well i broke my motor in properly and ive got 2k miles on it... and yet the car still has the compression in the mid 80's whats up with that? i was just thinking that maybe these seals just take forever to break in tell me your thoughts on this guys/

 

My questions are; did your use new or resurfaced side housings, are your rotor housings new, and besides the new apex seals, did you also install new side and corner seals?


These all contribute to total compression.

 

i just built mine with the new 2mm 2pc's,v.good comp.did u check all your tolerances were within spec.as far as housings(all).did u check that all your side/corner seals were moving freely on their springs? i installed new corner seals(gen.mazda) and one would not bounce on its spring infact when i checked it stuck itself down in the c/s bore so tight i couldn't lift it back out with a strong mag.pick up tool,in the end i pulled it with needle pliers to get it out,yes it broke.replaced it with a good used one.the apex seal corner sections can pinch between side & rotor housings,did u check the apexes by rotating the engine & pushing on each one through the ex.port to check mvement?

 

LOL. My was supposed to be done last week. I'll let you know what my numbers are when I get a call from the builder.

 

comp testing it next next saturday when i get 3k miles on the rebuild tell you how it goes!

 

Which seals are you talking about?(I am about to rebuild my engine and don't need compression in the 80s )

 

brand new mazdaspeed 2pc

 

not mazdaspeed my bad... MAZDA... factory mazda

 

How much are those?

 

Check MazdaTrix site for pics & price. These are the same ones that come from the Rx8. To me, they look awfully short and look like they could easily "roll" out of a slightly worn rotor.

 

Mazda doesn't make the 3-piece seals anymore from what I understand. They have been superceded by some new 2-piece seals. However, the RX8 seals are not the same as the new parts for the older 13Bs. Both are 2-piece, but the RX8 seals are "shorter" than the ones for the older 13Bs.

-Max

 

Just running in my new engine with the 2 piece 2mm tips. The builder has some good results so far with them.

Dan

 

That's got to be a record. Most repeated posts ever. 7 LOL.
I wonder why they changed the design of the seals?

 

I stand corrected. I naturally assumed those pics of the Rx8 seals were the same as the ones being used in the older 13b engines. I guess since the renesis has a higher rev limit that shorter lighter seals are neccessary to properly seal at higher rpms. By the way, anyone know whats the material used in the new seals?

 

http://www.rotaryaviation.com/apex_seals.htm

What about these? From the wording they use, it sounds like Rotary Aviation produces the seals, not Mazda. Anybody used em'? There well priced.

-Marc

 

I think they are just using the same material as the tips used in the RX-8, jsut at RX-7 sizes.

Dan

 

I have the new 2mm 2 piece seals and also get low compression. I am seeing 7,7,7 front rotor, 7,7,6.5 on rear rotor. Motor is Ported and race clearanced. It has not been installed or fired up yet so i dont know how high the compression will get after break in but i am putting in the motor anyways

 

Zoom, I am the same. I have just put 650 miles on my engine with these seals. Will get a compression check once at around 1000 miles.

Dan

 

Lets keep in contact then. I think we all would like to see some sort trend instead of just 1 guy with "X" results.

 

I orderd the 2mm 2 piece Mazda seals frome Mazdatrix 2 weeks ago. And did start my car on friday. And i have driven 590km(944 miles) on them and i have great vacume, and the engine runs great. Did start at once.

Im not going to check the compression but it looks to be god, it starts realy good.


So thanks to Mazdatrix for the fast service.

 

A compression check would give more tangible evidence that the car is sealing properly. Hard scientific results would be more appreciated. In fact if you do a compression check it would be a big service to the rotary community. We all will be trying to do this and get to the bottom of this possible issue.

 

yes please do so... when i first started my car vaccum was at 12 inches..... now at almost 3k miles im at 14inches.... that seems REALLY slow to me it should of gotten near peak compression by now..... anyways do us all a biiiiiiiiiiig favor and grab a poor mans tester and give us the numbers on your car..... thanks for your time man!

josh

 

I'm running the 2pc 2mm seals from Rotary Aviation. I think thier Hurley's but the Mazda seals should have similar compression. I don't know specific compression but vacuum is good. This is my second time through. I broke a seal on the dyno and had to replace them. I used the exact same housings as they had zero damage from breaking the seal. The first engine only made about 14" of vacuum. I spent some more time fitting side seals and really tightened up the gaps. They WERE within spec but I made them all around .006 or less this time. I'm now pulling a solid 15.5-16" of vac now. I've compared my readings on 3 different sources so I feel good about the accuracy.

So in a nutshell, side seal clearence CAN make quite a difference in compression.

 

still not comfortable with 14inches of vaccum

 

OK, then engine now has 1300 miles on it in just over 1 week.

I will get a compression check done at 1500, and will post results.

Sadly this wont be until next Sat. as work is gonna be heavy this week.

Dan