magnumP5's RX-7 Build Thread

[PrinceValorum]

Oh lord, 10k+rpms...

Will you need some kind of more durable seals than whatever they used on the RX8's from the factory? I've heard a number of stories of them blowing seals with as few as 30k miles. I mean there's always rotary hate, but it seemed that even more of it was directed towards the RX8's.

 

[magnumP5]

Oh lord, 10k+rpms...

Will you need some kind of more durable seals than whatever they used on the RX8's from the factory? I've heard a number of stories of them blowing seals with as few as 30k miles. I mean there's always rotary hate, but it seemed that even more of it was directed towards the RX8's.

No special seals required to run the RX-8 eccentric shaft and stationary gears. To run RX-8 rotors requires a lot of work though so I'm not going down that route. I have ceramic apex seals so I'm not too worried about them. However, I would want to put some kind of scatter shield on the transmission bellhousing before upping the engine speed to 10,000 RPM.

 

[R-X-R]

10K+ RPM, u r living the rotary dream

 

[magnumP5]

10K+ RPM, u r living the rotary dream

My ears are going to bleed.

 

[Lewis7789]

Perhaps, but totally worth it. You'll just have to crank up your stereo (that you didn't delete, pffsht).

 

[hat1018]

My rotary dream includes epic fireballs. My dream also needs a rotory powered car, and money, and time.

 

[Lewis7789]

^^^ And a lopey idle.

Will you have that gnarly idle, Jon?

 

[ajkulish]

usually that idle comes from bridgeporting the engine. i would really hope he would do that after all the work for a perfect exhaust and itbs. easy, free power.

 

[magnumP5]

^^^ And a lopey idle.

Will you have that gnarly idle, Jon?

usually that idle comes from bridgeporting the engine. i would really hope he would do that after all the work for a perfect exhaust and itbs. easy, free power.

Yeah, like AJ said you usually need to have a bridgeported or peripherally ported engine (like the Rolex RX-8's) to get that lope. I'm going to be running a very large street port in my engine and I plan on setting the idle around 1000 RPM so it may not be that aggressive. Sure it sounds cool but bear in mind the Rolex RX-8's are actually idling over 2000 RPM so it's not very streetable. Also bridge and peripheral ports are like running very large turbochargers - no power until 8000+ RPM. I'll hopefully have around 230 whp with a fairly useable powerband and stable idle.

 

[PrinceValorum]

I've always wondered why people considered a high idle to be non-streetable. Is it because of the noise, or what? I wouldn't really have a problem DD'ing a car with a full cage, but I know I'm kind of in my own boat drifting off to sea on that one, lol.

This thing's going to fly with 230whp!

 

[magnumP5]

I've always wondered why people considered a high idle to be non-streetable. Is it because of the noise, or what? I wouldn't really have a problem DD'ing a car with a full cage, but I know I'm kind of in my own boat drifting off to sea on that one, lol.

This thing's going to fly with 230whp!

I didn't mean to infer a high idle wasn't streetable. I mean, it is kind of annoying when the car takes off when you let the clutch out because it's already at 2000 RPM, but I was getting more at the unstable aspect. We've all heard the Rolex RX-8's idling. They run peripherally ported 20B engines and cannot maintain a stable idle between 2000 and 3000 RPM (seriously, watch their tachometer). Can you imagine trying to start from a traffic light with that? That's why they're always jerking around at low speeds. It's basically just an on/off switch and all power is made at 8000+ RPM. Since my RX-7 is still going to be a "street" car I'd like to be able to cruise around at 25 mi/hr occasionally and have some power/torque at 4000 RPM.

I'm basing the 230 whp number around Defined Autoworks test FB. They're running a 13B-RE (13B Cosmo) motor in it with the same port configuration, and similar exhaust and made 232 whp at 8600 RPM, I think. They also had some modifications to the rotors, which affects timing (makes it behave more like a bridgeport), but I should have better intake and ignition systems. Honestly, if I see 220 whp or above I will be very happy.

 

[THE Phen]

A lot of the jerking around is also due to a 4" clutch that weighs 8lbs... But yeah.

 

[PrinceValorum]

Gotcha. It wouldn't look too cool stalling the car picking up the kid from school in front of all those hot moms.

 

[ToNeZ90]

which is why you have your kid come out with a grin from ear to ear and you scare the s*** out of the rest when you restart the car.

 

[Lewis7789]

Jon, did you use a de-pinning tool or just jewelers screwdrivers? If a tool, can you direct me to a link? Thanks!

 

[magnumP5]

Jon, did you use a de-pinning tool or just jewelers screwdrivers? If a tool, can you direct me to a link? Thanks!

I assume you're talking about depinning electrical connectors? Yeah, I just used a very small jeweler's flathead screwdriver; like the ones you get in glasses repair kits. I had to grind the head down a little so it was more of a point when all was said and done. Most of the stock terminals are held in the connectors by little clips, which need to be pried up before the terminal can be pulled out. Aftermarket connectors are a whole different story.

 

[Lewis7789]

Cool beans. Thank you very much, good sir.

 

[magnumP5]

Woohoo, just dropped $1300 on engine rebuild parts, and that wasn't even all of them! I realized prices kept going up (they literally change weekly) so might as well purchase now!

 

[PrinceValorum]

Fun fun fun!

 

[magnumP5]

Fun fun fun!

Estimated ship date 8/30 I guess this is what I get for ordering every part individually instead of a rebuild kit (see why below).

Just snagged a TII oil pump off eBay. It's a different P/N from the N/A one I have and according the Mazdaspeed Motorsports they flow a little more. So for those keeping track I have parts from the following engines/models going into my engine build:

S4 RX-7 TII (13B-T): Intermediate housings (irons), exhaust port sleeves
S5 RX-7 N/A (13B): Rotor housings (sans exhaust port sleeves), rotor assemblies (sans corner and apex seals), alternator, water pump assembly, front and rear (auto) counterweights, oil filler neck
S5 RX-7 TII (13B-T): Oil pump assembly
S6 RX-7 TT (13B-REW): Corner seal springs, oil pressure regulator (rear)
RX-8 (13B-MSP): Eccentric shaft, front and rear stationary gears and bearings

You can see where ordering a series-specific "rebuild kit" would get me into trouble.

EDIT: I actually DID something with the car last night, or with its parts at least. I've started cleaning all the engine components to get ready for balancing and painting. It turns out a hose, some Purple Power, a shop vac, and some brake cleaner makes for a good parts cleaning process.