I cut all the new OEM rotor side seals and tried to stay within the 90' FSM criteria of 0.002-0.0059 in. (clearance between seal and corner seal). They all can be pushed down and bounce back. Question is do I need to order more side seals to redo the 0.0065 in side seals??? The FSM has a statement "0.40mm (0.016 in.) max". Any opinions on this??

All the readings in inches clearance:
Front Rotor - Gear Side
0.0065
0.002
0.0065

Front Rotor - Open Side
0.005
0.002
0.002

Rear Rotor - Gear Side
0.002
0.0065
0.002

Rear Rotor - Open Side
0.002
0.002
0.005

 

IMO i think .002"-.016" is way too loose of a spec, and i like to see the gaps even throughout the engine. so i'm happy when all the seals are within .002"-.0025" if its a turbo i could go .0025"-.003"

so if i had your measurements, i'd either swap seals around, or buy more

the seals grooves are NOT all the same length especially on used rotors.

 

Do you still have your old seals? Try a couple of them.

 

I'll measure the used ones, and if they pass, I'll try to fit them to reduce the clearance with the corner seal.

 

been running 2-2.5 thousandths on my engine for the past few years for all side seals on a high horsepower build. I did not want the clearance to vary much. I had to order extra side seals so I could re-do some.

If this is a non turbo engine I would make an effort to reduce the clearance for some of the looser seals but I'd say it's not worth throwing a ton of time and money into it. A tighter clearance (but still within spec) is going to have less blowby and better compression.

 

I found 3 new seals I forgot I ordered last year expecting me to mess things up some, mixed the arrangement up as far as positions, and now I think I'm good to go--this seal cutting process takes way too long. I prefer a tighter clearance on some, but it's within the factory specs. It's a NA engine by the way that i'm building stock. All readings in inches:

Front Rotor - Gear Side
0.002
0.002
0.0035

Front Rotor - Open Side
0.0035
0.002
0.003

Rear Rotor - Gear Side
0.002
0.002
0.0035

Rear Rotor - Open Side
0.002
0.002
0.002

 

That looks decent. I get to do this today. I've got a big pile of used seals to go through.

 

higher clearance in the side seals = more crankcase blowby. keep the clearances rather even across the board and towards the lower limit. since you spent the money on new side seals you may as well get replacements and do them all right.

the new figures look ok now.

 

that looks fine! chamber sealing is very important in a rotary. since the strokes are 270 degrees instead of 180 like a piston engine, there is more time for leakdown, and thus having good sealing is MORE important.

 

I'm glad I asked! I almost went with what initially I had because it was within the FSM max clearance up to 0.016 inches. Thanks guys. Anything else I should be aware of that is not really defined well in the FSM?

 

i'm a little more picky about a couple of the clearances, like this one, but other than that i actually almost literally follow the book nowadays.

in the FC manual there are a few pages in the back with ALL of the specs/clearances

 

That is pretty decent.

mine is something about 0.0025 to 0.006 then I was like ahh this is good enough I'm not going to have mega hp on this thing anyway and just continue with the build.

 

new clearances look a lot better

 

I stopped following the book years ago because the loose clearance in the FSM leads to a load of blowby with large turbochargers and/or higher boost. Now I make my clearances tight by just grinding the seal just to the point it moves freely in the groove.

 

i actually think that's what they do at the factory, once you've done a couple hundred rotors, its probably just as accurate and faster. there is also some technique with the feeler gauge too.

i measured the widths of about 6 of my guitar necks, and i was surprised at how sensitive my hands were, i could feel a difference as little as .005" and .010" is huge. the necks vary about .060" which is wizzard sleeves!

 

I'm using your video Aaron Cake for my rebuild along with the Mazdatrix video. Great video you produced!

 

I'm clearancing my side seals now. I've just ground them down so that they barely fit until I decide what clearance to run. I watched Aarons video and have seen what he means by just grinding to they barely fit. some of mine move pretty freely but I still can't fit 0.002 gauge in there, so I can pretty much choose my clearances still.

In my searching to answer what clearance I should run some people said they run zero clearance but then stated that this was for NA motors and that they would go for a clearance of 0.0025 or so for a turbo'd motor.

I hate to ask the question again but what clearances do you guys run? this is gonna be in a FD non-sequential motor that will probably see 10-12psi of boost.

 

I'd leave them as is. As long as they move freely.

 

thanks again Aaron, unfortunately to late I set the clearances to a little over 2 thou