ufc_fan1

hello everyone. i just have a couple questions. i am building my own p port and i was woundering if it alright not to have your rotors or e-shaft lightened. what are the pros and cons? also would stock 2mm steel apex seals be alright for this motor(12a) i was looking to run nitrous. and finally what kind of oil pump or oil setup sould i use?



thanks

Nospig

If you have rotors lightened you have to have engine balanced. 12a rotors have 3mm seals.

ufc_fan1

my mistake. meant 3mm. but is it needed. can you build a p port withought lightening? how much does lightening and balencing usually cost?

ColinRX7

You dont need to lighten anything when you build a peripheral port motor.





You can take an entirely stock engine, close the side ports and make peripheral ports in the rotor housings, and rebuild it with OEM parts and it will be fine.



It's more a matter of what you are looking to get out of the motor as far as application goes.

ufc_fan1

i am looking to put this motor in my 1st gen. i want it "somewhat streetable." if its hard to drive on the street its not going to bother me. i am 16 and that stuff doesnt bother me. im not going to have any a/c or that stuff. i was thinking of porting it to where the power band is a bit more mid range.i was wondering if i should buy some deep groove rotor bearings and a racing oil pump from RB. what do you guys think of those products?



again thanx for the reply

PDF

If you want a fairly drivable engine make the inlet port diam 40-42mm. Make the inlet opening D shape and take the exhaust port up not down. Leave the ex sleeves in, port to them or a little higher. Rotating assm doesn't need to be lightened, it will still be good for 10,000rpm, even with small diam inlet ports. Machine the rotor bearing grooves deeper yourself on a lathe (with bearings in rotors) and buy the MFR oil pump available from Mazda. Buy a race rear stationary gear or window the bearing yourself. Increase oil pressure to 90-100psi and give all your bearings about 4thou clearance. Use 2mm oil jets with no ball & spring in the crank. Clearance all your seals to Mazda specs but give carbon apex seals 2.5-3thou clearance. This is a rough guide only. I built engine to the same specs above that runs consistant high 12sec quarter miles.

ufc_fan1

thanx for the reply. what carb were you running? i have a weber 48 ida. i still need to jet it right though.whith a high rpm motor is it oil that people worry about? all these people talk about lightening there rotors and so on, but i read an article on rx7 club where a guy said pretty much the main drawback to not lightening the assembly is engine response and rpm acceleration. im not looking for an extreme engine here. i just want something somewhat "reliable" and streetable. this is just my weekend toy.thats all i can afford with gas prices the way they are . so i figure i will just do a lot of oil mods. im trying to keep the project somewhat cheap.



the replys are appreciated, keep them comin'

PDF

48 IDA will be fine. I ran a 48 sidedraft on a long manifold, car was a daily driver. The oil mods and clearances are most important, don't worry about lightening, spend your money elsewhere e.g 10 or 12lb flywheel & a decent clutch.