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Ys dz 180 cdi zero

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Old 04-01-2019, 11:27 AM
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richard_kis
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Default Ys dz 180 cdi zero

Hello all,
Please could you help me? As I mentioned in the DZ200 thread I noticed that my new YS DZ180 CDI ZERO is quite noisy when turned by hand. I removed the back plate today finally and noticed that the play between the crankshaft pin and bottom conrod eye seems to be quite high.
Please, check the video which demonstrates the problem:
youtube.com/watch?v=oRblPP9cFrQ
Should I replace the connecting rod?
The engine has one tank of ground breaking-in and three 10 minute flights, BTW it performs quite well, it is quiet and powerful on zero nitro and 18 percents of Molsyn 80-K
Greetings from Slovakia,
Richard
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Old 04-02-2019, 05:16 AM
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kenh3497
 
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That has way to much clearance. It looks like .005" to .006"??? I would think .001" to .0015" at an absolute maximum would be about right. At this point you don't know if it is the connecting rod or the crank shaft that is bad. If you have a calipers you can measure the rod. You would measure perpendicular to the length of the rod and in line with the rod. Those should be the same. If not the rod is bad. Measure the crank and it also should be round. If both are round then one is out of tolerance. Without specs we have no way of knowing which part is bad. It sure would be nice if the manufactures would publish specs for these engines. It would make repair easier.

As it seems it is a pretty new engine it might be worth sending it back to the YS distributor for repair under warranty, if it still has any warranty left.

Ken
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Old 04-03-2019, 03:45 AM
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Originally Posted by kenh3497 View Post
That has way to much clearance. It looks like .005" to .006"??? I would think .001" to .0015" at an absolute maximum would be about right. At this point you don't know if it is the connecting rod or the crank shaft that is bad. If you have a calipers you can measure the rod. You would measure perpendicular to the length of the rod and in line with the rod. Those should be the same. If not the rod is bad. Measure the crank and it also should be round. If both are round then one is out of tolerance. Without specs we have no way of knowing which part is bad. It sure would be nice if the manufactures would publish specs for these engines. It would make repair easier.

As it seems it is a pretty new engine it might be worth sending it back to the YS distributor for repair under warranty, if it still has any warranty left.

Ken
Thanks much for the answer Ken. I disassembled the engine and measured the crank pin and bottom rod eye. The pin looks be round but the eye is oval by 0,0035'' (0.09mm) inline with the rod. So I am replacing the rod for now. I experienced a backfire (the prop loosened, engine stopped) during my initial breaking-in. It was most probably too lean (1.5 turns stated in manual were not enough). Or maybe I flooded it before start and there was some fuel under the valve cover? (I have inverted installation). It seemed to run well on higher idle for about a minute so I tried to advance the throttle and it banged at midrange.. I suppose this bang could damage the rod.. Well In each case I think I have learned a lot about this engine during those my attempts and I ended with nice running engine at the end (well unfortunately also with ruined connecting rod as well. :-) )
My only previous experience with YS was FZ 140L in 1999 which I had borrowed from a friend with whole model for a short time for F3A WC 1999 In Pensacola :-)
BTW I think I am in love with this engine from the moment of the first takeoff..
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Old 04-04-2019, 07:14 AM
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Originally Posted by richard_kis View Post
Thanks much for the answer Ken. I disassembled the engine and measured the crank pin and bottom rod eye. The pin looks be round but the eye is oval by 0,0035'' (0.09mm) inline with the rod. So I am replacing the rod for now. I experienced a backfire (the prop loosened, engine stopped) during my initial breaking-in. It was most probably too lean (1.5 turns stated in manual were not enough). Or maybe I flooded it before start and there was some fuel under the valve cover? (I have inverted installation). It seemed to run well on higher idle for about a minute so I tried to advance the throttle and it banged at midrange.. I suppose this bang could damage the rod.. Well In each case I think I have learned a lot about this engine during those my attempts and I ended with nice running engine at the end (well unfortunately also with ruined connecting rod as well. :-) )
My only previous experience with YS was FZ 140L in 1999 which I had borrowed from a friend with whole model for a short time for F3A WC 1999 In Pensacola :-)
BTW I think I am in love with this engine from the moment of the first takeoff..
IMO it is very unlikely the backfire caused damage to the rod. The force would have been on the beam (the strongest part) of the rod. And no force would have been applied to stretch the diameter of the eye. There is another cause of the damage whether it be lack of lubrication or over revving or just plain many hours of usage. In case it is a lack of lubrication, I would check the cam lobes and lifters to be certain they are OK. That is another high pressure lightly lubed area of the engine.

At least you now know a new rod will fix the problem.

Ken
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Old 04-04-2019, 09:53 PM
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Originally Posted by kenh3497 View Post
IMO it is very unlikely the backfire caused damage to the rod. The force would have been on the beam (the strongest part) of the rod. And no force would have been applied to stretch the diameter of the eye. There is another cause of the damage whether it be lack of lubrication or over revving or just plain many hours of usage. In case it is a lack of lubrication, I would check the cam lobes and lifters to be certain they are OK. That is another high pressure lightly lubed area of the engine.

At least you now know a new rod will fix the problem.

Ken
Thank you for the answer,
Lack of lubrication: I used 18 percent of oil for first runs which is more than stated in the manual. After opening of the crank case, I saw an oil film on all parts inside..
Over revving: Certainly not in this case. I doubt I exceeded 7000rpm at all (used APC 20x10.5 prop)
Just plain many hours of usage: No. Engine really has really about 40 minutes of run.

I inspected the rod again trying to decide which site is compressed (if it is) and it really looks for the beam site. The eye has beveled edges and this bevel looks be thinner on the beam site (I am sorry if I abuse your language, hope it is clear what I mean)..

Originally Posted by kenh3497 View Post
At least you now know a new rod will fix the problem.
Ken
Well I am afraid I don't know if the problem will not happen again. But I suppose the problem was really caused just by the abrupt backfire.

Last edited by richard_kis; 04-04-2019 at 09:58 PM.
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Old 04-08-2019, 08:35 AM
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It certainly is an interesting problem to solve. While it certainly is a possibility the beam side is deformed it is much more likely the bottom, thinner, side of the eye is what got stretched, IF that is in fact what happened. MY OPINION is the rod was not machined correctly at the factory, given the circumstances you described. i would contact the YS distributor for your area and tell them what you have told here on this forum. I personally feel this is a situation where warranty should be used.

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Old 04-10-2019, 04:25 AM
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Originally Posted by richard_kis View Post
Thank you for the answer,
Lack of lubrication: I used 18 percent of oil for first runs which is more than stated in the manual. After opening of the crank case, I saw an oil film on all parts inside..
Over revving: Certainly not in this case. I doubt I exceeded 7000rpm at all (used APC 20x10.5 prop)
Just plain many hours of usage: No. Engine really has really about 40 minutes of run.

I inspected the rod again trying to decide which site is compressed (if it is) and it really looks for the beam site. The eye has beveled edges and this bevel looks be thinner on the beam site (I am sorry if I abuse your language, hope it is clear what I mean)..


Well I am afraid I don't know if the problem will not happen again. But I suppose the problem was really caused just by the abrupt backfire.
I will check on my engines once I get back home as I am on a business trip, but you can call YS and ask, that is the best option.

Ussually before throwing the prop the engine drops RPM, if that happens go back to idle inmediately and it won´t throw the prop and keep runing.
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