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Flat springs under the corner seals came stock in all 1993+ 13B REW twin
turbo engines in the FD third gens. You can use them on all 13B
rebuilds as well........I do, they are an "interchangeable part".
Marc Wiese
-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On
Behalf Of Steve Brooks
Sent: Monday, November 08, 2004 7:09 AM
To: Rotary motors in aircraft
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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