meet or two next weekend and will be on the look out!

  Model glow engines are kind of part diesel, they need compression to to make combustion. If it ain't there it ain't happening!  Have you ever read on here about guys having one of the newer engines fire and run just by flipping them through while tinkering on them with no battery? I worked part time at a local hobby shop also for about 35 years and was a resident engine guy. When the R/C car engines came about, I learned of the loose plug method of getting them to turn over for the first few runs. I was really surprised that it worked the first time I tried it! Those early engines were really tight, and I helped many a customer learn how to rewind a pull starter chord. The early Traxxas on board electric starter would eat the little motors they had, but Traxxas stood behind them and sent us boxes of new motors to hand out and install. Later on, I had heard of some local guys actually making prop mounting hubs so they could start and break them in on a test stand. I showed a couple of guys how to back flip it against compression to get them to start. I don't know if they still do that or not. A little more later on, guys kept monokote heat guns in their tool box to preheat the cylinders. I've been away from the shop for about 4 years now so I don't know what the current method is. Maybe nothing if the engine manufacturers have fine tuned their manufacturing methods to dial in a more friendly compression ratio.
  Type at you later,
  Dan McEntee
Logged
AMA 28784
EAA  1038824
AMA 480405 (American Motorcyclist Association)

Online Brett Buck

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 13737
Re: Engine Worn Out?
« Reply #10 on: March 24, 2019, 08:41:49 PM »
Quote from: Dan McEntee on March 24, 2019, 07:46:50 PM
   Just curious as to how common an iron liner version of the FP-20 might be? Iron piston also? I have heard this mentioned about early FP-.35 and .40's, but I don't think I have ever seen one of those either. I think I remember it was mentioned there is a slight difference in the bump on the case on the by pass port side? I have a couple of the steel fin OS.20 and .25 engines but I don't think they can be mistaken for FP versions.  I'm going to hit a swap meet or two next weekend and will be on the look out!
   
   They do not have steel fins/cylinders. They are built just like the ABC versions. The bypass shape is an obvious protrusion instead of smooth - there's are pictures of it somewhere here.

     There were A LOT of iron-liner versions made. Almost all the old 20FPs on eBay are iron-liner engines and I have seen a bunch of them. Replace the "862" muffler with the E-2030 muffler, and they run about the same.

 
Quote
Have you ever read on here about guys having one of the newer engines fire and run just by flipping them through while tinkering on them with no battery?

    Yes, I have read them, when I was writing them. I have had my PA61 pop when it rocked back onto compression, when it was something like 50 degrees out. I also have to give up trying to choke my 40VF at the 1993 NATs, it started without the battery any time I touched the prop without holding it, 5-6 times in a row. It started before the signal several time, fortunately I was able to stop it, signal, then hit the prop and still make the flights.

    Brett


p.s. https://stunthanger.com/smf/engine-set-up-tips/20fp-iron-vs-abn-cylinder/msg364861/#msg364861
     
Logged

Offline Dave Moritz

  • 24 supporter
  • Trade Count: (0)
  • Captain
  • *
  • Posts: 405
Re: Engine Worn Out?
« Reply #11 on: March 25, 2019, 01:49:47 PM »
Ty: I'll use the electric starter in the manner you suggest; I can imagine a long grind really wearing out the front bearing. Thanks.

Brett: Thanks for coming through with the comparison pics of the two OS 20FP's. You are correct in that the iron versions are much more common on line as well as off. Good to hear that the performance between them doesn't different too much with the 2030 muffler. Finally, the baked appearance of the piston on my engine suggests that the prior owner might have used hot R/C fuel, to the detriment of the compression.

Much obliged for the shared wisdom here.!

Dave Mo...

PS: Tip-o-the-hat to Sparky or whomever chose the spell checker for this forum. It's the best!

D...
Logged
It’s a very strange world we live in, Master Jack.” (4 Jacks and a Jill)

Advertise Here
Pages: [1]   Go Up
« previous next »
Tags:
 


Advertise Here