Apex Seal Groove
#1
Full Member
Thread Starter
Apex Seal Groove
I just finished rebuilding my engine a few days ago compression tested it and it failed. It has RA super seals. My question is how tightly should the apex seals fit in the groove. I believe I have mine in there so tightly that the springs cannot push them out enough to get compression. When I look through the exhaust ports some of the seals are easier to push in then others, and some are hanging out more then others.
#5
Old [Sch|F]ool
It is extremely unlikely that the apex groove clearance was too tight. I like to shoot for .002 and I rarely am able to get that, it's usually .0025 or so because of rotor wear.
I've never used RA seals though.
Now what is more likely is that a corner seal is hanging up or there is debris in a groove that is preventing the seal from moving.
Also it is somewhat pointless to compression test an engine that has never been run. I assume this is what happened.
I've never used RA seals though.
Now what is more likely is that a corner seal is hanging up or there is debris in a groove that is preventing the seal from moving.
Also it is somewhat pointless to compression test an engine that has never been run. I assume this is what happened.
#6
Full Member
Thread Starter
It is extremely unlikely that the apex groove clearance was too tight. I like to shoot for .002 and I rarely am able to get that, it's usually .0025 or so because of rotor wear.
I've never used RA seals though.
Now what is more likely is that a corner seal is hanging up or there is debris in a groove that is preventing the seal from moving.
Also it is somewhat pointless to compression test an engine that has never been run. I assume this is what happened.
I've never used RA seals though.
Now what is more likely is that a corner seal is hanging up or there is debris in a groove that is preventing the seal from moving.
Also it is somewhat pointless to compression test an engine that has never been run. I assume this is what happened.
#7
Rotary Freak
iTrader: (16)
Take the engine back apart and measure the clearances. What was the side seal to corner seal gap? How much end play? Why are you doing a compression test on an engine that has never run? That makes no sense. The apex seals should move freely. All the seals should move freely. If anything is binding and you start the engine it's either going to run poorly or its going to break and then run really poorly, if at all. Check the FSM, Haynes, pineapple vids... Google...to find "how to set the clearances". Do you have feeler gauges?
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#8
4th string e-armchair QB
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Did you thoroughly clean the carbon out of the apex seal grooves? I can't see any other reason why they would be that tight, unless the stock 3-piece seals let go and fucked up the groove.
Mazda has FSM with all the specs and clearances for a reason, if you choose to ignore them you're kind of on your own. If the apex seal does not move freely in the slot it will not have the ability to seal throughout the engine cycle, and you have wasted your time.
If that was me, I'd see if I can get a running used engine in there for your event while you take this one out and check everything over again, THOROUGHLY clean it, and make sure all seals move freely and are within tolerance.
Mazda has FSM with all the specs and clearances for a reason, if you choose to ignore them you're kind of on your own. If the apex seal does not move freely in the slot it will not have the ability to seal throughout the engine cycle, and you have wasted your time.
If that was me, I'd see if I can get a running used engine in there for your event while you take this one out and check everything over again, THOROUGHLY clean it, and make sure all seals move freely and are within tolerance.
#9
Full Member
Thread Starter
thanks everyone, i took it back appart, and my problem was excess glue that i used to glue the corner pieces to the apex seal. It made the apex seals wider then they should be and made it hard for them to slide in.
#14
Eats, Sleeps, Dreams Rotary
iTrader: (1)
Anytime you install a seal you need to get the clearance specs recomended for the type of seal and check them for each seal. The clearance for each seal will vary. Carbon seals for example need more clearance than stock or ceramic seals because they expand with temperature. Also get in a good habit of checking all your clearances for all the seals, bearings, housings, rotors, and irons. This will ensure good compression and a long lasting motor. Good luck.
#15
Full Member
Thread Starter
yea dude haha, i got it i scraped them and they fell in perfectly now. GOt alot to do in a short amount of time !
#17
Old [Sch|F]ool
...and that is a lot of why it's pointless to test compression on an engine that's never been run
Whenever I manage to glue seals in such a way that they actually stick together, they always seem to glue cockeyed and if they even go into the slots without popping apart, they bind a fair bit. They've only failed to crack loose once, and that time they popped apart a very short time after I (finally) got the engine started.
Helpful hint: When gluing seals, make them deliberately overlong, so tightening the tension bolts forces the glue to break free.
Whenever I manage to glue seals in such a way that they actually stick together, they always seem to glue cockeyed and if they even go into the slots without popping apart, they bind a fair bit. They've only failed to crack loose once, and that time they popped apart a very short time after I (finally) got the engine started.
Helpful hint: When gluing seals, make them deliberately overlong, so tightening the tension bolts forces the glue to break free.
#18
Moderator
iTrader: (3)
yeah, i try to keep them long. however, i'm happy with them just staying together and straight enough to fit the slot. single spring engines aren't so bad, but the double spring engines can be hell. it took a while for me to learn that i could just glue the small spring to the seal, then glue the long spring to the corner piece and it makes life so much easier.