Ram Jet

Nice engine! If it ain't btoke - run it!

landeck

My Feedback: (1)

Warning! I have a .15 and .29 Enya RC engines from the early '70s that I have been storing in their original plastic boxes since last used in the mid '70s. When I went to examine and possibly run them a few weeks ago I found that the foam padding used by Enya had disintegrated and turned acidic, corroding the aluminum on the engine and extra high compression head for the .29. The extra head and CL venturies are toast but the engines are still usable, they just don't look great. If any of you are storing the engines the same way, I suggest you get rid of the foam padding.

Bruce

1QwkSport2.5r

I did a search for CB spinners, and you are right on. Mecoa sells them. I couldn't get the prop tight enough with that nut w/ grub screw to where I felt safe, so I (just for now) put a standard nut on and backed it with a nyloc nut. This should hold it for a few runs today and I'll pick up an actual spinner nut this next week.


Thats a bummer that it happened, but good information to know. I dont keep my engines in their boxes but I do keep spare screws and piston rings in the boxes. Maybe pulling the metal parts out of the boxes isnt a bad idea.

Could you post pictures of your engines, Bruce?

-Tim

earlwb

I think many people are trying to over tighten the prop nut more than they should. I have seen people strip the threads off the nuts before too.
Fortunately, most of the time the prop nut strips out and not the crankshaft end, but not always though. Nowadays most people are using plastic composite propellers that can handle over tightening better than the old wood props we used to use. With wood props you pretty much knew when you over tightened the prop nut as it crushed the wood hub on the prop too. So once you got used to how much pressure was needed for the wood props, you found you didn't have to tighten up that prop nut so hard. Of course with the cheap plastic spinners and engine prop driver washers that don't have good serrated edge for gripping slippery spinners or propellers people have been really tightening down on the prop nuts more nowadays. I think the better prop nuts are found for the all metal spinners, as the prop nuts are longer and have more threads on them to grip the crankshaft better.

Ram Jet

Most people over tighten everything. If I can get a-little off this thread. I just finished building an RC sailboat (sorry) and It's made of ABS plastic. I turned the self tapping screws until I felt resistance and stopped. On model aircraft engines I do about the same. I have a K&B 3.5 engine that had 4/40 threads in the cylinder head which the previous owner stripped out. The crankcase was junk until I found a hobby shop owner who had 5/40 screws for which I found a 5/40 tap on eBay. I was able to restore the crank case. Just TRY to find a 5/40 thread Allen head cap-screws let alone a 5/40 tap today. Props, I tighten until I feel resistance and then apply another 1/2 turn. You don't need more than that I don't believe. Now for all of you precision freaks you could buy an inch/pound torque wrench?

Cheers,
Bill

Ram Jet

I'm no expert but in my book you can't beat a "fiber lock-nut", "elastic stop-nut" or, the modern term, "nylon lock nut". The first two name are courtesy of my father.

Cheers,
Bill

Ram Jet

Thanks for the tip Bruce. Does that go for the pink foam Enya sometimes ships it's engines in? You don't need to respond, I'll assume it does. Fortunately for me I love my engines so much I display them on a wooden shelf. They just get dusty.

Cheers,
Bill

1QwkSport2.5r

I tighten my props down until I just see the prop driver indenting the back of the prop hub. Then give it one more little "grunt" and I call it good enough. I overtightened my very first prop and heard it making "stress" noises. It never chucked a blade but it did vibrate some. I chucked it to be safe. It was an 11x7 k-series.

I've been trying to find an inch pound torque wrench for awhile and nobody has them locally. (I try to buy locally if I can..) I had an oooooollllllldddddd inch pound torque wrench with the long rod with a pointer on the end but it only went to 10 inch pounds and I dont know how accurate it was. It wasn't the modern ratchet type wrench.

On the rare screws bit.... I will have to go looking for .6 pitch metric screws for my old ST engines. I want to switch them over to socket head cap screws but have to source them online. I dont think the standard slotted screws will last long.

One of the previous owners ham-fisted the intake manifold screws on my 60-4C and stripped the heads out. I got lucky and found some 2.5mmx6mm screws at the hobby shop that fit perfectly. Enya must use a "standard" metric pitch unlike SuperTigre?

earlwb

I have seen quite a few folks strip the prop nut off at the flying field when they went to change out a prop. It sorta ruins the flying experience after that happens, if you only brought one plane to fly.

The inch pound torque wrenches are pretty neat. The last one I saw was used with high end expensive bicycles and it was from Italy. But it was quite expensive and used metric measurements though. Here is a review of it http://www.libertysportsmag.com/2011...torque-wrench/
and for sale here http://www.cantitoeroad.com/tools/to...taforza-ii-216
I think this italian torque wrench is good as it measures up to about 50nm which handles most all the screws and nuts on a model engine too. But maybe not the prop nut though.

There is this one here http://www.competitivecyclist.com/pr...&mr:adType=pla

I think Sears actually sells one though and the price isn't bad http://www.sears.com/shc/s/p_10153_12605_SPM6592989802P

Wiha has a really nice one, but I think it is a bit above what I could afford to pay for one. http://www.sears.com/shc/s/p_10153_1...&blockType=G37

The famous PArk Tools for bicycles has a nice one too http://compare.ebay.com/like/220653333104?var=lv

landeck

My Feedback: (1)

Earl, for 59 years I have been tighting engine bolts without a torque wrench. I have through the years thought of getting one to insure the bolts, for example, on the head are tigntened the same amount. What has stopped me from getting one is that I have not found any specs as to the recommend settings for an engine. Where do you find such specs or do you just guess?

