OMP-Pre-mix mod Write-up
04-29-03, 09:56 PM
#52
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Sorry this is kinda not on the topic, but after removing rats nest omp and some other stuff i have plenty vacuum nipples to cap. Where can I get some rubber caps for this purpose. Local stores for some reason don't carry any cheap ones.
05-04-03, 04:25 AM
#54
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What about the driving gear, that drives the OMP?
When I remove the OMP, the driving gear can slide around against the block off plate....I have heard a pair of U.S dimes could be inserted there to keep the OMP-gear from sliding around inside the front cover!
1987RX7guy: Have you heard any of this, how have you done?
When I remove the OMP, the driving gear can slide around against the block off plate....I have heard a pair of U.S dimes could be inserted there to keep the OMP-gear from sliding around inside the front cover!
1987RX7guy: Have you heard any of this, how have you done?
Last edited by Wankelman; 05-04-03 at 04:42 AM.
05-04-03, 03:55 PM
#55
Well I did not put them in there but I have had no leaks or anything. I believe you can remove the gear but you have to remove the front cover (i think) Thise was on the fc3spro stie and I suppose that it is ok to put in the dimes but I have not.
05-09-03, 08:36 PM
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nevermind!
but a few more suggestions to those who plan on doing this
use petmatex ULTRA black not just the black
to save your self alot of agravasion remove the air pump belt to get better access to the OMP
thats all i can think of for now if i can think of anything more ill add it
but a few more suggestions to those who plan on doing this
use petmatex ULTRA black not just the black
to save your self alot of agravasion remove the air pump belt to get better access to the OMP
thats all i can think of for now if i can think of anything more ill add it
06-03-03, 05:59 PM
#70
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I have just quickly skimmed this thread, and did not read the whole thing. So I apologize if this has been said already...
First things first: good write up. Clear instructions, easy to understand, and it pretty much covers everthing.
What I am worried about is that the disadvantages of this mod don't seem to be mentioned. We have a lot of people going "premix" without knowing the consequences of doing so. I just want to clear things up.
What is wrong with the premix theories is that there doesn't seem to be any conclusive scientific proof that it is any better then the stock metering oil system. And by scientific I mean results that can be trusted. Not something like "I've been premixing for the past 30,000 and my engine looks new inside". I mean someone taking 6 engines, running each on a dyno under changing loads and temperatures, using pump gas. In other words, exactly the same use you would see on the street. 3 of these engines would use the stock MOP system, 3 would premix. This would go on for the equivelant of 150,000 miles. Each one would then be disassembled and examined. Then we can deal with facts.
Speaking of facts, I learned some interesting things talking to the owner of Atkin's Rotary (25+ years of experience...) in April:
Fact: the carbon on the rotors that most people attribute to the metering oil system is actually caused by bad gas, short starts, etc. Makes perfect sense to me. Now, you're going to wonder why there is a clean spot where the oil nozzle is. Simple really: that's where a drop of oil lands. The oil slickness prevents carbon from sticking.
Fact: most people don't understand the stock metering oil system. They are under the false impression that it is supposed to inject oil under pressure. This is exactly opposite of how it is designed. The system is designed for form a drop of oil at the injection hole. As the apex seal sweaps around, it catches the drop which then flattens out along the seal. Thus, the apex seal is lubricated throughout it's travel. Oil is applied exactly where it is needed...Which brings us to:
Fact: premix lubricates the face of the rotor. This is wonderful, but what we really need is an oil film on the housings...Why doesn't this form with premix? Well, because it is designed to burn. It is, after all, meant to be used in two cycle engines. In the 2 stroke, the surfaces the oil is lubricating are not exposed to combustion. In a rotary, the exact opposite is true. The premix very easily burns off the housing. This, no firm forms. Since standard crankcase oil is higher in viscosity and much harder to burn, the apex seal leaves a nice slick film on the housings, exactly where it is needed.
Fact: Premix will more quickly clog injectors and foul plugs then the stock metering system. This is probably not a big deal for most of us here. Also, to much will clog exhausts, smell bad, cause smoking, etc. Again, probably not a concern here. Just something to be aware of.
Question: If premix is so good, why did Mazda not design the metering oil system to inject directly into the fuel line before the injector?
Premix is great when used in racing engines that are constantly >8000 RPM where the stock system cannot cope, but for street driven cars, it is my opinion that the stock system is more then adaquate.
First things first: good write up. Clear instructions, easy to understand, and it pretty much covers everthing.
What I am worried about is that the disadvantages of this mod don't seem to be mentioned. We have a lot of people going "premix" without knowing the consequences of doing so. I just want to clear things up.
What is wrong with the premix theories is that there doesn't seem to be any conclusive scientific proof that it is any better then the stock metering oil system. And by scientific I mean results that can be trusted. Not something like "I've been premixing for the past 30,000 and my engine looks new inside". I mean someone taking 6 engines, running each on a dyno under changing loads and temperatures, using pump gas. In other words, exactly the same use you would see on the street. 3 of these engines would use the stock MOP system, 3 would premix. This would go on for the equivelant of 150,000 miles. Each one would then be disassembled and examined. Then we can deal with facts.
