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Here we go - Rebuild time! I've owned this car for just over a year and have spent more time behind a wrench than the wheel. I spent all of spring troubleshooting the usual symptoms (redid vac lines, 3k hesitation, replaced turbos, exhaust leaks, etc) and had a functioning sequential TT RX7 for over the summer.
Unfortunately I wasn't willing to put it away early this year as we still have no snow on the ground(I'd still be driving it if it didn't blow). The rear rotor went out during a semi spirited drive on a cold November day. There were no other changes to the car prior to this so I suspect the temps leaned out the engine. I pushed the car all summer with no issues (14 psi on max boost with a Pettit Unlimited ECU - i know I shouldn't have but I did).
The only other things I did a few weeks prior to it blowing was steamclean, seafoam and change the oil. The seafoam was used briefly during steamcleaning and was followed with more water. I also added a little bit to the engine oil and idled it for a minute prior to the oil change. The car ran fine for the next two weeks with the only issue being that it leaked a whole lot more oil than usual. It used to leave a drop or two but after the oil change it would leave a puddle. I was just about to investigate this but then the engine blew.
Anyways I'll somewhat document progress in this thread and ask questions as I go. I wasn't planning to do anything until spring but we've had a fluke warm week here in WI so I can actually get the engine pulled and work on it inside. I will figure out whether I'm rebuilding, importing or sending the engine out once I have it torn apart.
I started last night and removed what I could from the top of the engine. AP, UIM, ALT, Rat's Nest, Ignitors, Intercooler, Intakes and other small parts have been removed. I plan to get the Y-pipe, turbos, manifold and exhaust out in the next day or two. I understand most of this can be left in while the engine is pulled but I felt comfortable doing it with it in the car and it has to be done either way. All removed parts have their accompanying bolts/nuts baggied and zip tied to the part and then are shelved to keep organized.
Do the AC lines need to be disconnected and recharged for engine removal? It doesn't like they are from the tutorials I've read but I'd like a clear answer.
If they are not disconnected how much play in bending do they have for working around them? I had to bend the dryer lines quite a bit to remove the intercooler duct.
Per the rotary resurrection walkthrough it looks like the engine is pulled up with AC lines still connected to compressor and then the compressor is removed when accessible in this position. Is there enough play in the lines to do this?
No. You can pull the engine without disconnecting any ac lines. Unbolt the compressor from the engine once it is slightly raised out and support it with a bungee cord or something. Guide the motor around the ac lines as it comes out.
I've got everything to the point where I just need to pick the engine. However the lifting lug on the UIM is missing (UIM is also removed). Is there another pick point I can use? Is one of the transmission mounting bolts okay?
Also I can't disconnect the oil cooler lines. The connection behind the radiator has the clips removed but the lines are seized in place and I can't get them to budge. I wonder how its been holding for the last 10 years without the clips? At the oil cooler the clips are in place but I can only remove one of the lines. Everything is soaking in PB blaster right now. If they can't be disconnected it can all come out still attached to the cooler, right?
I've also got the exhaust/turbos removed and took some vids of the rear seals. They all seem to be in tact and all had a little spring to them when I pushed on them. There is some buildup or something on the 3rd seal the way the light hits it. I'm not sure what it is. Comments?
The oil cooler lines can be a pain to disconnect. It's an O-ring fitting, the clip holds the line in place and the O-rings do the sealing.
It can help to twist the connection some to break that seal loose. Get some WD-40 in there, PB Blaster is good on rusty bolts but you are trying to get those o-rings wet and slippery, and WD-40 is typically better for that. Twist, pull, twist, pull, repeat. If it doesn't want to twist with your hands, use a wrench on the two halves of the connecction to get some twisting force going.
Also, make triple sure the clip isn't there or has been removed - sometimes a dirty line makes it hard to see the clip.
As far as the shots through the exhaust port, it's really impossible to tell anything of value looking in there. Most times apex seals break at the very end, and you can't see the side seals at all. Don't sweat it until the motor is out, it will tell its story soon enough.
