DAVID GRIMES

I'd like to know if anybody has purchased the OMP replacement from rotaryaviation ?

What are you using ... 2 cycle or MMO ?

Did you get the standard or "electronic" version ? What's the difference ?

What did you use for your new reservoir ? How did you plumb it ?

Do they supply the proper block off or way to disable the stock OMP ?

The only thing I know is they don't respond to email questions.

DAVID GRIMES

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Aviator 902S

I've posted this write-up several times on here, and you can order these adapters through rotaryaviation, but it seems strange that they're not answering your emails because this company is definitely on the up and up. Here's the info you need to order one straight from the manufacturer:

Manufacturer/ supplier: Richard Sohn
e-mail: unicorn@gdsys.net
Address: 8029 HWY 1087, DeFuniak Springs, FL 32433
Tel/ Fax: (850)834-4905.

For the record, I've been using this adapter on my 12A-powered '85 GSL for almost two years, and it consumes about 1 to 1-1/4 cup per full tank of fuel. This is about equal to the stock set-up, and I use TCw3 2-cycle oil that I purchase from Walmart at $2.50 per quart. Brand name isn't important here, and even the regular 2-cycle oil is a vast improvement over that crap that gets sucked out of the oil pan, but any TCw3 2-cycle will burn cleaner. MMO is hard to find in my area but from what I understand it's really no better than 2-cycle oil when used for this purpose. But depending on who you ask that is an on-going argument.

The 12A OMP is a mechanical unit, as is the series 4 unit used on the '86 to '88 13B, although the two are different from each other. All later models use the electric pump. These adapters act as a block-off plate in that they bolt between the stock OMP and the OMP mounting surface on the front cover. They block off oil flow from the pan, but contain a small drive shaft extension which links the stock OMP drive to the OMP. This way, you use the stock pump to deliver the 2-cycle oil to the intakes, but this oil is gravity-fed to the OMP via an orfice in the adapter.

This system works very well, and if your stock nylon feeder tubes were to ever break the engine would continue to run without damage for way longer with this system than it would with the stock set-up. This is because 2-cycle oil penetrates the pores of the metal surfaces better than 4-cycle stuff does, providing extra lubrication long after oil flow is interrupted.

The reservior needs to be mounted so that it's lowest point is at least 6" above the metering pump for proper gravity feed, and whatever you use for a reservior and feeder tube from reservior to adapter needs to be impervious to oil. This rules out rubber tubing and plastic washer fluid reserviors. Oil will destroy both.

I use a Nissan power steering fluid reservior (mounted on the front portion of the RH shock tower just aft of the coolant overflow container) and a 2' length of neoprene fuel hose, with standard hose clamps at each end. I also use a brass 90-degree elbow at the adapter end of this hose to resolve clearance issues between the hose and the fan.

If your car has a 12A you will also need to purchase two OMP gaskets from Mazda, one for each side of the adapter. These are about $3 each. The longer mounting bolts necessary for this conversion come with the adapter. Cost the last time I checked was $76 U.S. for the 12A unit, $85 for the 13B mechanical adapter and $90-ish for the 13B electric adapter.

A word of caution: If your OMP leaks right now, it will leak even worse once you begin running 2-cycle oil through it. This oil is runnier than 4-cycle oil and will seep into places that 4-cycle oil won't. I'd recommend replacing the seals in your OMP with VITON seals. These seals withstand higher temps, seal better and last longer. It's not difficult to replace these seals btw.

Once you have all the components you need to replace the OMP seals and install the adapter, the entire operation should take between one and two hours to do at the very most. Good luck.

Brett.

rustnrot

I have been doing a search on this subject and above is a great writeup. Two questions: 1. With the new oil reservoir 6" higher-i.e. always make sure that the oil IN the reservoir is 6" higher than the pump--Does this place, even when the reservoir is full, oil level higher than the output of the OMP lines that attach to the carb? If higher, I would be worried about gravity feed of oil thru the pump into the carb when the car sits for awhile. 2. Where to get Viton seals for the OMP?

