tofu_box

Hey

I am sure if you did your research you would have read somewhere on this forum that you should redline your car everyday.

I just had a engine fail compression and was pulled apart and diagnosed from Xtreme Rotary here in Australia

Before i list the findings just listing background of the motor.
Full stock 4port motor with around 78,000 kms on it. Spent 60k NA, 18ish Boosted at 7PSI.
Serviced with Penrite (Penzoil in states?) 5w-40 Semi-Synthetic for 60k of its life, before then MRO.
Oil + Filter Change every 5,000kms, Premixed for 30,000ish KMs using Amsoil Pre-Mix 200ml per tank.
Tracked Twice.
Seafoamed Twice, once at 35,000kms once at 60,000kms.
Flooded 3 times.

I wasn't able to get much photos as Rohan is a busy man and i did not want to waste too much time snapping shots here and there.

Main Cause of engine failure,
Housing Wear chrome gone
Apex Seals slightly warped (he stated it doesnt appear to be due to det but rather wear and tear), Rotor coated in carbon but acceptable, however the groves were flared out due to movement in apex seals. Rotor not reuseable with factory 2mm seals however possible with larger 3mm seals.
Exhaust port were clean of carbon
Bearings all in good shape
Plates all reusable, need to be resurfaced

There you have it, i made sure to redline once a day.
It appears* that it does indeed help with the carbon buildup in exhaust ports which is 1 of the top reasons they see engine failures here in Australia.

However on the other hand you have the excessive housing/apex seal wear.

So i guess its up to you to find that balance between getting rid of the carbon and reducing wear and tear on your housing, maybe higher levels of premixing?

I have attached a crappy camera photo i took of my exhaust ports

RIWWP

iTrader: (2)

While I applaud the tear-down, diagnosis, and information sharing, I would caution against using your engine to so definitively make a theory call one way or another. Don't get me wrong, I agree with some of the conclusions, but a boosted engine doesn't exist in the same environment as an NA engine.

For example, the wear and tear on the housing. How much of that is from the 60,000 km N/A and how much is from the 18,000 km boosted? We can't really answer that off of your engine. A boosted engine has much higher air/exhaust flow, and it would make sense that the engine can expel 'floating' carbon much easier out of the side ports with the increased air flow. The increased VE may have something to do with it as well.

bse50

^^^ This. Besides, how was the engine tuned when boosted? You stated some useless psi figures but how much was it flowing? How long did it take you to get a new flash before the unacceptable OE one that killed so many early engines?

Your situation should just be treated as an individual one, not as a theory or to form any general conclusions.

Engines that are really driven hard with the stock oil system see bearing wear and some other stuff.

tofu_box

Im just sharing what happened to my motor and what i saw when i pulled engine apart, not trying to say this applies to everyone's car. As you noticed i put the * next to appears

I didnt want to get into the nitty gritty, but it was flowing 340ish g/s of air on a centrifugal setup. Boost was at about 3psi at 4,000 rpm, which the car doesn't see on normal driving

This engine never saw the old flash, as it was changed with a new one shipped in from Japan before warranty expired

Just as a side note already had hard to start issues before boosting, and preboost i had the comp figures and it was in the mid 80s, now they are in the 70s at 250rpm

The engine was tuned via MAF based tuning and saw no higher AFR then 11.4.

Stock oil system, you mean in reference to low oil pressure? I was actually recommended not to go for a higher oil pressure by my builder.

RIWWP

iTrader: (2)

Just keeping it within the context of what it is.

If we were allowed to use just 1 engine as a sample set for theory conclusions, I'd say that Corolla engines are complete garbage and will blow every 60,000 miles (mine did), but rotary's last longer (mine is still going at 94,000 miles.)

This is obviously not exactly accurate



Always love seeing tear-down diagnosis.

tofu_box

Well you gotta start with a few tear downs, then side by side comparisons, so if anyone wants to further input what they saw when they pulled their engine apart it will only help

olddragger

iTrader: (3)

i think this was good info shared. Rarely do we see the results of a boosted 4 port engine teardown that hasnt been blown.
It is interesting that the housing chrome was gone, that the rotor groves were wallowed out and the seals where warped in less than 100K miles. It is also interesting that all your bearings where ok.
maybe yall have better gas than we do in the southern USA so that could be one reason for such a clean exhaust port? IDK for sure. The port also doesnt look overheated?
With the wear you had and in the locations you stated -- if this happened to me--i would use ceramic apex seals or at the very least the taller FD apex seals-- the next time.
Interesting--thanks for sharing.

olddragger

iTrader: (3)

You mean its not unusual that that the rotors last less than 100K miles? That is what made me say what I did--when the op was told that his rotors were not reusable with the oem apex seals? Wow didnt know that.

tofu_box

Hey Charles

I will try to get some more pictures bit later on in time, the problem is that it is just after the Christmas/Jan holiday season and everyone is flat out with work that accumulated during that break period. The parts i believe have been put into storage.

