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Okay folks, update time. I heard from Kevin at Rotary Resurrection. He got my engine pulled and torn down and shared his thoughts with me via email today. I'm including the photos he made available to me. The good news is that my engine is in generally good, rebuildable, condition. As Kevin explained it to me: "The block is composed of 8 major components, 6 appear to be fine to reuse with mild wear, pending further cleaning and inspection." That's the good news. The bad news is in the condition of the remaining 2 components: the rotor housings. Mine aren't in good condition and Kevin rates them as grade D to C minus. They could be reused but doing so would place this in the "budget build" category. This car's condition is quite nice and I'd like the engine build to match sooo...
I gave Kevin the go-ahead to replace the rotor housings with new. Hopefully this will contribute to many years of future zoom zoom!
And here's today's teaching moment with some visual evidence for any doubters out there: CHANGE YOUR OIL!!! Kevin put it quite well when he said: "The main bearings were worn more than usual and not too far from spinning/failing completely, which indicates the oil change history was probably poor. Someone treated it like a "regular car" and ran higher oil change intervals than the engine needed so that needs to be improved going forward. The main bearings get replaced during all renesis builds regardless, so it's no issue."
Anyway, I'll keep this post updated as things move forward.
Now without further ado... PICS!!!
Thanks for the pictures, glad you are investing some more for such a beautiful car. Glad you posted what Kevin said about oil. Long OCI on these cars is not a good idea. I bet it was 5w-20 all its life as well. That weight is OK in a lot of engines, not this one. I am always surprised by how different these engines look when taken apart. Very much like FI engines when the usage, and maint. pattern and the common sense of the operator is paramount, more than mileage or hours alone. Thank you.
As I suspected. Big chunks of carbon built up in the points of the exhaust ports.If I ever build a Renesis I'm going to have those exhaust ports polished.
Yes, this is a common issue with factory irons. They should be polished on a rebuild. That carbon flaking off can theoretically ruin the entire engine but it takes a long time for the carbon to chunk up like that.
Yes, this is a common issue with factory irons. They should be polished on a rebuild. That carbon flaking off can theoretically ruin the entire engine but it takes a long time for the carbon to chunk up like that.
I wonder how much of the carbon is due to the OMP controller malfunction that occurred. In terms of miles, the engine wasn't run very long with oil dumping into the chambers but when it occurred it dumped LOTS!
It happens irregardless. Over time, carbon will trap in that exhaust port no matter what. Sometimes is a problem, sometimes isn't. Engine could have failed long before that carbon chunk breaking off. Its the flaw of this engine that there are many potential failure points. And yes, I've dealt with OMP stuck on full blast before. Driving around like Uncle Buck is no fun lol.
Last edited by CaymanRotary; 09-18-2020 at 11:31 AM.
Looking good! I'm replacing mine with new as well. Irons didn't look bad on first glance and the rotors looked good too. When I tore my 83K mile engine down, most of the tolerances were either right in the middle, or slightly over. What I mean by that is, the step wear was half the max tolerance, the apex seal to rotor gap was half the maximum, etc. Makes me think that these motors aren't necessarily guaranteed to be usable much over 180-200K miles. By that time, most of the tolerances would be out of spec I'd imagine.
More pics. Kevin got the block back together today! I can't say enough good things about his attention to detail and transparency. How many professionals send you progress pics along with a detailed explanation of what they are doing? And I don't just mean mechanics. I'm talking ANY professionals. Truly a stand-up guy!
Great to see that everything cleaned up so well. Those new housings are a thing of beauty and the cleaned up irons and rotors look great too. Looks like the tolerances are good too.
Last edited by EarlyS2; 09-19-2020 at 10:57 PM.
Reason: Typo
It is amazing to me how nice those housings look, and how much wear is evident in a relatively short usage period on the same housings. The irons tend to hold up better.
TeamRX8 has spoken about the chaotic nature of the rotor motion in our smooth-sounding, low-vibration engines.
When you look at new housings vs used, and see all manner of streaks, divots, rub marks, chatter, bouncing, etc. it makes you think of what is actually taking place in there, and how much the lubrication system leaves to be desired. Compare to a fresh piston bore, vs a used one, even on a high output 2 stroke-- (Near 50 HP from 125cc, or almost 400hp per liter).
It looks nothing like our housings do. It's what makes me use what many would consider way too much oil for injection and premix.
