The Day the Earth Stood Still


June 10, 2006

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.


Yup...that's what a blown engine looks like.

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.



All the ancilliaries disconnected and held out of the way. Tweedle Dee and Tweedle Dum AKA Guido and Rich: "Hey, you might want to get your hand out of there before Chris comes back!"

Engine lift positioned to extract the engine...I need a bigger garage! Like my fender guards? Success!


A broken heart. A very disheveled looking engine bay.

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.


Fried main wiring harness and lots of oil pooled in the throttle body.

There shoudl be a locator pin in that hole. The dented inner side of the bell housing from the errant clutch locator pin.

Turbo. Engine front.

Alternator removed - wiring and OMP routing. Timing sensor plug.

Rear of the throttle body. Throttle body removed.

UIM removed. TPS connector and Idle air control connector. Coil packs

Oil filler neck removed - better shot of the coil pack mounting. Wiring and plumbing around the fuel purge solenoid.

Coil pack removed. Fuel line manifold.

Fuel rail inlet lines and wiring harness routing. Solenoid rack removed w/supporting brackets

coolant sensors in the back of the water pump housing and wiring routing. ACV removed. Fuel rail/injector electrical connectors and wiring.

Knock sensor wiring. Fuel rails and oil injector plumbing. Wiring Harness removed.

Fuel rails removed. Leftovers from my vacuum hose replacement 10 years ago!

LIM removed. Yes that is the ORIGINAL paper LIM gasket! Note orientation of fuel diffusers.

Routing of OMP lines and electrical harness. Water pump housing (and water pump and filler neck) removed.

OMP removed. Ignition triggers. Note white paint on top sensor.

Clutch removed - note the loose and missing locator pins. Coolant line quick disconnect configuration.

A workbench piled with parts. The bare short-block ready for teardown.

April 2007

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.


Broken 1/2" adapter. Sheared it off! The damaged apex seal tip - black arrow.


Broken Hurley seal tips.


Tearing down 3 engines - Ready for cleaning and build preparation.


Now it was time to Rebuild! Let's continue...
Rebuild Overview Part 2
Rebuild Overview Part 3
Rebuild Overview Part 4


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This page last updated March 19, 2009


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