85 12a OMP Leaking: Fix or Block Off
 

Im finally getting my Rx7 on the road today after months of time money and turning wrenches. So the OMP is leaking, well it and below it is covered in oil. I replaced the rubber parts of oil injection hoses on the bottom because they were cracked.
Now I am going to take the lines off the carburetor and test to see if it is infact injecting oil. (how long can the lines be off for test? will i need to run premix during test?)
-If its not injecting oil, well then im going to run the block off plate.
-If the OMP is working and it is injecting oil but still leaking at gasket, should I fix leak or replace with block off plate from mazdatrix.

Do you guys trust the OMP? Is it a PITA to run Premix? Should I fix the Leak or run with blockoff plate?
I just dont want my engine to have problems because of starving for oil if it fails. and if it does fail will it really cause that much damage?

Any insight or ideas would be great.

Thanks

I personally would just run pre-mixed. Works every time and it's one less thing to worry about.

And I know these threads are posted all the time and yes I am an rx7 noob. The more I research the more I want to run premix, but looking for input thats all.

Here's the problem with premixing: Every time you stop to get gas you need to pull out the premix tool kit, measure out the 2 cycle oil, pour it in the funnel, rinse everything with gasoline and then store the kit away in the storage compartment.

http://i764.photobucket.com/albums/x...7/DSCF6157.jpg

People look at you strange and you and your car almost always end up smelling like gas and oil, not necessarily a bad thing but something to keep in mind if you're going to work or out to dinner.

I've been premixing for a little over a year now and while I like not having to worry about the OMP and using the cleaner 2 cycle oil instead of motor oil for engine lubrication, the ritual at the gas pump is getting kind of old.

So I'm looking into installing a reservoir for the 2 cycle oil under the hood and hooking this up to the OMP instead of having the OMP draw oil from the engine.

As I understand it, OMP's are extremely reliable and essentially never fail as long as the OMP lines are not clogged up. So I'm willing to take that chance while checking for correct OMP delivery every few months to be sure it's working right.

Here's a 2.5 quart reservoir I found at autozone for $9.99 that I plan to use for the 2 cycle oil:

http://i764.photobucket.com/albums/x...7/DSCF6156.jpg

Now I just need to figure out how to convert the OMP to an external feed. I've done some research on the OMP conversion but haven't been able to find anything that makes much sense yet.

Anybody have a good description of how to hook an OMP up for a reservoir feed?

You will find people who will argue for every option, it comes down to personal preference. Some people think premixing becomes a pain after awhile
and others dont seem to have any problems at all injecting crankcase oil into their combustion chambers, so the preferances vary.

Personally I think the R. Sohn omp mod with a tank for genuine 2cycle oil is the best option and it is what I run.

If I had a dedicated race car I would probably run premix.

If money was a factor and I had a ragged daily driver I would just leave it stock.

and yea I would premix while I had the omp disconnected for testing purposes.

the omp system on these do what they were designed to do. racing applications is the only reason i can see premixing. i can't see going thru the aggrivation on a street driven car, same reason i've never owned a 2 stroke dirt bike. if it still leaks after replacing the gasket and the short rubber lines, can't remember for sure since it's been awhile since disassembly and cleaning of mine during an engine rebuild, but i think there's an O ring on the shaft. if u don't have it, download a copy of the fsm. it should have in it how to test the omp. search "fsm" and it should lead u to the member with a link to the download.

if its a daily driver just fix the omp, or do the R. Sohn omp mod and run a tank of oil like in ray's pic. some one sells the adaptor for it that replaces the omp. but i cant remember who selles it.

my car is turbo'd and it uses a tank or two of gas a month so i premix, once you have a good system its not to bad.

Anybody got a link to the R. Sohn omp mod?

Thanks!

Umm rya heres the only adapter sites i have
http://www.rotaryaviation.com/oil_in...p_adaptors.htm

I know last thread i read about this there was another one out there that was way cheaper. If i find it ill link it to ya.

does anyone have a step by step on what exactly you do once you have this adapter?

can someone that has it post pics on thier set up please.

attach a hose to adapter. Bolt adapter to Omp. Fill reservour. Profit

Thanks DarkD, that Rotary Aviation unit is my backup plan, but there must be a better way out there someplace (read: less expensive). $96.00 plus shipping is a bit steep.

And like Dr. T says, some pics of an install and reports on performance for the RA unit would be nice.

In the mean time, please do let us know about any those other methods if you find any information.

