togatoga

My Feedback: (42)

You're the man Troy! Always prompt with answers and assistance!!

P.J , I was just stating a point that there is very little bevelling of the valve seat in the order of a few microns and almost imperceptible.Most valve seat problems I have encountered are damage due to FOD, valve worn out (ring groove) and binding in the valve stem,guide. Anyway, I thank you for sharing the other possibilty that the valve seat may have a manufacturing defect.I know for real that the occasional poor casting of the combustion chamber next to the exhaust valve can result in small chunks coming loose after a while. It has happened to a few of my engines.
Overall, its still the only engine I will use for reliability and sheer power.

PJ_TankPilot

Yes, the valve seat mating surfaces are very narrow. The one piece cylinder head makes it difficult to see but with a good light and good eyes, you can see them. The valves are easy because you can remove them for inspection.
You can say that again. We have a lot of guys here who have been racing YS engines for many years and pushing them to their limits. They are amazing engines.

selnekav

Hi Troy,
Thanks for your help so far !
i remove the cylinder head, and now it's clear to me where the problems came from… both sleeve and piston and also the bottom of the connecting rod was scratched all over. when i looked inside the cylinder head i noticed that there is cracks near the plug screw, and also fractions on the top wall ( around the valve seats ). i moved my finger around, and i was able to see small peaces of metal on it !!

now it’s clear that the inside of cylinder head casting have a manufacturer
failure. ( since my camera have low resolution it’s impossible to see it on a regular picture, but it can be seen clearly by eye )

I have looked in the YS Japan site but I really don't know who I should connect there,

i will appreciate if you will be able to help me

Thanks Shlomo.

togatoga

My Feedback: (42)

Hi Shlomo, I had this problem on some of my engines. The casting especially near the exhaust valve can be bad and small chunks come off after a few runs.However what you've described with pitting on the lower end of the conrod, could also be the main bearing breaking up.Bits of fragmenting bearing do more damage than bits of cylinder head material because of the hardened steel. Check the bearing cage,it may have disintegrated especially the rivet pins that hold it together.This results in catastrophic damage to the engine.The liner,ring,piston,combustion chamber,crankcase , conrod and drumvalve all get a share of the debris.A telltale sign is bits of shiny metal embedded in the crankcase where the conrod moves thru'.

selnekav

Hi togatoga
you probably right since the crankcase have also scratches on it. ( i still didn't remove the main bearing so it's difficult to say, by the way what is the main bearing is that the front one ? i will do it tommorow and update) but i don't understand how it's possible that after only two gallons both cylinder head and main bearing breaks up ?? any idea ?


Regards,
Shlomo

togatoga

My Feedback: (42)

Its the inner bearing supporting the crankshaft,the one thats not sealed and bigger of the 2. A lot of things can cause failure - manufacturing defect,strong side or longitudinal forces (e.g a crash or a fall),corrosion - this bearing is exposed to raw fuel upwards of 20% nitro or excessive speed with little lubrication etc.That said, it shouldn't happen to a low time engine especially during breakin although some guys believe a starter, misused ,can cause serious damage to an engine. There should be a warmup time before opening up the throttle especially so as this is a supercharged engine and it runs at higher temps. And make sure you have adequate cooling.
Like Troy says, call the distributor to let him know or YS Japan- emails are next to impossible (they're very busy) calling them helps although knowing Japanese is a plus! They have a parts order section in their website but i reckon it could be for the Japanese market only.If i were in your position, I'd send the motor to a) local distributor - they'll send it back to japan for repairs b) YS in the US for a fix or c)if you can see what parts need replacing, then order them from HK and fix it yourself ( they don't send if there is an authorised distributor in your country).

selnekav

Hi Togatoga
Do you know if there is chance that YS Japan will cover the repair costs ?

Regards,
Shlomo

togatoga

My Feedback: (42)

Very hard to say.If your distributor supports your claim then its should be warrantied.My experience is that I have to fork out the cost ! It all depends on the distributor and whether he'll stand by you.The warranty states that YS will cover the repair costs within a year from purchase provided the engine was not run improperly or abused - very hard to ascertain sometimes!! and if improper fuel was used.I know the US distributor gives very good support and YS needs to protect it as its an important market I suppose!!

