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Oil shutoff valves

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wild.blue(at)verizon.net
Guest

Posted: Sun Feb 28, 2010 9:44 am Post subject: Oil shutoff valves

Way back in a previous life I had a wonderful Max Holste MH 1521 "Broussard.

  Kind of a poor (French) man's DH Beaver, P&W R-985, plenty of room, hauled

a good load, lots of fun, nuthin' sounds like a 985.  All this talk about

oil shutoffs and hydraulic locks reminds me that the Broussard had a

mechanical oil shutoff valve.  The valve handle was mounted on the panel

just about the mag switch right next to the FUEL shutoff valve.  The handles

on the valves were arranged in such a way that you couldn't turn on the FUEL

without also turning on the OIL, though you could have the oil on but no

fuel.  Simple, fool (and pilot) proof.  985's also have lines connecting the

rocker boxes to the sump, so residual oil can drain from the rockers

directly to the sump instead of seeping past valves/guides/rings etc.  HSAT,

none of the above relieved the necessity of pulling the engine though the

requisite number of blades before EVERY start to make sure the engine was

clear.  It was also part of the start drill to crank the engine half a dozen

blades on the starter BEFORE turning on the mags in order to distribute the

prime AND prevent inadvertent lockup while making power on the start.  Being

a taildragger, it was possible for oil to collect in the intake tubes

DOWNHILL of the cylinders that couldn't be purged without pulling the intake

drains.  If there was oil present in the tubes it could be pulled into the

engine on start regardless of how many blades were pulled to purge the

cylinders, resulting in lock and sudden, nasty, potentially serious-damage

stoppage.  I flew the airplane frequently, it was low time and burned

(relatively) little oil, but even though I used the shutoff valves every

time I shut it down, if the airplane sat for even just short while, oil

would come out while pulling it through.  Never got locked, but plenty of

oil found its way to the cylinders.  Just the nature of the round engine

beast.



Shutoff valves ain't no magic bullet.



Sure miss that airplane, tho, never shoulda sold it.



Jerry Painter

Wild Blue Aviation

425-876-0865

JP(at)FlyWBA.com

www.FlyWBA.com

viperdoc(at)mindspring.co
Guest

Posted: Sun Feb 28, 2010 10:41 am Post subject: Oil shutoff valves

Know where you can find another one if you want to go through the headaches

of getting it shipped to the States.

As for the tail dragger collecting oil in the lower intake tubes on the

M-14, you are absolutely correct. To help mitigate that I jack the tail of

my 50 up if it is going to sit any at all after flying her. If it is cold

when I pull blades, I prime her with the intake drain open. Then pull some

more and be patient until the goo stops dripping out of the intake drain. 

As for all the oil shutoff valves, I'm going to start dropping the chin cowl

and plug a drain hose on the sump drain. I'll open it to drain the sump into

a 5 gallon gas can. The plane is not sitting cocked to launch for an

intercept. 

Sorry I'm just being a simpleton.

Doc



--

radiopicture

Joined: 23 Jun 2008
Posts: 263

Posted: Sun Feb 28, 2010 11:22 am Post subject: Oil shutoff valves

As alluded to, you can also cause a hydraulic lock by over-priming. If  

you're prime-crazy, it's a good idea to have the intake drains open  

regardless of ambient temp.

On Feb 28, 2010, at 1:39 PM, Roger Kemp M.D. wrote:



[quote] 

 >



 Know where you can find another one if you want to go through the  

 headaches

 of getting it shipped to the States.

 As for the tail dragger collecting oil in the lower intake tubes on  

 the

 M-14, you are absolutely correct. To help mitigate that I jack the  

 tail of

 my 50 up if it is going to sit any at all after flying her. If it is  

 cold

 when I pull blades, I prime her with the intake drain open. Then  

 pull some

 more and be patient until the goo stops dripping out of the intake  

 drain.

 As for all the oil shutoff valves, I'm going to start dropping the  

 chin cowl

 and plug a drain hose on the sump drain. I'll open it to drain the  

 sump into

 a 5 gallon gas can. The plane is not sitting cocked to launch for an

 intercept.

