manifold/head port cleanup worth it? what else while engine out?
 

so, the whole engine and trans will be on the ground soon to swap from the parts car to the good car. its a (according to the po) roughly 250 RWHP turbo vics motor from a 99, with a 6 speed. runs great, unknown service history.
I'm thinking while its out I'm going to reseal everything, do input and output shaft seals on the trans, rebuild the shifter, swap timing belt, install the coolant reroute and silicone cooling hoses, and weld in the return bung on the oil pan. it blows a little smoke after being parked for a couple days, so I'm assuming valve stem seals are shot. ill probably have the head gone through at the machine shop instead of trying to do it myself.

anything I'm missing? I'm not quite super familiar with the Miata stuff. generally a chevy truck/old Mopar guy.

i was also thinking while i have it all torn down i may do some port matching, bowl blending, and casting flash cleanup on the head and intake and flyin miata maifold and downpipe. maybe a bigger throttle body.


I'm not necessarily looking for more power. as a matter of fact, i have no idea how to tune the aem fic-6 that the donor is running with. so I'm a little worried of messing with it too much. but, I'm hoping to get a little better throttle response and power under the curve. on my NA stuff, its always helped everywhere doing this kind of work, and not needed a retune or anything to compensate. what about a turbo Miata?

so, in short, other than the gaskets and head getting checked, what should i do while its staring me in the face? car weill be autocrossed, street driven, possible used for HPDE onoccasion. mostly abused on the street though, with AC and stereo blasting as a semi DD.

Generally the limit of the stock rods is about 250 WHP.I realize you didn't mention any bottom end work, but you might consider moving to forged rods if you're going to be beating on the car.

so, when i bought my donor car, the previous owner reported that it had a freshened engine with "h beam rods" forged pistons, and lower compression. I have no proof of any of it, and will be interested to see what i find on teardown. Im hoping he was honest, but he was going by what the guy he bought the car from told him.

Dropping the sump for the bung (where is the oil going now?) will show if the rods are stock, if not you are probably good to go - at least as far as the tune permits, and remembering the gearbox is the next weak link.

These are stock rods.
https://cimg0.ibsrv.net/gimg/www.mia...9dc8fddac6.jpg

Currently has what looks like an npt bung and heater hose for drainback. Id rather have a welded bung and ptfe lined an hose or something similar. Something i never have to think about again.