1994 RX-7: Xcessive LIM & Fuel Rail install (in progress)

[prrex4ever]

Nice mod with the wideband in the dash, looks good.

[scotty305]

Update:
Car passed an emissions test.
Coolant seals finally gave up the ghost.
I'm afraid the old engine won't have many useful parts in it, but don't have the free cash to spend on a Mazda reman.
Pulled the engine out a week or two ago, this is probably the biggest car project I've taken on so far. I'm going to try my luck with a used engine from Japan.





Trying hard to avoid doing too many 'while you're in there' projects this time, we'll see how that goes...

right now I'm very tempted to remove the power steering rack and modify it as shown here (guys on another RX-7 forum claim that our rack is nearly identical):
http://flyinmiata.com/tech/depower.php?x=1

[TitaniumTT]

I've got a detailed write-up in the 2nd gen section on depowering the racks, tons of pics. I used the flying miata as a guide

DO NOT just drop that used engine in. Learn from my mistake. When I got my 13B-RE I could tell it had already been rebuilt once becuase it had the TII/REW exhaust sleeves in it. It lived a short time and died a PAINFUL death becuase a few seals were carbon locked. It would've been cheaper for me to crack it open, clean everything out and replace all the seals.

Personally I would skip on buying the used engine until you crack your old one open and see what's bad. It could be about the same price to rebuild your old one that it will be buy a used/condition unknown engine and drop it in. I know of too many people that have dropped in "good condition" used engines and they don't last long at all.

Personally I think you're making an assumtion on your old engine being completety fragged.

[scotty305]

Just read through your de-powering thread, TitaniumTT... thanks for the insight. Looks a bit beyond my comfort level but I will show the info to a few friends and see if any of them are willing to help. Very cool thread... http://rotarycarclub.com/rotary_foru...ead.php?t=7900


The coolant seals have been leaky for at least a couple of years, and the original engine has about 88k miles on it... I'm afraid that I'll need to replace at least one rotor housing and two irons, which would bring the cost of a rebuild higher than what I want to pay at the moment.

Blurry photo, but one face of the front rotor looks pretty rusty, and there was a significant amount of water coming out of both F & R spark plug holes when the eccentric shaft pulley was turned backwards by hand. That's why I'm thinking the old engine is in pretty rough shape.



I've already purchased the used JDM engine, and the seller offered a 30-day startup warranty so I'm going to hustle to get everything together (and hopefully onto a dyno) before those 30 days are up.

My plan is to tear the original engine apart once the car is back up and running, then decide to either rebuild it without rushing to get the car back on the road (and then remove & sell the JDM engine) or sell what core parts aren't trashed. I agree that rebuilding will be the best solution, but was afraid the core wouldn't contain enough re-usable parts.


Update 2010-07-20: I'm not sure the exact year and mileage of the Japanese engine (96 or newer because it includes the 16-bit ECU harness and updated rat's nest), but the turbos look to be in good shape, not a crack to be found:

[speeddemon32]

SOOOOO???? whats goin on now? I know its up and running. If I remember right all is well? correct?

[scotty305]

Wow I haven't updated this in a while. The Japanese engine went in right around 30 days from when it was purchased, and is running pretty nicely. The car has done about 500-750 miles on the 'new' engine, went to Sevenstock and back and few other short trips. Found an oil leak that appears to be the rear main seal and/or rear stationary gear o-ring... replacement parts are on the way and I will be tackling that in the next couple weeks. At first it seemed like the leak may have been from the oil pan, but closer inspection shows oil coming from the bellhousing and seeping down toward the engine mounts & oil pan.

I'm not looking forward to removing the transmission and flywheel, but I'm lucky enough to have access to a lift so I shouldn't complain. I picked up an Exedy Stage1 clutch to replace the original, which seems to be doing OK but has nearly ~90k miles on it.

Aside from replacing an old stock engine with a less-old stock engine, the original engine mounts were replaced with aftermarket Himni polyurethane mounts; they added noticeable (annoying) vibration around 1500RPM but are smooth at idle and at cruising RPM. Throttle response is noticeably more crisp, and it seems they transmit a bit more noise from the engine and transmission into the cabin. If I had to do it again I would try to find something slightly less stiff but overall these are pretty nice.


Just for kicks, I haven't reinstalled the power steering pump yet. The PS lines are still installed but the connections are vented where they would usually attach to the pump. The feel is better than having the PS pump installed with the belt removed, but I think I prefer the feel of having power steering. I'm probably going to reinstall the pump and try to get a ride in a few cars that have been converted to manual steering before trying anything more drastic.

Per the advice of someone with lots of tuning experience, I flattened out the idle fuel cells a bit and the car is now pretty happy idling around 13.0-14.0 AFR once the engine is warm. For instance, if the car idles around 30-45kPa those cells are set to deliver the same fuel pulse. If the load increases to 50kPa because of the cooling fans turning on, or from slowly letting out the clutch to creep forward, the fuel map increases quite a bit so the resulting AFR is 12-13 or so.

[mazda244]

looks pretty clean