Bruce

Edit: corrected spelling and number of years

earlwb

landeck, that is why I haven't used a torque wrench on any of my model engines either. There aren't any specs for it.
But one could make a good educated guess using the screw torque charts from different screw manufacturers et cetera.
for example http://www.federalscrewproducts.com/torque-chart.htm
It does show some good specs for the 1/4x28 screw or nut which is used on model engines for example.

Ram Jet

Here's a couple of sources:

http://raskcycle.com/techtip/webdoc14.html

http://dodgeram.org/tech/specs/bolts/m_bolts.html

http://www.cncexpo.com/MetricBoltTorque.aspx (this is the best one)

Cheers,
Bill

landeck

My Feedback: (1)

Thanks Earl and Bill.

Bruce

Ram Jet

Your welcome Bruce. When you find a good inch/pounds torque wrench let us know.

Bill

landeck

My Feedback: (1)

There is one thing I do not like about Enya 4 stroke engines. That is that you can not rotate the carb to place the high speed needle valve and the contol arm on the side you want. For example, mounting the engine on its side with the head pointed to the right (pilots perspective) results in the HS needle valve being under the engine/plane. Mounting it upright requires that the carb servo be mounted on the left side of the plane. Both can be problems, particularly in ARF's. Mounting the engine inverted is the one way the current carb arrangement works. Any comments or suggestions?

Bruce

1QwkSport2.5r

If I had that problem, and had the tools, I would make a new intake manifold tube to put the carb where I wanted it. Though it may be crude, I see no reason why it wouldn't work.

I do see where (for me) the problem may surface later on.. I had to remodel my Test stand to accommodate my 60-4C's throttle linkage. I needed to make adjustments on it anyway.

Ram Jet

The only practical solution, I think, would be some pretty tricky belcranks or cable actuation. I wouldn't even want to think about fabricating a special intake manifold.

Cheers,
Bill

landeck

My Feedback: (1)

Bill, I think I am going to pass on getting one and continue doing it the way I been these many years. The reason is that in looking at the charts you referenced, they all start with larger bolts than what we use on our engines. Also the jump in torque between any two bolt sizes is relatively large. It would be hard to estimate the proper torque for our small size bolts.

Bruce

Ram Jet

I agree with you. It's a matter of common sense. "Snug" will do it. I've never had a crancase or cylinder head leak because I am conservatice about how I tighten bolts. Go snug and 1/4 turn and I think we'd all be amazed at the nuimber of pounds per square inch we are putting on the frail aluminum threads. Don't ask me what number that is.

cheers,
Bill

1QwkSport2.5r

I just came in from running my 60-4C. All I can say is... What a pleasurable sounding engine. Other than finding the "trick" to getting it started, it sounds really neat. I have it set rich and am following the "Saito" method to breaking it in. I ran about 8oz of fuel through it, about 1/4 throttle at 4000rpm or so. Probably 7-9 minutes of run-time. I removed the little muffler tip thingy after the first time I had it running and got it too rich and it quit. I wont put it back on.

I used what fuel and prop I had spare - a 13x7 APC and my Iron/Steel break-in brew of 5% nitro and 25% castor. I will make up a batch of fuel with 20% castor and 5-10% nitro. Do these 4C's really need that much nitro to run good? My buddy told me I should run 15-20% nitro and mostly synthetic oil. I run my engines often enough that I am not worried about the castor gumming things up. I usually go overboard with new engines but with the intent that I want them to last forever so extra oil and extra rich mixture doesnt bother me.

I am just tickled.

Ram Jet

I have a pen pal in Australia I met through this site. He favors castor in large amounts and I don't think you'll want to run more than 10% nitro. I hope other guys chime in here. Hey Col. from downunder, can you help us out?

Cheers,
Bill

1QwkSport2.5r

I favor castor too. A better majority of my engines are either AAC, Lapped Iron, or Ringed with one being ABN. The ringed engines are getting switched over to 50/50 castor/klotz as will the ABN but the rest will still get full castor with the 4-stroke being the one in question. I just dont want to run more nitro than whats needed. My buddy that suggested 15-20% nitro said with more nitro the mixture is richer and they dont smell "hot". I thought that to be sorta weird but... what do I know. This is my first 4-stroke.

I still have all of my fingers and the prop didnt come loose. My test stand got a facelift and worked perfectly to boot.

Ram Jet

I knew you would love that exhaust note! Hang on for a response from the hard core 4C guys.

Cheers,
Bill

Ram Jet

I mentioned that there is a member here with a-lot of four cycle experience. He and I had an E-mail chat about Fuel/oil mix. He seems to like 10% synthetic, 10% castor, 5% nitro. I don't have his experience but he thinks I'm all-wet with a recommendation of 20% castor. I'll bow to his experience. He is very good with engines and has a collection of nearly 100 engines. Think that's enough - nope, he's looking for just two more. I'm not buying another engine as long as I live - unless a good deal comes up on an Enya 240V Twin.

Cheers,
Bill

1QwkSport2.5r

Fair enough, Bill. I think I'll run it in on all castor and switch to the 50/50 oil blend like I planned. I might get it out tomorrow for a little more music.

I noticed a lot of oil coming out of the breather fitting since I ran it last. I'm not worried about lubrication, that's for sure.

Those VT240's are nice, aren't they? I love the sound. Beats a radial IMO.