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Old 03-07-2008, 11:32 PM
  #10276  
thrashin
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Checked that... inlet manifold is rock solid in the head, no movement. Any other ides? Does the highspeed needle effecting idle indicate anything you know of?

This is a fairly new .72 and has the reinforced backplate. Does it sounds like an air leak?
Old 03-07-2008, 11:33 PM
  #10277  
w8ye
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It is less than 18% by volume of the total fuel volume consumed.

The Saito's with two bosses in the back plate can utilize the Saito in-out check valve system.

you may be able to use a small fuel tank as a catch trap to accumulate the expelled oil when using the check valves
Old 03-07-2008, 11:38 PM
  #10278  
w8ye
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I never had a Saito where the idle mixture was materially affected by the high speed needle.

My initial impulse would have been to open up the low speed to be even with the outside of the throttle arm. Throttle the engine up to full throttle and adjust the HS needle for peak, then go back and adjust the LS needle for best compromise between smooth idle and transition to high speed.

In the end, the HS is re-adjusted 500-600 rpm rich
Old 03-07-2008, 11:50 PM
  #10279  
RPMcK
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Default RE: Welcome to Club SAITO !

Mike, the blow by oil is what I'd like to find a way to deal with. Just wondered how much is emittred and if it could be contained in small enough contairner to make it practical to catch it or just let it eject overboard. I haven't even ran my 180 yet so I have no idea what to expect. That's why I'm asking questions.
Old 03-07-2008, 11:54 PM
  #10280  
RPMcK
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w8ye - sorry about the -w8y3 thing - typo
Old 03-07-2008, 11:55 PM
  #10281  
w8ye
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No Problem
Old 03-08-2008, 12:11 AM
  #10282  
mike early
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I will be using a long fuel line routing the crankcase vent out of the bottom of the cowl. Not very pretty. My engine is still new, but I was amazed at the amount of oil coming out of there when running on the bench. I am sure it will decrease with time. My fuel has 20% synthetic oil. I presume that lower oil content would result in less mess. Less lubrication too, of course.

I wonder if castor oil creates a better seal with the piston, resulting in less blowby?
Old 03-08-2008, 12:15 AM
  #10283  
RPMcK
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Mike, Appreciate your input. Thanks. Ron
Old 03-08-2008, 12:22 AM
  #10284  
RPMcK
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w8ye, I hadn't thought about the small fuel tank thing. Good idea, thanks.
Old 03-08-2008, 07:55 AM
  #10285  
Hobbsy
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Mike, I have on several occasions ran Saitos for 10 minutes then immediately pulled the backplates to see how much oil is in them. I have done this with 16%, 18% and 20% lube oil and there is always the same amount in the crankcase, so one has to conclude that the higher %s flow through the engine faster than the lower %s. RCV recommends against more than 16% lube and if you watch my .58CD you can see why, it really spews oil when 18% is used although it has never hurt the engine. In the case of the RCV the caution is due to the small combustion chamber but the flow difference is visible.
Old 03-08-2008, 08:25 AM
  #10286  
Capt Lou
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Default RE: Welcome to Club SAITO !

Guys:

Regarding the vent tubing, I have read (altough I can't remember where I saw it) that the vent tubing should be no longer than 4-41/2 inches and you should use a large diameter tube. My recollection is that you need to be concerned about the tube bend creating back pressure and that this would also occur with too long of a tube. I wish I could tell you more about this but I don't recall the source. Maybe someone can jump in on this matter.
Old 03-08-2008, 09:33 AM
  #10287  
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So this means that the tube i have on my crankcase vent is to long and is going to create to much back pressure on my crank case. I seen no other option then to run the tube from the engine and route it to the bottom of the cowl and the tube is probably over 4 1/2 inches.

So buy looking at these pictures of the plane i have my saito in does this mean i'm going to have to route the vent tube out the top of the cowl. would hate to have all the blow buy going all over the cockpit and the top of the plane.

the tube has no kinks in it and the engine Seems to run fine with the tube routed over the top of the engine and looped around to come out the bottom.
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Old 03-08-2008, 09:58 AM
  #10288  
blw
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Default RE: Welcome to Club SAITO !

