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

I genuinely though Ted forgot the italics in his comment here until I saw it was actually closed. Not sure why you wouldn't want documentation of long term runner that someone has tested in one place? :dunno: (I will say mods/admin on other forums encourage keeping tech stuff in one place)

So, seems this is a goer.
http://i287.photobucket.com/albums/l...ps199cc73e.jpg


I would like to do this when I eventually get around to building one or other of my engines, the 12a will have to come apart for clearance/lighten/balance anyway as there was still vibes with what was sold to me as the correct series auto counterweight (will do the measuring check etc again but I want to port it anyway, will send to spinny bits to Freaky or Wilkins to machine) with after-market flywheel and there was an issue with leaking intake crossover o-rings/gasket filling housing with coolant too so I'm guessing it could be a bit messy inside.

If you don't mind me asking Barry do you cut them with a fine diamond disk with a dremel style thing or is it more like a milling bit. I guess I'm curious as to whether there is a tight or open radius under the side seal and how hard it would be for me to replicate it, given sending you seals/rotor from Aus would be cost prohibitive and I'd like to try it myself anyway. Is there enough length in generic side seals to do this effectively?

why do you knotch only one side of the corner seal.. why not both, or are the side seals not long enough?

i agree, lets keep it in one thread

Slides,
The Dremel diamond disk blade #545 is made to cut on a 7.344" arc.
The frame is angle iron.

Notice the stop screw for depth and the adjustment for width. On the width adjustment 90º =.008" with a 10-32 screw thread.

The apex seal shown, is stuck in the fixture to rock the corner seal to its full travel.

Use water to extend the life of the cutter. The seal holder is made from one corner of an old rotor and tapped/screwed to the angle.

If you were closer geographically it might be worth sending them to me and I would cut them for you for free.

On second thought it would be better for you to make the tool and provide the service for others over there.

I can send you more pictures if needed.

Barry

http://i287.photobucket.com/albums/l...erseal_IMG.jpg

88Turboii, it is redundant work cutting both sides of the corner seal, you only need to cut the one at the leading edge of the side seal as the rotation of the rotor against the side plate will maintain the gap tight at the trailing end, thus you only need the "labyrinth" at the leading end of the side seal to allow seal expansion without gas bypass.

Thanks for the detailed reply Barry. Perhaps just one photo from 180 degrees of the existing one so I can see how much of the rotor you have used and the way it approaches the seal.

I think I will try to put a jig together, as it happens I already have a diamond bit which looks pretty close (although I would make sure I had several of correct thickness before starting) and dremel style tool although I might not be pulling the motor for a while, I suspect I may have to make a career change to get cash flow happening (I'm hoping I don't have to sell one of the 7s in the mean time). I would certainly make any jig or tool I put together available to other rotary community members here, I have happily volunteered my time to help forums members (rotary and otherwise) with various bits and pieces before. I have learned a bit about air cooled porsche motors in the last few weeks, getting intake and head studs out isn't always fun, and they can run without head gaskets :smilielol5:

The problem is tolerance shift. Mazda manufacturing tolerances are very good but are still off a small amount. Each side seal and corner seal is slightly different and thus must be fitted carefully to eliminate any binding.

My thought is that using one cut is half the fitting and half the possibility of binding an apex seal. I have the side seal push on the uncut flat side and the normally gapped open side is in the labyrinth cut.

An additional feature is that on final assembly build.... the apex seal to corner seal alignment is perfect... just slide them in.

That said... if you want to do both, do both.

Barry

Wow Slides.

It is uncanny how close our thought processes are.... You just type faster!

Barry

Slides
I PM'ed a better picture of the tool's rotor fixture set-up.
Sorry for the delay.
Barry

There is some real dumb and wrong assumptions state above ^

The side seal is NOT constantly forced to one side!@ IF it were it would never wear a path into BOTH corner plugs as it does in reality!

A true ZERO BLOW BY design like I have made needs to be recessed into both corner plugs and not some ghetto cut off wheel doing a straight edge cut leaving a sharp edge too! that will not only seal like total crap but cause a very large stress raiser in the corner plugs = very poor idea.

If you look at the rotor path you will see the side seal rocks back and forth in the side seal groove on each minor dimension of the rotor housing points, thus it slams from one side to the other in the side seal groove! it needs to be recessed into BOTH, so not only is the clearance NOT zero as in the un thought out claims by others who have butchered this mod, but its also not the correct way to do this either as shown above.

Here is how its done right! below. This to work properly needs a bespoke material side seal and corner seal, as the stock parts are failure prone as is.
There is clearance to all parts! and needs to be done by not an engine builder wannabe but by toolmaker/fitter/turner who have precision parts fitting qualifications and experience, NOT GOOGLED!@

ZERO BLOW BY RICE RACING

:lurk5:

Very Pretty! ! :lurk5:

p
[QUOTE=RICE RACING;320079]There is some real dumb and wrong assumptions state above ^

The side seal is NOT constantly forced to one side!@ IF it were it would never wear a path into BOTH corner plugs as it does in reality!


Peter you are incorrect. Anyone who has disassembled a rotary has seen that you have blow-by on only one side of the corner seal. If you see wear on both sides you have set the side seal too tight and the corner seal may fail... (along with pinching the apex seals and adding high wear to the side plates)
You had problems in that area before with NRS corner seals... maybe that was the problem.

