w8ye

My Feedback: (16)

#22 is just a spacer

Lick your wounds - put it back together with the new crank and bearings - and go fly

BarracudaHockey

My Feedback: (11)

And running a gas engine rich doesn't help anything

SWORDSN

My Feedback: (13)

I to had to rebuilt my DLE55. I installed a new crank ,rod,piston,ring (Bowman)and Boca bearing severything was performing very well until this past weekend. While in flight the engine started sputtering and shut down.The wind was a little gusty and I knocked a gear out of my P47 while landing.
After examination I could see the prop hub had pulled away from engine about 1/4 inch.The magnet was away from the hall sensor causing the engine to quit.This was caused by the threaded part on the end of the crank breaking off.It is a machined part on the end of the crank ,So I need another crank.I had about 3 hours on the rebuild.

w8ye

My Feedback: (16)

And if you look at the crank, you will see a manufacturing problem of no radii at the junction from the threaded portion to the bearing diameter?

I doubt that it was heat treated properly, that after harding that it was never drawn back to normalize it.

Many of these people designing this stuff can only copy others, they have no metallurgical training.

Part of the problem is that they are cost driven and do anything they can to eliminate manufacturing steps or QC.

yak-54

hi
is this oil considered a good one?
i use it for a year with 0 problem run at 32x1
thanks
ilan

w8ye

My Feedback: (16)

yes

SWORDSN

My Feedback: (13)

I suppose that is why they are replacing it under warranty.

SWORDSN

My Feedback: (13)

Why 32:1 that seems high.

yak-54

i use 32x1 for many years and my engines are happey

"SHANA TOVA" (jewish new year 3 4 days from today) to all of you

ilan

tande

My Feedback: (48)

I thought "Mobil" was out of the 2 stroke oil business.....is there now a source for this in the U.S.? ......

SWORDSN

My Feedback: (13)

Well, the problems continue. After a complete rebuild,outlined above, I can't get a consistent low idle.There must be an air leak somewhere. Any ideas on finding the leak will be welcomed .All new gaskets were installed and the machined surface was sealed with Indian Head sealer.

BadAzzMaxx

Get some carb cleaner, Run the engine and spray it around the engine, If the RPM changes that is a air leak, Just do not spray it into the carb or the RPM will change.

Milton

av8tor1977

My Feedback: (6)

I use a vacuum/pressure leak tester myself. Simple to make. Invaluable in use.

Get this Mighty Vac tool. http://www.harborfreight.com/mityvac...ump-39522.html

Make plates with rubber gaskets to cover the exhaust port and the carb mounting adapter. 3/16" or 1/4" thick aluminum works great to make the plates, and cut pieces out of an old inner tube to make the gaskets. Use a bolt on tire valve stem available from any tire store, and install it in the center of one of the block off plates you made. In the center of the other plate, drill and tap a 1/4" pipe thread hole, and for now plug the hole with a 1/4" pipe plug. Take the valve stem out of the valve, bolt the plates to the engine, run a hose from the vacuum pump to the tire valve, and use the pump to apply a vacuum to the engine. It should hold a vacuum for several minutes. (20" of vacuum is enough)

If it doesn't hold, you know you have a leak. Even if it does hold the vacuum, it is good to pressure test the engine as well. Not very often, but occasionally an engine will hold a vacuum but not pressure if a seal is funky. Go to the hardware store and get a pressure gauge for checking propane and natural gas home plumbing systems. It is a low pressure gauge; about 0 to 15 lbs. or so. Remove the plug you put in one of your block off plates and install the pressure gauge, re-install the valve stem core in the tire valve, and USING A BICYCLE PUMP, pump the pressure up to no more than 7 lbs. Once again, it should hold that pressure for several minutes. If not, get out your soapy water and look for leaks.

For all tests the spark plug must be installed and tightened.

Note that trying to do this test with compressed air instead of a bicycle pump will almost certainly blow your gaskets and/or seals in your engine. The engine doesn't hold much air, and there is no way to use compressed air from a compressor without over pressurizing the engine. Use a bicycle pump, or with care, you can use a small air brush air compressor. Just keep the pressure below 10 lbs. max and you'll be fine.

AV8TOR

Truckracer

My Feedback: (19)

I'm not sure I'd completely trust the Indian Head sealer for split case sealing. Its been decades since I used that but if it is the same stuff I remember it dries hard and brittle and shrinks a bit during the drying process. There are probably much better sealers available today such as Yamabond or Permatex anerobic sealer.

I like the pressure / vacuum testing methods suggested by av8tor 1977. Never tried that but it sure sounds like it would work.

av8tor1977

My Feedback: (6)

It's cheap and easy to make, and it works great, and I've just gotten to the point where I go ahead and test each engine I assemble. It only takes minutes to do, and saves the headache of getting an engine all installed and then finding it has a problem. Using the tester, any leak is obvious and easy to find. Two stroke engines must be air tight to work properly.

