Where to begin? Virginia International Raceway. A cool clear summer morning. Wisps of morning fog
linger in the lower lying areas hinted at the oncoming afternoon humidity sure to hit. The smell of wet grass.
The snake of black asphalt was calling. It was a wonderful day to be at the track. MDA weekend on the full
course. I settled into my morning ritual of preparing for the track. Instructors go out first so as an
instructor I offered a colleague a ride to get him acquainted with the track. The car was ready. Nothing
major had changed since the last outing other than installation of an HKS TwinPower ignition box. Plug and
play. I always start on 10psi boost and run the usual 93 pump gas with 8oz of premix in the tank. The session
started well, picking up speed as the track rubbers in and the tires and driver warmed up. All was well.
Mid session exiting the lower esses and there it was. The tell tale popcorn sound of detonation.
Immediately I lifted. I knew exactly what that sound was. I finished the remainder of the session without
issue. Yet as I rolled into the pits and came to a halt in my paddock space there was the tell tale signs of
a “blown engine.” The lumpy idle. The low vacuum. The engine visibly doing its death shaker gyrations.
Mixed sensations of anger, perplexity, and sadness engulfed me. I did some basic checks for anything loose
or amiss but I was just going through the motions…I know my car too well to know when something is terminally
wrong. What next? I loaded up my Princess and brought her home. And thus began the two year saga of rebuilding
a better machine.
I shall start by saying that much has already been published about how to rebuild a rotary engine
so I will say little to that effect. The following pages will point out some of the things that, me as
a new “builder,” found tricky or particularly noteworthy. And also what I did to prepare for such an
adventure. This included doing 3 “practice” rebuilds, two Series 5 NA engines, one for my racecar and one
I ended up selling, and another FD engine to be used as a spare engine for anyone who might need it on short
notice, myself included. I was particularly lucky to have a good supply of spare parts – my own “blown”
engine, a spare blown short-block from a factory rebuild with only 8K miles on it I took in trade for some
help to a friend, and another “blown” low mileage (13k miles) short-block on “loan” from another friend. With these
three good condition short-blocks to work from I had a decent supply of matched rotating assemblies and at
least 4 good housings to choose from.
Back to my rebuild, I found that as I went along I wanted to change more and more, this being the
first time I had removed the engine from my FD and all. It is the kind of thing where you say to yourself,
“well, while I’ve got it apart I might as well do X…and Y….and Z….and….” And, thus why it took me two years
to simply rebuild an engine. So what exactly was it I did? Lots! I’ll break the specific work up into
separate pages to describe the technical details but in short I did the following:
Rebuild and porting of the 13B short-block to include port matching the intake side.
Custom baffled deep well aluminum oil pan.
Installation of dedicated 2 stroke oil feed system.
Replacement of all the fuel system lines with SS braided hose and AN fittings – tank to engine.
Installation of a dual fuel pump arrangement with fuel tank baffle box cover.
Replacement of all turbo hoses with SS braided hose and AN fittings.
Relocation of the ignition coil packs to the drivers’ side fender wall.
Simplification and rebuild of the engine wiring harness and removal of all un-used control solenoids.
Porting and polishing of the throttle body and removal of the double throttle control assembly.
Turbo “improvements” to fix lower grade hardware and potential trouble areas.
Installation of 3 Bar MAP sensor and tuning for higher boost applications.
There are many, many other smaller things that I did and which can be found by combing through
each of the above pages. Like I mentioned it has been two years of work to get it all back together
and it’s been a long road, I can tell ya! A lot of time went by before I was ready to face the music
and it wasn’t until March ‘07 that I actually got to the point of pulling the engine out of Princess.
The car sat for 6 months before I even went near it, more out of my disgust more than anything. Truth
be told I also had my hands full with my ITS racecar, aka Rusty, but I still could have, if I had
wanted to, done some work on the FD. Nevertheless I started with some initial teardown around the
beginning of March ’07. Before I started I made sure I had enough supplies – baggies, pens, paper,
tape for tagging, small boxes for parts, lots of cleanup equipment and pans to catch fluids, and enough
space to put parts as they came off the car.
First were the basics like, hood removal, AC removal, PS pump removal, disconnecting the ignition and
main wiring harness (the main wiring harness is unplugged at the ECU and pulled through the firewall - it
comes out with the engine - I unbolted the ABS to facilitate this), and disconnecting coolant, fuel, and oil lines. I had made a conscious decision to remove the
turbo with the engine and was able to pull it off but it was tight. I don’t know which would have been
easier. By the time my good friends Rich Mills and Guido Debartelemeo came to lend a hand. Pulling the
engine went smoothly and took only about an hour before it was sitting on the stand. Throughout the whole
process I was sure to take copious photographs of EVERY step and each and every line, wire, and hose was
tagged. All removed hardware was ziplock bagged and labeled also. If I could, I reinstalled the bolt
or nut back into the hole or on the stud it came out/off of. And I can say that even after two years I
was pretty much able to resurrect every step and find every bolt I needed to reassemble the whole lot.
The million dollar question was, however, were there any signs of what caused the engine to let go?
Nothing immediately apparent was amiss but some things were not pretty. The main wiring harness was badly
heat damaged where it crossed over the downpipe, there was a lot of oil in the throttle body, and most
disturbing was the flywheel was missing one of the three locator pins and the other two were close to
falling out. With the engine out of the car and on the stand the other ancillaries could be removed.
Intake manifolds and throttle body came off. Alternator, electrical harnesses, fuel rails and lines
were removed. Coolant lines, coil pack, solenoid rack, oil filler neck, water pump housing and water
pump, pulleys and timing gear, OMP and lines, any remaining sensors, and the morass of vacuum hoses…
all disassembled. What a mess! The below chronicles the teardown and provides a photographic record
of where what went and how.
Yes this was nearing the one year mark! It was time to step up the pace now that
the grief of blowing up the engine in my car had worn off. I finally found the wherewithal to start
the engine short-block teardown process. My friend Rich was again kind enough to swing by and help
me out with the tear down. It was kind of a learning exercise for Rich but I think we were both equally
interested in what the insides of my engine looked like. Sure enough there was one apex seal tip that had
broken off from the detonation. Bummer. I took photographs throughout the entire process
since I knew it was going be weeks (little did I know how long it would really take me) before it all
went back together and I was certain I would forget “something.” After struggling with the front e-shaft
bolt for about 45 minutes it went fairly easily and we had the block entirely in pieces in about another 45 minutes. The
front bolt was a real PITA. Repeated impact wrench hammering, lots of heat followed by ice, both of us
leaning on a 3 foot breaker bar (even me STANDING on the bar) did nothing. I even snapped a ¾” drive socket
adapter. It eventually did let go. It was the original nut and had never been removed.
This whole process of longblock teardown was repeated for the other two engines I had available.
Unfortunately all with vERY similar undoings. The 8k mile engine had a broken seal tip just like mine. And the 13k mile
fitted with Hurley seals had the tips of two seals in one rotor missing. A real shame and evidence
of how temperamental a rotary can be. More details will be provided in the subsequent rebuild pages so, read on.
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This page last updated March 19, 2009