Next, we installed the Atkins Rotary Solid Corner Seals and went to work grinding the side seals for the proper tolerance. Mazda recommends between .002”-.006” of clearance between the corner and side seals, with a maximum tolerance of .016”. Many engine builders run on the tighter side, but if the side seal smashes against the corner seal, it can bow upward and lose a lot of compression. We ended up right in the middle setting our gap at .004”
Abel repurposed one of the many rotors that he had laying around as jig to grind down the side seals at the correct angle.
12 side seals later, and our rotors were ready to be installed.
Our WPC Treated and CTP Cryogenically Treated irons were prepped and ready to assemble. These two processes should improve the strength of our irons, reducing the chance of cracking, and reducing friction and heat from the WPC process which also equates to more power.
With the front iron bolted to the engine stand, we were ready to start stacking.
9 comments
Is the blurred out images of the port, really NSFW, or just a proprietary secret?
Otherwise, love the assembly porn!
It’s a bridgeport with a semi-peripheral port.
Lol I figured it must be some JDM mosaic NSFW material too.
Great documentation. Can’t wait to see further progress.
When researching components for my RX-8 engine rebuild a lot of people recommended avoiding Atkins solid corner seals because all else being equal, you’ll see lower compression compared to an OEM corner seal. In this case is the added strength a worthy tradeoff for the compression because you can add a bit more boost to make up for it or are you just not seeing a compression loss on the RX-7 version of the seal?
Dylan,
I have had experience with both. You only crack corner seals if you have an incorrect tuneup. Oem for everything and stay away from Atkins. Their coolant jackets and apex seal springs are not oem and will cause problems in your build. See my thread on rx7 club titled Warped Apex Seal Teardown.
I think Able is one of the best engine builders and I would stick to his advice.
Hi Mike,
Why does Atkins recommend not using their solid corner seals with lapped side housings?
Thanks
Atkins does not recommend lapped side housings in general. From their website:
Side housings have a nitrided surface, which is a heat treating process that diffuses nitrogen into the surface of a metal to create a case hardened surface.
When you lap a side housing you remove this nitrided surface.
We do not offer this service nor do we condone it.
When this nitrided surface is removed excessive wear can occur when using any seal that comes into contact with the side housing, including Mazda corner seals and Atkins Solid Corner Seals.
It can also cause excessive wear to the side seals and oil rings when they come into contact with raw side housings with no nitrided surface.
According to Abel, the Atkins solid corner seals will improve compression over stock, and stock corner seals start to see limitations at certain power levels where solid corner seals become far more necessary and beneficial.