hcccs

hcccs

Well Known Member
Working on the oil pressure line on my O-320 E3D I spotted this little plugged port right beside the port that comes from the oil cooler. If I could use it for the oil pressure line it would simplify the installation. If it is not good enough for that I can't understand what it would be used for. It looks as if it is connected to the left oil gallery and the 'normal' pressure port is in the front of that so it should work if my guess is right. The question is if the pressure here gives the correct reading. Right or wrong?



 
I don't think you want to use that port for oil pressure.

The pressure coming from the oil cooler will be affected by the operation of the Vernatherm valve.
 
Oil pressure port again.

Mel
In another post on the forum they pointed out another port most people use for oil pressure lines and it is on the right side on the O-320 close to the upper right focal mount. I haven't seen it before because it was obscured by the engine mount. Is this the one to use?

 
hcccs said:
Mel
In another post on the forum they pointed out another port most people use for oil pressure lines and it is on the right side on the O-320 close to the upper right focal mount. I haven't seen it before because it was obscured by the engine mount. Is this the one to use?

Click to expand...

Yup, that's it :D Rosie
 
Plugs, plugs everywhere.....

hcccs said:
Working on the oil pressure line on my O-320 E3D I spotted this little plugged port right beside the port that comes from the oil cooler. If I could use it for the oil pressure line it would simplify the installation. If it is not good enough for that I can't understand what it would be used for. It looks as if it is connected to the left oil gallery and the 'normal' pressure port is in the front of that so it should work if my guess is right. The question is if the pressure here gives the correct reading. Right or wrong?
Click to expand...

Hans,
Those plugs are a byproduct of the manufacturing process. There are a number of plugs like that throughout the crankcases, accessory cover & sump. They are there to plug a hole which was drilled to create an internal oil passageway. The plug is there to prevent a leak [where the drill went into the casing] There are two such passageways [one in each crankcase half] which parallel the camshaft. They supply oil to the lifters and the camshaft bearings. You will find a plug at the front of each crankcase half where the drill [a very long one] went into each case half to create those oil galleys [aka passageways]. Either of these plugs would also make a good place to tap into, for your oil pressure. The readings at this point would be somewhat lower than taking it at the proper tap on the accessory cover.
That is because oil [and therefore pressure] has been bled off by the camshaft & lifters at that point. If your oil pressure gauge only goes up to 100 psi, you will peg the gauge less by using one of these forward tap points, due to the pressure reduction. You might want to check out the web links below for more info. The first link explains the logic behind using these forward points to monitor your oil pressure. See

http://egaa.home.mindspring.com/new.htm

http://egaa.home.mindspring.com/valves.html

I hope this helps. I've probably muddied the water for you.

Charlie
PS Lycoming SI 1479A [mentioned in the second link] is not available on line. Contact me via PM or email and I can send you a copy of it.
 
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Oil pressure port and Vernatherm

Charlie
Interesting reading. The port just to the left of the right dynafocal mount is very awkward to work with and I will probably need to loosen the nut and bolt to screw in a 45? fitting - a 90? won't screw in here. I was thinking of an alternative port and if I don't have a Vernatherm (I don't know if I have one) then oil will flow through the cooler at all times. In that case the port marked with '?' on picture two could work since there will be no fluctuation in oil pressure. Does my reasoning make sense or not? Where would I find the Vernatherm if I have one installed?





oilport.jpg
 
Your Vernatherm

Hans, the plug you point to in picture 1 of your last post....are you sure that is just a plug? That is what the vernatherm looks like, so that may be it.

It is usually installed in the housing where the filter screen or oil filter adapter mounts.
 
Just a plug

scsmith said:
Hans, the plug you point to in picture 1 of your last post....are you sure that is just a plug? That is what the vernatherm looks like, so that may be it.

It is usually installed in the housing where the filter screen or oil filter adapter mounts.
Click to expand...

Yes, it's just a plug - I removed it today to see what was in there and there was no spring or plunger, just the plug and washer. Do you think I need to install a Vernatherm? Without it I may have a problem getting the oil temp up during the cold seasons.
 
The vernatherm screws into the bottom of the oil filter adapter. You should have one. It looks similar to the plug you have on top.
 
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A few observations....

I think normally you would want to monitor oil pressure after the oil cooler and after the oil filter. You could get pressure readings that were relative form the port in the first picture but the pressure there is before the filter. So if you had issues at the filter with restriction, you would see good pressure while the engine had lousy oil pressure after the filter. So not a good choice. The same for using the bypass spring and plunder plug port. the reading is before the filter.
Any 1/8 plug after the filter should be used. Depending on the engine vintage there could be three ports or six you could use:
1) The normal and preferred place depicted in the picture at the 1:00 o'clock position on the accessory housing.
2 and 3) At the front of the lifter galleys on the nose of the crankcase
4.) a 1/8 port that is perpendicular to the port listed in item 1.( you don't have this one)
5.) a port just above and behind the oil pressure relieve valve cap.( cant see if you have this one but unlikely as it is only on the latest cases)
6 A port on the right side of the oil filter/ oil screen mounting boss on the accessory housing. (You don't have this one)
All engines will have items 1-3 and some may have any combination of the last three depending on vintage.


The vernatherm port can also be just a plugged or have a vernatherm. I assume it is there but can't see it in the pictures. You should be able to see it with the filter not installed in the large port on the left of the oil filter adapter plate where the filter would mount.
If there isn't a tapered valve with a spring behind it visible in the port, then the vernatherm isn't installed.

The bypass spring and plunger cap isn't safety wired in you pictures!


Good Luck,
Mahlon
?The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at your own risk."
 
Plug is seized ?

I am having the same thoughts as Hans. In my instance the plug that is properly used for oil pressure is a swine to get at and it is either seized or held in with loctite. I could only get at it with a 3/16 ball on allen key due interference from the engine mount. Yes it snapped off. I am considering getting onto it with a propane torch but an concerned the 1 ) engine mount will be in the way 2 ) I will damage something with the torquing / heat combo. Last thing I want to do is chew out the inside of the plug or damage the thread.

It seems nasty to have to pull the engine forward off the mounting bolts to get access with a proper allen wrench but if that's what it takes - so be it.

I am really concerned I might damage something. The engine is quite an antique - built in the mid 70s and has about 500HTR.

Any tips from the brains trust to set me on the right course of action ?

THX in advance ..

Mark Bolton

http://rv-4builder.blogspot.com.au/2010/04/motor.html
 
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