Zero clearance side seals round 2. (If you don't mind Barry)

[Barry Bordes]

Originally Posted by RETed

Nah, I like the truth actually...

My conclusions are with discussions with someone with a Masters degree in Mechanical Engineering.

We blew up a 13B-REW with no turbo (long story) that only managed to put down 130 - 160hp at the wheels on a DynoJet.
The engine was running milled 3mm rotors with 3mm apex seals.
HOW DO YOU BLOW UP SOMETHING LIKE THAT?

The apex seals did not have chipped corners like most of your failed apex seals.
(You did tear down enough engines to observe this, right?)
The apex seals were cracked straight down the center - height-wise, of course.
I have never seen apex seal failure like this except for this one particular incident.
The mechanical engineer stated that this failure was a consistent with a harmonic oscillation failure of that type of material.

Why am I talking about apex seals when you're taking about side seals and corners seals?
You're smart enough to make that connection, right?

Oh, and just to back that up...
It's been documented by Mazda in a Mazda technical review used as reference for an SAE paper.
You're smart enough to go look that up too, right?

So, you posted a pic of just about 3 engine's worth of corner seals...
How about the other thousand you've come across in your experience?
Are you going to state that all the other thousands of corner seals look exactly like the ones in your pic?


-Ted

Ted... my guess would have been that there was an interference fit in the freshly milled 3mm slots causing the seal bind when heated.
That combined with the infamous peaks caused by the hot spark plug area caused the seal to break in the center.

Maybe we could add a #5... when installing all seals make sure that there is absolutely no interference and that the seals spring freely (per the manual).

By the way Ted if you have a reference please post it! It will only help the forum.

I also noticed that you have not provided any pictures of double worn corner seals. I actually have some but they are ones that I reversed from the last rebuild.

To be fair to your thought process... I might theorize that possibly on very hard decel... like at an autox that the seals might be slung forward... but I have not seem any evidence of it.

Barry