I am converting an old OS 15 plain bearing glo to diesel , hopefully to turn a 9.5 x4 prop in a slow combat model , It will be done in about a month and I will put up some pictures

Warren, you're a lucky modeler.
gkamysz, thanks for the info.
hastf1b, thanks for the link, hope I'm doing that good when I get there.

The Schlosser vs the Valentine, how does the quality compare? Yes, both very different engines, with the Valentine being smaller and no throttle.
If we had both, same size, which would be the better engine?

NX-687, sounds interesting. I got a Norvel .15 with a diesel head made by some one else.
See Andy's post further back. He was running bio diesel on the .15.
A few pictures of the parts you are going to make, and perhaps why you are doing them the way you are would be nice.

Hi John, as it happens I also have a Valentine 0.1 (maybe it's time to admit I have a problem?).
The Valentine is less than half the size of the Schlosser 0.25 (and cost less than half as much). As an amazing example of workmanship the little Valentine is superb, but as a practical and useable engine, it does not compare at all to the Schlosser.

Both engines are tiny and need to be handled with care, but the Valentine demands extra special care. It's very tricky to start and very critical on adjustment too. Even 50% ether doesn't help. Maybe it's just my example, but it's probably better suited to a glass case than the flying field.

By contrast the Schlosser 0.25 is just about the easiest engine to start I've owned of any size (but it's tiny size makes it completely unsuitable as a first diesel).

Whilst the Valentine has just about enough power to run itself, the Schlosser is a real little racer -wonderful!!!

Originally Posted by JohnAV8R

NX-687, sounds interesting. I got a Norvel .15 with a diesel head made by some one else.
See Andy's post further back. He was running bio diesel on the .15.
A few pictures of the parts you are going to make, and perhaps why you are doing them the way you are would be nice.

I will throw a few pictures up as I finish the parts , I need a new piston ( its half made) and the whole new diesel head and the rod has no bronze bearing , am a little worried about that , but Im a 20% Castor ( well who isn't ) man so I think the rod will survive , I make good uniflow tanks and I dont overcompress , most important
Anyone out there running a unbushed rod with success

Originally Posted by NX-687

Anyone out there running a unbushed rod with success

Many of the classic "non-wearoutable" diesels had unbushed big ends....I am thinking of all those old Webras, PAW's etc, of which many are running on their 40'th or 50'th C/L season....

If the bearing support area isn't exceptionally small, I think there is no reason to worry...




PS
I feel 20% castor is a tad on the low side....I would go for 25%....

Originally Posted by NX-687

Im a 20% Castor ( well who isn't ) man

I isn't.

The greatest routine malady with diesels is the stuck contra. It's almost impossible to fix without stressing the rod, or disassembling the engine and ruining those beautiful fits. With synthetics it doesn't happen.

Just incidentally, I found the most effective/least intrusive method is to pass some soft string into the bore through the exhaust ports. Fill up the cylinder as much as you can, then gently rotate the shaft until you hear that rewarding click!. Still stresses the gudgeon and rod though.

OS part number 21805000 conrod .15 RX fits the Norvel .15. Andy figured this out some time ago. What material are you using for a new piston for the Norvel .15? BTW, Andy's biodiesel test showed it wasn't really burning much, if any, of the biodiesel.

Schlosser over the Valentine any day. I own neither, but will never buy a Valentine. after seeing the Schlosser and running it, it's on my list. I have an AE0.1 that has issues I have to fix. Overall the AE is a disappointment.

Greg

Chas ,

I like that idea to dislodge the contra piston . Perhaps some heat on top of the cylinder would help also .

Mike1484

Thanks for the info on the above two “comparisons”. I’ll take your advice with thanks. The owner wants $350 Cdn for this specimen. Seems very steep. That’s more than the new OT!

Warren, I don’t think you are alone, “maybe it's time to admit I have a problem?”
As Bill said, this place needs a serious clean out.
Chas, what was the term you used earlier….”I can only think of Crankologist, a name with a nice ironmongery ring about it and just about the right shade of meaning." Engine addicts, crank, not crack, addicts.

I picked up a Merco .29 (5cc) in what would probably be called good condition. I’ve soaked it with penetrating oil and used a fair amount of heat, but I cannot get the last head bolt to loosen up. I could leave well enough alone and not polish the inside of the cylinder (to clean the varnish and crud out), or I could risk snapping the bolt. Would I damage the metal if I tried to shock it with freezing (liquid nitrogen). Freezing the engine, then quickly warming the outside might loose the bolt threads, or I just might damage all.

Hi John,
$350 is rather steep for a 0.25 Schlosser, but expect to pay around $200-$250.
The trouble is finding one at any price.

My method for contra pistons is to remove the comp screw and push the contra down with a suitable pin punch through the screw hole in a drill press.

Once the "seal" has been broken, and with a bit of fuel squirted in on top, the piston has a much easier time pushing it back up.
If the engine can be disassembled, pushing the contra up and down in the bore a few times, again using a pin punch in the drill press, will ussally free it up.
This also works quite well on engines which are not completely stuck, but where the contra is bordering too tight anyway.

Using the drill press as a press is also the best way to press off prop drivers etc.

Iv'e had to deal with a few impossible Merco head screws (I have too many of those too!), only way I've had success is to drill off the screw head, then once the cylinder head is removed, remove the screw stump with vice grips. I've tried easy-outs but the screw diameter is too small and the extractor is easily broken off in the screw -doubling the problem!

John, Years ago faced with the same problem I took the motor to a machinist who set it up in a vertical mill then end milled the head of the screw off ,he pulled the head off leaving the threaded remains wich was a lot easier to remove, that worked for him, but I would not be positive that it would work in all instances.

Forgot to mention the best way I have found to extract the headless screw stub.
Grab it witrh the drill press chuck, then wind it out, works better than vice grips and less likely to break the stub off.

Greast things drill presses, lot's more use than just drilling.

you got that right ,the only problem on some of those other uses the chuck arbor can come loose

Pylonius, John.