The 13B Rebuild Chronicles :: Chapter 8 :: Engine Install, Part 2

12 03 2009

Sunday came and I could not stay away. After brunch with the family I spent some time online researching the oil injector issue, then snuck out to the man-cave with my son (got to get him initiated sometime).

What I found is that the stock 13B’s have an oil metering pump (OMP) mounted to the front cover, just beneath the water pump, which feeds oil directly into the rotor housings via the oil injectors. This is for the purpose of lubricating the metal on metal contact between the seals and the housing. The oil injectors have been known to clog up from time to time, so some enthusiasts jettison the OMP in favor of running premix (two stroke oil mixed in with the gasoline). This made sense to me for a race application as it removes the possibility of engine damage due to a faulty OMP or clogged oil injectors.

So, upon my arrival at the cave I inspected the engine to see what the story was. If you recall, the oil lines to the injectors were missing. I compared pictures I had found online to my oil injectors and found that the harnesses of the oil lines were intact on the injectors but the lines had actually been cut…very strange. Then I inspected the OMP…oh, hold on, I don’t have an OMP. The OMP mounting area on the front cover had been covered up with a cover plate (standard issue when doing the OMP removal modification).

Now, some of you (who have read this blog from the first chapter) might be smelling a rat at this point…I certainly was. The guy who sold me the car had removed the OMP. Which means that he was running premix. Which means that I should have been running premix. Uh, information I could REALLY have used BEFORE I ran my car at Daytona with straight gasoline! $3.99 worth of Valvoline two-cycle oil could have saved me over a thousand dollars worth of rebuild parts, and 18 months of no racing. But then I would never have started this blog, so I suppose everything works out.

Truthfully, this experience has been worth it to me, as I have learned so much about my car by doing this rebuild that it is worth it. By the time I get her back on the track I will know the car and engine inside & out…literally.

Anyway, so the other thing this dork of a previous owner did was to just snip off the oil injector lines without capping them. Not sure how much of an effect this vacuum leak would actually have on the engine, but it would certainly not help.

So, to business. I removed the oil injectors from both the rotor housings and the lower intake manifold, and plugged all four holes with 10mm bolts. Sorry, forgot to take pics of this.

Then I climbed underneath and installed the new exhaust manifold gasket and bolted up the exhaust headers. Below photo taken from underneath the engine. That was all for Sunday.


Then Tuesday afternoon Doug and I ditched work a little early and met up at the cave to try and finish things up.  We installed the distributor, spark plugs and wires. Luckily Mazda had the good sense to mark the top of the distributor cap with the spark plug positions. What a simple yet profound concept…how come all auto makers don’t afford us this simple convenience?


Then the new oil filter went in, the fuel rail and fuel injectors, the alternator & belt, and finally the upper intake manifold. Not much to tell about all that…pretty straightforward. I had all my nuts & bolts in clearly marked zip lock baggies from disassembly so it was just a matter of bolting parts on.

The tricky part was connecting up the electrical harness, as I had marked those with magic marker on duct tape (stuck to each plug/connector etc.) and many had worn off or faded so as to be ineligible.  After quite a while of trial and error and assessing wire and vacuum line shape, length etc. we finally got everything hooked up correctly (we hope).


We flipped on the power, ignition lights came on, fuel pump fired up, everything seemed to work fine.  Even though we had not put in fluids yet we just wanted to hear her turn over once or twice, so I hit the started button…and…nothing happened!  Oh bugger!  We’ll have to check the starter wiring and do a little troubleshooting on that but I doubt it will present a problem to our enormous brain power.

Next we went to install the radiator but found that I have apparently lost a vital piece from below the engine. There is nothing down there for the radiator to rest on or bolt on to.  I vaguely recall removing a skid plate type setup from below, but we scoured the shop and it is nowhere to be found. I’ll have to go back to the old house and hope that it is leaning up against the wall in a dark corner of the garage or fabricate something new to secure the radiator. Luckily we have all the tools available in the shop to cut, shape and weld metal.

So, the final punchlist grows shorter:

1. Install radiator.
2. Install airbox and hoses.
3. Troubleshoot starter.
4. Flush fuel cell and replace with fresh (premixed) gas.
5. Top off all fluids.
6. Fire her up!

We should be able to easily take care of all those items this Saturday.  After that we’ll turn our attention to an all-around brake job, suspension & alignment check (camber/caster), replacing a dented quarterpanel, and of course the very important new paint job (blue & white Mazda colors)!

So, until Saturday then,

Grant Boshoff
Thrust Motorsports




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