The side seals were ok, there was slight carbon build up that gotten in under the side seals causing the springs to be slight stuck but it was still ok and not the reason for failure. Clearance is like normal OEM always out by a fair bit.

In regards with the bearings i was shown bearings and the oil pump from a rx8 that was not well maintained also with MRO, as you may have guessed heavy wear on the bearing, also of interest is the oil pump, the badly maintained rx8's oil pump was heavily stained and the color became a dull dull bronze, whilst mine stayed relatively quite clean.

I had a new motor that was rebuild OD before i pulled this one out. It has Xtreme Rotary Ceramic Seals and are 3mm, the rotors were made to fit the seals, they also feature Mazda Racing Side Seals which had to be cut to fit the renesis, also ceramic bearings

olddragger

iTrader: (3)

now that sounds like a sweet engine. what happened to it?
Interesting that yall saw that on the oil pump/oil pump area. I have seen a good deal of varnish like discoloration in that area too In the limited amount of engines I have seen taken apart ( Not mine!) I have seen a couple that have that. It was thought at the time that whatever oil that was being used was allowed to get too hot? IDK for sure.
Keep us informed.
thanks

09Factor

Yo OD,
Not everything in the AT dept is about "How do I whatever to make my AT like a MT ?" unlike others around here think that, not saying you are one of those. There are a few jewels of well though out, properly planned preformance builds. Jase's build is one of the few and a good read as well !


https://www.rx8club.com/series-i-specific-performance-mods-97/jases-hybrid-4-port-auto-6-port-parts-224822/

wish mine was that good.

tofu_box

Thanks 09!

Grass is always greener on the other side, wish my FI build was as good as yours!

olddragger

iTrader: (3)

enjoyed that link. Rotor on big boys
Always learn something from you fellows.

Nadrealista

what was your oil consumption like? Perhaps the OMP was not working properly(clogged nozzles) causing high housing wear?

PeteInLongBeach

That was my first thought, and one of the first things I would examine closely...

rotarygod

My thought from the first post is that there is inadequate lubrication to the center of the apex seals causing them to warp a little bit and unevenly wear the housings. This is a known problem on all S1 Renesis engines that may or may not lead to issues later.

olddragger

iTrader: (3)

he was premixing 200cc/tank + the omp. Thats about 6-7 ozs per tank? Shouldnt that be enough?

PeteInLongBeach

Right... but taking the chromed surface with it to this degree? Seems premature...

PeteInLongBeach

For long-term, I doubt that's enough premix if the OMP was non-operational...

tofu_box

omp was fully functional, cant remeber exact oil consumption but was inline for around half a litre every 600-700kms.

Nozzles were not clogged when removed to change to new engine (cleaned anyways)

I have installed new sohn adapter with a suzuki 2 stroke oil canister very visible 1 liter on new engine to keep monitoring, will be using protuner to up OMP.

Interesting thing i was told about ceramics by my engine builder, ceramics requires less lubrication then your factory apex seals, however at the same time if no lubrication at all they will destroy the housing instantly.

Nadrealista

very interesting. so omp was working properly and you did premix to boot..oil was getting there but it didn't do its job leading me to next conclusion that this particular oil you used is not best for your application.
have you done any oil analysis?

I would suggest going with good full synthetic oil and start doing oil analysis. redline oil would be my preference or M1 0w-40 if redline is crazy expensive down-under.

olddragger

iTrader: (3)

No doubt ceramics will be easier on the housings, and they will not bow. That is interesting about the lubrication! Guess if you go ceramic then you best pre mix too.
I wish we had more info on the SII model omp and how effective it is. I dont personnally know of any real engine teardowns on the S II model?
The area around the spark plug is a known area of concern. I have seen multiple housings with the death cracks around both plugs. One builder I know opens up the water jacket area around the plugs for better coolant flow and so far he has had very good results. I am not sure of the details involved in doing that.
This sure is interesting.

rotarygod

If it was premixed then the apex seals were probably lubricated just fine. The question then is what caused this? I'm not drawing conclusions but rather throwing out ideas. It still sounds like a heat issue but why? If the car isn't overheating and the apex seals are lubricated, what else could be causing it? This is assuming it is even a heat related issue. Does the shorter height of the apex seals on the Renesis compared to older rotaries play a role? My guess would be no since the older engines with their 3 piece seals had individual pieces that were equally as short. They were just stacked. Is there a flaw with the chrome plating process on these engines? I'd again think no since they've been doing this a very long time. The chrome issues have historically been linked to apex seal issues and not the other way around. I'm going to have to think about this one for a bit.

09Factor

Hey Fred, how about a out of balance rotating assembly?

bse50

Perhaps more stress on the shaft thanks to the supercharger?