I've seen some guys show pictures of just tapping into the OMP, if that works I could do the entire mod for less than $20. Anybody know how to do that?

Yeh i remember the tap thread. But ive been searching ill find it. Some1 asked the question and got a link to a inexpensive one like less than 30$ shipped for the kit. And for some ungodly reason i didnt bookmark it =(. Ill find it.

Here's a crazy idea. What if you could make a resovior with a hand pump that attaches to the gas downpipe? The pump would put a pre-measured amount (maybe 1/2 once per pump) in the tank then you filled the gas tank with gas. The pump/resovior could sit inside the bin area and would hold 1/2 gallon of oil. Everytime you fill up, open the bin, pump a few times, fill with gas and your off.

Lol that would work extremely well. Main issue ur gonna have is its ALOT of work when you could just carry a funnel and a mesurin cup =P. I do like the idea tho. Im sure you could get the stuff to make the contraption for it at a decent price.

Wow lots of good info! The car hasnt been run or driven to much since it hasnt been on the road. I still need to investigate the leak better because it could be from the old cracked lines still on the block. However the oil does get on the exhaust manifold on cold start up and smokes. If the OMP is really reliable then maybe I will just replace the O-ring/gasket. I could see how premixing every time would get pretty old. I just want to make sure I do the right thing and dont ruin this thing, i may have OCD at times about it but rather be safe then sorry.

I also registered and drove the car today. The car did sit for 12 years and on my way back from my short trip to the gas station I broke the metal line from the 3rd Catalytic converter to the back of the engine. (I cant believe I just mentioned a 3rd Cat!) It broke right by the cat so prolly gonna wip out the welder and try to fix or see if I can remove the whole line and block it off both sides, prolly will have to do full rats nest removal as well. Car did have brand new exhaust put on before it sat, but its still 12 year old steel.

One last thing, and I may or may not recieve this request because this is not the titled thread for it. But I REALLY need a picture of the winshield wiper assembly. Like where alll the platic peices are where the wiper screws to the spindle. I took it apart because It was seized up, now its unseized but cant figure out how all the plastic peices go back on. (I may have to start another thread for this but man it would be helpful)

Thanks everyone and great info.

There is a paper gasket behind the OMP that can and does fail. Cheap and easy. Oil going into the OMP is pressurized at a very low psi so it'll take the path of least resistance when given one. Out the side instead of up the OMP lines.

If you are planning to keep the OMP - rebuild it:
$30 kit from pineappleracing.com, includes how-to DVD. Brainless.
-AND:
if your OMP lines are older than 10yrs, I'd buy a new set: $40 IIRC

Stu Aull
80GS
Alaska

Okay that I may do. On the two oil lines there are two short black rubber hoses on each end. I was able to pull the old black lines off of the clear line (even tho there glued together) and put new ones on that fit really tight. The clear lines were clean (I was able to blow air through them). So I will run them for a bit and hopefully they wont leak.

Thanks,

https://www.rx7club.com/1st-gen-archive-71/oil-12a-mop-mod-illustrated-597431/
This modification to the stock pump is working for me. One thing to note about tank placement is that it needs to be lower than the oil line connection point on the engine or oil will syphon into the engine.

I've replaced those black lines on the clear ones with new vacuum line before and ran into a problem. What I did was put supper glue on the clear tube then pushed the new black line on about two inches. This worked great until the engine heated up. The black hose became really flexible and leaked oil.

Just be careful and check your work after a few miles.

Crap well considering I used vacuum line im probably going to have a problem. If a rebuild kit is $30 and new lines are $40. Or I could spend $4 or so for a blockoff plate and not have to worry. Now considering I am poor college kid with 3 cars <--nothing special, I think i might go with the block off plate and premix for a little while. Im not gonna be driving this car every day.

Now if I do go with a blockoff plate, what should I use to seal it? Certain gasket or permatex w.e its called? Silicone?

Thanks guys,

The factory gasket is just regular gasket material. I always make my own for the OMP. If you ever plan on using the OMP again, I would'nt us any permatex. I'd made a gasket out of reagular gasket material and not cut out the oil hole.

Also, make sure you get the right size bolts. Some people get them too long and crank them down and break off the aluminum bolt hole.

I used permatex red, it's for pressurized applications. Used large fender washers to spread the load of the block off plate evenly.

Okay So I need to get some longer bolts or shorter bolts? Ofcourse get the same thread pitch and all. Whats wrong with the bolts that are on there now?

Ive read both gasket material or Permatex. Idk