J

jeff beckley

Well Known Member
We are having trouble getting the oil pump to prime. This is the first startup on a OH engine. Tried everything that we can think of.
Pulled sump to check for blockages/gasket
Pumped STP up the cast tube to the pump gears.
Pulled oil cooler lines and checked for flow while turning over engine.
Checked pressure valve, good seat,added washers just to check.
Ran engine at low idle for short time.
Pumped oil in every line,hole,plug that we could find.
No oil at check valve after running engine.

This is a Lycoming A3A that was overhauled directly after being removed from service from another plane. Our next task is to pull the accessory case off to inspect the pump and to validate that the tooling plugs were installed. Are there any other plugs that are inside the case that can not be inspected other than the accessory case?
Can I get some advise before removing the case?
 
I can answer one of your questions

Jeff,
There are no oil galley plugs inside the crankcase halves that I'm aware of.
I'm just about ready to assemble my 0-360-A1D, so I've had a pretty good look all around :D

There's three oil galley plugs in the crankcase halves under the accessory case.

Gosh, sounds like your oil pump is not turning.

Mark
 
Last edited:
Thought of something to look at.

Jeff,
On the accessory case just below where the oil filter adapter is (or oil screen housing) there's a 3/8" pipe plug. This plug can be removed and with a flashlight and mirror you can see the oil pump gears. I'd try to do this to make sure they turn when the prop is moved.

The gears are way back in there and you can only see the tips of them.

engine41207004sciq4.jpg
[/IMG]

Hope this helps.

Mark
 
Last edited:
Mark, I am looking at your photo and I don't see a pipe plug. Are you talking about the hole just up and to the left of the prop gov mounting pad?
On my engine the bottom cooler hose connects there. It looks like that port would be a direct path to the pump.

Jeff
 
That's it

jeff beckley said:
Mark, I am looking at your photo and I don't see a pipe plug. Are you talking about the hole just up and to the left of the prop gov mounting pad?
On my engine the bottom cooler hose connects there. It looks like that port would be a direct path to the pump.

Jeff
Click to expand...

Jeff,
Yep that's the hole! The plug is not installed in the photo.
I went out and slipped one of the oil pump gears into my accessory case and you can see the tips of the oil pump gear while looking in that hole.

Mark
 
Last edited:
Priming oil pumps at OH

I have only built up 2 aircraft engines and don't consider myself an expert but I was told when installing oil pump gears to fill the gears with grease so they will have enough of a "seal" to suck the oil through them. In fact, I saw one person use vaseline for this. Supposedly, the oil will displace the grease out of the pump and dissolve in the hot engine oil. This may not help now that your engine is already built but keep it in mind if you can get to the pump gears. It worked for me on both engines that I did build up.

Dick DeCramer
Northfield, Mn
RV6 N500DD 180 hours
RV8 Wings
 
Thanks Mark. This gives me an idea. I could try to pump slick fifty into that hole while I rotate the prop backwards. I have been using a mighty vac hand pump to squirt oil into other holes.
I will look for the rotation of the gears first.
Is there a gasket used in installing the gear housing?
Jeff
 
Sounds good

jeff beckley said:
Thanks Mark. This gives me an idea. I could try to pump slick fifty into that hole while I rotate the prop backwards. I have been using a mighty vac hand pump to squirt oil into other holes.
I will look for the rotation of the gears first.
Is there a gasket used in installing the gear housing?
Jeff
Click to expand...


Jeff,
Yes, I agree that rotating the prop backwards will suck the slick fifty into the pump housing (if the gears are turning). That may work. Regular engine oil might be even better for this.

There is no gasket on the oil pump housing, it's just a very precise metal to metal fit.

Good luck tomorrow!
Mark
 
Last edited:
Ney Nozzle holes...

Mark Burns said:
Jeff,
There are no oil galley plugs inside the crankcase halves that I'm aware of.
......
Mark
Click to expand...

Unless it was drilled for "Ney Nozzles", or whatever they are called now, for squirting oil directly on to the cam. If it was drilled, and the nozzles not used, then plugs should be in... :rolleyes:

I would hope that this wasn't overlooked... I think the drilled holes for nozzles are an ECI (and maybe others) overhaul option.

gil in Tucson
 
Vacuum......

If you have access to a small vacuum pump you can connect it to the oil pressure line that goes to the gauge and suck the oil from the sump all the way out, filling everything up. I did this once on an IO-520 that stood vertically for two months and wouldn't prime either. Go from the vac to a jar then from the jar to the line so you don't lock up the vac with oil.

Regards,
 
There are three oil gallery plugs in the crankcase halves without pulling the accessory case. You can remove both magnetos and with flashlight and small mirror locate them directly above the magneto center line. the left half ( looking from left seat) has one plug, the right side has two. This can be verified rather easily.

On some wide deck cases, there are provisions for piston cooling nozzles. The only way to verify that there is either a gallery plug or nozzles installed in these locations is to pull a jug partially off and look behind the bearing web. PITA, but may be necessary.

When installing the oil pump, it needs to turn freely by hand with no 'catches' during the rotation. If it doesn't turn free, it will destroy the housing in pretty short order.


Allen
 
Well my bad. I removed the accessory case after all options were exhausted.
Looked at the oil pump only to find that we had left the washers for the three studs under the oil pump case between engine case and the pump case. DOH!!!!
Stupid! I think these washers are so thin that they were shrouded by assembly oil that they could not be seen very well. That left a small gap that kept the pump from priming.
O well. Learned another lesson.
 
jeff beckley said:
Well my bad. I removed the accessory case after all options were exhausted.
Looked at the oil pump only to find that we had left the washers for the three studs under the oil pump case between engine case and the pump case. DOH!!!!
Stupid! I think these washers are so thin that they were shrouded by assembly oil that they could not be seen very well. That left a small gap that kept the pump from priming.
O well. Learned another lesson.
Click to expand...

Jeff,
Wow! That would do it.

Glad you found it, and thanks for letting us know what it was.

Mark
 
Last edited:
You must log in or register to reply here.