The block off plate for the intake carb adapter will fit all engines with the Walbro carb bolt pattern. You will need to make different exhaust block off plates for each engine, but that is quick and easy to do. Some of the engines with exhaust port bolts that are not too different can sometimes be serviced by just slotting the mounting block holes in your exhaust block off plate made for a different engine.

AV8TOR

Captain John

With no radius near the crank throws is just inviting a crack to develop. Be careful what you buy.....

bcchi

Probably works good,seems like a lot of work to me. But I am old and lazy and tired. I guess I never had much problems with air leaks.
BCCHI

w8ye

My Feedback: (16)

The air leak sequence goes like this . . .

Use 1/2 atmosphere pressure (7 psi) or (50KP) or Vacuum (15")

Any more and you may damage the seals like mentioned above.

The test has a pass-fail point. All engines leak a little so the test is with the pressure or vacuum for 30 sec. The pressure or vacuum should not change more than 25% of its value in this 30 sec.

Pressure is more convenient for finding leaks for you can use soapy water on the outside to find the leak.

The Harbor Freight Mity Vac is intended for vacuum use. This Mity Vac does have a pressure outlet on top suitable for about 10 psi. But there is no gauge for the pressure. You will need to buy a pressure-vacuum gauge at the auto parts to use the plastic Mity Vac for pressure.

SWORDSN

My Feedback: (13)

Thanks for all the input. I will try the carb cleaner method first. A club member suggested using propane torch.unlit of course! As for the Indian Head sealer I could not find another sealer that said use it when exposed to gasoline. Truckracer are the above brands gas proof?

Truckracer

My Feedback: (19)

Yes, both are intended for the very purpose of sealing ungasketed, metal to metal surfaces. Yamabond comes from Yamaha as the name would suggest and is there product designed for the purpose. There are others such as Hondabond, etc. Most any large motorcycle company should have the product in their parts department. There are some different compounds of these so you might want to consult product listing or the parts man for the one most suitable ....you'll want Yamabond 4 though. I believe Hondabond 4 is the same stuff or at least very similar. Like all modern sealers, you'll find them a bit expensive so be prepared for the sticker shock.

MTK

A few years ago I modified a DLE55 which required taking the engine apart and putting it back together. It was a bit tough getting the two halves of the case to separate but once separated I saw that a sealant was used that looked to me to be epoxy. So that's what I used when putting the engine back together. Has worked great since and epoxy is gas proof and is extremely cheap, and is found in almost every one's shop. No need for any new stuff

SWORDSN

My Feedback: (13)

Are you talking about engine design/cost?

av8tor1977

My Feedback: (6)

It is usually really obvious when you have a leak, as the air pressure or vacuum either won't pump up, (or down), at all, or drops immediately.

I actually originally built my setup for testing the Stihl Four Mix, four stroke engines. They too must be air tight like a two stroke engine, but have more potential leak sites. In addition to all the normal places like a two stroke engine such as crankcase, shaft seals, carb adapter, etc., the Four Mix engines can also leak at the camshaft cover and the rocker cover gasket and attachment screw. It really only takes a couple of minutes to bolt the adapters on and do the tests. Like you Bill, I never really found one necessary for many years, but now that I took the time to make it I am glad I did.

Here's the gauge similar to the one I use. Such a low pressure gauge is rarely used in automotive applications. They do use them sometimes for fuel pressure sensing on carbureted car engines, but this one is big, easy to read, and cheaper than anything you'll find at an auto parts store. This one even has the "tire valve" built in but will need a reducer to go from it's 1/2" pipe connection down to a more suitable 1/4" or 1/8" pipe connector.
http://www.homedepot.com/p/DANCO-0-1...6#.UmA-XlMueSo

AV8TOR

Propworn

My Feedback: (3)

Your not going to order replacement bearings from DLE again are you? Why not take them to your local bearing dealer and buy the best quality they have. Bearing failures on offshore products is a constant pita even in large commercial operations. These bearings are the first thing to get the heave ho!!!!!!

As to the oils brand name oils are plenty sufficient for our model aiplane motors. Errors in the ratios are more cause of failures than anything. There is such a thing as to much oil in the mix and that can cause all kinds of carbon build up, stuck rings and underside piston carbon as seen in the photos.

Dennis

2walla

My Feedback: (10)

You are usually 100% right on things. but the red in redmax glow fuel is not the oil in it. And it definatly is not klotz. Well at least not the primary oil in it. The red is less than 1% of what is in the jug. It is some sort of anti corrosive additive. The oil they use is light brown/clear. I had a few gallons that came inadvertantly without oil.. And they sent me the oil to add to the fuel. They were a stand up company in the deal and made it right. If i still flew glow i would buy my fuel from them. I have a couple of enyas my dad handed down to me from the late 60's that have well over 50 gallons of red max through them and they look like new inside. Course that is good quality metalurgy and running them on good oil.