Author Topic: Brett and Dan got it right... Dem Blue engines Part Duh! (Read 3955 times)

Paul Taylor · « **on:** February 27, 2012, 09:14:03 PM »

OK for yucks and grins I put a glow plug in my ebay engine and turned it over. It felt great! I then took the glow plug out of one of my other blue 46 engines. No bind. Turn over freely. I then took a heat gun and warmed up the head like Dan suggested on the new engine. And with the plug out turned the engine over. No bind.

So looks like this engine might be OK and just needs to be broken in.
I'm going to run it when I get some time in the next few days.

Thanks Dan and Brett - wish I knew everything you have forgotten about this stuff.

First thread
http://stunthanger.com/smf/index.php?topic=25385.0

Clint Ormosen · « **Reply #1 on:** February 27, 2012, 09:53:55 PM »

Never doubted them for a second....

Brett Buck · « **Reply #2 on:** February 27, 2012, 10:00:04 PM »

Quote from: Paul Taylor on February 27, 2012, 09:14:03 PM

Thanks Dan and Brett - wish I knew everything you have forgotten about this stuff.

Problem is, I keep forgetting it!

Sounds like you have a winner there. You *want* them that tight. The super-high-end engines like the Jett and PA still have that feel after 5 years. If it didn't do that, then, question it.

Brett

W.D. Roland · « **Reply #3 on:** February 27, 2012, 10:22:14 PM »

Well it do help to pay attention Paul.

Usually save ya time and $$ and doesn't tie everyone up.

ABC engines are enjoyable in long term. I think you gona like it

Dennis Moritz · « **Reply #4 on:** February 28, 2012, 04:39:46 AM »

So it was a "pinch." Heating the head with a heat gun would bring the engine closer to operating temperature. Easing the pinch. Any thought about being able to move the crank at top dead center, without the piston moving up and down. At flea markets I've steered away from engines that seemed to do that. I thought that signified an ovaling of a connecting rod bearing. I've had s few engines that did that. When I dissembled them, the conrod bearing fits seemed o.k. in one. Another was obviously shot.

Allen Brickhaus · « **Reply #5 on:** February 28, 2012, 05:50:02 AM »

Randy Smith will tell you NOT to bring the engine up to TDC and hold it. This could damage the fit of the piston and cylinder. Always prop through without stopping it.

john e. holliday · « **Reply #6 on:** February 28, 2012, 05:53:57 AM »

Don't pop them thru dry either. In fact, don't prop them thru until you are ready to start one.

George · « **Reply #7 on:** February 28, 2012, 06:16:54 AM »

For early ABC engines, George Aldrich recommended running just on the rich side of peak for the first two minutes to smooth (break-in) conrod and crankcase (for non BB) bearings. That method relieved stresses imposed by the pinch.

I think OS was the first to use materials that closely matched expansion between the piston and cylinder so they could recommend a rich mixture during break-in. Perhaps their incentive was to produce an engine that could easily be used by a beginner as well as an experienced modeler, whereas most ABC setups were created for high-performance engines in the hands of experienced modelers.

Just an opinion.

George

W.D. Roland · « **Reply #8 on:** February 28, 2012, 08:26:23 AM »

Super Tiger, Rossi and OPS pioneered the ABC( officially?)
http://www.mh-aerotools.de/airfoils/pylon_engines.htm

Although TWA(sort of a K&B top secret type stuff)may have quietly been first.
http://modelenginenews.org/people/images/WisObit.pdf

Of the ABCs the K&B 6.5(Bill Wisniewski's design), ST X-40, OPS, Rossi, that I used in early 70s for racing mostly Fast Rat the 6.5 was the better engine.
At least until last few years the 6.5 set/held the speed record for Formula 40. by Paul Gibeault I think.
Not bad for 40 year old design.

Double Duce can probably tell more. Where are Ya Luke?
Some pics of your most recent engine design would be fantastic!

Brett Buck · « **Reply #9 on:** February 28, 2012, 08:49:31 AM »

Quote from: George Bain on February 28, 2012, 06:16:54 AM

For early ABC engines, George Aldrich recommended running just on the rich side of peak for the first two minutes to smooth (break-in) conrod and crankcase (for non BB) bearings. That method relieved stresses imposed by the pinch.

