The engine is S5 JDM 13B that I'm rebuilding. It's my first rebuild so all opinions are appreciated.

I'm checking wear on my side seals to decide whether to reuse or replace them. Using a micrometer I have some numbers.

Haynes manual has specs on height wear to be between .1122 - .1240
All of mine measure between .1205 - .1198

I didn't do percentages but that has me with about .0035-.0042 worn and .0076-.0083 left to still be within spec. or about 1/3 worn and 2/3 left.

Opinions on whether to use or replace would be greatly appreciated.

Some sidenotes and questions.

I started to check width but found they were wider than spec...then I realized that whats throwing that off is probably carbon build-up. If I use them should I clean that carbon off before assembly or leave it be?

Also if it matters I"ll be prepping the irons using a method I learned about on "another" forum. I'll be using an orbital sander, fine grit paper and kerosene to prep the irons. Is this method appropriate for used side seals or primarily to help with break-in of new side seals?

I haven't finished testing the irons to make sure they are all useable, but so far they all look good.
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Whow nelly do not just sand your plates, LAP them.................. without going into why??? Your surface should be flat and smooth otherwise you will end up with a stinky oil burning mess that eats your oil control rings and blows compression past the side seals.... Ps If you can afford it put in new ones in and gap them. I use .005 and they run well and don 't bind the corner seals, if your tight with cash,at least try to install new side seal spings which will help to seal the used side seals, if you want to learn how to Build a reliable engine use the Mazda speed specs and really read the Racing Beat Catalog .its all there........good luck............................... one more thing use new 93 +corner seal springs Too. good luck................FP

 

Thanks for the feedback

I'm planning to use at minimum all new springs, FD corner springs and new atkins apex seals ciding if I'll reuse side seals and corner seals. I was set on new solid corner seals but I just clearanced one side seal with a pair of old corner seals, just to kinda see what I had. They were between .003-.005 IIRC I didn't write down the numbers and my brain was starting to boil from the heat....I was actually starting to see mirages of some 20B parts in place of my 13B!!

I'm planning to clearance all the side seals to all the corner seals once the sun and heat are gone.

I"ll look for some mazdaspeed specs. If you have a link that'd save me from googling it. I do remember finding an official mazdaspeed website but as I remember it I couldn't access info cause I'm not registered as racing. But it was a while ago so who knows IIRC???

About prepping the irons...I'm still reading on the other forum and researching if it's appropriate for me. Other forum has a pretty good write-up on it.

 

I have built alot (30+) motors in my personnel opinion, you hardly ever have to replace your side seals, they really dont wear out as easy as the apex seals. If you use the old ones, you MUST keep them in the same spot in the rotor

Example Rotor1 Left side Slot 1, Rotor1 Left side Slot 2, Rotor1 Left side Slot 3,
Rotor1 Right side Slot 1 ect.....


On the irons most of your wear will be in between the Intake and exhuast , and in between the spark plug, this is where most of the over lap happens.

PM me if you have more questions

 

^ thanks I appreciate the help

 

Chuck's right. If you do replace the side seals, replace all 12 and do them one groove at a time during assembly (meaning already have the corner seals slotted). I clearance mine 0.0025"-0.003". They'll work fine. Plus 12 new ones aren't too expensive.

B

 

Agreed they're not too expensive, like $100 or so from Atkins. My problem is that this being my first rebuild I'm nickle and diming myself to death with needing tools, finding my clutch is worn more than expected and needs replaced, might need to rebuild or replace my turbo, etc etc.

 

Sideseal width isn't a big concern. Remove all the carbon buildup with acetone and a soft cloth. It takes a lot of careful rubbing to keep them from bending. Make sure they drop back into the grooves and move up and down freely. Set the side seal to corner seal gap to 0.002". I hand lap the plates with valve grinding compound using a figure 8 motion. If you have more than 0.002" of sideseal wear on the irons you should use the orbital sander and kerosene method. I'd still hand lap them for a smooth finish. If the finish is too rough the side seals will wear down fast.

The sideseal grooves on the rotor are not all the same length. If you spend some time mixing up the sideseals with the grooves you might be able to reuse some that were out of spec.

 

for side seals, i haven't found height dimensions to vary too much out of spec. i think length is a little more important. that said, i don't usually replace the seals themselves, however, i make sure to use new springs! i concur with making sure to mark where they came from and to put them back in the exact spot on the rotor.