Speaking of facts, I learned some interesting things talking to the owner of Atkin's Rotary (25+ years of experience...) in April:
Fact: the carbon on the rotors that most people attribute to the metering oil system is actually caused by bad gas, short starts, etc. Makes perfect sense to me. Now, you're going to wonder why there is a clean spot where the oil nozzle is. Simple really: that's where a drop of oil lands. The oil slickness prevents carbon from sticking.
Fact: most people don't understand the stock metering oil system. They are under the false impression that it is supposed to inject oil under pressure. This is exactly opposite of how it is designed. The system is designed for form a drop of oil at the injection hole. As the apex seal sweaps around, it catches the drop which then flattens out along the seal. Thus, the apex seal is lubricated throughout it's travel. Oil is applied exactly where it is needed...Which brings us to:
Fact: premix lubricates the face of the rotor. This is wonderful, but what we really need is an oil film on the housings...Why doesn't this form with premix? Well, because it is designed to burn. It is, after all, meant to be used in two cycle engines. In the 2 stroke, the surfaces the oil is lubricating are not exposed to combustion. In a rotary, the exact opposite is true. The premix very easily burns off the housing. This, no firm forms. Since standard crankcase oil is higher in viscosity and much harder to burn, the apex seal leaves a nice slick film on the housings, exactly where it is needed.
Fact: Premix will more quickly clog injectors and foul plugs then the stock metering system. This is probably not a big deal for most of us here. Also, to much will clog exhausts, smell bad, cause smoking, etc. Again, probably not a concern here. Just something to be aware of.
Question: If premix is so good, why did Mazda not design the metering oil system to inject directly into the fuel line before the injector?
Premix is great when used in racing engines that are constantly >8000 RPM where the stock system cannot cope, but for street driven cars, it is my opinion that the stock system is more then adaquate.
06-03-03, 11:13 PM
#71
First things first: good write up. Clear instructions, easy to understand, and it pretty much covers everthing.
What I am worried about is that the disadvantages of this mod don't seem to be mentioned. We have a lot of people going "premix" without knowing the consequences of doing so. I just want to clear things up.
) I hope I am correct though.
What is wrong with the premix theories is that there doesn't seem to be any conclusive scientific proof that it is any better then the stock metering oil system. And by scientific I mean results that can be trusted. Not something like "I've been premixing for the past 30,000 and my engine looks new inside". I mean someone taking 6 engines, running each on a dyno under changing loads and temperatures, using pump gas. In other words, exactly the same use you would see on the street. 3 of these engines would use the stock MOP system, 3 would premix. This would go on for the equivelant of 150,000 miles. Each one would then be disassembled and examined. Then we can deal with facts.
Speaking of facts, I learned some interesting things talking to the owner of Atkin's Rotary (25+ years of experience...) in April:
Fact: the carbon on the rotors that most people attribute to the metering oil system is actually caused by bad gas, short starts, etc. Makes perfect sense to me. Now, you're going to wonder why there is a clean spot where the oil nozzle is. Simple really: that's where a drop of oil lands. The oil slickness prevents carbon from sticking.
Fact: most people don't understand the stock metering oil system. They are under the false impression that it is supposed to inject oil under pressure. This is exactly opposite of how it is designed. The system is designed for form a drop of oil at the injection hole. As the apex seal sweaps around, it catches the drop which then flattens out along the seal. Thus, the apex seal is lubricated throughout it's travel. Oil is applied exactly where it is needed...Which brings us to:
Fact: premix lubricates the face of the rotor. This is wonderful, but what we really need is an oil film on the housings...Why doesn't this form with premix? Well, because it is designed to burn. It is, after all, meant to be used in two cycle engines. In the 2 stroke, the surfaces the oil is lubricating are not exposed to combustion. In a rotary, the exact opposite is true. The premix very easily burns off the housing. This, no firm forms. Since standard crankcase oil is higher in viscosity and much harder to burn, the apex seal leaves a nice slick film on the housings, exactly where it is needed
I also beleived that two stroke engines burn oil by there very nature. This is why two stroke oil is made to burn cleaner and leave a lubricating film behind after being burned. This is what I have read on it.
Fact: Premix will more quickly clog injectors and foul plugs then the stock metering system. This is probably not a big deal for most of us here. Also, to much will clog exhausts, smell bad, cause smoking, etc. Again, probably not a concern here. Just something to be aware of.
Question: If premix is so good, why did Mazda not design the metering oil system to inject directly into the fuel line before the injector?
Premix is great when used in racing engines that are constantly >8000 RPM where the stock system cannot cope, but for street driven cars, it is my opinion that the stock system is more then adaquate.
On the other hand I feel that if it is better at 8k rpms then it should also be good at lower RPMs: since you say that two stroke oil does not lubricate well because it is designed to burn then why would it be any different at 8k RPMs? If what you say is true then it would probably be worse since at such a high RPM range the engine would run at a higher temp than at say 3500 RPMs in a normal car the pre-mix would be even lees effective.
Well if you have any other info let us know man.
