Rotary Engine Run In!

[Mazdabater]

With my engine coming back from overhaul I figured that I would ask you guys whats your opinion on running them in. Originally I was told to run it for an hour, do an oil/filter change. Another at 500kms and then one more at 1000kms and its good to go, however to keep right off the boost untill 1000kms.

Then talking to a mate today and he was telling me that when you rebuild a dirt bike they are good to go pretty much after startup.

All I'm wondering is how long do you really need to run them in for, surely most of it would get done within 300kms. Even only doing 3000rpm is surely going to bed into the housings quite fast.

[RICE RACING]

IF it has all new rotor bearings and stationary gear bearings then it will require 1500km at least to bed these in properly.

Oil control rings take up to 5000km to bed in right.

All other seals when used on excellent used parts will bed into each other within 500km. IF your rotor housings are second hand and your apex seals are hard (stock or other harder types) then this will take 5000km or more to bed in properly before full power and least stress is achieved. New un warped or scored parts will bed in within the 1500km limit.

All other seals like side seals and new corner seals take about 1500km to fully bed in if it was made correctly and not cut at funny angles etc.

1500km is a general rule that covers most from hack 2nd hand parts whore builds to BNIB factory engines. Progressive loads and revs on Mineral oil (no synthetic) 3000rpm, 4500rpm, 5000rpm, 6500rpm, 8000rpm in 300km steps from 0 load to 2 psi to 10psi boost is sufficient across this running period. Plenty of "cycles" full cold to operating temp starts (50 minimum, 100 or more is best) also facilitate best running in procedures of bearings especially.

Stick by this and you wont go wrong.

If in doubt of hobo build, drop the oil after 100km drive then drop again after the 1500km. If its a build like I do then no need to drop oil on initial start up, but some cunts build them homo and fill engine with all kinds of shit and foreign crap so dump after even first warm up cycle 20 min running in shed is good insurance.

Hope this helps!

[FC Zach]

A two-stroke engine is a completely different animal, in your case you will need to do immediate service(s) after rebuild.

Upon initial start up allow the engine to reach a normal operating temp. then drain and replace oil and filter. This is important because of all the assembly lubes, sealants, and whatever else that is washed away within the motor.

After the first oil change is done I guess you could just simply change it at 500kms and once more at 1000kms. If you had a bearing failure prior to the rebuild then I would change the oil before 500km. I say that because no matter how well you think you flushed your oil cooler there always seems to be a lot of debris still within the cooler, I disassembled a few filters and seen first hand.

Other than that just take it easy on it and keep the RPMs varying, reason why I drove mine mostly around town during the first few hundred miles.

[j9fd3s]

IF it has all new rotor bearings and stationary gear bearings then it will require 1500km at least to bed these in properly.

Oil control rings take up to 5000km to bed in right.

All other seals when used on excellent used parts will bed into each other within 500km. IF your rotor housings are second hand and your apex seals are hard (stock or other harder types) then this will take 5000km or more to bed in properly before full power and least stress is achieved. New un warped or scored parts will bed in within the 1500km limit.

All other seals like side seals and new corner seals take about 1500km to fully bed in if it was made correctly and not cut at funny angles etc.

1500km is a general rule that covers most from hack 2nd hand parts whore builds to BNIB factory engines. Progressive loads and revs on Mineral oil (no synthetic) 3000rpm, 4500rpm, 5000rpm, 6500rpm, 8000rpm in 300km steps from 0 load to 2 psi to 10psi boost is sufficient across this running period. Plenty of "cycles" full cold to operating temp starts (50 minimum, 100 or more is best) also facilitate best running in procedures of bearings especially.

Stick by this and you wont go wrong.

If in doubt of hobo build, drop the oil after 100km drive then drop again after the 1500km. If its a build like I do then no need to drop oil on initial start up, but some cunts build them homo and fill engine with all kinds of shit and foreign crap so dump after even first warm up cycle 20 min running in shed is good insurance.

Hope this helps!

agreed. i do keep an eye on the oil though, if its a new combo, and needs tuning, it can dilute the oil with gas real quick.

[NoDOHC]

agreed. i do keep an eye on the oil though, if its a new combo, and needs tuning, it can dilute the oil with gas real quick.


Really? How? Does the fuel leak past the oil control rings?


IF it has all new rotor bearings and stationary gear bearings then it will require 1500km at least to bed these in properly.

Oil control rings take up to 5000km to bed in right.