This was true in some cases. George also related an incident where he ruined his first ABC engine, an ST29. He got it felt the extreme pinch in this racing engines, and took a hone to it to loosen it up. Of course, it just ruined it.

I think that after that he became overly-enamored of the idea, and took it to absurd extremes. His ABC stunt engine liners had FAR, FAR too much taper and were FAR, FAR too tight at TDC. Stunt engines don't need a tremendous amount of taper because they don't get all that hot, so you don't have to plan for a large amount of expansion. The results were that the engines were extremely hard to handle cold, and put tremendous strain on the crank at it tried to jam the piston into the liner 220 times a second.

The early GMA-Jett stunt engines were hopeless, and that was after (reportedly) Dub Jett had wisely talked him out of most of the taper he wanted to put in. Get that baby stuck at TDC, and it was either pound on the prop until it moved (or the crank broke), or get out the torch to heat it up enough to let go. I heard Larry Fernandez' engine *squeaking while it was running*. It had good chrome on it because it kept going for a long time but overall it was a disaster. Dub later started putting parts fit the way they do the RO-Jetts and those work very well with no particular problem.

For ABC stunt engines you just need a little bit of taper to correspond to the relatively low operating temperatures and keep the liner from "bell-mouthing" at the top.

Brett

Randy Powell · « **Reply #10 on:** February 28, 2012, 10:11:24 AM »

"Dub later started putting parts fit the way they do the RO-Jetts and those work very well with no particular problem."

I know both .65s I've had were a bear to start the first time. The pinch would stop the engine from turning. After one run they were fine, but getting them to start that first time was something.

Larry Fernandez · « **Reply #11 on:** February 28, 2012, 11:24:59 AM »

I heard Larry Fernandez' engine *squeaking while it was running*. It had good chrome on it because it kept going for a long time but overall it was a disaster - Brett

-Nothing a little mustard could'nt remedy-

. Dub later started putting parts fit the way they do the RO-Jetts and those work very well with no particular problem. -Brett

Correct. Dub put a new piston/ liner in the old GMA Jett (with a little milder timing) I could not have been happier with that motor.
It pulled a plane way heavier than it should have been pulling and did just fine.

Larry, Buttafucco Stunt Team

W.D. Roland · « **Reply #12 on:** February 28, 2012, 04:37:29 PM »

This I have to ask as just not sure.
Are most engines nowadays ABN?
Nickel Not Chrome plated brass?

Quality chrome plating that sticks properly has to go on top of Nickel is my memory.
Getting plating inside an object takes reversing polarity from outside object plating.

Paul Taylor · « **Reply #13 on:** February 28, 2012, 04:56:42 PM »

Well here it is.

I still have a Randy Smith NVA on the way.

It would have started on the first flip but it did the kick back and prop came lose. It would have started on the second flip, but it kicked back again and caught the tip of my flipp'n finger. Good thing I had my leather glove on. Put a good crease in the leather and my finger hurts every time I type the letters I and K. (Ouch)

Looks like it is a keeper guys. Thanks again for all your expert advice.
That is what I like about this hobby. I'm still learning new stuff.

Bill Little · « **Reply #14 on:** February 28, 2012, 06:11:27 PM »

Quote from: W.D. Roland on February 28, 2012, 04:37:29 PM

This I have to ask as just not sure.
Are most engines nowadays ABN?
Nickel Not Chrome plated brass?

Quality chrome plating that sticks properly has to go on top of Nickel is my memory.
Getting plating inside an object takes reversing polarity from outside object plating.

AFAIK, OS is ABN all the way through. Of course, some of the higher priced engines *might* be ABC, not sure on those.

BIG Bear
RNMM/AMM

Brett Buck · « **Reply #15 on:** February 28, 2012, 08:05:44 PM »

Quote from: W.D. Roland on February 28, 2012, 04:37:29 PM

This I have to ask as just not sure.
Are most engines nowadays ABN?
Nickel Not Chrome plated brass?

I think only OS engines are ABN, certainly the PA and RO-Jett are chrome AAC. There's been a lot of hand-wringing over nickel, but for our purposes it's fine, and for consumer engines I would consider it superior because break-in is much faster, essentially, you can fly it with no prior running. I can tell you for certain that it takes A VERY LARGE NUMBER of flights to wear the piston/liner out in a OS 40VF, more than anyone reading this is ever likely to fly.

