Goopy apex seals effect on housings
 

Like to get feedback from those who have had experience with Goopy apex seals.

I just ordered a scope to get a good video recording of my rotor housings' surface. I will link to the video once it’s done. I took a video w/my smartphone of what I could get thru the port and don’t like what I saw. Imaging having carbide nails and running your nails down the rhousing's surface. I ran my finger across the surface near the port and felt the traces.

The engine ('87 TII) was rebuilt ~7K miles ago. The housings were resurfaced. Along w/the OMP, I’ve religiously added 2 stroke oil since rebuild at a ratio of 1 oz per gal. The engine is set up for 300 whp. Broke it in tenderly for the 1st 1K miles. No boost during break in.

Here are the videos taken w/the endoscope. about 4 minutes for the front, 3 minutes for the rear.
Was challenging hunched over the fender getting the scope to do what I wanted it to do so need to be patient as you watch the videos.

is that extreme chatter present? you'll see the apex seal towards the end of the front's video. i'm surprised they still have a crown on them considering how the housing's surface look/feel. not sure I have much life if any left on the housing.

The housings had 86K miles on them and the surface was smoth prior to resurfacing as suggested by Goopy. OEM 3mm had ridden on them. The resurfacing gave them a satin like finish.

front:
https://www.youtube.com/watch?v=g5j9...ature=youtu.be

rear:
https://www.youtube.com/watch?v=6FlW...ature=youtu.be

do you premix?

:

some line wear is pretty typical for the soft seals but the chatter isn't something i often come across even with the indestructable bendy seals.

seems to be little ryhme or reason as to what causes the chatter to develop but once it does start it just continues to worsen.


honestly im not sure what causes some engines to wear like that, i have had others run for long periods of time at higher power levels that came out looking perfect at 9 times that mileage.

i have thought about it overnight and the only conclusion i can consider is that perhaps the softer seals need even more lubrication to prevent the material differences from binding and transferring. the main issue is heat, which causes the seals to basically heat to the point of nearly breaking down when EGTs peak, causing the seals to soften enough to begin to attempt to bond to the chrome, basically trying to weld themself to the housings.

this isn't something that is directly related to Goopy seals, i have seen it happen to every seal on the market. even the second hardest seals which are Atkins(a variant of cast iron treated alloy) did my last engine in at about 80k miles.

i may have to do a little testing with my engine and up the premix to 2oz per gallon and see if it cures this issue, as it has 1k miles on it now and due to be tuned as soon as i rebuild the turbo and fix the fan motor.

another relatively easy thing to do is to cool the EGTs by tuning with conservative methods, most of the time i see this happen it is due to running leaner AFRs at higher boost levels(generally over 11.5:1).

I'll throw in my opinion.

I have tuned some cars, seen rebuilds (4 of them) and have taken mental notes and used some common sense. I am a manufacturing engineer for aerospace.

When I tuned cars with aftermarket seals the engines always have higher knock. I am guessing some of this knock is exactly what you are seeing on those housing walls. When I use the same timing and everything, AFR table is the same, etc the stock seals are always super low knock. This is with respect to unopened engines and also rebuild 2mm 2piece OEM seals. They always have low knock. the noiser engines always have aftermarket seals.

If you get down and really think about how much R&D mazda spent, teams of engineers and PHD types in materials science and the knowledge of designing rotaries for many many years, they know that the seals must be of a certain hardness and the interface between the seal dn housing is of the utmost importance to engine function, reliability, etc. There is a reason that the OEM seals are of a certain hardness and have certain manufacturing processes to make them what they are. These aftermarket companies have probably a couple of guys who say they can make it, and dimensionally they do make them to fit, but functionally they aren't even in the same category as stock and never will be. They simply don't have 40-50 years of R&D know how with super expensive equipment analyzing everything to death to eek out a little more reliability. I understand that everything has design parameters and the engine in stock form has lower power due to many things. Most people buy aftermarket seals to put a band aid against a detonation event which is a root cause of something else failing. Now if these aftermarket seals don't get much life out of the engine, and destroy housings like they have shown to do, the cost benefit vrs. risk still favors buying the oem stock 2 piece or 1 piece seal. I have no idea why people continue to buy aftermarket seals with all the evidence supporting otherwise. We just ripped apart an engine this weekend and rebuilt it. it had stock seals in the engine and the housings and rotors looked new. The person who rebuilt it said every engine of the 40-50 engines he has rebuilt that he has seen with aftermarket seals have waddled out the apex seal grooves on the rotors. Stock seals for the most part have all looked good. He also says the housings all looked trashed with aftermarket seals, OEM seals for the most part look good.