The good thing about YS Japan is that the cost of parts replacement is low as they charge a different price for them unlike if you buy from the shops.They will replace everything that needs replacing and things that still work will be left untouched eventhough cosmetically they don't look that good! I have calculated that if I buy parts off the shelf, it would cost about the same if they did all the work replacing ,fixing it back and postage costs.The engine is then bench tested and adjusted before they come back to you. YS will present a bill whereby if it is disputed,the distributor will try to mitigate on your behalf.It takes about a month.Normally the distributor will wait until he has collected enough stuff or he has an impending order before he sends the motor to be repaired off.

What you need to do is make a case,although it looks like the LHS will not be of any help!

togatoga

My Feedback: (42)

If you want to do the replacing yourself then I think its fair to assume that you need to replace a) F7102- cylinder head ( you can remove the valves,spring set and rocker arm and reuse them to save cost) b) F1224 - piston ring ( same part number as the YS120) and c) a new main bearing if its the culprit- use ceramic from rc bearings if you can or just a normal good quality bearing from the bearing shop (od32mm, id15mm, width 8mm). If the piston (F1421) is badly scored than it needs to be replaced too or it'll ruin the liner. The piston is more than half the cost of the liner!! Sometimes fine sanding the piston works.Most of the rest should still be functional.
Hope this helps.

selnekav

Thank you ! i will contact the distributer again to see what he have to say about.

Shlomo.

selnekav

Hi Troy
I spoke with the local distributer, and as i thought the new info about the small peaces of metal dosen't change nothing to him and he still claim that it's related to the break in. anyway i decided that the only reasonable option at this point is to send the engine directly to YS Japan with a letter that describes the engine faulire.

anyway i noticed that the only mail address in the YS Japn site is :

YS PARTS & SERVICE
1370 PORTER DR MINDEN, NV 89423 U.S.A.
Phone:775-267-9252
Fax:775-267-9690

do you know what is the YS Japan address ?

Thanks again
Shlomo.

jb86

My Feedback: (8)

as far as break in, i have heard that YS don't want to be bench run. mount it on the a/c, let it warm up a bit, set the needles for a a bit rich, adjust it to run reliably, and fly it with varying throttle.
i have a 110 FZ that i bought in the spring, have not run yet, will do in a few weeks. just making sure i get it right. for my H9 F90. i was told to use 16.5x5W or 16x6. according to what i've been reading, i'll have to use 30% heli.
is it worth upgrading to the new FZ110-S? does it have any more power?
jon

Troy Newman

bench running is OK as long as you don't do it for long periods of time. If running it without flying it I usually only let it run for about 5mins at a time.

Its true the best thing you can do is to fly it...this will keep the air flowing over the engine and keep it cool. However you need to make sure the engine is running reliable enough to not risk your aircraft, and you don't want it too lean that it can damage it. A little running on the ground is common for a few tanks. Run 5mins and let it cool completely between runs. The idea is to get it in the air as soon as you feel its reliable.

As for having to run 30% heli...this is not a requirement. It will make the YS or any 4 stroke for that matter run at its best performance. It also makes it easier to get the mixture setting correct. The higher nitro will require a richer overall needle setting and will mean more oil is flowing through the engine. This si what keeps it cool...So its easier to operate on higher nitro. It will run on 15% but the setting become more critical.

As for the 110FZ vs the 110S. Yes the 110S has a little more power. Its not extreme but it is more powerful.

I wouldn't scrap the 110FZ as its still a powerhouse and runs great. The 110S is ajust a next generation and has a few refinements. Both are excellent engines.

Choose a prop and fuel combo that gives about 9000-9500 rpms....I prefer the 9400-9500 rnage but lots of folks are having success in the low 9000's. Basically if you run only 155 nitro you will need a smaller prop than if running 30% heli fuel.


Troy Newman
Team YS