Brett

Brian Hampton · « **Reply #16 on:** February 28, 2012, 08:49:06 PM »

Quote from: W.D. Roland on February 28, 2012, 04:37:29 PM

This I have to ask as just not sure.
Are most engines nowadays ABN?
Nickel Not Chrome plated brass?

It's easy to tell if an engine is either nickel or chrome plated. Nickel plated liners are plated all over, both inside and outside so there's no discontinuity, while chrome is only needed on the bore itself. Usually you can just look through the exhaust port where part of the outside of the liner is visible and if you see bare brass then it's ABC. An ABN liner will look somewhat like nicely finished steel. A steel liner (as used in some Enyas up to the .40 size) can look like ABN and even the piston can appear to be alloy but a strip off a fridge magnet placed on top of the piston soon reveals that it's cast iron. Enya 61's are listed as being ABN (with ring) but in fact they're a type of Nikasil as used in exotic cars and Formula 1.

Dennis Moritz · « **Reply #17 on:** February 28, 2012, 09:44:50 PM »

I have seen ABN engines with peeled liners. More than a few. Usually a quick leak down when the piston is held under compression is the tip off. Used engines that I bought, have shown the brass, you can see where the nickel has separated. Very clear. These were not engines that I ran from new. These were RC engines bought from the bay or at a swap. I have returned two which had this problem. Having no use for them. Since engines like that do not run with the consistency we require. It's possible that the peeling happened because of constant overheating and poor quality fuel. Or perhaps the original plating had a flaw. I have also bought more than one new appearing engine from the Bay. Pristine in appearance. Perfect looking. But the piston/cylinder fit was too loose. Engine did not hold compression. A few fly mates thought the compression would come up with running. It did not. Having other choices, I went with other engines. One of the best compression used LA46s I own, looked in terrible shape. One or two of the mounting holds were slit in an odd way. Tho it was possible to clamp the engine well when a washer was used under the screw head. Which I guess we all do anyway. This engine is running great. But the screws need to be tightened now and then. Maybe it's a matter of manufacture tolerances. And the assembly line. Perhaps engines that are not carefully hand fitted vary in the quality of piston/liner clearance. Some great, some not great. Lately, as I said, I've been buying new. Decided that it wasn't worth the gamble of saving some dough. This conclusion was reached after years and years of fun buying, tho. Truth is I have a near life time supply of 40s and 46s. At least the reasonably priced consumer models. Now. Soon. On to the high priced stuff.

W.D. Roland · « **Reply #18 on:** February 28, 2012, 10:42:54 PM »

Dennis, that was a problem with the early ST X-40s. 30 seconds from new and chrome blistered.
Have wondered if this was due to no Nickle 1st coat or contamination or wrong plating polarity.

Ah
Nickle/silicon carbide...should be able to have this re plated by the many who do it for 2 stroke motor cycles and 4 wheelers.

So the next question would be are any modern model engines using Hypereutectic Aluminum for pistons and or liners?

Brett Buck · « **Reply #19 on:** February 28, 2012, 10:53:47 PM »

Quote from: W.D. Roland on February 28, 2012, 10:42:54 PM

Dennis, that was a problem with the early ST X-40s. 30 seconds from new and chrome blistered.
Have wondered if this was due to no Nickle 1st coat or contamination or wrong plating polarity.

If you have the wrong polarity the chrome will go to the electrode instead of the liner, so you get nothing.

Brett

W.D. Roland · « **Reply #20 on:** February 29, 2012, 12:22:14 AM »

Quote from: Brett Buck on February 28, 2012, 10:53:47 PM

If you have the wrong polarity the chrome will go to the electrode instead of the liner, so you get nothing.

Brett

cathode to anode? instead of anode to cathode(part)?

This is kind of what I thought until asking the plater why he wanted so much to do the inside of some tube suspension parts. WHAT? WHY?... His response was kind of polarity and different chemistry in vat.
Needles to say my few parts did not get inside plating in the Bus sized vats.

Don't know if it makes any difference that I stuck with Nickel only for field repair purpose and to me looks better than chrome.

I never plant to do any plating personally but do want to understand more about it for Choices.
Real help always desired.

Dan Bregar · « **Reply #21 on:** March 01, 2012, 04:33:02 PM »

Thanks Dan and Brett - wish I knew everything you have forgotten about this stuff.

[/quote]

Paul

Yeah, I wish I knew everything I have forgotten about this stuff too !

Dan