Trimming side seals?
 

I need to trim a set of new side seals I have. Waht is the best tool to use and does anyone ahve tips?

There's a thread about this on the other forum; I'm interested to see this sites info on it as well though.

dremel with a cutting wheel, sand it to get rid of any burs and finish it up. keep it as tight as possible without it actually getting bound up. many people have said they have had success with running little to no gap. that way you also don't have to worry about compression leaking into your oil pan and pressurizing it as much.

dremel with a cutting wheel, sand it to get rid of any burs and finish it up. keep it as tight as possible without it actually getting bound up. many people have said they have had success with running little to no gap. that way you also don't have to worry about compression leaking into your oil pan and pressurizing it as much.

Side seal gap
 

I have alot of interest in this too. I know you want them as tight as possible, but they still must be able to maintain clearance under varing thermal loads.

Any veteran engine builders out there that can give the minimal gap that is okay on a boosted engine? I believe Mazda reccomends ~0.002"?

Justin

You really need to use a feeler gauge on this one, Matt. I use a bench grinder with a very fine grinding stone wheel. Other methods that've been suggested will work as well. Mazda specs are 0.002" to 0.006" being the maximum. I vote for 0.003" myself as you want to leave a little room for the growth of the seal when at operating temperature. If the gap is already too skinny, then the side seal has a chance of eating into the edge of the corner seal.

B

Well if i use zero Clearance wont it gouge the corner seal ,and make a groove. Wich would be the samea as if I cut thme to .002

If you left 0 clearance, they could bind and get stuck in....then you'd have compression problems.

Get a set of feeler gauges and cut the seals within Mazda's specs.

Zero clearance tends to put to much pressure on the corner seals. You have to understand that when the side seals expand their length, they will put pressure on both sides of the corner seals. When this happens the corner seals can break. I use 100grit emery cloth and clearance mine by hand. Emery cloth is just sand paper with a really tough backing that doesn't tear that easily. This gives me a lot more precise control so I can clearance all my seals to the minimum .002 which allows for the highest compression possible.

Yo von, how long does it usually take you for all 12?

Well I'm never in a rush when I do stuff like this. Maybe like 5min average each.

shi it took me almost a hour on each seal I didnt want to use my grinder so I useds a nail file.lol ghetto right

Well about 10 yrs ago doing my first rebuild, I notice that the new side seals were extremely long for my 12A. The 13b ones I've ordered from Mazdatrix have only needed minor trimming.

proper sideseal clearance is essential if you want a tightly sealed engine.

i wish to repeat...

sideseal clearance is essential if you want a tightly sealed engine.

BDC knows his stuff and uses .003. i use .002, a number i was given by a seven second quarter mile engine builder/pilot who has yet to give me a wrong turn as to advice.

it is as important to get the face of the sideseal square w the meshing face of the cornerseal. some have built jigs to accomplish this.

it seems every good engine builder has his own method so as to achieve a proper clearance, 90 degree cut and face angle...

i recommend you purchase a 10X loupe, around $15, so you can see what you are doing.

practice on the old sideseals and buy yourself a .002/.003 feeler gauge.

howard coleman

As Howard stated above the finished edge has to be square with regards to corner seal fit. That's most important. I've built a jig to do so. The present rx-8 side seal must be done this way ie. using a jig due to the tapered design. There is no way you can file the rx-8 seal by hand and get the proper angled/tapered fit.
As for clearance I use 0.002 with great success in most combinations.

* nevermind *

Side seals should be ground precisely in order to achieve good compression and long strong life. A fixture is necessary. Mount/bolt an old rotor to a drill press table. Install a stone grinding wheel, the size of a corner seal so it will stroke into the cavity. I use a small dental pick to put a slight pressure on the end of the side seal. The fit is so good that the Mazda ends should be dressed also. Measure all of your seals in one rotor location; segregate them in .001” groups. Measure all 12 rotor locations with a standard seal to determine their relative length. Always grind the longest location first, (it can always be used in a shorter one if over-cut). I reuse side-seals if still in spec.
Barry

That's how I do it. I was wondering who would be first to suggest this in the internet world. :lol:
To make it a little easier to use the jig cut off one end of the rotor so you can push on the seal by hand. You got to be gentle when doing this to avoid deforming the natural shape of the side seal and to also keep the seal at the proper angle.
I have one for every generation of side seals including the rx-8 which is actually the most difficult one to do.
Also have a small file at hand to de-burr the end of the seals after grinding on the jig. If not you'll have a hard time fitting the seal back into the groove to check clearances. If you're familiar with grinding/cutting piston rings you would understand what I meant.

Yeah, above comments about dead rotor based jigs. Personally, I cut off a corner, and milled some of the rotor out so I can use T-slot nuts and such to bolt it to my milling machine's table.

I got my brand new rx-8 rotor jig donated to me after going a little to far in the lightening process. :rlaugh: I was able to donate a second one to a fellow after messing up again doing the same thing. I gave up aftet that. Thank Mazda for the cheap prices on the early rx-8 rotors. Like they say there's only one way to do actual R&D. :lol:

What a funny coincidence... my 12A jig came from the exact same sort of thing! :rlaugh: Well, with less expertise behind it... gotta start learning somewhere though, no?

how freely should the feeler gauge fit between the corner and side seal and should it be freely movable back and forth?

ive clearanced the sideseals to the point where i can get the feeler gauge in but the sharp edges bind it.

seal compression/decompress is good but there is a feeling of metal-metal contact although this feels likes its caused more by the length of the seal rubbing against the edges of the side seal groove.

pictures at bottom of this page https://www.rx7club.com/3rd-generation-specific-1993-2002-16/time-rebuild-d-progress-updated-654291/page2/

If you can get the .002" in then its right. When you question yourself try a .0015", one size below, and a .003", one size above. Feel the difference? One goes in too easy and one doesn't. Have confidence the veil of knowledge has been removed.
Barry

Would .0015 side seal clearance be the bare minimum clearance for side seals?? I ask because I remember seeing Aaron Cake grind his side seals until they barely fit in one of his youtube videos.... please let me know because I'm currently redoing my side seals for my rebuild. Thank in advanced.