Lost engine oil pump prime

[PA1195]

Re: Lost engine oil pump prime

If that's indeed the case then I guess it's copper to the rescue for me. My mechanic did say whatever Taylorcraft did was ok by him when we cleaned the oil line and I asked about something different firewall forward. With a loop between a standoff holding the line to the motor mount and case fitting 8" or so away it should last a few years. Currently mine is just a blue offset fitting in the case to 1/8" copper. I don't believe that fitting has a restricted end and depends on the 0.065" I.D. of the copper line to act as one...sort of.

Gary

[3Dreaming]

Re: Lost engine oil pump prime

I don't think the primer fitting will be compatible with the end of a flexible hose, unless there is some kind of special hose fitting to mate with the primer fitting.

[PA1195]

Re: Lost engine oil pump prime

Gary,

I am LOL.

I did all that work for a net savings of $4.70! ($16.70 - $12.00)
next time I will get that An4022-1.

Dave R

I guess Dave the real cost then becomes the oil line. From the Spruce ad:

"What are the thread sizes on both ends of this discharge nipple AN4022-1?
1/8 NPT on the cylinder end and 5/16-32 on the primer line end."

I know almost nothing about what fittings or line size goes on a 5/16-32 thread. Maybe you could offer some info? But yes it's cheap enough to buy one but add shipping I suppose. I also had one already installed on my induction spider for the former fuel primer now manifold pressure gauge in case the 1/8" copper line cracks or leaks. Might not run as lean that way?

Gary

Re: Lost engine oil pump prime

Good inventions Dave. Even if the solder were later drilled with a fine drill it would work.

Just occurred to me that when I had primer lines installed on my new cylinders they used a special fitting that was supposed to atomize the fuel. How about that for an oil line restrictor? AN4022-1.

http://www.aircraftspruce.com/catalog/hapages/primperfittingsan4022-1.php

Gary

Gary,

I am LOL.

I did all that work for a net savings of $4.70! ($16.70 - $12.00)
next time I will get that An4022-1.

Dave R

[PA1195]

Re: Lost engine oil pump prime

Thanks Edwin for the post and idea. Yes I wondered about the cost of hose and fittings and what you do makes sense on both counts.

Too bad we can't cut and paste these great ideas as a group in a separate oil pressure line thread?

Gary

[Edwin Otha]

Re: Lost engine oil pump prime

I like to use a standard AN816 steel fitting and thread the nipple end ID for a 10/32 set screw. Tap the ID of the nipple and drill your small hole through the set screw. Lock-tite it and secure the set screw with an allen wrench. The ID of the nipple is a pretty close for the 10/32 tap, been working for decades. I like the -4 size because the fitting and hose costs are about 1/10th of the -3 and -2 sizes.
EO

[PA1195]

Re: Lost engine oil pump prime

Good inventions Dave. Even if the solder were later drilled with a fine drill it would work.

Just occurred to me that when I had primer lines installed on my new cylinders they used a special fitting that was supposed to atomize the fuel. How about that for an oil line restrictor? AN4022-1.

http://www.aircraftspruce.com/catalog/hapages/primperfittingsan4022-1.php

Gary

Re: Lost engine oil pump prime

You may chuckle at this one but it has worked well for 30 years.

Regarding the oil pressure line restriction I take a brass AN fitting with a pipe thread on one end and a flare on the other.

I set it upright on the pipe thread end down on a flat piece of steel.

Then pull a wire out of a stainless steel wire brush with a pair of needle nose pliers and straighten the wire as best I can.

Get some flux core solder and heat the fitting the melt the solder and let it drop into the fitting and fill it about half way up.

While solder is still liquid take that wire and using the needle nose pliers insert the wire into the liquid solder and push it all the way down to the steel.

Hold still until the solder becomes solid.

After it cools or using a second set of pliers pull the stainless wire out.

Apply some air pressure to the fitting a see that air comes thru the hole left by the wire by making a bubble test.

Sometimes you have to remelt solder and remake the hole.

Install fitting on engine and manually fill pressure line with oil and/or after the fitting is installed on the engine leave the engine idle and crack open the fitting at the gauge and let the air out until oil flows out at the gauge.

I end up with a real real slow leakout rate if a line breaks and once the line is filled with oil the oil pressure will indicate almost immediately after startup (assuming it did so with no restriction as well).

Cost is about $12 for brass fitting and I assume you have a wire stainless steel wire brush or a friend has one.

Dave R

[PA1195]

Re: Lost engine oil pump prime

I would use a fitting like that and a flex line. Then tie it to the copper line to the gauge with a union or bulkhead fitting. I would not run solid copper from the firewall to the engine loop or no loop. The original was like a flexible wheel cylinder line with crimped brass ends on the hose.

