Premix Ratio??
Ray, please pardon the sidebar....
& thanks for bringing up this topic. Need to test when she comes out of hibernation.
Psychomantis,
At the top of this forum, first sticky post is a link to FSM (Factory Service Manuals).
I have an 84 GSL, so I downloaded all the 85RX7 files.
The one for the OMP is 85RX7(2)lubrication. There is a section for testing the OMP.
& thanks for bringing up this topic. Need to test when she comes out of hibernation.
Psychomantis,
At the top of this forum, first sticky post is a link to FSM (Factory Service Manuals).
I have an 84 GSL, so I downloaded all the 85RX7 files.
The one for the OMP is 85RX7(2)lubrication. There is a section for testing the OMP.
Old [Sch|F]ool
Joined: May 2001
Posts: 12,848
Likes: 563
From: Cleveland, Ohio, USA
Lot of "interesting" info in this thread...
I premix at 60:1 because I don't have the ***** to add more oil. I have found increased compression, drivability, and POWER by going richer than "1oz/gallon".
OTOH i only drive 20k per year or so, it's not like I have as much experience with this sort of thing...
I premix at 60:1 because I don't have the ***** to add more oil. I have found increased compression, drivability, and POWER by going richer than "1oz/gallon".
OTOH i only drive 20k per year or so, it's not like I have as much experience with this sort of thing...
carb whisperer
Joined: Jan 2008
Posts: 1,485
Likes: 4
From: Greenfield, Ohio
ray, return the coolant tank and get a used 2stroke tank from ebay (motorcycle, jetski, snowmobile, etc). i've read of people having issues w/ coolant tank cause it's a different type of plastic used which is not compatible w/ oil. btw, i have modified my OMP and can clearly see that 2stroke oil is being delivered.
Junior Member
Joined: Feb 2012
Posts: 8
Likes: 0
From: Summerville, SC
I drove rotary motors in racing applications for nearly 20 years. Also, raced 2 cycle dirt bikes, when you could buy them "new".
When adding the oil at the gas pump, would suggest "layering" the oil in. Add 1/3 the volume before adding gas, 1/3 when you are near half filled, and the balance at the end. It is not an exact science, but it helps get a better blend of oil mixed in the gas tank.
A one quart oil can with the visible side markings is a good suggestion that someone has made. Just top it off each time you fill up. The plastic is compatible with the oil. Plastic containers designed for the cooling system will not last.
Get a package of longer plastic ty wraps and attach with them to someplace under the hood. Try to make a support bracket, with 2 vertical and one horizontal. A single strap supporting a quart of oil over time, in the heat of under the hood, will fail.
For the rotary, I always premixed. Mixed it with 1 oz of 2 cycle oil to 1 gallon of gasoline. More than 1.5 oz per gallon is too much. Always used a better grade 2 cycle brand. Two cycle oil is blended to mix more evenly with gasoline.
High octane gas is not of much use in the rotary, because of the low compression ratios. Ran stock porting and street porting over the years, rules limited the modifications. Could never find any additional horsepower on the dyno using more than 98/100 octane. We ran from 5,500 to 8,500 RPM on the track in 30 minute races, so had to keep a close eye on water and exhaust temps, ignition timing and carb jetting. There was no room for error, or would burn out an apex seal.
Using a 13B, steet ported, 48 IDA Weber and headers yielded about 230-240 HP on the engine dyno. The car was about 2,300 pounds, with the driver.
When adding the oil at the gas pump, would suggest "layering" the oil in. Add 1/3 the volume before adding gas, 1/3 when you are near half filled, and the balance at the end. It is not an exact science, but it helps get a better blend of oil mixed in the gas tank.
A one quart oil can with the visible side markings is a good suggestion that someone has made. Just top it off each time you fill up. The plastic is compatible with the oil. Plastic containers designed for the cooling system will not last.
Get a package of longer plastic ty wraps and attach with them to someplace under the hood. Try to make a support bracket, with 2 vertical and one horizontal. A single strap supporting a quart of oil over time, in the heat of under the hood, will fail.
For the rotary, I always premixed. Mixed it with 1 oz of 2 cycle oil to 1 gallon of gasoline. More than 1.5 oz per gallon is too much. Always used a better grade 2 cycle brand. Two cycle oil is blended to mix more evenly with gasoline.
