The 1MZ powered AW11 MR2 debuted at the Halloween Hooptifest at NHMS. I didn’t update here for a while due to working on the car around the clock to get it ready!
What we got done on the car:
- Completed the engine mounting – mounts worked great
- Custom exhaust – worked great, wasn’t too loud
- Clutch and shifter modifications worked well
- Installed a Grand Cherokee radiator in the car – extensive hood mods and seemed to cool fine (but it was also very cold for the race)
- Installed a custom oil accumulator, oil cooler and remote filter – there were some challenges here, more details later
- We didn’t finish the baffled oil sump – led to our downfall!
- The 1MZ needs more than the oil accumulator – we need to finish the baffled sump
- The oil accumulator (without a piston) may be filling up with oil foam over time rather than fresh oil. As it empties and then refills it may be getting more foam with every refill (from the air/oil mix sucked by the pump) – leaving it basically just an air tank after a while. The piston based unit doesn’t have this unit since you can mount it in any orientation.
On Friday of race week we went out for testing but only got out there for about an hour. We had a fuel leak when we showed up – the injector seals on the 1MZ are a bit fiddly so we had to change another set. Our oil cooler was also inexplicably leaking like a sieve. This was the same cooler we had on the car back in 4AGE mode so I’m not sure why. It appeared that our bracket had damaged it over time. We swapped that out which took a little while. When we got out the was running well but seemed to be leaking oil somewhere on the back of the engine. Testing was concluded when I blew the oil hose off the filter inlet – spraying all the oil all over the engine bay. We didn’t light on fire though and I shut it off immediately. We cleaned it up and all seemed fine.
On Saturday we were ready to go for the green flag. Car ran like a demon – I truly felt that we were one of the fastest cars out there despite my terrible driving. It only lasted about 45mins though. The oil temps had been solid around 210F for the first 40mins, but after that I noticed they were climbing up around 250F and still rising. Oil pressure was fine but seemed a bit lower than before. Since it had been smoking the whole time (the rear oil leak we never found) I brought it in to check the oil figuring it was low. It was a quart low but this didn’t seem significant. We filled it up and went back out. After another couple laps I noticed a lack of power and oil temp rapidly climbed up over 300F. The engine then seized and I coasted off the track.
We swapped the engine that day with our spare and were almost back on the track for Saturday. Instead we were ready for Sunday. Sadly the second motor only lasted a few laps before expiring. Might have been residual metal chunks in the oil lines… or may have been a bum motor to begin with.
Some lessons learned here:
I am going to go back and document some of the details we finished up over the last few weeks. Our plan for next season is to have two complete engine/trans units ready to assemble so if any failures happen we can swap the entire engine/trans unit without swapping anything over. We found that during the engine swap it only took ~1hr to drop and install the engine… it was moving all our stuff over from engine to engine that took the time (clutch, flywheel, trans, engine mounts, oil adapter etc). We think if it was ready to swap in we should be able to change powertrains in about 90 minutes which would let us get back in the track quick. Of course we hope that with a better oil system we can avoid that entirely!
Photos of the race were all posted here: https://www.facebook.com/TheCosmonaughts