The trans bolt holes are good for a motor lifting point, one of them I believe is threaded all the way through so you can run a bolt in from the front side and put a chain on it. I would use a junk bolt, the chain can tear up the threads, and you don't want to damage your trans to engine bolts if you can help it.
Just take your time pulling the engine, the turbo wastegates like to get hung up on the AC lines, be very watchful there.
I got the oil cooler lines off. I managed to get them freed up at the cooler and worked my way back to the first connection by the block. I had to remove them at the threaded connection because they would not pull apart. The clips are definitely not there and trying to knock the ends off against the floor or with a hammer yields nothing. I'll have to soak them in something for a while.
I believe the engine if finally 100% ready for the pick. Question is how do I get the trans to clear the PPF? I've removed the nuts but the studs in the transmission are still nested in the PPF holes. Will these lift out once the cherry picker starts pulling it up?
Got it pulled out last night. My lovely wife actually did an excellent job of helping me guide the engine out.
Interestingly the trans looks like it's been had some work done as it appears to have been resealed (obviously not OEM beads of gasket exposed) and painted a greenish gray color. Are there any special trans out there or is this just an OEM rebuild? I didn't think too many of them would get rebuilt as most lean towards a swap. My understanding of the car history is that this transmission would have been replaced at the 80k mark so i don't think there would be a reason to not use the original trans unless it had crapped out at that point.
I strongly advise against buying a used motor. 9 times out of 10 the used "jdm" engines are bad out of the box. There is no way of telling how many miles are on them and how they were stored. I've seen them with rusted internals, debris inside, etc. Even if they compression test ok you could still have a bad coolant seal or oil control ring. the only time I suggest a customer buy one is if they have no core to start with. Best thing is to have your existing motor rebuilt by myself or one of the other reputable forum sponsors on here. I also have access to a very limited amount of Mazda Reman engines.
An auto engine will swap in but 2 of the trans bolts will not be able to be used" so technically it will be a little weaker. That being said, there are plenty of cars running around like that. The airpump pulley is also smaller and some of the vacuum hose routing is slightly different. You would use your 5 speed harness.
Got the rear iron off yesterday and the results are in. It looks like I broke the ends of two apex seals on the rear rotor. The apex seals were three piece design.
The rotor has a gouge on two faces. One face has a couple dimples and the other has a long gouge with what looks like a piece of embedded apex seal.
The housing may be okay as from what I can tell there is only one gouge where the exhaust chamber would be (starts at about 6:00 position and runs until it hits the exhaust port). However it is very deep so most likely it's crap (definitely more than just a fingernail catch). I have an endoscope coming in soon so hopefully I can inspect the turbos.
Seeing that I now most likely need a new set of turbos, housing, rotor and transmission a JDM swap seems most practical as buying all those parts individually would cost about the same. If the JDM motor doesn't plug and play I can hopefully strip both engines to rebuild one or swap/sell parts as needed.
Pick up good used housing and rotor ($200-400/100-150 on average) and rebuild your existing motor. The 3 piece seals are extremely weak after 20+ years of heat cycling and stress. A full twin turbo rebuild kit is around $1700 or so (can be cheaper if you reuse stuff but I don't recommend it) and should come with just about every seal, gasket, and oring you need to rebuild the motor and drop it in. A used set of turbos can usually be found for $200-400. I have 3 or 4 sets laying around as well as housings and rotors. Buying a jdm engine and trying to run it without rebuilding it is a ticking time bomb. Blow it up and you will trash your replacement turbos too.
I picked up a used trans from charlies7 over the weekend and yesterday I couldn't get my shifter to mount into it. Upon closer inspection it seems the mounting plates are different even though the overall trans appears to be the same. I swapped the shifter mounting plates over from mine to his and was able to properly install the shifter. Any idea what happened here? Was his or mine the original and what exactly is the difference? Mine is on the left.
I've got everything back in the car and it doesn't want to start.