The rotor can only go one direction... and parts of it may sweep faster or slower, but all portions are always going forward... rethink your position.


http://i287.photobucket.com/albums/l...5-2540_IMG.jpg

A true ZERO BLOW BY design like I have made needs to be recessed into both corner plugs and not some ghetto cut off wheel doing a straight edge cut leaving a sharp edge too! that will not only seal like total crap but cause a very large stress raiser in the corner plugs = very poor idea.

If you look at the rotor path you will see the side seal rocks back and forth in the side seal groove on each minor dimension of the rotor housing points, thus it slams from one side to the other in the side seal groove! it needs to be recessed into BOTH, so not only is the clearance NOT zero as in the un thought out claims by others who have butchered this mod, but its also not the correct way to do this either as shown above.

Here is how its done right! below. This to work properly needs a bespoke material side seal and corner seal, as the stock parts are failure prone as is.
There is clearance to all parts! and needs to be done by not an engine builder wannabe but by toolmaker/fitter/turner who have precision parts fitting qualifications and experience, NOT GOOGLED!@
QUOTE]

Easy Cheeby..... technical discussions are aight

In a PERFECT environment, this is true...

You might find it surprising, and most of us live in reality...

Under less than ideal conditions, seals can resonate back and forth.
I.E. under pre-ignition and / or detonation

If you can guarantee that your engine will never see such conditions, then you would be right.


-Ted

Boost vac boost vac boost vac boost vac..... see where I'm going with that?

Can you explain even further... :D


-Ted

:rofl:

Ted, I am a little surprised that you, as a moderator, would become an advocate for someone over the truth.

I was under the impression that you had disassembled many engines.....
Certainly you should have observed what is depicted below.

On the left side you see the wear from driven side seals... on the right observe that there is a ghost of wear ..... no wear whatsoever.

Barry

http://i287.photobucket.com/albums/l...psbvhj0p2s.jpg

Barry, what do you mean by #3?

Make sure its not too lean/rich under boost? all parts of the map?

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

Too complex...

1) Strap car on dyno
2) Adjust fuel maps
3) Adjust ignition timing maps
4) Go back to #2 and #3 until you're satified

This is how I tune my cars for highest horsepower, even NA...

Oh, here's a secret: this works for piston engines too...


-Ted

Barry, could you elaborate on #4

Aiming for a certain peak chamber pressure vs a given crank angle is fine in theory as most people don't have access to in-cylinder pressure monitoring so its kind of a moot point. In practice, OEM level calibration involves monitoring the crank angle at which 50% of the combustion charge has been consumed. The optimal point for CA50 has a 2-3 degree range for any engine, whereas peak cylinder pressure can be deemed "optimal" for a range more than twice that.

knonfs,
This is what the Excel program looks like.
send me a PM and with your email and I can send you a copy.
Most people don't understand the importance of an ideal mixture and it's to improvement to the burn rate.

http://i287.photobucket.com/albums/l...pboard02-1.jpg


Then on the second folder you take your corrected base map and check it any anomalies.
Barry


http://i287.photobucket.com/albums/l...elmapchart.jpg

Brian,
This screenshot is a little hard to make out but it shows that the closer to 45 degrees (in the 5000 to 8000 rpm range) the more peak pressure is made.
Notice that each ignition event is different and that the best pressure point can be determined comparing pressure to degrees for peak.

Location is the on the bottom chart and in this example we would add degrees of advance as noted then retest.

Barry

http://i287.photobucket.com/albums/l...location-2.jpg

Happy Bday the other day Barry.:biggthumpup:

I'm a bit sceptical about side seal vibration causing apex seal failure, the pressure differential across the long sides combined with deposits would mean a massive frictional force to overcome sliding back and forth in the side seal grooves, with a minuscule area at each end to provide motive force via gas pressures and very small distance for the seal to build up momentum.

Thanks for your continued input Barry.

Edit: couldn't let this go, and wanted to give a basic explanation for those playing at home.

The only way motion of a rotor could push/turn a side seal "backwards" (remembering that the oil seals have directional springs as well) was if you had entirely different e-shaft/seal/rotor design (leaving large dead zones on the sides of the rotors) which allowed the side/corner seals on one side of the rotor to be inside the tooth contact radius of the rotor gear. Not practical or desirable.

You can see this simply for yourself by drawing a rotor and stat gear and taking a radius from the point of tooth contact (the stationary point and centre of motion at any time) to anywhere on the rotor, only points lying inside the rotor gear can have a back/forth motion relative to the side plate (through an engine cycle). Even then it would only present a problem if the majority of an independently moving seal part was inside an arc of radius equal to teh gear radius from the tooth contact. That is you could have an engine design with circular oil control seals inside the rotor gear radius (on the off-gear side of the rotor) with the same directional spring design as ours without a problem.

Compare the above Fraction Burn and Combustion Rate rate to the result achieved in this much later experiment.
You can see the dates of each test in the top left corner.
This total increase happens by many very slight incremental improvements.
Barry


http://i287.photobucket.com/albums/l...ps6pgtgro9.png