So I just found out that pretty much all the internal parts to my original 87 TII 13b are junk. My question is what parts should I use to build it in order to get the best engine. By best I mean a solid balance between reliability and power. I dont want to spend 2 grand on an engine that will only last 10K miles. I have heard so much misinformation that I don't really know what is correct any more. What housings would be best, what irons, what rotors. I'm only curious about engine internals for the moment. I'm still debating on porting it, but I will probably end up doing a middle of the road street port.

So lets hear it guys, what parts should I start looking for?

 

ha, best.

I'd personally go with an s5 non-turbo rotating assembly. Makes better torque and all-around power, but you'd need a standalone ecu. Depends on how experienced you are, or how much you're willing to learn.

 

You have to use the factory service manual and check if your irons and housings are within spec. As far as internals, it's the same thing. Are they in spec? If they are in spec, the engine will be fine (assuming it's built right). The part quality, not the series, will determine the engine life. Also the tune and driving habbit, but that's a different issue.

 

there is no more reliable way to build an engine, mainly because the irons are the weak point.

if you want to step up your game, get some ceramic apex seals during the next rebuild, be sure to premix your fuel and maintain your cooling system religiously. that is as reliable as you can get it aside from tuning.

 

So buying all S4 components that are in spec or as close to perfect as possible will build a reliable performance ready engine? sounds like a plan

 

For the overall best reliable/streetable build. Ceramic apex seals as mentioned earlier (maybe even 3mm seals if you're planning on some high'ish boost levels) with some S5 N/A Rotors/counterweights and a streetport. You won't necessarily need a standalone as long as you have something that can control timing (even Rtek 2.1 has adjustable timing maps).

 

The best balance between reliability and power:
- All new parts
- Assembled by a professional who offers a warranty

If your internals are all junk, I would imagine that your housings are also junk or close to being junk. Plan on spending $4,500 to $6,500 for the rebuild. Add about $1,600 to that if you go with ceramic seals.

 

mazda has updated some parts. the irons have the big dowel lands, the rotors have side clearance like the Rx8 rotors.

you want to upgrade to the FD/Rx8 spec stationary gears/bearings.

FD oil pressure regulator, S5+ tension bolts

that's the strongest engine you can build using OEM parts. a new housings +rotors engine ALWAYS runs better.

keep in mind though, if you have an ECU that can't handle the ignition side of the rotary, it'll break housings no matter which ones you use.

if you look you'll see the people who break irons are only running a couple of ECU brands.

 

irons break regardless, im referring to the thin coolant seal walls breaking versus twisting the engine and cracking dowels.