I think Kevin at RR does great work. I think his knowledge of these engines is underrated. It takes a lot of experience to rebuild engines successfully for all budgets, as he has done for years, quietly. Many well-known, well advertised builders, with racing experience would likely not be able to do what he has done. I hope to visit his shop one day. Early S2, did he mention how many Renesis engines he has rebuilt to date?
Last edited by kevink0000; 09-20-2020 at 05:09 PM.
It is amazing to me how nice those housings look, and how much wear is evident in a relatively short usage period on the same housings. The irons tend to hold up better.
TeamRX8 has spoken about the chaotic nature of the rotor motion in our smooth-sounding, low-vibration engines.
When you look at new housings vs used, and see all manner of streaks, divots, rub marks, chatter, bouncing, etc. it makes you think of what is actually taking place in there, and how much the lubrication system leaves to be desired. Compare to a fresh piston bore, vs a used one, even on a high output 2 stroke-- (Near 50 HP from 125cc, or almost 400hp per liter).
It looks nothing like our housings do. It's what makes me use what many would consider way too much oil for injection and premix.
I think Kevin at RR does great work. I think his knowledge of these engines is underrated. It takes a lot of experience to rebuild engines successfully for all budgets, as he has done for years, quietly. Many well-known, well advertised builders, with racing experience would likely not be able to do what he has done. I hope to visit his shop one day. Early S2, did he mention how many Renesis engines he has rebuilt to date?
No problem with posting the pictures. I'm glad others can benefit from and /or enjoy them!
I agree that there does seem to be excessive wear, relatively speaking. I wonder, though how this wear truly compares to a true 2-stroke. If an RX needs rebuilt at 80k miles and is driven at an AVERAGE speed of 40 miles per hour, then that works out to 2000 hours of use. I've had a few 2 stroke dirt bikes over the years but have no idea what the expected lifetime of a good 2 stroke motor is, in terms of hours. No doubt that a rotary can benefit from premix. In a perfect world they would have been marketed and maintained as true 2-strokes AND still met emissions requirements.
Kevin is what I would consider a true specialist. I can only imagine how many engines he's done. He didn't say but he did mention that business has been picking up and that he did about 40 last year. He also said he's been doing them for 20 years. I'd say that would make a conservative guess at least 400 or 500 rebuilds.
The engine is done and I've got the car back! It's driving great but keeping it under 4k rpms (for 500 mile break-in) is almost unbearable. Can't say enough good things about Kevin and his work. Glad to get this back together so I can enjoy it for the fall. I think I see a run up the Dragon in my future!
Wow, even cleaned the SSV haha. I bet it’s like a brand new car now.
Cleaned the SSV and replaced the 3 intake solenoids. I furnished him a new thermostat and belts while he was at it. Yes, it's driving like new. I've only got a little over a hundred miles on it. So far it keeps running better and better. Can't wait to hit 500 so I can really try it out!
Cleaned the SSV and replaced the 3 intake solenoids. I furnished him a new thermostat and belts while he was at it. Yes, it's driving like new. I've only got a little over a hundred miles on it. So far it keeps running better and better. Can't wait to hit 500 so I can really try it out!
Yea, the break in is the most important part. You want to give the engine the time to wear the new parts in a bit before going all out on it. Congrats my friend!
Well I've been incredibly busy with other projects but...
The RX has been running really well. No starting issues, cold or hot. Idle is really nice. It just runs like it should. I hit the 500 mile mark over the weekend. This is the milestone at which Kevin recommends that the oil be changed and that the redline can be enjoyed. I changed the oil yesterday and was finally able to open it up. It runs GREAT! Smooth as silk with very linear acceleration. No issues whatsoever.
A shout out to you, Onefast, for supplying the cat. Having the stock pipe is much better that the cobbled up pipe that was on it. I'll leave it to the next owner to upgrade the exhaust if they prefer.
I did have one issue come up while driving last week: the $#%*! window regulator mechanism broke on the driver's side! A quick Google search revealed that this is a common issue due to stripped plastic gears. I've already ordered a replacement gear set and will get that fixed upon arrival of parts.
Other than that all is well. Hopefully I'll get it on the Dragon in the next week or two.
Sounds great! I'm so happy everything worked out minus the snafu with the window regulator, but I feel you on that one. I had my passenger side break and so I ordered the gears for both doors and did them both. Hopefully you can enjoy the car a little bit before you sell it
09-18-2020, 09:18 AM
