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Hi everyone!
I am trying to do a failure analysis of my seized 13B NA engine. I am down to just the keg, and after removing the tension bolts, I cannot get the rear iron to come off. Am I missing something?
Should I remove the stationary gear first?
I do have a slight gap at the top of the iron, but the bottom edge is tight even after hammering on it!
you did use the word "seized" so ... who knows what's going on in there? maybe you should try to take the gear out first. maybe tap it back to flat and try to start with the bottom.
if that doesn't work, put two tension bolts back in and flip over, then start from the front.
I tried removing the rear stationary gear but no luck. Flipped it over and removed the bolts holding the front stationary gear in place, a few taps with the ball peen hammer and it was free!
The two pictures that follow are what awaited me upon removal! First thing I noticed was a gray sludge buildup where the paper towel is? Then there is the black sludge buildup at one of the apex seals? Finally, there is a lot of moisture present in the lower two open areas but not in the top intake area?
What the hell happened? Also, all three of the corner seals are turned in their bores so their slots do not line up with the apex seals? This is my first failure analysis, this is a Atkins rebuilt with about 70k miles on it when it seized up on me. I just want to understand what happened so that I won't make the same mistake twice.
I bought the car off the showroom floor and it has been my daily driver when it isn't up on jacks. So it is my hobby car, and anything you can help me with understanding how things work with this technology will be appreciated!
Front Rotor
Front rotor deposits
What do you think of my nice green handle on the hammer!
Upon removal of the rotor it looks like the black sludge is carbon that fell off the face of the rotor as it sat in storge for the last five years!
The next picture is of the face on the other side, not a pretty sight! Why is it wet and rusted, I looked over the front iron and only noticed an area about an inch long where the water seal groove has a bit of a round over?
Now we get to meat of the matter, two of the side seals were stuck in their grooves and snapped in half when I tried to remove them. Two of the apex seals were also slightly stuck in their grooves also, I am thinking from long term sitting in a seized engine. Again, all the soft seals are turned in their bores, what causes that to happen?
Now for the mystery, one of the corner pieces of the apex seals has gone missing! I carefully searched through all the debris and found no trace of it!
I will remove the front rotor housing and post some pictures of it, it does not appear to have been damaged. I still can not turn the e-shaft, so the big failure is on the far side of the middle iron.
What caused all the carbon buildup? I am deleting the OMP and EGR on the replacement engine, less carbon in the intake sounds right!
This Atkins rebuilt engine has 3mm apex seals and a street port modification!
carbon is a relatively normal find. the amount is what varies and i'm not informed enough to give all the reasons why. my guess is efficiency and how often the engine actually runs hard enough to achieve good efficiency are probably among them though (puttering around town for relatively short periods vs. running on the highway for a while).
also, i'm very interested in you measuring those apex seals and posting your results. i don't know if it's the angle of the photo, but they look like they're worn down on one side. curious ....
assuming it didn't pop a water seal, if the engine was sitting without something covering the openings (intake, exhaust, plug holes) and it was in a place where humidity varied with the atmosphere, then moisture could easily get in and rust anything in the chamber exposed to it.
Thanks for your input, I had a closer look at the housing and it has alot of grooves going around the surface.
The apex seals are very rough on the contact surfaces. I also noticed that they appear to be worn at an angle! It seems they were designed that way. There is a foot area where the triangle piece fits that is missing from the other side, I will post some pictures of them later. Something also going on with the springs, why the funny shape and only one per seal?
Here is a picture of the leading plug from this housing.
Note the deposits that were not on the other three plugs. This deposit is also present going across the housing at the plug opening! What would cause this? I will post pictures as soon as I remove the housing.
Now for the history, after installing the Atkins rebuild, I had to add coolant fairly regularly to the overflow catch tank, just about an ounce per week. It kept pulling the coolant inside the system. It did not seem to affect the engine's performance, just added it to my weekly maintenance. Could this be where all the moisture is from, the engine was sealed from the elements with all parts in place while in storage.
There is a foot area where the triangle piece fits that is missing from the other side, I will post some pictures of them later. Something also going on with the springs, why the funny shape and only one per seal?
yeah, i noticed the little support area for the spring missing, but i have no clue as to how or why. likewise, i have no idea as to why the springs would come out twisted like some of them looked. all in all, your engine has/had some pretty weird flaws.
i've never had to convert a rotor to 3 mm, but i know 3 mm engines from the factory were all single spring. so my guess is aftermarket (Atkins) followed suit with that design.
Here is the picture of the tops of the apex seals.
Here I found one of the actuator sleeves with a loose pin!
This picture tries to show the wear on the front edge.
That is an awful large amount of metal wear for a part that barely moves, wonder what caused it?
I measured the apex seal height at both ends and they differ by .038". The "foot" at the beveled end tapers .007" along its .653" length. It has to be designed this way along with the funny shaped single spring used with it. It works!
After loosening up everything with some vodka and attacking it with my green hammer it finally came apart.
Here is what awaited me:
And here is what happened to the rotor:
It actually smeared the metal of the rotor like butter!
I have yet to examine the e-shaft for damage.
So, the bearing spun, and the stationary gear got hung up and shattered. Which happened first? And more important, what caused the failure?
I'm leaning towards a bearing failure first, Atkins warranty states they will not cover bearing failure! Wonder why?
So, bottom line, would you reuse these irons and e-shaft (if it checks out ok). What do I do with the front rotor that is milled for 3mm apex seals?