I have seen this with the engines (4) I have seen taken apart. aftermarket is trash, OEM look good. perhaps we are misrepresenting as most aftermarket seals are subject to rebuild tolerances and most oem's have come from OEM assembled motors, but not all have. I just have ZERO faith in all these engines with aftermarket seals, including mine which has RA super seals. When I rebuild my engine it is getting stock 2 piece oem mazda seals, and probably new housings that won't be ported. I also run AI in mine and premix 1oz/gal with a working OMP running 2 cycle engine oil.


I am willing to bet when he rebuilds that engine those apex seals will have destroyed both the rotors and housings.

if your knock testing has been with the OEM knock sensors then they are very unreliable, the gel that seals them and acts as a buffer can either harden or melt away and cause erroneously high or low readings.


plenty of engine builders use aftermarket seals, thousands are built each year with them. a percentage of those engines simply do not last due to excessive wear caused by unknown reasons. the real question is: what is the root cause, not whether they are complete garbage or not. if they were then why would so many continue to use them year after year? companies like RA, Atkins and Goopy would have folded after a few short years if it was common for a set of seals to only last 10k miles. yes, it happens, but not in every case as you have alluded it to be.

generally where i have seen these failures is only after the seals have been pushed to the limits of their tune. so what is the correlation? i tried to address it above before you went on your side trip.

I knew I was going to be a test bed when I decided to go ahead w/non OEM seals. During assembly, noticed one of the seals had a minor imperfection that I was able to file away. I was stunned of the softness. I don't show the apex seal of the rear rotor on these videos but the intitial video I did w/my smart phone show them what seem to have minute pieces of chrome on them. The seal also doesn't have the smooth feel to them you'd see on the OEM seal.

The thought that came to me during the rebuild noticing how soft the seals are was: "maybe the trick is to have a non-OEM side piece matched to the main OEM piece to at least have its durability/reliability along w/the non destructive nature of the OEM corner piece has on housing's edge".

Prior to the rebuild, the OEM 3mm seals had about 30k on them. During them 30k miles they've had their fair share of some serious detonation. On one occasion boost spiked to 18lbs near redline due to the vacuum line popping off. All the seals (main and side) were intact when I took the engine apart but a few of the corner pieces had self destructed.

it is very possible excessive heat has been the caus. engine has gotten quite hot on a couple of occasions while getting on it driving up Malibu canyons but not to the point were coolant was spewing out of the radiator. When the temps got a little extreme for my taste, I'd let the engine cool off. I also haven't installed my UEGO wideband gauge so I don't know if the engine has run lean during peak load. But I did monitor duty cycle during the 1st 2K+ miles and never saw it above .90 at boost levels I've never exceeded.

Bingo!

When the rotary engine was being designed in its early stages....those pictures/videos reflect the SAME EXACT pics other engineers were having when they were trying to perfect the Wankel engine. Its a matter of resonance frequency. People buy aftermarket seals and yet blow money on non essentials and expect the motor to last. No amount of premix will help you. JUST buy OEM Apex Seals.

The exception are race cars...but those motors last how long? exactly!

Funny, how i've pulled apart some nasty engines and engines with dirty (dark as night) oil and the housings don't have chatter marks or wear as some of the motors with aftermarket seals. Engines with 100,000+ miles :nod:

Im not knock aftermarket sellers. But I wonder if the sellers run the same seals in their daily drivers?:scratch:

For those that hold out hope that more lubrication will stop the galling from incompatible materials in aftermarket seals.

Unfortunately not in my experience.

I used RA Classic and Super Seals and kept the factory OMP and premixed 50:1 (one quart of premix per fill up).

The engines definitely took a long time to break in this way when driving gently. I have no doubt an engine used to commute would last many many miles this way.

Once I started racing on the engines they seemed to "wear out" (wear abnormally) just as quickly as before with just the OMP being used.

Once you introduce the high combustion pressures of making peak power behind the seals pressing them into the housing surface, no amount of lubrication you can add overcomes the incompatibility of materials that causes galling.