Dom

The rebuild kit for the OMP can be found here:

http://www.loweperformance.com/

Aviator 902S

The gravity feed when parked issue has been brought up before, and is a valid concern. With my set-up, the highest level is slightly above (by about 1") the level of the metering lines where they enter the carb. In theory, the oil "could" feed into the engine and flood it, but in practice this has not happened. It appears that the OMP when not in use stops this from happening. My levels do not drop overnight, and Richard Sohn, the manufacturer of these units tested this by placing the reservior several feet above the engine. No siphoning was observed.

I bought my Viton seals from a local wholesale o-ring supplier. I took my OMP apart and physically measured the outside diameter and cross-section of each seal and then made the purchase. This was for the 12A OMP. I have yet to tear down an OMP for a 13B. Lowe Performance, the link mentioned in the above post, also supplies a rebuild kit consisting of the necessary seals.

vipernicus42

iTrader: (4)

The loweperformance site is down and has been for quite a while, but the company itself is still alive and kicking. A quick search on lowe performance should yield their phone number, which I used to order their OMP Rebuild kit.

Replacing the seals in the OMP took no more than an hour, and most of that time was soaking the OMP in Mineral Spirits to clean off the years of oil residue buildup. I was extremely satisfied with the kit and it's instructions (both come in a single, standard sized envelope, no extra shipping or duties to Canada, bonus!). I HIGHLY recommend the lowe performance OMP rebuild kit to anyone still running the stock OMP. Especially considering that over the 20 years the OMP has been running on your car the rubber seals inside have undoubtedly started to fail.

As for the OMP adapter from rotaryaviation, I haven't tried it yet, but I definitely want to. Thanks to Aviator, I won't be using my original idea - Using the Sub-Zero fluid resivoir as a 2-stroke resivoir.... but I will probably use it's mounting point at least. It's a conveniant out-of-the-way place, and I'm not driving the car in sub-zero temps anyway.

Jon

luiml73

iTrader: (1)

Is it ok to inject the oil through the intake manifold, if the oil injector holes in the housings have been sealed?

rustnrot

Aviator, any chance you still have the part numbers for the viton o rings for the 12A pump and can post them here? Did you buy from McMaster Carr or similar?

rustnrot

These outboard motor tanks are common on ebay http://cgi.ebay.com/ebaymotors/ws/eB...spagename=WDVW

It appears they siphon from the top. I would worry about the siphon breaking and would think a bottom feed tank would be best. Ideas?

Aviator 902S

Not to mention that the stock sub-zero setup is as useless as **** on a bull. And yes, the original seals on my OMP were toast--- especially the ones under the end caps, which were so brittle they resembled hard plastic.

Aviator 902S

Honestly, I don't have those part numbers. I picked them up from a place here in Calgary whose name I can't recall, but it wasn't McMaster Carr. These guys sell 0-rings in bulk to industry rather than to induviduals, and they had a minimum $20 purchase rule. $20 is a ****-load of small o-rings, but the guy took pity on me and gave me the three seals I needed for free!

As for part numbers, I have no idea. But as long as you know the material you need (Viton), the outside diameter and the cross-section diameter (ie: the diameter of the seal material) you'll be able to provide your supplier with all the info needed for them to give you the proper seals.

To measure these seals you don't need much. A micrometer is nice, but you can get an accurate measurement of the cross-section by carefully reading the info off an accurate ruler or measuring tape.

As for the outside diameter, this was an issue with the ones under the end caps because they had sat for 18 years in a diamond-shaped groove and were no longer round. I simply placed the now-diamond-shaped o-ring on end on top of a sheet of paper. I then put a fine mark on the perimeter of the o-ring and paper where the two made contact. Next I carefully rolled the o-ring to the right one complete revolution until the pen mark on the o-ring was again touching the paper, and made a second mark on the paper at this point.

The distance between the two marks is = to the outside diameter of the o-ring. The new round replacement o-rings will conform to the diamond-shaped grooves under your end caps.

BTW, the above assumes you are using the same 12A metering pump that I have. I've never taken apart a 13B OMP, mechanical or electric and for all I know they may be identical. But even if their not I'd assume the design is similar. Can anyone elaborate on this?

This btw is a lot of leg work. If you don't wish to go this route you can always tell Lowe Performance what engine and OMP you have and they'll send you exactly what you need.