 Sorry I'm just being a simpleton.

 Doc



 --

viperdoc(at)mindspring.co
Guest

Posted: Sun Feb 28, 2010 7:01 pm Post subject: Oil shutoff valves

Even though I'm claiming to be a simpleton...I now understand why these are

called threads...once pulled they unravel.

Okay to clarify my pre-flight prep to fly, the intake drain is opened at the

end of the sortie. Whether it is just a break between last sortie and the

next or if it is the last one for the day. The intake is opened. It is only

closed once I have pushed her out on the ramp to go fly. That occures after

I have completed the preflight and blade pull through. If it is cold and the

oil coming out of the drain is slow flowing, I prime it with the intake

drain open (which it is because it was left open from the shutdown after the

last sortie). I then pull more blades. I prime it up to 6 times which is

generally enough to see fuel and oil running out of the intake drain of the

50. I even do that for the 52. Pre-flight is strictly by the RU manual. How

many blades do I pull you ask? A minimum of 12 but generally 16. Why? I like

the exercise and also I pull whatever it takes above 12 to see that there is

no oil leaking out of the stacks or the intake drain. Call me OC (Obsessive

Compulsive personality for the politically correct ...or just plain

anoretentive). I just figure the more blades you pull the less likely I am

at missing that 5 to 10 ccs of goo that could ruin my day. Nothing is

perfect though.

Also, if I see oil running out of the intake or the stacks I stop pulling

blades until it has stopped dripping. And yes I do pull blades after she has

sat longer than 10 min say at the pumps in the fuel pits or stopping to

visit a friend at their hanger. That engine does not start without blades

being pulled. Yes, I know the risk of desieling if the blades are pulled

with the engine hot right after shutdown. That is why I wait about 10 min

before moving the blades say to hook up the tug to push her back into the

hanger. 

Hope this clarifies any misconception that may have been taken from my

previous post on this unraveling thread.

Doc



--

netmaster15(at)juno.com
Guest

Posted: Sun Feb 28, 2010 7:54 pm Post subject: Oil shutoff valves

Doc, When you prime your 50 with the intake drain open --if you're putting enough primer fuel in to flush the intake tubes aren't you also washing residual oil off the cylinder walls at the same time?Perhaps it"s a matter of priming judiciously.   

Cliff Umscheidl 



--------

jan.mevis(at)informavia.b
Guest

Posted: Sun Feb 28, 2010 10:45 pm Post subject: Oil shutoff valves

I'm proceeding exactly the same way on my 50.



Jan



--

N13472(at)aol.com
Guest

Posted: Sun Feb 28, 2010 10:45 pm Post subject: Oil shutoff valves

That would be hard to do as the prime nozzle is in the blower  case, not the cyl.

  

Tom Elliott

CJ-6A NX63727

702-595-2680  



 [quote]         From: owner-yak-list-server(at)matronics.com    [mailto:owner-yak-list-server(at)matronics.com] On Behalf Of    netmaster15(at)juno.com

Sent: Sunday, February 28, 2010 7:46    PM

To: yak-list(at)matronics.com

Subject: RE: Oil    shutoff valves

   

   

Doc, When you prime your 50 with the intake drain open --if you're putting    enough primer fuel in to flush the intake tubes aren't you also washing    residual oil off the cylinder walls at the same time?Perhaps it"s a matter of    priming judiciously.     

Cliff Umscheidl 



--------

mark.bitterlich(at)navy.m
Guest

Posted: Mon Mar 01, 2010 10:31 am Post subject: Oil shutoff valves

Maybe I am missing something here?  

 

Look carefully at where the prime fuel goes when you prime the engine.  

 

When you prime the 50, the fuel goes into the output size of the supercharger manifold which feeds the intake tubes.  The airplane is sitting tail down which means the engine is also at an angle.  The fuel runs down  and some may end up getting into an open intake valve on the way down to the bottom tubes, but not too much really if any.  Most of it ends up at the bottom and runs right back out the open intake drains, which makes it pretty darn hard to over-prime.  I won't say impossible,  because I guess if you wore the pump right on out, you might be able to do that!  However, most of it runs right out the drains.  I have used the same procedure Doc has for 10 years now and over 900 hours on the 50 and I am still running the same engine with the same rings.  

