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The flat corner seal springs are the improved FD (3rd gen) springs.
That is what we supply in all the overhaul kits whether they are 3rd gen or
not.
Tracy
----- Original Message -----
Sent: Monday, November 08, 2004 8:08
AM
Subject: [FlyRotary] Re: Assembled 13B
block today...
David, Your engine looks really good, and it sounds l ike
you came out really good with your ebay engine. I recently rebuilt my
engine, and I could relate easily to your description of the
rebuild.
One thing about the corner seal springs. My engine was
also a jspec, and it had wire springs in the corner seals. My
understanding is that the flat speings, like the ones that come with the
rebuilt kit, are a heavy duty spring, and are most probably
aftermarket. Perhaps that engine had been either rebuilt or
modifyed.
Steve Brooks
-----Original Message----- From:
Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]On Behalf Of
David Staten Sent: Sunday, November 07, 2004 11:09 PM To: Rotary motors
in aircraft Subject: [FlyRotary] Assembled 13B block
today...
Well.. the moment arrived... We (Chris Barber and I)
obtained 3 as-is/where-is blocks back in mid August I believe, from an
Ebay auction, and drove out to retrieve them personally (the engines
cost $700 on ebay, shipping would have been another $1000 we guess).
Since the project was moving slowly due to other concerns, I took my time
and built my shop, bought tools, played with "THE NUT OF HELL" on the
back of the first one, etc.. The first bit was kind of tedious..
hand brushing off the carbon from the rotors, scraping the
housings/grooves and in general just expending lots of elbow grease. In the
course of things I build a bead blasting booth and blasted the housings.. I
used a drill and wire cup to polish the rotors and really remove the
carbon.. and in general just took my own meticulous time. All of this was
for ONE of the three engines, the other two were sitting untouched at
this point. Originally I had planned to tear all 3 down at once, but
that turned into "do this one, and if its good, rebuiild it first"
rather than "pick the best of 3 once stripped".
Well, Chris surpised
me this week, after I had finished porting, then painting, the housings. He
had ordered the Master Rebuild kit and it arrived within the past 48 hours.
I spent part of the day out at the hangar socializing, standing in Chris's
light while he tried to work, and read the instructions in the master kit.
At this point, Chris has his tools and his "workshop" moved out to the
hangar, but I havent had the inclination to do so just yet (working nights,
its real convenient to step into the garage on a night off at 1am.. raises
less questions and eyebrows on field).. Well, we closed up shop around 8ish
last night and I was up bright and early this morning. By 11 am, I had
called him and said "lets do this" and by 1230 he was in my garage and we
got down to business. I had done several dry assemblies of the block at
this point and I didnt expect it to take too long.. maybe 2 hours or so..
BOY was I mistaken.
The first course of business was doing a quick
dip in the solvent to knock out any shavings that I had missed during the
porting.. I had gotten a little careless and gotten shavings on EVERYTHING
before I realized what I was doing and covered the parts up. Unfortunately,
I had already painted housings.. Obvious Lesson #1.. kerosene based
solvents will thin/dissolve engine paint. The Rotor housings took the
biggest hit.. and its not BAD.. but its no longer perfect looking...
Choke cleaner doesnt help either (video recommends spray housing surfaces
with choke cleaner and blow dry)...
The next big chore, which I had
NOT practiced.. was rotor assembly and paying attention to all the details.
We were pretty much able to get the oil seal o-rings into the seals, and
seated without too much drama. Bruce's video is GREAT, but with regards to
the rotor assembly his nomenclature, while technically correct, it
unnecessarily confusing. I can follow open versus gear side, but once you
conceptually know which rotor is front and rear, you should be able to
QUICKLY know which side (gear or open) is the front and rear. THEN, based
on front or rear, placing the oil seal springs is much easier. "FRRL" Front
side, square tabs point to the RIGHT; Rear side, tabs point to the left.
That way the rotor seal springs lock into their notches and keep the seals
from spinning. Seating by hand went smoothly and a GREAT device for
pressing them in with uniform pressure (once you initially seat by hand) is
to use a NEW, plastic wrapped roll of Duct Tape. Its wide enough and
thick enough as a roll to cover BOTH oil seals and you can push down
uniformly with it quite well. Also, KEEP the oil seal springs when you tear
your old engine down. The master kit does NOT supply new springs. New
Seals, New gaskets.. yes.. New Oil Seal Springs.. No..
The
master kit comes with slightly oversize side seals which have to be trimmed
to fit. It doesnt take much to go from "too big" to "too little". Goals for
new are a gap of 2-6 thousands. 16 thousands is replacement. time. Lets
just say two of the BRAND NEW side seals ended up not going into the final
assembly, and 2 of the used ones were able to meet acceptable tolerances to
replace them. Tools included using a bench grinder with incremental
grinding, and then when at the very last bit, I used a flat file laid on
the bench and ground a slight bevel to each end of the side seals (the
bevel to contour along the corner seals). I was able to acheive 2-4
thousands clearances on more than one occasion. My advice? Order 3-4 extra
ones if you are a first time builder. It wasnt so much about being
impatient but a simple slip of the hand can render a seal that was "almost
there" into " a neat cleaning tool".
