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