Lost engine oil pump prime

[astjp2]

Re: Lost engine oil pump prime

Don's sends it out, there is only one place that can reweld and mill the cavity and I just cant remember their name right now. If there is too much copper in the magnesium, then it cannot be repaired either. Aluminum accessory cases can be welded all day long. Tim

[Garry Crookham]

Re: Lost engine oil pump prime

Drake Air in Tulsa reworks the accessory cases (reweld and mill the oil pump cavity). It's been 10-12 years since I had one repaired. I think it was around $700 at that time. Drake Air has farmed out their marketing and sales to Quality Aircraft Accessories in Tulsa so I think you have to contact them for assistance.

[Guest]

Re: Lost engine oil pump prime

Drake Air in Tulsa reworks the accessory cases (reweld and mill the oil pump cavity). It's been 10-12 years since I had one repaired. I think it was around $700 at that time. Drake Air has farmed out their marketing and sales to Quality Aircraft Accessories in Tulsa so I think you have to contact them for assistance.

That's where I sent mine in 2001 sat on shelf until last year when i used it.

But the year before I called Drake for a customers acc. case and I think they said they no longer did which matches what you said Garry.

I don't recall a reference from them for a company that did the oil cavity though, just for the shaft bores.

But then again I may have forgotten.

Dave R

[PA1195]

Re: Lost engine oil pump prime

Here is "the rest of the story" from this thread I started. No indication of oil pressure in 30 seconds noted earlier this Spring. Worked slow to rise and fall off but ok when warm this summer. Just finished annual inspection and the following was done:

Confirmed via work order that the O/H shop did the pump, plate, and acc case per specs less than 100 hrs ago. All met min specs not max. Good. New parts and O/H certified parts noted.
Nothing on the oil screen indicating aluminum or ferrous metal wear. Two small pieces of carbon and a good health report.
Removed 1/8" oil line between case and gauge. Flushed with solvent. Full of 76 year old black debris and barely flowed solvent at first under pressure but then flowed lots clean.
Filled line with Mil 5606 hydraulic fluid and purged air before tightening fittings. Cold weather fix for Alaska instead of thick oil.

Now the oil pressure gauge responds quickly as I crank up the engine and falls off quick when I shut it down. Before it was a 10-15 second response for both in summer, longer in winter when the unheated cockpit is cold. Oil comes out of the case port less than 5 seconds when started. Maybe lesson learned.

Gary

[Guest]

Re: Lost engine oil pump prime

Well that is a happy ending Gary, glad it worked out.

Dave R

Here is "the rest of the story" from this thread I started. No indication of oil pressure in 30 seconds noted earlier this Spring. Worked slow to rise and fall off but ok when warm this summer. Just finished annual inspection and the following was done:

Confirmed via work order that the O/H shop did the pump, plate, and acc case per specs less than 100 hrs ago. All met min specs not max. Good. New parts and O/H certified parts noted.
Nothing on the oil screen indicating aluminum or ferrous metal wear. Two small pieces of carbon and a good health report.
Removed 1/8" oil line between case and gauge. Flushed with solvent. Full of 76 year old black debris and barely flowed solvent at first under pressure but then flowed lots clean.
Filled line with Mil 5606 hydraulic fluid and purged air before tightening fittings. Cold weather fix for Alaska instead of thick oil.

Now the oil pressure gauge responds quickly as I crank up the engine and falls off quick when I shut it down. Before it was a 10-15 second response for both in summer, longer in winter when the unheated cockpit is cold. Oil comes out of the case port less than 5 seconds when started. Maybe lesson learned.

Gary

[PA1195]

Re: Lost engine oil pump prime

Thanks Dave. But it still begs the question for we owners how to determine if the pump is worn beyond acceptable or why it looses prime. Direct inspection of the pump parts is probably the best. Next might be noting how quickly then engine builds oil pressure at the engine's oil pressure port Then like I as an owner only tried monitor the gauge at the other end of the pressure line. It also assumes warm oil in the engine and pressure line, and in my case a non-restricted line.

If I lack oil pressure indication on startup I now have a better idea what to do. My mechanic would have done this a while back of course. Yea I know...call them first.

Gary

[N96337]

Re: Lost engine oil pump prime

I like the idea of the 5606 in the line!
John

[PA1195]

Re: Lost engine oil pump prime

It wasn't my idea and maybe my mechanic picked it up from some old timer he worked for. He trained with one of the best (Tom Kushida - started Northland Aviation locally with Don Shultz - both former Wien Airlines mechanics) so maybe that's the source.

The other question is does the fluid in the line ever change out? We had coffee over that and I suggested we bleed it next annual and see color what comes out.

Gary

[Hank Jarrett]

Re: Lost engine oil pump prime

When I rebuilt the 41 the oil P line was clogged pretty bad but still passed fluid (SLOWLY when the fitting was cracked at the gauge). I REALLY didn't like that the oil line was in one piece from the back of the gauge to the engine and was a PAIN to pass through the firewall. I bought the parts for a firewall connection so I could run the line from the engine to the firewall, then the back of the firewall to the gauge. Worked GREAT! Only issue was the fitting used a larger tube size, which turned out to NOT be a problem, but a solution. The engine fitting was modified to put the plug with a small hole in (really helps if an oil line breaks so you don't pump all of your oil overboard! Plus if I remember right it is REQUIRED!) The new, larger line was run to the firewall and a new larger line was run to the gauge with an adapter at the gauge. The gauge now responds much faster and I eliminated one rubber grommet in the firewall for a through fitting that actually seals.

[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

[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.

[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

[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

[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

[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.