Renesis side seal discussion
09-07-2004, 02:32 PM
#76
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If the side seal spring is indeed looser then before. Could this be the reason why soo many aftermarket companies are haveing troubles with FI. I would also like to know if Synthetic oil would be better
09-07-2004, 03:13 PM
#77
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I have zero proof that there is a side seal spring issue. It "could" theoretically explain what has happened though. Don't just extrapolate that there is a spring issue based off of this just as we shouldn't necessarily assume all engines have a side seal problem. The only issue is the clearances and this I do find to be an error on the part of Mazda.
09-07-2004, 03:17 PM
#78
All very interesting. But I'm interested in how the 13b can have that timing.
RG, how do the 13b primary ports open at 32 ATDC and close 40 ATDC?
That is some real short timing. But then the REAL TRICK is
the 13b secondarys open at 32 ABDC and close at 30 ABDC?
That is the longest timing I have ever heard of.
But I'm a rotary freshman and need the education.
Did I miss something? Or are you just testing to see who is paying attention?
RG, how do the 13b primary ports open at 32 ATDC and close 40 ATDC?
That is some real short timing. But then the REAL TRICK is
the 13b secondarys open at 32 ABDC and close at 30 ABDC?
That is the longest timing I have ever heard of.
But I'm a rotary freshman and need the education.
Did I miss something? Or are you just testing to see who is paying attention?
Last edited by Richard Paul; 09-07-2004 at 06:07 PM.
09-07-2004, 05:01 PM
#79
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would the seals on the renesis rotors eating up the housing in the 13b have something to do with this increased gap, maybe for the housings protection or something?
09-07-2004, 06:34 PM
#80
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Richard I started getting confused with the whole ATDC/ABDC thing and apparently got some terms mixed up. They all open at wherever ATDC and close wherever ABDC. Thanks for catching that! I'll go back to fix it.
Remember also that the rotaries timing is based on a 1080 degree eccentric shaft rotation rather than a 720 degree piston engine crankshaft rotation.
Remember also that the rotaries timing is based on a 1080 degree eccentric shaft rotation rather than a 720 degree piston engine crankshaft rotation.
Last edited by rotarygod; 09-07-2004 at 06:39 PM.
09-07-2004, 06:55 PM
#82
RG, one more thing. It seems to me that the seal clearence is like piston ring end gap. However the gap on a ring closes as they heat up. Is there any sort of thermal effect in the rotary that would close it's gap?
Say if the rotor expanded within the case. And there was less expansion of the cases.
Say if the rotor expanded within the case. And there was less expansion of the cases.
Last edited by Richard Paul; 09-07-2004 at 06:57 PM.
09-07-2004, 07:08 PM
#83
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Originally Posted by Richard Paul
RG, one more thing. It seems to me that the seal clearence is like piston ring end gap. However the gap on a ring closes as they heat up. Is there any sort of thermal effect in the rotary that would close it's gap?
Say if the rotor expanded within the case. And there was less expansion of the cases.
Say if the rotor expanded within the case. And there was less expansion of the cases.
09-07-2004, 08:11 PM
#84
If the rotors are aluminum it expands at a rate of .0012 inch per 100F per inch. Meaning if they are 3 inches wide that is 0.0036 per 100 degrees of rise I don't know how hot they get but if they go to say 400 then that would be a rise of 300+. So it is .011+ expansion.
Now what is the case made from and how hot does it get?
You guys know these things, I do not.
BTW if the part is steel it will expand about half as much.
Now what is the case made from and how hot does it get?
You guys know these things, I do not.
BTW if the part is steel it will expand about half as much.
09-07-2004, 08:16 PM
#85
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Originally Posted by Richard Paul
If the rotors are aluminum it expands at a rate of .0012 inch per 100F per inch. Meaning if they are 3 inches wide that is 0.0036 per 100 degrees of rise I don't know how hot they get but if they go to say 400 then that would be a rise of 300+. So it is .011+ expansion.
Now what is the case made from and how hot does it get?
You guys know these things, I do not.
BTW if the part is steel it will expand about half as much.
Now what is the case made from and how hot does it get?
You guys know these things, I do not.
BTW if the part is steel it will expand about half as much.
The housing is steel.
09-07-2004, 08:31 PM
#88
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FYI - I was thumbing through the engine workshop manual and found some specs that you may find interesting.
Clearance between side and corner seals
Standard - 0.0020-0.0059in
Maximum - 0.0160in
Rotor and side housing clearance
Standard - 0.0020-0.0074in
Maximum - 0.0020in
Clearance between side and corner seals
Standard - 0.0020-0.0059in
Maximum - 0.0160in
Rotor and side housing clearance
Standard - 0.0020-0.0074in
Maximum - 0.0020in
Last edited by Speed Racer; 09-07-2004 at 09:46 PM.
09-07-2004, 08:47 PM
#90
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Originally Posted by RX8-TX
Could you point me out to where in the manual you found those tolerances?
Thanks!
Thanks!
and richard, thatd make a lot more sense.
09-07-2004, 09:10 PM
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Originally Posted by shelleys_man_06
No. There is a separate engine manual for the RX-8, at least that's what robertdot told me. 
09-07-2004, 09:48 PM
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Originally Posted by Richard Paul
Did you mean .020 max?
Are these the numbers for the Rx 8? Because they do not seem to match what has been said here.
Are these the numbers for the Rx 8? Because they do not seem to match what has been said here.
09-07-2004, 09:51 PM
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Originally Posted by shelleys_man_06
No. There is a separate engine manual for the RX-8, at least that's what robertdot told me.
09-07-2004, 10:07 PM
#95
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Off-topic:
My Mazda dealer told me the engine manual is included with the rest of the workshop manual, which is wrong, unless they meant the externals. Sucks how I have to get two manuals; the old RX-7 manuals included the entire engine workshop manual.
edit:
I was wondering if one could design seals with different materials.
Are the side seals constructed of iron? What about the corner seals? I think it's pretty weird too regarding the clearance issue. I can't really visualize what is going on without a working model.
My Mazda dealer told me the engine manual is included with the rest of the workshop manual, which is wrong, unless they meant the externals. Sucks how I have to get two manuals; the old RX-7 manuals included the entire engine workshop manual.
edit:
I was wondering if one could design seals with different materials.
Are the side seals constructed of iron? What about the corner seals? I think it's pretty weird too regarding the clearance issue. I can't really visualize what is going on without a working model.
Last edited by shelleys_man_06; 09-07-2004 at 10:21 PM.
09-08-2004, 01:05 AM
#99
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Originally Posted by cortc
Ok, spoke to a few different individuals on this including one of my contacts at Mazda (We have many as we are a very large dealer group…) and our number one rotary tech at our Mazda dealership who has 15+ years experience with Mazda rotary engines, and has already worked on a few RX8 engines with 35K + miles, and there is absolutely nothing wrong with the Renesis and the seals...
This issue does not exist; it is actually funny how some of us have taken this even remotely seriously...
This issue does not exist; it is actually funny how some of us have taken this even remotely seriously...