 

You then get out and pull the prop through a few times, to pull some of that gas into the cylinders.  Starts easier that way.  Yes, I know everyone knows that.  

 

If you did not have intake drains, or you left them closed and you then pumped the daylights out of it, I guess it might be possible to fill up the bottom and have fuel run into an open intake valve, but even then... the bottom pistons are upside down and it will be very hard to get the fuel to run backwards up the cylinder wall.  

 

If you had no intake drains and/or left them closed, you could easily puddle enough fuel to have it cause a hyd lock when you went to start... assuming it mostly all got sucked into one cylinder.  

 

However, with the intake drain open, it is next to impossible to have enough fuel to wash oil off of the walls.  Fuel can't run uphill until the engine starts turning.  

 

Mark Bitterlich

 



________________________________



From: owner-yak-list-server(at)matronics.com on behalf of netmaster15(at)juno.com

Sent: Sun 2/28/2010 10:45 PM

To: yak-list(at)matronics.com

Subject: RE: Oil shutoff valves



Doc, When you prime your 50 with the intake drain open --if you're putting enough primer fuel in to flush the intake tubes aren't you also washing residual oil off the cylinder walls at the same time?Perhaps it"s a matter of priming judiciously.  



Cliff Umscheidl 



--------

viperdoc(at)mindspring.co
Guest

Posted: Mon Mar 01, 2010 7:24 pm Post subject: Oil shutoff valves

Cliff,  

Yes, I run that risk but the stuff is already the consistency of glue. I’m not pumping more the six strokes which is equivalent to priming about 3 good pressure stokes. My system has not even built up pressure until the 3rd or 4th stroke. I stop when I see fuel start to flow out of the intake drain. I then immediately pull additional  blades while the fuel is dripping out.   

I cannot say for sure that I’m not washing some oil of the cylinder walls though.  

Doc  

     

From: owner-yak-list-server(at)matronics.com [mailto:owner-yak-list-server(at)matronics.com] On Behalf Of netmaster15(at)juno.com

 Sent: Sunday, February 28, 2010 9:46 PM

 To: yak-list(at)matronics.com

 Subject: RE: Oil shutoff valves  

  

   

Doc, When you prime your 50 with the intake drain open --if you're putting enough primer fuel in to flush the intake tubes aren't you also washing residual oil off the cylinder walls at the same time?Perhaps it"s a matter of priming judiciously.    

Cliff Umscheidl 

 

 --------

mark.bitterlich(at)navy.m
Guest

Posted: Mon Mar 01, 2010 8:26 pm Post subject: Oil shutoff valves

You're not Doc.  Cliff is thinking about an engine that injects fuel right into the cylinders.  Like an opposed 6 cylinder engine, with direct cylinder priming.  Our engines do not work like that. 

 

Mark

 



________________________________



From: owner-yak-list-server(at)matronics.com on behalf of Roger Kemp M.D.

Sent: Mon 3/1/2010 10:20 PM

To: yak-list(at)matronics.com

Subject: RE: Oil shutoff valves



Cliff,



Yes, I run that risk but the stuff is already the consistency of glue. I'm not pumping more the six strokes which is equivalent to priming about 3 good pressure stokes. My system has not even built up pressure until the 3rd or 4th stroke. I stop when I see fuel start to flow out of the intake drain. I then immediately pull additional  blades while the fuel is dripping out. 



I cannot say for sure that I'm not washing some oil of the cylinder walls though.



Doc



 



From: owner-yak-list-server(at)matronics.com [mailto:owner-yak-list-server(at)matronics.com] On Behalf Of netmaster15(at)juno.com

Sent: Sunday, February 28, 2010 9:46 PM

To: yak-list(at)matronics.com

Subject: RE: Oil shutoff valves



 



Doc, When you prime your 50 with the intake drain open --if you're putting enough primer fuel in to flush the intake tubes aren't you also washing residual oil off the cylinder walls at the same time?Perhaps it"s a matter of priming judiciously.  



Cliff Umscheidl 



--------

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