Some of you may have read my accounts of my rebuild of my DL 50. To bring anybody who may be interested up-to-date, I crashed my plane a few weeks ago. I rebuilt a replacement plane, but after a couple of flights I noticed black "gook" coming out of the front bearing. Initially I thought it was a destroyed font bearing and maybe a bent crank case. I ordered the parts from DL USA and proceeded to disassemble the engine to have it ready for the new parts. But then I couldn't extract the woodruff key from the crankshaft, so I ground it off thinking I could extract the remains after removing the crankshaft from the case. But now I doubt this will be possible, so I ended up ordering a new crank shaft assembly too (with con rod installed).

In the mean time Scott from dlenginesaustralia kindly posted pics and thorough instructions for disassembling and assembling the DL 50 (on page 114 of this thread). The instructions and pics have proven to be invaluable.

So all my parts have arrived and I got my Loctite 620 Bearing Mount today. So right after work I rushed home to begin assembly of my baby so I could put it back into my other baby!

But before assembly, I took Scotts instructions/notes and wrote them in chronological order in a way that I could understand a little better. I also took a few pics that might be of interest.

Scotts instructions were right on, but I have a few things to add about my particular re assembly;

1. The rear bearing did not require a pipe to tap it onto the crankshaft - mine slid right into position. Same when installing the rear bearing/crank assy into the case/front bearing assy - dropped right in.
2. I also put the front bearing and crank in the freezer, thus shrinking them for easier assembly.
3. The assembly process went perfectly fine and I had no problems - well, maybe the woodruff key was a bit of a problem - but just a bit. Mine fit rather tightly into the slot in the crank. Also, you want to install it so it is slightly angled toward the front of the crank shaft. This way the heated prop hub will slide into position a little easier.
4. In my pics you can see the hub holder tool I made from 1/4" ply. This worked well for disasembly and assembly. You can use your prop drill jig (or a prop) to make your own. You'll just have to open up the hole in the middle to accommodate your deep - well socket. (I got my deep well socket from Sears. I was worried if they would have one or not, but when I got to the tool dept. they had a whole wall full of sockets - many deep well of which there were quite a few that would have worked. Both 13mm or 1/2" work fine.)

Lastly, although I ordered a new front/rear case assy, after disassembly I noticed how short/stout the case is, so I'm quite certain the case is not bent from the crash, so I didn't use my new one. Therefore, I have a case assy. for sale if anybody wants to make me an offer - brand new in the bag.

One more thing; when preparing for assembly, I would refer back to the photos in dlenginesaustralia's pics back on page 114. Well, here are my revised instructions followed by a few assembly pics just in case anybody is interested in what the inside of a DL 50 looks like.


I. Preparation/Assembly Notes:
Loctite 620 Bearing Mount (High Temp) is required to securely mate the bearings to the crank shaft and to the crank case (and other parts as instructed). Bearing Mount can be purchased or ordered in small quantities (5ml – 15ml) for as little as $5.00 - $15.00 from ball bearing retailers.
Protect your workbench and engine parts by working over a sheet of cardboard or other relatively soft barrier.
Clean all parts thoroughly for easier assembly and best adhesion of Bearing Mount.
Do not use excessive Bearing Mount. Do not apply until ready to fit the parts. As you proceed, remove excess Bearing Mount with cloth.
Keep all tools within reach so you can work quickly while parts are still hot.
Wear clean, leather gardening gloves when handling heated parts.

II. Crank Installation
1. Place front crank case half, rear bearing and propeller hub into oven heated to 280F.
2. After about ten minutes, working quickly, remove case from oven, apply Bearing Mount to case and outer race of front bearing. Install front bearing into case.
3. Replace front case/bearing assembly in oven to re heat for installation of crank shaft/rear bearing assy.
4. Working quickly again, remove rear bearing from oven, apply Bearing Mount to inner race of rear bearing and crank shaft. Tap bearing onto crank shaft with 15 – 16mm I.D. pipe applying pressure only to inner race of bearing—do not apply pressure to bearings, seal or outer race.
5. Install aluminum bearing spacer onto crankshaft.
6. Working quickly once more, remove front case/front bearing assy. from oven. Apply Bearing Mount to outer race of rear bearing and in case for rear bearing. Install crank/rear bearing assy. into case. Allow to cool.

III. Hub Installation
1. Apply Bearing Mount to woodruff key and crank shaft. Install key into crank shaft.
2. Remove propeller hub from oven. Turn off oven. Proceed immediately to the next step.
3. Working quickly and supporting center of crank assy. with hardwood dowel or similar (so as to keep force centered on crank shaft—not on con rod/counterbalance), lightly tap heated hub onto crank assy. just far enough to expose crank threads so prop shaft can be fitted.
4. If necessary, apply more heat to hub (using heat gun), then use a tool to hold hub while tightening prop shaft drawing hub the rest of the way down.

IV. Final Assembly
1. Install bearing, piston, wristpin and wristpin clips to con. rod. Be certain wrist pin clips are fully seated and the “tails” of the clips do not have any nicks in them which could cause them to break off inside the engine.
Note: The arrow stamped into the top of the piston points toward the exhaust. The anti-rotation pin in the ring groove is located opposite the exhaust.
2. Join the case halves using a thin film of gasket sealer or the Loctite Bearing Mount used for bearing installation (which is thin, fuel proof and normally sufficient—if desired, Loctite 518 or 573/4 could also be used, but usually not necessary due to the good fit of the case halves).
3. Apply a drop of blue Loctite to the case bolts. Tighten evenly in a standard chris-cross pattern.
4. Lightly oil all parts including the piston ring and cylinder walls—the two-cycle premix oil you have been running your engine with is suitable.
5. Compress the piston ring with your fingers while sliding the piston into the cylinder.
6. Tighten the cylinder to the case halves with blue Loctite on the bolts.

Thanks to Scott at dlenginesaustralia!