All other seals when used on excellent used parts will bed into each other within 500km. IF your rotor housings are second hand and your apex seals are hard (stock or other harder types) then this will take 5000km or more to bed in properly before full power and least stress is achieved. New un warped or scored parts will bed in within the 1500km limit.

All other seals like side seals and new corner seals take about 1500km to fully bed in if it was made correctly and not cut at funny angles etc.

1500km is a general rule that covers most from hack 2nd hand parts whore builds to BNIB factory engines. Progressive loads and revs on Mineral oil (no synthetic) 3000rpm, 4500rpm, 5000rpm, 6500rpm, 8000rpm in 300km steps from 0 load to 2 psi to 10psi boost is sufficient across this running period. Plenty of "cycles" full cold to operating temp starts (50 minimum, 100 or more is best) also facilitate best running in procedures of bearings especially.

Stick by this and you wont go wrong.

If in doubt of hobo build, drop the oil after 100km drive then drop again after the 1500km. If its a build like I do then no need to drop oil on initial start up, but some cunts build them homo and fill engine with all kinds of shit and foreign crap so dump after even first warm up cycle 20 min running in shed is good insurance.

Hope this helps!


Awesome info! should be a sticky or something.

[RETed]

Really? How? Does the fuel leak past the oil control rings?

Amazing as it sounds, it really does happen...

There is so much fuel in the engine that it bypasses the metal oil control rings and the oil control o-rings.
Remember, Mazda designed the oil control ring system to keep oil out of the combustion chamber.
Oil is significantly more viscous than fuel.

I have a feeling the oil control rings are just "hydroplaning" over the gobs of fuel inside the engine in a disgustingly overly rich condition, which allows the fuel to eventually enter the oil supply.

I've drained oil pans where the "oil" flowed as thinly as water...
You can smell the gasoline mixed in with the oil too.


-Ted

[speedjunkie]

Interesting, I was wondering why my oil sometimes smelled like fuel, and as a result got me turned away from dumping my oil at the auto parts store lol.

[NoDOHC]

There is so much fuel in the engine that it bypasses the metal oil control rings and the oil control o-rings.
Remember, Mazda designed the oil control ring system to keep oil out of the combustion chamber.
Oil is significantly more viscous than fuel.

I have a feeling the oil control rings are just "hydroplaning" over the gobs of fuel inside the engine in a disgustingly overly rich condition, which allows the fuel to eventually enter the oil supply.

I've drained oil pans where the "oil" flowed as thinly as water...
You can smell the gasoline mixed in with the oil too.


That is a new one to me. I have never seen any oil dilution or oil contamination in any way in a rotary engine. I have 1,000 miles on the oil in my engine right now and it is still clear and clean looking. Initially I concluded that this was because combustion by-products could not get past the side seals to get to the crankcase.

Then I saw a rotary that pressurized the crankcase when revved, it turned out to have a worn out spring under the inner oil control ring (the ring had been spinning relative to the spring - the spring tab apparently was not installed correctly). This disproved my theory about the combustion by-products leaking past the side seals, as only combustion by-products or pre-combustion compressed air (coming from same chamber) could pressurize the crankcase.

These findings would tend to reinforce that oil dilution is possible, only I haven't seen it. What conditions will cause oil dilution? Does it have to be rich-misfiring?

I never let an engine run rich of 13:1 (in vacuum), as this will wash the oil film off the seals and decrease compression, accelerate wear and waste fuel for no reason. On a piston engine sometimes you have to run rich to protect valvetrain, but the rotary is immune to burned exhaust valves (although not exhaust sleeve failure).

[RICE RACING]

This is VERY COMMON on cars not running oil metering pump but even on cars fitted with them.

I have seen this mostly on Bridge Ported cars, both Weber fed and also fuel injected. The problem is that bad that the sump smell like petrol, and always raises in level.

This happens on well cut side seals too, its mostly to do with the excess overlap period and other factors seen in these engines.

[j9fd3s]

I never let an engine run rich of 13:1 (in vacuum), as this will wash the oil film off the seals and decrease compression, accelerate wear and waste fuel for no reason.

that's why you're not really seeing it! my P port was pretty bad, my first time with a weber+short drives/lots of idling = dark gas smelling oil really quick.

with the carb much much better tuned, and some heat* in the thing, it went a few laps on the track and the oil still looks and smells perfect, still tastes bad though :o13:

*the radiator stopped working between 2002 and 2011, go figure