onefastrx7turbo

I bought this 2010 with only 79K on the clock. The seller had stated it had a blown motor and I picked it up cheaply.



In the meantime, I installed the Bennet Built coilpacks and changed the plugs; she fired right up. I drove it like this for a few thousand fun miles and one day, it didn't want to start. I thought it was odd so I puled the plugs and cleaned them, which seemed to help. A few days later, same situation. Hard start when cold, OK start when hot. I thought I smelled coolant so I popped the hood and was greeted with this



So, I yanked the engine out and got to work.

onefastrx7turbo

I decided I wanted to add some additional oil cooling, so I pulled the stock oil coolers from another S2 in a junkyard for $85 complete and hauled them home



I swapped the stock RX8 oil thermostats to the FD RX7 oil thermostats which open at 170F instead of the RX8 230F!!! I cleaned them up by straightening the fins and then added a light coat of black paint to church them up a bit



to this. Not perfect, but you need new oil coolers to achieve that. This was good enough for me.



Then I got to work cleaning, measuring, and checking.



I wanted to delete the coolant hose and circuit going through the throttle body so I pulled the rear iron nipple out and tapped it, then installed a hex head plug.




I cleaned the intake manifold and the SSV completely. I was happy with the results.



I reassembled the intake manifold with all new gaskets, seals, and bolts on the slide valve pivot points and torqued to spec.

kevink0000

Nice color! Looking forward to more.

TeamRX8

iTrader: (25)

well I hope you understand that S2 including the engine is very limited production, and this engine was done in under 80k miles despite all the supposed improvements.

I would have found an S1 in equal or better condition to start with myself. Because at some point parts for the S2 are going to be harder to come by than the S1, and some are already NLA from Mazda btw, but best wishes just the same
.

onefastrx7turbo

Yes. This one had a partially damaged cat due to the owners not changing the coil packs when they failed. I think had they done this, it would have last longer.

onefastrx7turbo

Next came a new radiator and I cleaned the fans up a bit



I added foam to the radiator on the bottom and the sides. I did a small write up on this in the S2 forum


Next I cleaned up the journals of the stationary gears in preparation for two new main bearings. Red loctite on the lock screw completed the installation of both





Two new rotor housings completed the remaining hard engine parts to be replaced.



The rotors were next to be pre assembled. New side seals, corner seals and apex seals + springs along with new oil control and oil scraper rings, all new and all new springs


Shortblock stacked and torqued


Run out was checked, came in at .003



An Atkins Rotary thermo plug replaced the stock thermostat in the eccentric shaft and that completed the shot block build.


Everything on the engine was meticulously cleaned and inspected. I opted to replace the oil metering lines with new along with all the crush washers with new. Oil nozzles were cleaned and checked; all passed inspection


New waterpump installed, almost done



Engine ready to go back into its home!



A couple of new motor mounts and I had the engine back in the car



Almost there!



Racing Beat supplied the cat replacement pipe and after this, I was basically done with the installation



Engine fired right up on the first try and smoked me out of the garage for about 15 minutes as the oil, vaseline and assembly lube burned off. I took it for a quick 20 minute drive and all was well



All in all, the rebuild was easy enough. I set my own side seal gap at .0020. Currently the engine has about 115 miles on it. It semi hard starts each time but it has never not started. I am hoping that goes away as the engine wears in. Cheers!

Snox801

Awsome rebuild. You did a great job. That car is gonna be much more fun for you now with the pride of doing that yourself.

onefastrx7turbo

I hope so, Snox! It feels good to be driving it again, I had almost forgotten how it drives...

cbmmm3

awesome job. I salute you. I admire those that take the time to rehab - and do it in a meticulous fashion no less ! thanks for sharing

delhi

Fantastic work there! But all that for an auto rx8...... Just breaks my heart.

onefastrx7turbo

Thank you haha well, yes it's an auto RX8 but I use it for commuting and such. I still have the manual FD and the manual LS3 powered FC when I want to enjoy a few pulls

axiomatik

Damn. Impressive work and nice to see another S2 being kept on the road.

wannawankel

Keep that S2 going!

Prototype_uk

Did you do a compression test to see what it was after the rebuild and did the Hard Starts improve?

mazdaverx7

iTrader: (6)

Great work on the rebuild!!!! How has the car been running and driving since?

onefastrx7turbo

I did an initial compression test at roughly 600 miles and was getting 100s and 105s on both chambers. It still hard starts to this day and I have been troubleshooting the cause since I put the engine back in and I believe it to be caused by a vacuum leak somewhere although I haven't been able to find it with starting fluid or propane. I tested the solenoid tank with a vacuum tester and it holds vacuum, I checked the accordion tube and it's tight. I think I'm going to pull the intake manifolds off and check them for cracks and security. I used all new gaskets and I double checked all the vacuum lines, so this is aggravating.

Symptoms are:
hard start hot or cold - makes no difference
relatively high LTFT (14-18%)
MAF reads about 4 g/s at idle

mods are:
throttle body coolant loop delete
cat delete
air pump delete
GM coil packs and updated dwell settings

So far I have verified:
No vacuum leak at solenoid tank
No vacuum leak from tank vapor solenoid
intake tube is ok
Verified fuel pressure peak and bleed off, both within spec although the fuel pressure was closer to the low end, but still passed per the manual

10KRPM

Impressive work on the rebuild. I'm curious about the hard starting, will be interested to see if you find anything with the intake. Great color!!!

spectre6000

Did you have any issues finding any S2 specific parts? It was mentioned above that many S2 parts are already NLA, but you seem to have managed just fine, even with the even more rare automatic.