Here is where I have to admit I
had a MAJOR goof.. Actually I goofed a while ago and didnt realize it. I am
guessing I DROPPED one of the rotors Not only did I drop it, I apparently
dropped it on a corner and didnt notice the damage then. It closed the gap
a bit on the apex seal groove.. which we discovered, and hand filed it to
allow the seal. THen when we got to the corner seal it was clear that the
corner had encroached on the corner seal hole as well and the seal wasnt
going to fit. It was clear at this point that the rotor was damaged and
we elected to not to use it. At this point I was willing to concede
defeat and let Chris go on about his business today... He was willing
to put the extra time in to tear down enough of one of the other two
engines to salvage one rotor. Given my previous problems tearing the first
one down quickly I felt this was a long shot.. but.. within 20 mins we had
the intake, rails, bell housing and oil pan off. The NUT FROM HELL
came off on the third try with WD40 and 100 PSI on the impact.. no heat
this time. Let me say that Air tools made this a QUICK endeavor. Yanked
the rear housing off, extracted the rear rotor and plopped it in a
solvent bath and started yanking seals and scraping carbon. Within 20 mins
I had the rotor on the tailgate of my truck wire brushing the carbon off
with a drill/wire cup. Within the hour we had the NEW rotor from the
other engine all bright, cleaned, new seals placed in and ready to go. I
was pleasantly surprised with how smooth that went.. It tells me that
the next time I rebuild one it will be a quick, down and dirty affair to
say the least. One concern we had was that even though the engines are
both supposed to be 89-92 turbo II's, the rotor was slightly different
in appearance (im assuming for individual balance purposes). Our worry
is that there is some reason that they are not equally
balanced/equal weight. In theory they are of the same manufacture, both
were on manual tranny engines, and that block of engines have all the same
stock rotors. I noticed that the FIRST engine had the wire corner seal
springs and the second one had the wide/flat corner seal springs. Chris
thought maybe the engine had been rebuilt, but being Jspec I dont think
thats likely. My guess is the flat springs are a factory
install.
Ok, once the rotor crisis was solved, we began with our block
assembly. We had to use a little more than "sparing" hylomar to get it to
hold the seals in their grooves. The first rotor was installed and then we
placed the seals in. Bruce's video has pics of the OLD style 3 piece apex
seals that are glued together. In this case, the two piece apex seals
involve putting in the corner seals from the rear after the rotor is
in the housing. The front rotor I placed the springs in, THEN put in the
apex seal corner pieces, then the lil rubber plugs.. went smoothly. The
REAR rotor, I thought.. maybe the video had a point about the corner
pieces being in before adding the springs. As a practical matter I can now
say THAT WAS A BAD IDEA. An apex seal corner piece took flight when
the spring launched it out, and it took us a good 10 minutes to find
it.. turns out it had landing in a coating of brushable sealant and was
not conspicuous in the least.
The last big hurdle was doing the
tension bolts.. I placed on 2 layers of 3/8" shrink wrap on each bolt.
After the first one or two of em I even remember to put the washers on
FIRST (hint hint).. Chris wanted to put the RTV sealant as well.. plus blue
locktite on the threads.. Video instructions say to place some marvel
mystery oil in there to boot. Lets just say it was crowded in them there
bolt holes. We had a few that we wanted to get locktite on that we had
already placed in the boltholes.. but they were VERY snug with two layers
of shrink wrap on their midsection. I quickly remember that the engines
could pull apart and spill seals everywhere if we werent careful and we
just left those alone. All I can say is WHEN this engine ever comes back
apart its NOT going to be easy at all.
We spun the engine over by
hand/breaker bar and we were VERY pleased. All the apex seals have good
springiness.. and we have a GREAT sounding compression "chug". I need to
get a starter and try and turn it over for a real compression
test..
We got as far as the end play measurement when we decided to
call it a night. The end play was excessive so I will need to purchase a
different size spacer.. or maybe see whats in the 2nd engine (that is now
just for parts).. So at this point Chris headed home to pacify the missus,
since we had been doing plane stuff all day. I cleaned up the garage
and covered all the ports.
So.. to top it off...
1) dont
paint until you are done with solvents. DUH.. 2) KEEP the oil seal
springs.. you WILL need them 3) Oil Seal Springs: FRRL: Front points right,
Rear points left 4) A new roll of duct tape works great for pressing in Oil
Seals (works on the rear main oil seal on the rear stationary gear
too) 5) Dont Drop rotors. 6) Dropped rotors arent the end of the world
if you got the parts on hand. 7) Take your time with side seal trimming to
fit. Order a few extras.. or save all the old ones.. cause you just might
need to re-use one. 8) Put in the apex seal springs, THEN the apex seal
corner pieces.. we actually had to hunt TWO different corner pieces that
got lost because they were launched. 9) If you do the shrink wrap on the
tension bolts, plan on it being a SNUG fit.. and pay attention to detail so
you dont have to take em back out anytime soon. 10) you may need more
than a "sparing" amount of hylomar. The supplied tube should be
enough. 11) I discovered Lock-Tite is expensive when you buy the big bottle
not knowing you didnt need that much.. Sheesh.. $20 for 1.2 oz bottles..
RED and BLUE.. oh well.. aviation is expensive. 12) watching the video
several times helped. Having Chris there concurrently (and having watched
the video too) helped. The two "dry runs" I made before we got to the REAL
rebuild..
Today has been a long day... and Im actually wiped out even
though we didnt do anything backbreaking. But.. this is one more step
completed. I am hoping to load up and transport the engine to the hangar by
next weekend. We will put the Stainless on Chris's firewall and mount
the block to the airframe and begin the job of fitting all the
accessories and plumbing. Pics to follow.
David Staten Velocity
N17010 (reserved) - airframe by Chris Barber Mazda 13B REW
rebuild
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