Compression - It's got nice even pulses with the plugs removed. I ran a compression test and got an even 60 psi on all 6 faces. I know thats low but this is on a Harbor Freight tester and I got similar numbers on a known working rotor.
Fuel - with spark plugs removed there is noticeable fuel smell when cranking. Fuel lines appear to be routed correctly near the ingniters.
Spark - tested all four wires and there is spark. Tested with actual spark plug grounded to chassis.
There is no tach movement during cranking. I've gotten a couple almost hopeful farts during cranking. Starting fluid makes it almost happen and there is smoke exiting the exhaust but ultimately no dice. I've tried adding a capful of oil and ATF to aid compression. Any other advice?
Well I'm sure that's frustrating. Try a better compression tester to verify you are pushing 60 psi. That may be too low to crank over.
If you smell fuel, you may have some flooding. Did you do a lot of cranking with the EGI fuse in? If you are getting fuel and spark (with good compression), the only other thing it could be is timing
Looks like I may have the connectors backwards. Of course I took this picture on the way out the door for work so here I am waiting for the day to finish.
Swapped the CAS plugs around and i fired right up on the first try. Smoked the heck out of my garage for the first few minutes but everything seems to be well. So far I've a had it running/idling for just under an hour and gave it a little drive around the block. Only issue is that it seems the fans only come on if the AC is on (it started doing this before I blew the engine).
So what are people using for rebuild kits? Looking for something reliable that will handle 3-400hp with high boost. I've heard atkins, goopy, and a mix between seals for both soft and hard seals.
1) To answer Houstonderk I just used an Atkins kit with Atkins apex seals and water jackets.
2) There are no major visual leaks or smoking issues that I've found so that's a good thing.
3) Every other day the low coolant light comes on but goes away once the thermostat opens. I keep having to top off the coolant about a cup or two at a time. I'm assuming it's just slowing getting rid of air pockets? I didn't open any bleeders and initially just poured coolant in.
4) Hot start issues. The car starts up perfectly when cold but once warmed up it doesn't want to start right away. I have to tap the gas pedal and after a couple tries it'll start up. It seems the hotter it is the harder it is to restart.
5) On several occasions the car has died right away after starting. It'll rev up once it turns over and then drop down and shut off but starts right back up (during cold starts). In some instances it did this back to back before being able to idle.
6) On three occasions the car has died while driving. During all three occasions it was when I went into neutral and had my foot on the clutch while slowing down.
7) The idle is very high. About 1700 without AC and 1200 with AC on. The AAS is screwed all the way in and the throttle cable adjustment is all the way out (barely touches). I didn't spend too much time adjusting these as the only adjustments left on them increases the idle speed.
Are 4,5,6 and 7 related somehow? It seems to be the only issue I'm having and everything else seems to be in good shape.
Turns out I pinched a thrust bearing during the rebuild. Noob error, I know, but I did double and triple check it during the build. Maybe I had a brain fart and turned it on it's side to torque it down? I don't know, either way it happened.
Sourced new used front stack components, pulled the engine, rebuilt and reinstalled. The engine ran perfect for about a day and then.....
...fuel leak at the supply hose. Replaced the supply hose and it ran perfect for about a day and then....
FPD started leaking. Bypassed the FPD like I should have the two previous times I had the fuel rail out and also replaced all the fuel hoses and then....
...intermittent primary boost problems. Pulled the UIM to reinspect all vac hoses only to find out that I just needed to hit the CCV actuator with two squirts of WD-40 (yay! but *groan at the same time) and then....
...no issues- it has been running smoothly for the past month! I thought I'd wait to update because of all the little gremlins. I am now almost 2000 miles into the build and have started incorporating stock level boost into my daily drives. The 3k hesitation has reared it's ugly head again (got rid of it pre-rebuild) but I can live with it for now. It seems the rebuild of the front stack somehow cured all the idle, stalling and hot start issues somehow. Perhaps someone can enlighten as to how? Either way I'm glad they are gone and I'm a happy camper.
12-09-15, 09:52 AM
