12a Rebuild: Rotor Side Seals
12a Rebuild: Rotor Side Seals
Almost ready to assemble.
The rotor side seals I have are shiny on all sides, but new ones are dark grey.
If my side seals have the correct tolerance at the ends, are they worth replacing?
Is the "shine" to be expected on used seals?
(This is my first rebuild.)
The rotor side seals I have are shiny on all sides, but new ones are dark grey.
If my side seals have the correct tolerance at the ends, are they worth replacing?
Is the "shine" to be expected on used seals?
(This is my first rebuild.)
Joined: Jun 2008
Posts: 8,376
Likes: 30
From: Chino Hills, CA
Your new ones are dark grey because they have no wear. Shininess is due to wear.
New side seals have to be cut to length, to fairly tight tolerances. Done right, each seal fits properly in only one specific groove on one rotor - that's why you're supposed to keep track of which side seal came out of which groove.
The primary two tests for side seal replacement are:
1) Seal top-to-bottom thickness, measured at several places along the length of the seal.
2) seal end clearance with the corner seals you intend to use. Corner seals will dimple slightly from side seal wear over time, so if you replace worn corners the side seal clearance will get smaller.
There's also a test for seal-to-groove side clearance, but unless something was seriously out of whack in the motor, the seal height is what wears out first, due to sliding wear on the end plates.
All this is covered in great detail in the FSM, and expanded on in the book "How to Modify Your RX-7" both of which are downloadable from foxed.ca.
New side seals have to be cut to length, to fairly tight tolerances. Done right, each seal fits properly in only one specific groove on one rotor - that's why you're supposed to keep track of which side seal came out of which groove.
The primary two tests for side seal replacement are:
1) Seal top-to-bottom thickness, measured at several places along the length of the seal.
2) seal end clearance with the corner seals you intend to use. Corner seals will dimple slightly from side seal wear over time, so if you replace worn corners the side seal clearance will get smaller.
There's also a test for seal-to-groove side clearance, but unless something was seriously out of whack in the motor, the seal height is what wears out first, due to sliding wear on the end plates.
All this is covered in great detail in the FSM, and expanded on in the book "How to Modify Your RX-7" both of which are downloadable from foxed.ca.
Your new ones are dark grey because they have no wear. Shininess is due to wear.
New side seals have to be cut to length, to fairly tight tolerances. Done right, each seal fits properly in only one specific groove on one rotor - that's why you're supposed to keep track of which side seal came out of which groove.
The primary two tests for side seal replacement are:
1) Seal top-to-bottom thickness, measured at several places along the length of the seal.
2) seal end clearance with the corner seals you intend to use. Corner seals will dimple slightly from side seal wear over time, so if you replace worn corners the side seal clearance will get smaller.
There's also a test for seal-to-groove side clearance, but unless something was seriously out of whack in the motor, the seal height is what wears out first, due to sliding wear on the end plates.
All this is covered in great detail in the FSM, and expanded on in the book "How to Modify Your RX-7" both of which are downloadable from foxed.ca.
New side seals have to be cut to length, to fairly tight tolerances. Done right, each seal fits properly in only one specific groove on one rotor - that's why you're supposed to keep track of which side seal came out of which groove.
The primary two tests for side seal replacement are:
1) Seal top-to-bottom thickness, measured at several places along the length of the seal.
2) seal end clearance with the corner seals you intend to use. Corner seals will dimple slightly from side seal wear over time, so if you replace worn corners the side seal clearance will get smaller.
There's also a test for seal-to-groove side clearance, but unless something was seriously out of whack in the motor, the seal height is what wears out first, due to sliding wear on the end plates.
All this is covered in great detail in the FSM, and expanded on in the book "How to Modify Your RX-7" both of which are downloadable from foxed.ca.
I'll get the Modify Your RX-7 and look again in the FSM.
Thanks for the info.
(And I was very careful to keep all the seals, springs, etc. in separate identified by location containers when removing and cleaning.)
Full Member
Joined: Apr 2014
Posts: 138
Likes: 1
From: Wheeling WV
this is a good site for reference, for rookies like me and experienced builders. ROTARY ENGINE OVERHAUL
this is a good site for reference, for rookies like me and experienced builders. ROTARY ENGINE OVERHAUL
I think I'm good to go as I've already checked the end to corner seal clearance.
Thanks for the link. (printing now)