ZDZ 40 engine oil question

[Desertdualsport]

For the ZDZ 40 (rotary valve engine) the manual calls for any 2 stroke oil at 50:1 after break in. I have about 5 tanks run through iut at 40:1 using Stihl air cooled 2 stroke oil mix and premium fuel. (Stihl oils are high quality)
What 2 stroke oil does everyone use for the long run? Should I switch to a synthetic by Honda or are there special oils made for plane engines?

Thanks,
Nick

[classclown]

Only use regular Pennzoil 2 stroke and 87 octane on that motor. ZDZ does not recomend synthetics. High octane is a waste of money as these motors have low compression.

[BTerry]

Desertdualsport, I need to jump in here and correct the record. ZDZ engines, when compared to almost all other RC engines, ARE HIGH COMPRESSION!!! Use PREMIUM (93 octane in the US) or better. The ZDZ compression ratio is over 10:1, while most gas engines we use are in the 7:1 range.

I have 4 ZDZ engines and use premium grade gas, it is only 20 cents more per gallon, and the engines run better on it. Our Taurus, DA, DL, and other engines can run lower octane gas and I don't notice a change at all when I run premium in them, but the ZDZ definitely makes a difference.

I also use the Stihl oil at 40:1 and it is one of the best oils on the market, but have also had good success using Honda HP2 at 32:1 (Honda's reccomended ratio), Redline at 40:1, and Belray at 40:1 for synthetics, and Penzoil Air Cooled at 40:1 is a very good straight-dino oil.

For what it is worth, RC Showcase used to recommend using dino oil for a minimum of 6 hours before switching to synthetic. There is a lot of good information here (although I don't know how much longer they will keep the site up): http://www.rcshowcase.com/html/faq.html

With the ZDZ resist any recommendations to run an oil mixture leaner than 50:1. The rear-rotor design requires more oil to properly seal than do piston-port or reed-valve engines.

Basically, just follow the directions on that engine and you will be fine.

[flymorerc]

BTerry,
Hope you're still watching this thread.
I have a ZDZ40 that has me puzzled. I bought it used from another club member and the motor came with the Brisk UR17 spark plug. Recently the cylinder head had to be fixed as the spark plug threads had stripped out. After the head was fixed, but not reinstalled, I trial fitted the sparkplug with the associated spark plug cup and it appears that the plug does not seat into the combustion crown. In reality, the plug only goes screws in about 2.5 turns - hardly enough to hold it in place. It was the outer two threads that stripped requiring the repair.
The BMR6F plug that ZDZ says to use has the threads as the Brisk.
Is this your experience?