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a stupid question about porting/ taking an engine apart.
hi guys, i have a question about porting, one im sure i know the answer too, but im curious as to your guy's experience.
if i tear my engine down to do a streetport.... do i need to get a rebuild kit/ replace all the seals and apex,corner, and side seals? what do i *need* to replace when i do this. im sure new apex seals etc would be nice, but i figured i would ask and see whats needed versus whats wanted.
IME the main wear items are side seals and oil control rings, not necesarily the apex seals. For certain you WILL need soft seals (coolant seals,gaskets) and I'm cheap enough that I make my own coolant O-rings and use generic dowel O-rings from Harbor Freight, make my own intake gaskets from bulk material, and use Right Stuff for the rest (aside from the front cover gasket, which I upgrade to the RX-8 metal gasket because it's WAY BETTER than an O-ring)
I got burned once so I won't do an engine without new side seal springs. Apex seal springs are usually "bent" and should be replaced as well. I have never replaced oil control rings unless they were really, really bad, and I've never replaced oil ring springs period.
IME the main wear items are side seals and oil control rings, not necesarily the apex seals. For certain you WILL need soft seals (coolant seals,gaskets) and I'm cheap enough that I make my own coolant O-rings and use generic dowel O-rings from Harbor Freight, make my own intake gaskets from bulk material, and use Right Stuff for the rest (aside from the front cover gasket, which I upgrade to the RX-8 metal gasket because it's WAY BETTER than an O-ring)
I got burned once so I won't do an engine without new side seal springs. Apex seal springs are usually "bent" and should be replaced as well. I have never replaced oil control rings unless they were really, really bad, and I've never replaced oil ring springs period.
Order the parts from a mazda parts dealership. I found the best prices with University Mazda in New Mexico. I picked up some parts from Atkins, where they had the better price, Apex seals, rear engine seal. I got my water seals through Pineapple racing. I shopped around and found some good deals. I also feel that as I was building my first engine, this process helped familiarize myself with the parts. parts collected for rebuild.
No they can't. I don't like pulling a good running 12A apart until it's time for a rebuild.
...at which point the rotor housings are scrap, the rotors are scrap, the side housings are worn through the hardening, and the bodyshell is also garbage.
The great thing about 12As is they last forever, the sucky thing about 12As is that everything wears out about equally fast.
I've had zero problems with porting an already good running engine, once I did it as a street port and once I did it as a peripheral port. Both engines still had wonderful chrome on the rotor housings (the P-port engine started as a 120k mile engine, the other was unknown)
Just make sure that every seal goes back where it came from, since they're all sized a little different.
Well, when I did a compression check I got a dead even 84 across all faces on both rotors. Would you say that's good peejay? For a 12a? It has given me zero crap about starting hot or cold. When I used a calculator to adjust for elevation and crank speed it came put to something like 93 psi. From what I've read that is fine for a 12a.
How much does it cost for your seals total when you did your porting peejay and Richard?
...at which point the rotor housings are scrap, the rotors are scrap, the side housings are worn through the hardening, and the bodyshell is also garbage.
The great thing about 12As is they last forever, the sucky thing about 12As is that everything wears out about equally fast.
I've had zero problems with porting an already good running engine, once I did it as a street port and once I did it as a peripheral port. Both engines still had wonderful chrome on the rotor housings (the P-port engine started as a 120k mile engine, the other was unknown)
Just make sure that every seal goes back where it came from, since they're all sized a little different.
"Time for a rebuild" doesn't have to mean once it pooped out. I think compression numbers would be a good indicator of when it's time. 85 is my number.
Not exactly on topic, but I was curious if using the rx-8 front cover gasket requires any major modification. I'm in the middle of rebuilding my 12a at the moment and I've seen using the later gasket mentioned a few times but with no real specifics. Is the one linked above the correct PN - there are two rx-8 gaskets that I have found - or was that simply an example (just making certain here) and when using the rx-8 gasket do you still use an o-ring or not? I'm also assuming that if it is used, there's no need for a seperate water pump housing to block gasket? Not trying to thread jack, it was just already mentioned so I figured it was worth asking here.
I usually put a smear of silicone (or Aviation Sealer or whatever goop) around the water pump passages on both sides, because the side housing and water pump housing are usually "imperfect" and I want to ensure no pesky water leaks.
No O-ring. The reason you use the gasket is to eliminate that O-ring.
I take it that the correct gasket is the 04-08 one then. Or at least that's what was linked, and by the looks of it, it's physically the most similar to the stock 12A one.
And maybe I'm crazy, but it looks like some extra material would be sticking out around the edges?
05-30-19, 06:44 PM