Yes good point. Thanks. I'll get one of the modified AN823-4 fittings with 1/8" NPT and have my mechanic figure out a flex line that can be adapted to my existing firewall bulkhead fitting. The Pipers I've owned have had a combo flex line then copper. The flex was the Univair 71061 Rob noted above or the similar original Piper part. It allowed some engine movement and the copper line was then attached to the engine's mount I believe.

Other things to watch for breaks on my plane are two 1/8" copper tubing lines to the engine. One feeds the cylinder primer fittings in the two forward jugs via a splitter, and one senses intake manifold pressure at the former primer hole in the induction spider. It feeds a 2 1/4" manifold pressure gauge I use to detect carb icing and MP at takeoff, cruise, and idle. Both lines have a loop and are supported.

Gary

[3Dreaming]

Re: Lost engine oil pump prime

Here's a 1/8" NPT restrictor fitting that feeds an oil line (I assume flex hose or rigid copper) larger than 1/8":

http://www.aircraftspruce.com/catalog/eppages/oilfuelflow05-11908.php?clickkey=57727&theme=spruce2

Edit: There's also some chatter about pushing a soft rivet into the flared outlet of a similar fitting w/o a restrictor already installed and then drilling a small hole in the rivet. The oil line that attaches then holds the rivet in place. Gary

I would use a fitting like that and a flex line. Then tie it to the copper line to the gauge with a union or bulkhead fitting. I would not run solid copper from the firewall to the engine loop or no loop. The original was like a flexible wheel cylinder line with crimped brass ends on the hose.

[Robert Lees]

Re: Lost engine oil pump prime

Here's a 1/8" NPT restrictor fitting that feeds an oil line (I assume flex hose or rigid copper) larger than 1/8":

http://www.aircraftspruce.com/catalog/eppages/oilfuelflow05-11908.php?clickkey=57727&theme=spruce2

Edit: There's also some chatter about pushing a soft rivet into the flared outlet of a similar fitting w/o a restrictor already installed and then drilling a small hole in the rivet. The oil line that attaches then holds the rivet in place.

Gary

Hello Gary,

That NPT restrictor fitting certainly fulfils the purpose of restricting flow in the case of an oil pressure gauge line failing.

Rob

[PA1195]

Re: Lost engine oil pump prime

Here's a 1/8" NPT restrictor fitting that feeds an oil line (I assume flex hose or rigid copper) larger than 1/8":

http://www.aircraftspruce.com/catalog/eppages/oilfuelflow05-11908.php?clickkey=57727&theme=spruce2

Edit: There's also some chatter about pushing a soft rivet into the flared outlet of a similar fitting w/o a restrictor already installed and then drilling a small hole in the rivet. The oil line that attaches then holds the rivet in place.

Gary

[Hank Jarrett]

Re: Lost engine oil pump prime

I had a gauge and line once that DID have oil circulation. Usually in the form of oil drips on my shoe. It was NOT a good solution to the problem. ;-) Maybe this is another one of those things we should be doing every once in a while. Annual seems too often but maybe whenever the bungees are changes we should also disconnect both ends of the oil line and flush it out. If it always looks clean we could make it a longer period.

Hank

[Robert Lees]

Re: Lost engine oil pump prime

To continue the discussion on oil pressure lines, Univair sell a fitting (with flex hose) with the correct small orifice (as Hank says, to prevent rapid oil loss in the case of a line break). I believe their part number is U71061-000. Other suppliers are available using Piper P/No 71061-000.

I modified an AN840-4D fitting myself before I knew that Univair had them. Mind you, at $110.00 I would still have made my own!

The photo below is what I made: thread the inside of the AN840-4D fitting; make a threaded male plug to suit with a tiddy tiny hole (I think I went for #30). Thread it in with loctite, stake it for security, voila!

It's a good tip to check the line for sludge, thanks for that . Remember, there is no flow through the oil pressure line.

[PA1195]

Re: Lost engine oil pump prime

In my installation the pressure line is 1/8" copper from the engine to firewall. There's a loop in the line I assume for potential flex firewall forward. There's a double male bulkhead fitting (AN?) on the firewall then another 1/8" line to the gauge. The copper line's ends are flared with AN? flare nuts as the fastening means. On the case is a small threaded 1/8 pipe fitting screwed into the case with a very small restrictor outlet as Hank notes above.

I think I'll ask my A&P if he can install something like hose between the engine and firewall. The factory may have done copper but to me hose seems like it would be safer and less prone to breakage (?). Copper has a way of work hardening and the flares can crack if over tightened repeatedly. Maybe that line can be annealed or just replaced with new copper.

Gary