Motor Build
The motor build ended up, like everything else on this project, taking longer than expected. Mazda Motorsports sent me some wrong parts, I kept deciding to replace more parts (hoses, o-rings, etc.), and then the M-Tuned rail didn’t fit right. Every step of getting new parts is another week down the hatch, and waiting for a decent response from M-Tuned took a while too. Last night, though, I finally made the final necessary modifications (read: liberal application of angle grinder) and bolted the last things to the motor. It’s now basically ready to go in (sans needing a few sensors off the 1.6 motor that’s still in the car) so I should probably talk about it a little bit.
The motor is, actually, a somewhat mild build. It started life as a running-but-smoking 99 motor that I got from Panic Motorsports (who are awesome, by the way.) I was planning on just throwing the motor into the car as it sat so that I could start figuring out the EMS/wiring harness situation piecemeal, but as the schedule continued to push back, I decided to just go ahead and do the full build straight off the bat. So, I gave it to Eastside Machine, the guy who’s done all my motor work for the last several years, and got it back with a bunch of nice new goodies installed. I had them assemble the short block and head separately, and I took it from there.
For the block, I replaced the oiling system with 2002+ parts. The later motor has a better windage tray/support plate, and the later oil pan fits it without modification, so I just used both. The new oil pump theoretically flows a little better as well. I got some unnamed H-beam rods from 949 Racing and paired them with the crazy Wiseco pistons that Flyin Miata sells. I’m using a stock crankshaft, wrapped in ACL Main and Rod bearings, held in with ARP main studs. The full rotating assembly was balanced, then the clutch/pressure plate were balanced to it separately.
The head is pretty mild as well. I’m basically just using everything Supertech sells. 1mm oversize valves all around, with their spring/retainer/seat combo pack. Stock cams should make the wide torqueband I want, but can be reevaluated later if necessary. I’m keeping the 99 puck-on-bucket shim system for now. I’m only planning on spinning this thing to 8000 RPMs (for now?) so nothing too intense is necessary on that end of things under the current plans. My main question is if the head will flow well enough without doing any other major modifications for the amount of air I’m going to be cramming through it, but there are several other people on MiataTurbo that are making similar power, with less built motors, so I’m hopefully safe.
I’m doing a coolant reroute (using the BEGi kit, flipped around), so I’m using a 99 head gasket (which has the fully spread-out coolant passages), and holding everything together with ARP head studs. I’m going to be using a half-width radiator on the driver’s side, so I’m running the coolant re-route down the hot side of the motor, which will keep all of the cooling system on that half of the car. The intercooler will be on the passenger half of the radiator opening, so that can keep all of the forced induction goodies on that half of the engine bay. Hopefully this will keep everything as clean as possible in what I’m sure will be a crammed full engine bay…
For fueling I’m running the M-Tuned dual feed fuel rail with 725cc Injector Dynamics injectors with an adjustable rising rate fuel pressure regulator. The M-Tuned rail intersected the valve cover, so I had to grind down the tips a few mm so that it would clear. I also had to grind away a bit of the third rib of the upper half of the 99 intake manifold so that it would clear the rail. Nothing too major, but it all needed to happen or else it wouldn’t bolt in and tighten. Finally, I’m doing the standard Toyota 1ZZ coil-on-plug conversion (you can see it in the picture of the motor at the top of the post). I got the very nicely designed mounting plate from Trackspeed, which made mounting easy. These will be sparking through the NGK race plugs that Flyin Miata sells. I’m trying out gapping them at 0.030 to begin with, and we’ll go from there.
As you’ve probably noticed, for the first phase here, the motor is going in without a supercharger. This will let me try to work kinks out of the wiring harness and get the EMS up and running happily without also dealing with forced induction. Corky Bell is fabbing me up a custom intake manifold with integrated supercharger mount (see pic at right), but it’s unclear how long that’s going to take before it’s ready. That’s the vision, though.
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