RA OMP adapter install on a S5 T2 writeup

[Pete_89T2]

I decided to try out the Rotary aviation oil metering pump adapter on my '89T2, and this writeup describes the installation. The RA adapter fits between the stock MOP and the front cover, blocks off the supply of engine sump oil to the MOP, while allowing you to route a supply of 2-stroke oil into the MOP instead. You need to supply a tank for that, that needs to be installed at least 6 inches higher than the MOP for it to gravity feed.

Here's a picture of the contents of the RA kit. Since my S5 uses the electronic MOP, I ordered the "13B Electronic MOP" adapter model.



Next thing I needed was a tank for the 2-stroke oil. Found a 1.5 Quart tank at US Plastics. This one is chemically compatible with the oil, is translucent, and comes with a barbed nipple on the bottom for 1/4" hose and a vented cap. Cost a little more than $20 shipped. Since I no longer run an air pump, I used that space for the tank install. Here's a picture of the tank, and the bracket I fabricated out of some 1/8" thick AL stock.



You would think this should be a simple & painless install, but I ran into one PITA problem - the turbo oil return pipe interferes with the MOP once the RA adapter is sandwiched between it and the front cover. So if you have an NA, this job should be much easier! This pre-installation photo shows the lack of space between the turbo oil return pipe and the MOP



With the turbo oil return pipe removed, I was able to install the RA adapter with the stock MOP. You'll need to be very careful that you don't kink & break the oil lines, and a little bending of the metal line guide/bracket is necessary to ensure the lines don't rub/interfere with anything. Fortunately, my stock lines were relatively new and had enough slack and pliability to do the job. This picture shows the mounted RA adapter & MOP. Note the barbed fitting on the adapter, that's where the line from the tank gets connected to.



Part II will show the tank install. Then I'll need to find some flange-to-AN fitting adapters to fabricate a new oil return pipe for the turbo. I figure a -10 should do the trick. That will be Part III

[Pete_89T2]

Part II - Tank install. As noted before, I'm installing the tank in the area vacated by the air pump. Two of the 3 bolt holes from the air pump bracket mounting points will be used. Here's a picture of that area. I'm using the bottom and upper right holes for my bracket.



Next pictures show the tank in it's installed position. Hard to see in the pictures, but I connected the tank to RA adapter with some 1/4" fuel line that I had in the garage, clamped down tight with some spring clamps.





Now I just need to find a source for those flanges so I can fabricate am oil return pipe for the turbo to complete this job and the write up.

[JustJeff]

Nice!! I thought about doing an adapter during my rebuild but decided I had enough on my hands getting the car off jack stands.

I love the mod but after seeing your thread I'm glad I didn't. I don't have the tools to mod the oil line from the front cover. But who knows, maybe after seeing your work I'll learn enough to do it...somewhere down the road...if I can ever get my car off the jack stands and back on the road.

[Pete_89T2]

Originally Posted by JustJeff

Nice!! I thought about doing an adapter during my rebuild but decided I had enough on my hands getting the car off jack stands.

I love the mod but after seeing your thread I'm glad I didn't. I don't have the tools to mod the oil line from the front cover. But who knows, maybe after seeing your work I'll learn enough to do it...somewhere down the road...if I can ever get my car off the jack stands and back on the road.

Thanks - and don't let the turbo oil return line discourage you. After work today, I decided to get under the car again and do a test fit of the stock turbo oil return plumbing (without gaskets) just to verify that it wouldn't fit back on before ordering parts to fabricate a custom line.

As it turns out, I'm happy to report I was premature in thinking there would be interference. The stock return pipe barely clears the RA adapter, MOP and all lines with maybe 3/16"~1/4" space between the pipe flange at the closest point. You'll need to carefully route your premix line from the tank to the RA adapter to make sure engine vibration doesn't cause it to rub against anything, but this is easily do-able with some strategically placed zip ties.

You definitely need to remove the stock oil return pipe to give yourself enough room to install the RA adapter & MOP as an assembly. I also found it helpful to remove the stock M-fan. You can get by without removing it if you have smaller hands and/or better dexterity than I. Another caveat to add is to ignore the line in RA's instruction sheet that says not to remove the oil injector lines from the MOP. I started trying it that way, and soon found that the job was impossible with the lines attached.

