Ys dz185 zero
 

There has not been much information about the YS DZ185 ZERO engine, therefore I thought I should share my experience. The only difference to the nitro variant is the piston.

Initially the idle was too high, and transition not great. After consulting YS about the high rpm at idle they recommend to run the ignition on 2s-LiPo and increase the spark plug gap to 0.4 mm. It improved but still not fantastic.

But trying my new airplane with a YS Super Mount, voila, the engine problems were gone and the engine was running great. Changed the mount in my old airplane, and installed the YS Super Mount instead, this cured the engine problems I previously had with this airplane.

Clearly the movement of the engine has an influence on the pump, i.e. inertia load on the pump piston. The nitro probably masks this at idle and transition, and tolerate better the variation in fuel/air mixture. Any other thought/comments?

The props I use is APC 20.5x10 (Carbon) and APC 20x10.5. None of them feels “heavy”, so the power output is at least comparable to a YS175CDI nitro.

The fuel I use is 90% methanol and 10 % oil.

Valid in all sports: “Precision before power.” My feeling is that I do not lack any power with the ZERO, the precision in my flying is another matter.

Arnstein

Hi Arnstein,

The Zero has higher compression to compensate for no nitro, so I would expect the idle to be a bit higher.

What mount were you originally using?

Scott

Hi Scott,

I have used different types of Hyde mounts. I modified one mount adding an extra layer of rubber, it improved the idling a little. However, the to get down to 2K, both the Hyde Evo and the YS mount works, both fitted with hydraulic damper. Have not tried the Tubasakoubou-mount.

May be the higher compression causes the engine to idle at a higher rpm. The experience I have with the ZERO tells me the engine mount has a big influence on the idling and transition. A mount with a hydraulic damper I found is the way to go, get the same idling speed as with the nitro version.

My theory is that the vibration of the engine has an influence on the fuel pump. On the first versions the intake valve spring rate was very high, I experienced excessive cam gear wear. The 185 was the first (?) to have the same spring rate on both the exhaust and intake, may be the intake valve spring rate is a little on the soft side?

The YS 185 ZERO impresses me, same idling and throttle response. A little down on power, similar to a 175. The fuel cost very low, we pay a lot to get that extra power.

Best regards,

Arnstein

Very interesting input, thanks.

I have never used anything but YS supermounts, but I have seen other engines run, and ussually mine is smoother, your comparison and point of view shows some things to take in consideration.

An engine with a higher compresion will most likely need to run on a different ignition advance also I presume, is the ignition standard or "ZERO"? Just curious.

Regards

Hi all,
Just digressing a little I two had some issues with the softer intake valve spring on the 185 red CDI .
It allowed the pushrod to lift too far and jam the pump..

I have installed the TU mount but not yet flown with it ....will report back when I do.

Also according to YS the tube C to the injector should be changed regularly as it greatly affects the operation especially transition of the engine.
If it becomes too soft it will slide of the injector easily and it should be replaced.

Best regards

Mavros,

Which hose are replacing the injector one with? I just need to buy some fuel tubbing and I have not run my RED yet but will in a month. The hose replaces the spring on the injector and if it is too soft it might not pulverize well and too stiff will probably have bad idle and transition......


Regards

Hi Apereira,

As far as I know the tube is not replaced by anything different but has to be replaced if it starts to soften up.

According to YS normal fuel tubing is not suitable only the YS should be used.

regards

Yes,

That it was my understanding, but better ask....

Regards

I was having the same issue with my DZ 140 and replaced the tube with a peice of 3mm ID teflon. Haven't given it another thought since.

Not that I know anything... but my thought from a "mechanics' view is the tubing to the injector should be quite "rigid". The harder the tubing the less loss of fuel pressure from the tubing expanding with each pulse. Ideally, IMO, it should be a wire braid like a hydraulic hose.

ken

I doubt you are off base here Ken, my 140 runs more consistent with the ridged teflon tube. I feel,I was able to get a finer tune on it.

Hi Arnstein,

I have used the Hyde LR85 mount, (no damper), as well as the YS Super mount. I didn't notice any difference in idling or transition between the two, but I do think the Super mount is a bit smoother.

Interesting theory on the vibrations affecting fuel delivery. I haven't had any issues from this, but something to keep in mind.

In regards to fuel tubing, I'm not convinced that is a issue. I've used YS tube, Dubro medium tube and now Prather medium which I've been using for a few years now. Haven't had problems with any of them. But whatever works.

For the 185 Red and 200, the manual specifies that the carb to injector line, (tube C), must be a soft tube with 3mm ID and 5mm OD. This is to do with the new injector not having the check valve on top.

An engine with a higher compresion will most likely need to run on a different ignition advance also I presume, is the ignition standard or "ZERO"? Just curious.

Not aware of any special ignition unit for the ZERO. Had the same question myself.

Arnstein

I am not convinced that you reached the same conclusion if using 0% nitro. I guess you are running closer to 30%.

Arnstein

my my problem was that the tubing kept splitting. Even the Prather medium line.

This is different, it is a specific hose that works as a relief valve would, it is only on the injector, you would need to see it, it is not in any drawings and found only the 185 Red and later models.

Was it the pump to carb line or carb to injector line that was splitting?

Yes, pump to carb.

The Prather Medium is splitting? that's the one I have used for many years, but there's a hose clamp on that hose on both ends, do you have them installed?

Regards

Yes, I did have clamps at each end. The hose would split in the middle leaving about a 1/2” long split. Richard had warned me to keep an eye on that tube and replace when it started bulging. Never got to that point, I would get 3 to 5 flights and the tube would split in flight. Installed a Teflon tube and no issues since.

Oh, I see, good to know.

Regards

Hi Ken, the pressure is controlled by the regulator so any elasticity in the line between the pump and throttle body wouldn't cause a reduction in pressure but would cause an increase in the volume of fuel stored at that pressure. This would result in pump pressure being applied to the metering circuit and injector for a longer period of time.

It's not beyond the realm of possibility (pure speculation on my part!) that pressure in that line is supposed to remain for a while after the pump completes it's pressure stroke (a bit like filling up a bagpipe bladder) so the injector can continue to inject fuel as the valve is closing. After all, even fuel injectors in vehicles today can spend lots of time spraying at a closed intake valve under certain conditions. There may just be a Goldilocks zone of tubing rigidity for each engine??

It would be worth trying YS fuel tube.