High octane gas is not of much use in the rotary, because of the low compression ratios. Ran stock porting and street porting over the years, rules limited the modifications. Could never find any additional horsepower on the dyno using more than 98/100 octane. We ran from 5,500 to 8,500 RPM on the track in 30 minute races, so had to keep a close eye on water and exhaust temps, ignition timing and carb jetting. There was no room for error, or would burn out an apex seal.
Using a 13B, steet ported, 48 IDA Weber and headers yielded about 230-240 HP on the engine dyno. The car was about 2,300 pounds, with the driver.
Old [Sch|F]ool
Joined: May 2001
Posts: 12,848
Likes: 563
From: Cleveland, Ohio, USA
The OMP adds roughly 120:1 oil at full throttle.
It is also drooling the oil directly down the sides of the intake port or even better, right up against the rotor housing where it can get to the apex seal.
When premixing, not all of the oil will get anywhere close to the rotor housing surface. In fact most of it goes nowhere near it. This is why I firmly believe that to use OMP injection rates as a guide for how much to premix is horribly flawed.
I've found noticable power gains from adding more and more oil. I stop at 60:1 because blue smoke becomes evident when in warmup enrichment, and this annoys me. Carbon is not an issue, it's meant to burn after all
No poorly-burning additives like viscosity enhancers such as you'd find in motor oil.
It is also drooling the oil directly down the sides of the intake port or even better, right up against the rotor housing where it can get to the apex seal.
When premixing, not all of the oil will get anywhere close to the rotor housing surface. In fact most of it goes nowhere near it. This is why I firmly believe that to use OMP injection rates as a guide for how much to premix is horribly flawed.
I've found noticable power gains from adding more and more oil. I stop at 60:1 because blue smoke becomes evident when in warmup enrichment, and this annoys me. Carbon is not an issue, it's meant to burn after all
No poorly-burning additives like viscosity enhancers such as you'd find in motor oil.
So let's see, what you're saying PJ is that the Mazda engineers had it right in the first place?
The best way to lubricate a rotary is with a throttle-regulated crank case-fed OMP that drools motor oil right down the sides of the primaries in a four barrel Nikki, directing the oil straight into the intake ports without mixing with the fuel?
If so, that's a radical departure from oil delivery via premixing in the tank and something that needs to be taken very seriously.
And since motor oil isn't designed for mixing like 2 cycle oil is, maybe delivering oil from the crank case is the best option after all?
Nikki's keep looking better all the time.
The best way to lubricate a rotary is with a throttle-regulated crank case-fed OMP that drools motor oil right down the sides of the primaries in a four barrel Nikki, directing the oil straight into the intake ports without mixing with the fuel?
If so, that's a radical departure from oil delivery via premixing in the tank and something that needs to be taken very seriously.
And since motor oil isn't designed for mixing like 2 cycle oil is, maybe delivering oil from the crank case is the best option after all?
Nikki's keep looking better all the time.
Joined: Mar 2001
Posts: 31,796
Likes: 3,210
From: https://www2.mazda.com/en/100th/
Mazda just did a study of oil flow in the engine in 2014, and they didn't try premixing, but they found a portion of the oil from even the metering nozzles doesn't get to the seals, if you're premixing it seems likely that most of the oil doesn't get where you think it does.
see SAE papers 2014-01-1664 and 2014-01-1665
see SAE papers 2014-01-1664 and 2014-01-1665
I'm with you on the OMP metering the oil Ray and using a Nikki. I think the best solution is to
modify the OMP to take 2 cycle from a reservoir and the let the OMP and Nkki do their thing.
Seems like the best of all to me.
I think I have a new project now!
modify the OMP to take 2 cycle from a reservoir and the let the OMP and Nkki do their thing.
Seems like the best of all to me.
I think I have a new project now!
That's the way it seems to be headed Tim, let the Nikki do its thing. But I'm starting to wonder what's the best oil?
If dribbling the oil into the combustion chamber without mixing with the venturi gas flow is best, so that the oil can make it's way to the seals while retaining its maximal lubrication properties, wouldn't 2 cycle oil be a bad idea? Or at least not as good as motor oil?
