Yair G'Day Dave,
END PIECES
The easy way is to glue the end pieces on with
superglue. All late model Madza seals are supplied pre-glued. Trouble
is, if you have to dissassemb;le the engine, they need to be
re-glued. I've been doing this for 25 years now. All you need is
just a TINY drop. Lay a piece of
"Gladwrap" down on a FLAT surface, lightly oil your fingers and
wipe gently with a rag (so the superglue doesn't stick to them), and
make sure the mating surfaces of the apex end piece and the apex seal itself
is clinically clean (I use carby-clean, but nail polish remover,
MEK, or acetone does the job equally as well). I normally give
them a light scuff with some 800 wet&dry as well.
Put a SMALL drop of the superglue on the end of
the apex seal, lay it down on the "Gladwrap", and then lay the
end piece down and push together. Make sure that the sides are in the
one plane (otherwise, you won't get the endpiece past the corner
seal). Voila! C'est magnifique!
You then avoid this silly business of
putting the end pieces in first (almost guaranteed to cause a problem as you
can't see what you are doing). Trim off any overflow of the
superglue, and then fit the seal trouble free. (As long as you
made the superglue bond correctly! Otherwise they become "devil" pieces -
where the devil did that go! REAL "fun" at 2:30 am on a Sunday morning when
you have to be at scrutineering at 7:30 am - NOT!!!).
One other trick is to make sure that the end
piece is SLIGHTLY up the diagonal. The "pointy" end of the end piece
needs to be SLIGHTLY proud of the top of the apex seal. As the
motor is torqued, the end plate will push the end piece down the
diagonal and will break the superglue bond - you can distinctly hear
the clicks as the superglue lets go. (If you don't get it right,
you will have compression problems until the superglue bond breaks with the
heat. (Go figure how I know!! (}:>)
SIDE SEAL FAIURE
As for your compression problems, I
reckon that you had a side seal SPRING collapse. They tend to wear on
the bends. They don't have to wear much to seriuously compromise their
strength. Get one of the old ones and try bending it. Most
probably it will bend easily, and probably break. Once the
spring fails, the side seal itself is not properly supported,
and will in the fullness of time, do what yours did - break!
SEAL DURABILITY
As for the durability of the side seals
themselves, I've over the past 30 odd years, I've re-used second hand
ones over & over in cheap rebuilds several times, as long as they
come up to thickness and depth and length specs. But I ALWAYS, ALWAYS,
ALWAYS replace the corner seal and side seal SPRINGS - EVERY
rebuild, as well as ALWAYS fitting NEW corner seals. 90% of
comprtession problems in rotaries comes from the corner seal
clearances. If the new seal is a little too tight, you can
usually make it fit by linishing off the top edges a little with some
Wet&Dry (320 is about the right grade). On second hand
rotors, the corner seal hole ends up slightly oval, so a
slightly bigger seal will fit if you reduce down the ends where the apex
seal goes.
The corner seal should NOT fall out when you
turn the rotor over. If it does, it's too loose!!! They should
be a nice sliding fit with just enough resistance to NOT fall out when
upside down. If you measure each corner seal diameter, you will
find a variation. Careful selection and fit will ensure perfect
compression. Buy an extra packet of them to make sure you get the sizes
right.
They are cheap, good insurance, and
it is just common sense that the side seal springs, being so
fine, (especially the REW ones) are pretty delicate little
things. BTW, always use the latest corner seal springs
too. The twisted sheet ones (out of the REW and Renesis
engines), not the wire ones. They are much more resistant to
heat stress.
Enjoy,
Leon
----- Original Message -----
Sent: Wednesday, October 12, 2005
6:16 AM
Subject: [FlyRotary] Help!!
Installing Tracy's apex seals
In Bruce's video he talks about putting the corner piece of the apex
seal toward the front of the engine. But with Tracy's seals the
corner piece is not attached. So I cannot get the apex seal spring to
slide in because the corner piece (now down at the bottom of the slot) has
slid back a little.
If I put the corner piece toward the rear of the engine, I am able to
get everything in place just fine.