Santiago
06-04-03, 04:35 PM
#73
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aaron makes good points - all things that have kept me from doing this
-rotor face lubrication concerns (as opposed to housing concerns)
-running the oil through the FI system clogging fuel injectors, etc..(wouldnt we need a higher octane fuel to run premix?)
-another point (may not have been covered.. i have read this thread but it a few weeks ago) the injectors are injecting, so.. when you downshift (rev high) and let off the gas.. there isn't oil being injected, is there? as where the MOP system is doing it with the speed of the engine..
3 of my main concerns..
aaron covered my thoughts (which is good) so im still quite skeptacle on doing this mod..
if i could afford it, i would get 2 13B engines, and run one MOP one premix, to solve this ongoing debate. anyone want to go splits on a big research project? maybe just use running scrapper engines.. run them both for a few days at high rpm, see what happens.. wont be bulletproof material, but it will be SOMETHING.. know what i mean?
anyways, back on topic.. about aaron's remark with the carbon buildup on the apex seal area from the MOP system, i would think that if you run the car at high rpms, it wouldnt carbon up like that.. maybe at low rpms all the time (as an unknowing previous owner think they are baby-ing the car) and also using the wrong oil (as an unknowing owner might do as well) that i would imagine might cause the buildup people feel the seals are being ruined by..
anyways.. just my thoughts on this..
-rotor face lubrication concerns (as opposed to housing concerns)
-running the oil through the FI system clogging fuel injectors, etc..(wouldnt we need a higher octane fuel to run premix?)
-another point (may not have been covered.. i have read this thread but it a few weeks ago) the injectors are injecting, so.. when you downshift (rev high) and let off the gas.. there isn't oil being injected, is there? as where the MOP system is doing it with the speed of the engine..
3 of my main concerns..
aaron covered my thoughts (which is good) so im still quite skeptacle on doing this mod..
if i could afford it, i would get 2 13B engines, and run one MOP one premix, to solve this ongoing debate. anyone want to go splits on a big research project? maybe just use running scrapper engines.. run them both for a few days at high rpm, see what happens.. wont be bulletproof material, but it will be SOMETHING.. know what i mean?
anyways, back on topic.. about aaron's remark with the carbon buildup on the apex seal area from the MOP system, i would think that if you run the car at high rpms, it wouldnt carbon up like that.. maybe at low rpms all the time (as an unknowing previous owner think they are baby-ing the car) and also using the wrong oil (as an unknowing owner might do as well) that i would imagine might cause the buildup people feel the seals are being ruined by..
anyways.. just my thoughts on this..
06-04-03, 04:46 PM
#74
Well the worries about the fuel injection system having problems I covered please read my post in response to aaron. On the coasting from high RPMs issue by its very nature two stroke oil leaves a lubricating coating behind when burnt in the engine there for this is what provides protection from friction in theses situations.
About carbon build up obviously a large part of it is also due to the gasoline left after short trips or quick starts and these kinds of scenarios. Ofcoarse most of us do not do these things for fear of flooding the car. It was my understanding that oil from the engine was partly responsible for the buildup because of the simple fact that it is not ment to be burned therefore burns incompletely and leaves deposits of carbon behind and other trace contaminants that were not filtered by the engines oil filter thus causing more problems down the road.
Just my thoughts in response yto yours guys keep this going I am enjoing this very much.
Santiago
About carbon build up obviously a large part of it is also due to the gasoline left after short trips or quick starts and these kinds of scenarios. Ofcoarse most of us do not do these things for fear of flooding the car. It was my understanding that oil from the engine was partly responsible for the buildup because of the simple fact that it is not ment to be burned therefore burns incompletely and leaves deposits of carbon behind and other trace contaminants that were not filtered by the engines oil filter thus causing more problems down the road.
Just my thoughts in response yto yours guys keep this going I am enjoing this very much.
Santiago
06-04-03, 08:14 PM
#75
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i did notice you covered that.. and thats good too.. but still.. were talking about something that wasnt designed to be injected through injectors.. (well the way the bone stock car was designed.. it wasnt designed for it.. wether or not it has its effects, especially with an oil that says it's ok for use via injectors)
im still with aaron on this one (his question i mean.. it makes total sense to me..) if the injection design was so effective, then why didnt they set up oil to be injected just before the fuel injector?
but again, this is something that cannot be answered..
i wish we could talk to the rotary designers back when they released the 13b..
like i say i think a cool experiment would be to take a couple running engines, clean them up, then have one run an OMP at high rpm for a few days, and another on premix at high rpm for a few days..
dont be surprised if i do something crazy like this sometime down the road (unless someone beats me to it)
im still with aaron on this one (his question i mean.. it makes total sense to me..) if the injection design was so effective, then why didnt they set up oil to be injected just before the fuel injector?
but again, this is something that cannot be answered..
i wish we could talk to the rotary designers back when they released the 13b..
like i say i think a cool experiment would be to take a couple running engines, clean them up, then have one run an OMP at high rpm for a few days, and another on premix at high rpm for a few days..
dont be surprised if i do something crazy like this sometime down the road (unless someone beats me to it
)