I'm assuming here that 2 cycle oil mixes with gas more quickly than motor oil, since that's what it's designed to do. But isn't mixing a bad thing in this case?
If dribbling the oil into the combustion chamber without mixing with the venturi gas flow is best, so that the oil can make it's way to the seals while retaining its maximal lubrication properties, wouldn't 2 cycle oil be a bad idea? Or at least not as good as motor oil?
I'm assuming here that 2 cycle oil mixes with gas more quickly than motor oil, since that's what it's designed to do. But isn't mixing a bad thing in this case?
Old [Sch|F]ool
Joined: May 2001
Posts: 12,848
Likes: 563
From: Cleveland, Ohio, USA
Motor mixes very well with gasoline, too. 2 cycle oil, however, doesn't have plasticizers to alter the viscosity curve or detergents to absorb contaminants or other stuff that I can't think of, which can actually detract from lubricity and/or the ability to burn cleanly. We don't care how much moisture it can absorb, its job is to lube the apex seals a bit before it gets burned off.
And yes, the OMP is probably the best method. Downside: I've never had one that actually worked. And making linkage for one-off intake setups is a pain.
And yes, the OMP is probably the best method. Downside: I've never had one that actually worked. And making linkage for one-off intake setups is a pain.
OK, sounds like 2 cycle oil does have advantages over motor oil and assuming a properly functioning OMP, Tim's plan for an adapted OMP hooked up to a reservoir filled with 2 cycle oil is the way to go.
And I still have the oil reservoir I bought for that purpose a couple years ago:
I've always had good luck with the stock OMP set up. Regular checks over a ten year period of heavy daily driving using the FSM method Tim Wilbers posted above always showed the OMP was working fine.
A bigger problem for me has been making sure the lines are properly connected and free of obstruction. More than once I've opened the hood to find the engine bay splattered with oil because I forgot to hook the lines back up after working on the Nikki.
So now we just need to know what's the best way to adapt an OMP to a reservoir intake instead of crankcase intake. There was that expensive airplane kit mentioned earlier in this post, but there has to be a better, more available and less expensive option.
Opinions most welcome on the best way to adapt the OMP to a reservoir these days!
And I still have the oil reservoir I bought for that purpose a couple years ago:
I've always had good luck with the stock OMP set up. Regular checks over a ten year period of heavy daily driving using the FSM method Tim Wilbers posted above always showed the OMP was working fine.
A bigger problem for me has been making sure the lines are properly connected and free of obstruction. More than once I've opened the hood to find the engine bay splattered with oil because I forgot to hook the lines back up after working on the Nikki.
So now we just need to know what's the best way to adapt an OMP to a reservoir intake instead of crankcase intake. There was that expensive airplane kit mentioned earlier in this post, but there has to be a better, more available and less expensive option.
Opinions most welcome on the best way to adapt the OMP to a reservoir these days!
It looks like this post is doing what it intended, which was to help sort out the numerous opinions on pre-mix and OMP set ups. For the record, we should leave some bottom line recommendations for the newbies.
The first thing to do in every situation is make sure the OMP system is in good shape and working properly. Check to be sure the lines are correctly hooked up, without any leaks or blockage. Then check the OMP output using the FSM procedure that Tim posted above.
Then, assuming a properly functioning OMP, here are my four recommendations on options:
1) one way to look at pre-mix is as an insurance policy to cover possible OMP failure. This is what I usually do, adding 0.5 oz per gallon at each fill up. This approach makes sure you get plenty of oil to the engine, no matter what the circumstances, but it's probably excessive, you may get a yellowish deposit on the bumper and fender over the tailpipe (isopropyl alcohol takes this right off) and it's a bit of a nuisance and expense having to add the oil all the time.
2) or, you can ditch the OMP and go straight with pre-mix. Here you probably want 1 oz per gallon (but opinions differ with circumstances) and you will have the same issues as noted above.
3) believe in the Rotary Gods and just rely on the stock OMP to take care of all your rotary engine lubrication needs. This is probably the best option, I've got friends who do this and have put better than 200,000 miles on an original 12A, but it makes me nervous.