Your vent tube installation looks fine and I wouldn't change it. I think the 4 1/2 inch length was an observation by someone and not a factual limitation. A large diameter wouldn't hurt anything if you can keep it attached to the vent nipple.
Old 03-08-2008, 09:58 AM
  #10289  
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Link,

I run my case vent out the bottom of my cowls on all my planes. They are all more than 4 1/2 inches. I have not had any problems with excess back pressure. On my test bench the vent line is run to a tank and is about 18 inches long. The oil has no problem getting to the tank. I can see a problem if it kinks. Has anyone else had a problem with a long tube?

Jim
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Old 03-08-2008, 09:59 AM
  #10290  
w8ye
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The vent tube should be looped and run out the bottom of the cowl
Old 03-08-2008, 10:06 AM
  #10291  
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Thanks everyone i worried there for a minute.
Old 03-08-2008, 10:59 AM
  #10292  
RPMcK
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Default RE: Welcome to Club SAITO !

Jim,

What's the story on the muffler on your beautiful blue bi-plane? Doesn't look like one of your's!

Ron
Old 03-08-2008, 11:20 AM
  #10293  
SigMan
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Default RE: Welcome to Club SAITO !


ORIGINAL: RPMcK

w8y3 Then I am assuming from what you say that the main purpose of the breather nipple is to vent the crankcase, not to eliminate the excess oil. The oil being expelled is a side effect. I guess my next question is how much unburned oil is being expelled as a side effect?
Would it be possible to devise a air/oil seperator to contain the expelled oil rather than let it be ejected overboard. Could one use the in/out check valves used on the larger Saito engines for this sort of thing and would it be worth the effort in terms of reducing oil contaminatiom of the airframe?
i was thinking of running a line from the breather nipple up to muffler to help burn some of the oil off, instead of having a oily mess on the bottom side of my plane. has anyone ever tried this?
Old 03-08-2008, 11:34 AM
  #10294  
mike early
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Default RE: Welcome to Club SAITO !

The 4 1/2" max number probably came from the max suggested length of line from the crankcase to a Perry Pump.


If you have 2 pressure fittings on your exhaust, or are not pressuring your fuel tank with exhaust, I don't see how the crankcase blowby oil would hurt anything by going to the exhaust. Actually I like the idea. What say the moderators?
Old 03-08-2008, 11:37 AM
  #10295  
w8ye
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I often pipe the crankcase vent to a point along side the exhaust outlet so they both come out the same place
Old 03-08-2008, 11:44 AM
  #10296  
mike early
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Another great idea from the Saito Club! Thanks!
Old 03-08-2008, 11:47 AM
  #10297  
mike early
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Ah, after re-reading your post, w8ye, I see that I misunderstood. You are not tapping your exhaust. I think I will add another pressure fitting to my flex pipe and route the blowby out the exhaust, in the manner SigMan has suggested. Any possible problem with that?
Old 03-08-2008, 12:09 PM
  #10298  
w8ye
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However there is some resistive back pressure inside the muffler.

Anything is worth a try.

In my escapades, I never piped the crankcase into the exhaust. I just put the crankcase vent beside the exhaust outlet. I used a short piece of K-S brass tubing fastened to the muffler with a small hose clamp. I used a piece of fuel tubing between the crankcase vent and the piece of tubing fastened beside the muffler.
Old 03-08-2008, 03:57 PM
  #10299  
Michaelh
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Going on the idea that the breather is sucking and blowing I guess it would be sucking in exhaust gasses into the crankcase now.
Old 03-08-2008, 04:38 PM
  #10300  
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Hi Thrashin,

Your problem still sounds like an air leak issue to me. When checking that backplate, did you notice if all the screws on the backplate were tight? I presume that you did. The first thing that I would recommend is to put in a fresh plug of the type that you were using before and had success with - you said you had tried a variety of plugs, so I want to suggest putting in a new one. Then, read the manual and reset the needle valve and the LSN to the factory specs, then try it again.

Is anything different from when the engine had been running before? Is it in a new plane with a different fuel tank location? Where it remains side mounted, I'm guessing that the answer is 'no', that it is still in the same plane.

How about the fuel lines? Could they have a small puncture in them, whether it be the fuel line or the pressure line from the muffler? I'd be curious to find out what the solution is.

Bob

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