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Date: Mon, 02 Mar 2009 07:57:39 -0700
From: Dale Rogers <dale.r@cox.net>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] No oil pressure
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Second source support for Lynn's advise:

http://bdc.cyberosity.com/v/Technical/Front-Cover-Assembly/FrontCoverORingInstalled.Jpg.html

Note the RH sidebar, indicating that failure of the o-ring will yield
oil pressure in the 0-25# range.

Dale R.

Lynn Hanover wrote:
>   No luck today.
> >
> >     I filled the line out of the engine just after the pump, then
> >     cranked it over with the starter. I did get a little flow, but not
> >     very much. I reconnected the hose, and added components as I went,
> >     checking that I had oil flow after each. Still had flow after the
> >     cooler and just barely a trickle after the filter, where the oil
> >     should go back into the engine. From this I am thinking either I
> >     am not picking up enough oil, or the pump isn’t pumping enough oil.
>  
> There should be some large amount of time between filling the hose and 
> trying to crank the engine. The object is that the oil in the hose 
> will flow backwards (very slowly) through the pump and back into the 
> sump. Keep adding oil to the hose to keep it full (highest head 
> pressure), or if you can rig up a way to add shop air pressure to that 
> hose full of oil it could shorten the process to a few seconds from an 
> hour or so.
>  
> I would not use shop air to pressurize the block, as you might turn a 
> seal inside out.
>  
> You could stick the end of the hose in a glass jug or similar. Place 
> the end of a shop vac hose over the neck and pack a rag around the 
> junction. Turn on the shop vac until oil ( a lot of oil runs out of 
> the hose).
>  
> Flow rate will not be great, but it will wet the pump.
>  
> You could fill the sump with oil to a level higher than the pump. Then 
> it would be charged just sitting still.
>  
> I never used a gasket on the end of the pickup. I just lap the flange 
> dead flat and bolted it on. Then safety wire the bolts. No bug screen 
> and a nice bell shape on the end of the pipe.
>  
> If the pump has a prime it will put out a 2" high vertical column of 
> oil past the hose end at cranking speed.
>  
> Several things come to mind with the OMP removed. Is there a hole that 
> needs to be plugged with the OPM gone?  I block off the oil supply to 
> the OMP at the gasket face with a bearing ball pressed into the oil 
> gallery.
>  
> And, now the ever popular "O" ring between the front iron and the 
> front cover. It is prone to failure on cold start ups. If it would 
> just blow out, there would just be a reduction in oil pressure. It 
> does not just blow out. The "O" ring extrudes out of one side of the 
> junction to release the pressure, and remains clamped in that 
> position, providing a big oil leak, that can only be repaired by 
> removing the front cover, and installing a new ring. I recommend a 
> solid aluminum or copper ring that will not fail. The front cover is 
> quite flexible, and high oil pressure on startup can push the cover 
> off of the junction and allow the "O" ring to escape. 
>  
> The avarage 5th grade girl would not have engineered anything this 
> stupid, but you cannot tell the Japs anything. Later they place a 
> Nylon reinforced washer around the is junction, and used a fatter "O" 
> ring. The washer takes up space and improves clamping force around the 
> land area. Later still a stainless gasket fits around the junction.
>  
> If either the cover or the iron had this land area left proud of the 
> gasket surface even .010" or .015" this "O" ring would probably never 
> fail. The front cover gasket leaves this junction standing open a bit. 
> The hot street deal is to leave out the gasket to get the gap to close 
> up.
>  
> I blocked that junction with a thick aluminum disc, and took the oil 
> out the end of the gallery with a dash 10 tube to boss fitting. Do not 
> use a pipe thread in that gallery, it will crack open and ruin the iron. 
>  
> Note the core support plug missing in this iron.
>  
> Lynn E. Hanover  
> >
>
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>
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