4) take charge and install a dedicated reservoir filled with 2 cycle oil and hooked to a modified OMP. This one is for the modification junkies, but if someone comes up with a good procedure it could get more popular.
I'm sure there are plenty of other recommendations for the less initiated, so lets here what the real experts have to say.
The first thing to do in every situation is make sure the OMP system is in good shape and working properly. Check to be sure the lines are correctly hooked up, without any leaks or blockage. Then check the OMP output using the FSM procedure that Tim posted above.
Then, assuming a properly functioning OMP, here are my four recommendations on options:
1) one way to look at pre-mix is as an insurance policy to cover possible OMP failure. This is what I usually do, adding 0.5 oz per gallon at each fill up. This approach makes sure you get plenty of oil to the engine, no matter what the circumstances, but it's probably excessive, you may get a yellowish deposit on the bumper and fender over the tailpipe (isopropyl alcohol takes this right off) and it's a bit of a nuisance and expense having to add the oil all the time.
2) or, you can ditch the OMP and go straight with pre-mix. Here you probably want 1 oz per gallon (but opinions differ with circumstances) and you will have the same issues as noted above.
3) believe in the Rotary Gods and just rely on the stock OMP to take care of all your rotary engine lubrication needs. This is probably the best option, I've got friends who do this and have put better than 200,000 miles on an original 12A, but it makes me nervous.
4) take charge and install a dedicated reservoir filled with 2 cycle oil and hooked to a modified OMP. This one is for the modification junkies, but if someone comes up with a good procedure it could get more popular.
I'm sure there are plenty of other recommendations for the less initiated, so lets here what the real experts have to say.
There's a DIY thread on modding the OMP so that it can serve the 2 cycle from a gravity fed
reservoir. I'll have to dig the link up but its pretty trivial, you drill a hole and place a 1/4" barb
at the right place on the OMP, block off the pump opening into the OMP and use a dremel make
small opening to allow the 2 cycle oil to get into the OMP pump passage.
reservoir. I'll have to dig the link up but its pretty trivial, you drill a hole and place a 1/4" barb
at the right place on the OMP, block off the pump opening into the OMP and use a dremel make
small opening to allow the 2 cycle oil to get into the OMP pump passage.
here's how i did the OMP modification: https://www.rx7club.com/se-rx-7-foru.../#post10852897
if i was to do it again, i would use a small brass barb like in the link i provided instead of a brake line hose end (i think that's what i used).
if i was to do it again, i would use a small brass barb like in the link i provided instead of a brake line hose end (i think that's what i used).
Thanks for the link Fred.
I can see how the block off plate works, as shown in this photo:
But it's unclear how you tapped the OMP and how you plumbed the OMP to the reservoir.
Do you have anything on that?
Thanks!
I can see how the block off plate works, as shown in this photo:
But it's unclear how you tapped the OMP and how you plumbed the OMP to the reservoir.
Do you have anything on that?
Thanks!
Ray, see t his thread for the details with pics.
https://www.rx7club.com/1st-gen-arch...trated-597431/
I think this is a more complete thread on it:
https://www.rx7club.com/rotary-car-p...up-pics-372329
https://www.rx7club.com/1st-gen-arch...trated-597431/
I think this is a more complete thread on it:
https://www.rx7club.com/rotary-car-p...up-pics-372329
hey ray,
i just drilled a hole to reach the chamber in the OMP that a fitting could be epoxied to. you want to avoid hitting the mechanism which regulates the amount of oil though. with an OMP in hand, it's pretty obvious where to one can drill to be able to do that.
as for the reservoir, i just put it in a convenient place in the engine bay where i could run a hose from it to the OMP (i believe it may have been where the old cruise control stuff waw located). i did put it higher than the OMP so gravity could help get the oil from the reservoir to the OMP.
i just drilled a hole to reach the chamber in the OMP that a fitting could be epoxied to. you want to avoid hitting the mechanism which regulates the amount of oil though. with an OMP in hand, it's pretty obvious where to one can drill to be able to do that.
as for the reservoir, i just put it in a convenient place in the engine bay where i could run a hose from it to the OMP (i believe it may have been where the old cruise control stuff waw located). i did put it higher than the OMP so gravity could help get the oil from the reservoir to the OMP.
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