I have a 33% Raven with a ZDZ80 single. First 3 gallons were run on mineral 1:32 and max temp on engine was 133C. After 3 gals I changed to fully synthetic 1:40 and the temp shot up. i am usually getting 150C now and one flight was 202C It is not lean. What could have caused it to overheat when I changed to synthetic oil? The oil is good quality Mobil Racing 2T.

RCToon,
We have had 2 zdz 80's different generations and you really have to watch the type of oil and the mix ratio. My current "blue" 80 is in a 101" QQ yak with the cowl opened and some balsa plate ducting, and still runs 230F. I switched to amsoil this summer, only because all our DA's are on it and it got hot. The motor runs great, tons of power, and is very reliable, but I went back to mineral based oil (last mix I think was pennnzoil air cooled oil) @ 32:1 and it did indeed run cooler.

Before RC showcase closed I had alot of discussions with Tom and he did mention to stick with a rich mix and natural oil. We smoked our first 80, well after it was broken in, by switching to 100:1.

Other than the incredible mess on the bottom of your plane I haven't noticed any performance or carbon build up issues.

I also found this summer that the 26" props seem to run cooler. Tried a Vess 27A and it ran hot.

Hope this helps.

Doc B.

Thanks Doc, that does help.
I think I will switch back to mineral and see if it helps. If it does, I am sticking with it.
BTW My ZDZ was purchaesd from RCShowcase in 2001 or 2002. BUt I started it for the first time only last summer.

ZDZ's like more oil....

I've tinkered with mine using different oils and they definitely like a 32/1 mix the best. Dick Hanson (Mr. ZDZ if you will) used to like the Mobil synthetic but they quit making it and he doesn't fly big stuff anymore so I don't know what he's suggesting now.

I also found that mine run cooler with dino oil and the oil question always starts big arguments, but anecdotally and in my experience my ZDZ's run better on dino. So I use the Stihl dino oil that comes in the six packs with a fuel stabilzer. The ZDZ's like it, my chainsaw and weedies don't seem to mind and so far, my new DA-120 seems to like it as well...

Hi

I have always flown my ZDZs with Castrol TTS fully syntetic mixed 1:40.
I don´t know what temperature I´ve got.
I have had 80,120,160 and 50cc ZDZ engines.

//Mikael

Thanks for the posts.... the problem is I doubt if we will get all the oils you mention here in Dubai.
I doubt if I will get Dino oil. I think I will try the Mobil at 1:32 and if that does not help will try going back to mineral oil.

Well hopefully I didn't confuse the issue by saying "Dino" with a capital letter....

All I meant was a non-synthetic oil and I tend to shy away from saying mineral oil because in the full scale piston world, that is available, frequently used for new overhauls and does not contain any additives. Then there is a regular oil which is made by the likes of Shell and others which is also a non-synthetic oil but with additives, then there are mineral/sythetic mixes like Stihl and others so when I say "Dino" that isn't a brand.

Sorry if I caused confusion or misunderstood your last post. I also forgot to mention that Dick was a real advocate of the 32/1 ratio on ZDZ's and he used to run 'em all including being part of ZDZ's new engine test group, he'd get all the cool new engines to test before they were released to the public.

Oh ! thanks for the clarification Zeeb. On forums like these I get to hear all kinds of brand names that we dont see here, so assumed that Dino was a brand of oil.

So Dick is our man... well if he ran 1:32 all the time, my action plan will be; increase the synthetic to 1:32. If it still heats, move back to dino... :-)

The ZDZs like high oil content as you get a better seal on the induction disc valve driven off the rear of the crank.

Originally Posted by Coke

The ZDZs like high oil content as you get a better seal on the induction disc valve driven off the rear of the crank.

The company recommends 4th gallon synthetic at 1:40 and after that at 1:50...my ZDZ certainly didnt like that.

ZDZ have not recommended 50:1 mix for a long time now they upped their oil content advice to 40:1 several years back and I like Dick Hanson find 32:1 works even better. The factory advice can be seen here http://www.zdz.cz/instructionsENG.pdf

Originally Posted by Coke

ZDZ have not recommended 50:1 mix for a long time now they upped their oil content advice to 40:1 several years back and I like Dick Hanson find 32:1 works even better. The factory advice can be seen here http://www.zdz.cz/instructionsENG.pdf

Yes, you are right, I was reading the instructions that came with the engine, which I had purchased way back in 2002.

That "mess" on the bottom of your plane carried a lot of heat out with it.

I changed the ratio to 1:32, retuned the engine and the temp is now 124C max. I think I will stick with 1:32 fully synthetic.