Inverting the Gypsy 30 engine

Jeff Brooks · 11 August 2015, 10:15 AM

Hi all,
I am looking for help inverting my Gypsy 30.
I know Pavel Novak did a pretty good job on Tim Plunket's Gypsy 175, but I don't have all the details of how it was done. Pavel, if you are seeing this, I'd love to hear your input.

It looks like Pavel removed the stock intake manifolds, and fabricated his own.
You can see he replaced the carburetors with fuel injection. You can see the fuel injectors on the manifold and the fuel distribution unit mounted on the side of the manifold.

It also appears that he replaced the oil bath with what appears to be oil jets on the valve rockers and the oil either drains into the valve pushrods or he has converted the oil breather holes into drain holes.

Jeff Brooks · 11 August 2015, 10:19 AM

From some of the pictures I got from Udo, he took another approach.
Udo, I'd love to hear more about how you did your engine.

Udo used a banjo fitting to supply oil to the valve rockers, but it doesn't look like he made any special drain lines for the oil to escape. I guess the tube surrounding the pushrods is enough.

Udo also used the original carburetors, but made these unique intake to flip them over upright again.

Neat

Jeff Brooks · 11 August 2015, 10:25 AM

My question is,
on the internal oil scavenge, there is a sump on the front and back of the case that collects the oil to the oil pump.

how did either of you guys invert this?
I know there is an internal hose from the front sump to the lower scavenge pump that I am sure I can use to reroute to the lower case, but the rear sump in the case looks more challenging.

Also, I notice that the oil pump is below both sumps, so there may be some cavitation if the sumps are dry, but once oil starts flowing again, they self prime.
When the engine is inverted, the oil pump will be near the top, while the case is at the bottom. How did you get the scavenge pump to re~prime itself?

Dart · 11 August 2015, 12:13 PM

Hmmm, could it be as simple as the oil tank above the engine, so the sumps are gravity fed when the engine isn't running?

Jeff Brooks · 11 August 2015, 01:18 PM

The Gypsy manual says that the engine is a dry sump type.

The description in the manual says that there are two scavenge pump, and each scavenge pump has a greater capacity than the pressure pump, so the engine is kept "DRY" at all times. The location of these pumps is below both sumps inside the case. It appears that this cavitation issue was normal for this engine, it was designed to do it while the motor is running.

Flipping the motor over empties the sump built into the case, and it moves the scavenge pump up, keeping gravity from feeding the pump.
I was thinking of adding an oil boost pump near the lowest part of the engine, which could reprime the scavenge oil pump. but then, why have three oil pumps?

If there was some way to lower the scavenge pump to the lowest point, that would solve the problem.

Because I am not familiar with the strength of the scavenge pump, they may just be strong enough to pull the oil back up into the gears even with air in the lines.

Dart · 11 August 2015, 07:20 PM

Ah, dry sump makes things a lot harder.

I'll be quiet now and let the adults talk.

franzkait · 13 August 2015, 02:26 AM

look for " Gibsy Queen Inverted " 8 May 2013

" Gypsy Queen Mags " 6 May 2013

Jeff Brooks · 13 August 2015, 03:06 AM

Udo,
Thanks for the input.
I went over both of those threads and there is no mention of how to tackle the internal scavenge oil problem. I would love to hear how you did it.

I spoke with Roger Freeman over the phone about how he inverted his Gypsy, and he too was having trouble with this. He said that once the scavenge pump cavitated, the engine drained all the oil from the tank, filling the crank case. He tried a couple of other options, but he can't remember how they turned out.

franzkait · 13 August 2015, 04:51 AM

Is the engine apart ? I believe not . So first take this engine apart ( you have to do this anyway )and investigate it . Because you see problems who do not exist and do not realize the real Problems wit the GQ engine . It is not a easy job to get this engine ready for a D7. Up to today , I did not see a good conversion .

snj5 · 13 August 2015, 05:17 AM

Jeff, not sure if this will help as you may not have an electrical system planned, but there are high temp high flow electric oil scavenge pumps used full time by racing cars (NASCAR) that are quite rugged and may be an option. I know of one being adapted to a Rotec Dr1 in Houston with good success so far.
R