I am assembling my replacement engine now. I made the decision to delete the egr, omp, and the air control valve to cut down on the carbon build up. I will start my premix at 2 oz. per gallon of gas. What should I be aware of doing these changes?
Any advise will be appreciated very much! I have just enough knowledge to be dangerous! Rotory engines are the shizz bot!
all i have to say is ... WOW! i'm not sure i've ever seen a stationary gear break in a non-turbo application before. i can't remember one, so this might be a first for me. i also didn't know a corner seal could deform like that. i've only seen them break. i guess those lines (at around 10 o'clock) could be fracture lines though.
what did the oil pump and pick-up tube look like?
if the side housings are not damaged, then i think it would be okay to use them. looking at that bearing though, i'm not sure i see the shaft meeting spec, but even if it does, i'd probably opt not to reuse it. pull the jets out before you toss it though. i'm curious to see if it reveals anything. i'd probably retire that front rotor as well. get a pair of OEM-spec (2 mm) rotors and a shaft.
So, the bearing spun, and the stationary gear got hung up and shattered. Which happened first? And more important, what caused the failure?
Bearing spun which makes the rotor not spin right so the rotor gear doesn't mesh with the stationary gear correctly then brakes their teeth.
I had a rear rotor bearing spin, happened suddenly while cruising on the highway. It made the engine sound like it had rod knock.
I was able to drive it back home and a little more to try to diagnose it then parked shortly after so it didn't get as badly damaged as yours.
I'm leaning towards a bearing failure first, Atkins warranty states they will not cover bearing failure! Wonder why?
They probably don't replace them unless a lot of copper is showing.
i would reuse the irons, if they are in spec. make sure they get cleaned again, especially the oil passages in the rear iron.
the eshaft is junk, no matter what. even if the journal is ok, it'll be full of metal shavings and bearing debris
i would try and find a matching set of 2mm rotors. those 3mm seals were totally shot, and they ruined the rotor housings too
you are overly worried about the carbon, but like piston engines have carbon like that too, its part of using a hydroCARBON as a fuel...
Here is the front e-shaft bolt and what Atkins replaced the relief valve with! Also, never found the crush washer that is supposed to be with the bolt! I do have the spring.
What is the purpose of the relief valve and why replace it with a plug.
I will be micing the e-shaft on my v blocks to check the run out and will post a picture of the journals,
Here is the front e-shaft bolt and what Atkins replaced the relief valve with! Also, never found the crush washer that is supposed to be with the bolt! I do have the spring.
What is the purpose of the relief valve and why replace it with a plug.
I will be micing the e-shaft on my v blocks to check the run out and will post a picture of the journals,
i would reuse the irons, if they are in spec. make sure they get cleaned again, especially the oil passages in the rear iron.
the eshaft is junk, no matter what. even if the journal is ok, it'll be full of metal shavings and bearing debris
i would try and find a matching set of 2mm rotors. those 3mm seals were totally shot, and they ruined the rotor housings too
you are overly worried about the carbon, but like piston engines have carbon like that too, its part of using a hydroCARBON as a fuel...
I just thought of a way to remove ALL the debris from the oil passages! $29 universal rifle cleaning kit!
The assortment of bore brush sizes and the long cleaning rods would get all the way to the back of the main oil passage. And the rifle bore solvent is no joke!
The jet passages would be easy to clean up with Q-tips, if it would save the shaft for reuse it would be worth it.
What do you think?
I saw a web page years ago that distilled water was introduced into a hot running engine through the small vacuum port beneath the BAC valve. I don't recall how much water was used but the idea was to have the water flash to steam and clean the carbon from the rotors!
How often, I don't know. I have a scope that I can put through the spark plug hole and do a before and after thing with it.
I'll put 10K on the engine running just pre-mix and see how it goes.
Yeah, I am overly concerned about carbon build up, the original engine threw an apex seal, I always thought it was clogged OMP lines. Now this second engine spun a rotor bearing, I kept the oil level topped up at all times, and changed the oil once a year. Now I will change the oil and filter twice a year.
Thank you all for your input, I have learned much from your posts.
I'm off to install the oil relief plug into my new engine, one less thing to be concerned about.
My goal is to be able to throw a suitcase into the back and drive to California without any worries that the car will break down on the way!
I just thought of a way to remove ALL the debris from the oil passages! $29 universal rifle cleaning kit!
The assortment of bore brush sizes and the long cleaning rods would get all the way to the back of the main oil passage. And the rifle bore solvent is no joke!
The jet passages would be easy to clean up with Q-tips, if it would save the shaft for reuse it would be worth it.
What do you think?
I saw a web page years ago that distilled water was introduced into a hot running engine through the small vacuum port beneath the BAC valve. I don't recall how much water was used but the idea was to have the water flash to steam and clean the carbon from the rotors!
How often, I don't know. I have a scope that I can put through the spark plug hole and do a before and after thing with it.
I'll put 10K on the engine running just pre-mix and see how it goes.
Yeah, I am overly concerned about carbon build up, the original engine threw an apex seal, I always thought it was clogged OMP lines. Now this second engine spun a rotor bearing, I kept the oil level topped up at all times, and changed the oil once a year. Now I will change the oil and filter twice a year.
Thank you all for your input, I have learned much from your posts.
I'm off to install the oil relief plug into my new engine, one less thing to be concerned about.
My goal is to be able to throw a suitcase into the back and drive to California without any worries that the car will break down on the way!
Don't forget to clean the oil cooler too. There are companies out there that ultrasonically clean oil coolers. That's recommended standard procedure when replacing piston aircraft engines.
09-23-23, 05:26 PM
Coolent in the rotor housing
