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-   -   YS 170 DZ CDI new problem (http://www.rcuniverse.com/forum/rc-pattern-flying-101/9654003-ys-170-dz-cdi-new-problem.html)

pattratt 04-11-2010 08:51 PM

YS 170 DZ CDI new problem
 
Hi All
Thanks to all who helped on my loose header problem. I am now having a huge oil down problem. By the end of a day of flying everthing from the prop back plate back is covered in a very thick clear oil! Even the wheel pants are covered! Unless the oil is coming from the front crankshaft bearing I don'y know how it would oil down the whole engine bay and cheek cowl. The oil is very clean and clear in color so I do not feel it is exhaust residue!! Any ideas welcome. I did notice in parts break down that there was a seperate oil seal behind the front bearing. Could a bad seal put out enough oil in five flights to completely cover the entire bottom of the fuse.?

Thanks
Dick

tuny 04-11-2010 09:51 PM

RE: YS 170 DZ CDI new problem
 
check the spark plug, it could be loose or broken, also change all fuel lines.

TUNY

pattratt 04-11-2010 11:16 PM

RE: YS 170 DZ CDI new problem
 
Tuny
I will check both but engine is running very strong and has excellent compression.
Thanks for the reply as I had not checked either.
Dick

PeterP 04-12-2010 12:23 AM

RE: YS 170 DZ CDI new problem
 
Dick,

Could this residue be coming from your vent line ?

iflyrctoo 04-12-2010 12:42 AM

RE: YS 170 DZ CDI new problem
 
Head Gasket.

Joe Dunnaway

Jon Wold 04-12-2010 03:15 AM

RE: YS 170 DZ CDI new problem
 
Head gasket + 1 [8D]

vbortone 04-12-2010 07:50 AM

RE: YS 170 DZ CDI new problem
 
Head gasket +2

Vicente "Vince" Bortone

UKpatternflyer 04-12-2010 08:14 AM

RE: YS 170 DZ CDI new problem
 
I think if the engine is running well and the compression is good then I would be looking for leaks in the fuel system. I recently had a broken plug where the insulator had cracked and this sprayed loads of slightly coloured fuel / oil out. Took me ages to track; the fact that it was slightly discoloured suggested an exhaust related issue. I believe you say that this is not the case with your problem? Hence anything pre-injection would be suspect including the one way valve and the rocker box cover. Look also for missing / loose screws. Finally if you still can't track it then try siliconing up the joints for a quick test to see if you have poorly mating parts.

Hope this helps

Keith

pattratt 04-12-2010 10:14 AM

RE: YS 170 DZ CDI new problem
 
Peter
The vent line exits at the landing gear area way back of the engine. Don't know how oil would get to engine from there?
Dick

pattratt 04-12-2010 10:19 AM

RE: YS 170 DZ CDI new problem
 
Joe, Jon, & Vince

If it was the head gasket the oil residue should be discolored I would think? The engine runs very strong and has good compression. I have a compression gage so I will check to make sure compression is where it should be.

Thanks
Dick

pattratt 04-12-2010 10:30 AM

RE: YS 170 DZ CDI new problem
 
Keith
This is a new engine and all new fuel tubing but good idea to replace all to be sure this is not the problem.
I have already checked the valve cover gasket for tightness and this engine does not use an external check valve. I will check the plug and head bolts.

Thanks
Dick

UKpatternflyer 04-12-2010 10:41 AM

RE: YS 170 DZ CDI new problem
 
Hi Dick,

When I mention the one way valve, I'm referring to the black plastic valve that sits on top of the injector. This has a vent to atmosphere which sometimes leaks, but is unlikely to leak a lot unless faulty. Look also at the six backplate bolts.

Best wishes

Keith

vbortone 04-12-2010 11:02 AM

RE: YS 170 DZ CDI new problem
 
In the non CDI version the oil residue is very clean. I am not sure about the CDI. Again the chances of head gasket is very high since we have seen it many times.

Good luck,

Vicente "Vince" Bortone

pattratt 04-12-2010 11:14 AM

RE: YS 170 DZ CDI new problem
 
Hey Keith

Will do.

Thanks
Dick

pattratt 04-12-2010 11:16 AM

RE: YS 170 DZ CDI new problem
 
OK Vince, I will check the head carefully. Did your engine run strong when you had this problem?

Dick

shepga 04-12-2010 12:33 PM

RE: YS 170 DZ CDI new problem
 
How about cleaning the entire area & surroundings thoroughly then running the engine (with belly pan of off) for a very short period. Then inspect closely for the first signs of a leak.

Glen

iflyrctoo 04-12-2010 01:53 PM

RE: YS 170 DZ CDI new problem
 
Dick.... With a head gasket leak, the engine will still run strong. Look at the head closely while turning the prop up against compression. You can usually see a few bubbles leaking around the head if you look closely.

Joe Dunnaway

vbortone 04-12-2010 02:55 PM

RE: YS 170 DZ CDI new problem
 
Yes. It was difficult to notice any change in power.

Vicente "Vince" Bortone

pattratt 04-12-2010 05:19 PM

RE: YS 170 DZ CDI new problem
 
Hey Glenn

Will do if I can not find any issues from what I have learned here. There is enough oil that I should be able to see where it is coming from!!
I talked to Richard Verano today and he feels pretty sure it's probably a loose head. I will check that and a number of other things people have suggested. I am sure I will find it as this is not a small problem. Richard also gave me some good advice on how to prime the engine on the first flight of the day. Much harder to prime this puppy than the old style 140's.
Thanks for the reply.

Dick

pattratt 04-12-2010 05:22 PM

RE: YS 170 DZ CDI new problem
 
Will do Joe.
Thanks

Derek.Koopowitz 04-12-2010 05:43 PM

RE: YS 170 DZ CDI new problem
 

Quote:

ORIGINAL: pattratt

Keith
This is a new engine and all new fuel tubing but good idea to replace all to be sure this is not the problem.
I have already checked the valve cover gasket for tightness and this engine does not use an external check valve. I will check the plug and head bolts.

Dick,

Even though your valve cover may be tight there may be a slight high spot on the surface thus allowing air/fuel to escape. Take the valve cover off and remove the gasket and sand it on some 600-800 sandpaper until you get it shiny all over - then clean it in alcohol and put it back with a new gasket.

pattratt 04-12-2010 09:35 PM

RE: YS 170 DZ CDI new problem
 
Hey Derek
I took the cover off and it appeared to have imprinted the gasket pretty evenly.
I will remove it again and make sure it is even. I have done this before by laying the sand paper on glass and then moving the mating suface over it until it's all shinny.
Thanks
Dick

PS to all
Head bolts were tight but I turned the cap on the black plastic valve on top over a half turn in thr process of tighting it! It took an hour to get everything "clean." Next step will be to run the engine exposed to try and see the leak visually. Stay tuned!!

Pomales 04-13-2010 09:04 AM

RE: YS 170 DZ CDI new problem
 
Check your front push rod cover O rings.
I had the same problem one of the top O rings broke.
Good luck.


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