When I have time to reinstall the oil return pipe properly this weekend, I'll take some pictures & finish the writeup.

[Pete_89T2]

Originally Posted by Pete_89T2

As it turns out, I'm happy to report I was premature in thinking there would be interference. The stock return pipe barely clears the RA adapter, MOP and all lines with maybe 3/16"~1/4" space between the pipe flange at the closest point. You'll need to carefully route your premix line from the tank to the RA adapter to make sure engine vibration doesn't cause it to rub against anything, but this is easily do-able with some strategically placed zip ties.

^I WAS WRONG!!! I should have tried to fully torque down the bolts on BOTH sides of the turbo oil return pipe when I test fit it earlier this week. Turns out it DOES interfere - you can bolt up the front cover side, but when you try to line up the bolts & torque down the flange on the turbo side, it's not going to happen. The bend on the stock pipe by the front cover flange interferes with the MOP. So now I need to order some flanges and some AN line & fittings to get this done.

[Pete_89T2]

Time to update this thread... Solved the interference problem with the turbo oil return line. First failed attempt used some cheap-o E-bay AL flanges with -10 fittings. These were machined in one piece. As it turns out, the turbo flange also fits the front cover, so I picked up two of them and the needed -10AN line & fittings to get from point A to B. Problem was the sub-standard AL used on those flanges was so soft that you couldn't tighten the fittings enough to make a reliable leak-free seal that would hold over time & miles driven. After less than 20 miles test driving, they started leaking, and tightening down a little more stripped the threads on the flange.

So then I got in touch with David Garfinkle of Garfinkle's Motor Works, and he fabricated a set of -10 AN/JIC custom fittings for me. These are a work of art and made of steel with proper fittings. No leakage problems now! I decided to retain the short stock return pipe on the S5 that bolts up to the front cover, add the Garfinkle's flange at the end of that, put the other Garfinkle's flange on the turbo and connect the two with -10AN line. There's a 90 degree fitting under the turbo, a short length of -10AN hose (< 1 ft), then a 60 degree fitting at the other flange. Picture below shows the result from the front cover side, where you can see how the 60 degree fitting routes around the extended OMP. I tried with 90 degree fittings at both ends, but that still interfered with the OMP.

[Garfinkles Motor Works]

Good work,I also use an OMP adapter on my third gen with Amsoil 2 cycle oil .I made the oil tank from sheet metal and it holds over 3 qts .I have made several tanks that bolt on in the air pump space using the air pumps mounting holes .I do not like the burning of dirty motor oil either .Good work and skill to you . Keep updating for us .

[vrracing]

How many miles will your 1.5 qt tank support?

[Pete_89T2]

Originally Posted by vrracing

How many miles will your 1.5 qt tank support?

Too soon to give you a hard number, as I'm still on my first full tank of gas since doing the mod. So far the level in the tank has dropped ~1/4 inches or so below the molded fill line on the tank that I topped it off to, after covering about 150 miles.

Since this mod just provides a different oil source to the OMP, the expectation is it will consume premix at the same rate that the stock system did, roughly 1 quart per 1000 miles. More if the car is flogged hard, less if just cruising around.

Another thing to add - if you do this mod, it's a good idea to also run some premix in the gas tank for at least the 1st tank of gas post-mod. It will take a couple of miles of driving (<10) for the system to "prime" itself, and for the premix to reach each of the injectors. One good thing about the stock lines is you can see the color change and know it works when you do this - color in the lines changes from the honey color of crankcase motor oil to the color of the premix (the stuff I got is blue).

[vrracing]

That's cool, thx. Might not be a problem on a rotary but I would wonder if the vibration from being mounted on the engine couldnt cause frothing in the oil.

Using a snowmobile oil tank with a level sensor and putting an LED in the cluster next to the fuel gauge would make it almost OEM.

[FC3SDrift]

sweet I saw these a couple years ago and thought they were a good idea

[beefhole]

FWIW, using my aftermarket TD06 turbo, my oil return was done real easy. The stock flange on the front cover was simply cut leaving about 1.5 inches of tube. Then a small flare was made and I simply slipped a rubber return hose on it with a band clamp. Simple, dirt cheap and no leaks. It's fine that you had custom flanges and AN fittings done, but that's also expensive (compared to a rubber hose and clamp). However, I can understand if you didn't want to cut any stock pieces up.