Almost forgot: The original o-rings for these pumps are most likely a metric size, but I found that my end cap o-rings were 13/16" diameter by 1/16" cross-section. The small o-ring for the actuator shaft inside the OMP measured a (very fine) shade under 1/4" diameter by 1/16" cross-section. This place did not have the metric dimension but the 1/4" diameter o-ring they gave me (slightly larger than stock) worked just fine and likely took up any wear in it's bore in the OMP housing that may have taken place in the previous 20 years.

CrackHeadMel

iTrader: (2)

Being that this is the only thread current on the subject, would anyone know which pump is required for the 13b-re. It comes stock with a electric unit but i am unsure if it is the same as a 3rd gen electric unit

-Jacob

Aviator 902S

The 13B-RE--- you are referring to the one used in the GSL-SE, right? If so, that engine came with the same mechanical OMP used in the '86 to '88 13B 2nd gens. And according to Richard Sohn, the electric pump used in the 3rd gens is different from the electric unit used in the '89 to '91 2nd gens.

luiml73

iTrader: (1)

cough..cough

DAVID GRIMES

Hey, I wondered the same thing. I would much prefer to run the line to a "Y" and into my sidedraft intake where the two "bung holes" are. I hate the spaghetti lines !!!

What would be wrong with that ? Aren't we talking about a drop of oil every once in a while ? That drop of oil on either side would be atomized into the CFM's of air and fuel flying past it, right ??? WHat would be bad about that method ?

QuagmireMan

i think it would be too great of a vaccum and pull loads of oil into the engine. Just a guess but i dont know

luiml73

iTrader: (1)

If you put oil in the gas tank, how does it get to the engine? My method, I would just be bypassing the fuelpump, filter and injectors?

Anyone please feel free to correct me if I'm wrong.

[qouote]i think it would be too great of a vaccum and pull loads of oil into the engine. Just a guess but i dont know[/quote]

You might have a point. Damn!!! now you got me thinking.

DAVID GRIMES

In your picture, I'd go with the left side scheme ( adding oil after the fuel:air mix ) instead of oil into the air intake before mix.

I'm thinking we could use one of these for the reservoir and the plumbing ( mounted where the cold assist tank was ):
http://cgi.ebay.com/ebaymotors/ws/eB...category=46098

What do you think ?

luiml73

iTrader: (1)

That is exactly what I was thinking of using. my friend uses one on his repu, but for coolant. I'm going to buy it right now.



I think we should ask the FC guys for input on our dilema. I think AaronCake, Bdub, casio and some other guys over there a little bit more on premixing.

luiml73

iTrader: (1)

Well I sent an E-MAIL to PCV Technologies, Inc the guys who make the adaptor, and this is what he wrote:

Hi Luis,

You can do that if you also us the injector valve. Just dripping the oil into the manifold will not do it.

Richard Sohn

This is where the Fc's LIM have the extra oil injectors

Todd Staples

So running a 12a with a RB intake, 600 Edelbrock, should be able to tap the intake below the carb base and feed my oil like that or not?

luiml73

iTrader: (1)

I'm pretty sure you could, but I'm still doing some more reading on this subject.

http://www.rx7.net.nz/newrx7.htm

Apex seal lubrication has become a critical issue. In a race engine, oil supply to the rotor housing by means of injection was precisely monitored and controlled, whereas in the production unit, a larger amount is supplied, just to be on the safe side. Some of the lubricant is fed into the trochoid chamber through a metering nozzle. The previous nozzle's oil passage was 2.0 mm (0.08 in.) in diameter. Negative pressure created in the rotor chamber would cause all the oil within the nozzle to be sucked out.
When the engine accelerated rapidly, oil supply could not keep up with the speed. To prevent oil starvation, the previous system supplied a larger amount of oil to be on the safe side. In the new metering nozzle, the passage diameter has been reduced to 0.08 mm (0.003 in.), halving its volume of 0.0005 L (0.03 cu. in.). A new rubber seal is also inserted to fill a gap within the nozzle body where oil used to be sidetracked. Now, there is still some oil left within the nozzle after each suction, so that the lubrication system responds to the apex seal's requirement

Movie

http://www.zeroglabs.com/rx7/howoilmeteringworks.htm