Hey all. I recently picked up a 94k mile 1990 GXL. Obviously, the engine and transmission are out of the car haha.

Besides general things, like fluids and cracked hoses, what kind of seals/gaskets/maintenance parts should I be on the lookout for? I am a rotary noob but have experience with Mazda BP engines. If I had a BP engine on a stand, I would change out the timing belt, seals, water pump, accessory belts, rear main seal. I don't know what the equivalent would be.

I'm planning on removing the transmission and getting the engine on a stand for awhile. Might as well go through it while I tidy up the engine bay. So, while I have the engine up on a stand, what sort of preventative maintenance should I look at? The PO said the engine ran perfectly fine before being removed and I believe him considering the state of the engine when it was removed. If I could check the state of the internals easily I wouldn't mind, but I don't want to start the process of a full rebuild. However, what kind of seals, gaskets and things should I look for while going through the engine? Any wear parts that are easily accessible when the engine is out of the car that I should just do now to save a headache later?

Speaking of preventative maintenance, anything in the engine bay or other parts of the car that I should look at while there's space in the engine bay? Anything that I should probably just do now? I have to replace some hoses and the engine harness, but I don'y know if there are other things I should look at, considering I have 0 experience with rotaries and rx-7's. I'll be doing the clutch slave cylinder, clutch hose, and obvious things like the clutch, transmission seal, and rear main (is it called the rear e shaft seal?).

Thank you all for the help, any tips or insight for a rx7 noob is greatly appreciated, or links to articles that have good information is also greatly appreciated.

 

The same ideas transfer over from your BP engine. Rear main seal is a good idea while engine is out (don't check front, it requires you to loosen the front hub bolt which is a big hassle). There is no sure-fire way to check the internals, but you can put a borescope in the exhaust ports to see if there's anything horribly wrong. It should look smooth and consistent.

Do not loosen any of the tension bolts when you have the flywheel off to get at the rear main seal.

As far as engine-out, that makes it a lot easier to clean the engine bay. Give the harnesses a good inspection and check for broken connectors or cracks in the wrapping. Check for rust on the drivers side frame below the brake master cylinder. Clean all the grounds (drivers shock tower, firewall, etc).

On the engine itself timing is done by a chain which is basically maintenance free. I've never even heard of one going bad actually. Water pump is on the front of the engine, it has its own seal and the water pump housing behind it has another. They should be replaced together because they are both held in by the same bolts.

The rubber vacuum lines, oil metering pump lines, and intake gaskets tend to leak at this age. I don't really advise fixing something that isn't broken, so generally I would just replace anything visibly wrong and leave it at that. It's very likely that once you get the engine in though, more leaks will appear and you will have the intake off anyways. Rebuilding the intake is not that difficult, I have a guide on it in this section. The guide is for an S4 but the process is mostly the same. I have done this with engine in more than once so it isn't critical to do it now, I just mention it in case you want to rebuild it pre-emptively.

Otherwise you seem to have everything covered. Rad hoses are always a bit crusty at this age. Check the oil cooler hoses too, normally they're fine but they live below the power steering so I have seen my old set get eaten by ATF, requiring replacement.

Good luck, and post pictures of the car when you get a chance

 

obviously the clutch and rear main seal, metering pump O ring (N350-14-604) you might consider the oil pan too. coolant hoses. honestly there isn't much on the engine that can't be done in the car.
Mazda updated the intake gasket from paper to metal, so maybe, but sometimes its better to leave it alone.

i do always end up checking everything to make sure it works. make sure the 6 port and VDI sleeves move. thermowax hoses aren't full of crud. now is also the chance to clean the subframe and firewall and stuff too

 

This is exactly what I was looking for. I'm not aware of things like the OMP O ring so I probably would've glossed over it if you hadn't commented. I have a great opportunity to once over the engine rn, so I really want to make sure I do the most I can get seal it up right.

Also, what are the thermowax hoses?

 

Thanks for the tips. I saw you on reddit too, so we can also talk there. I think I can visual the seals better with all the accessories of the "block". I need help with the oil cooling system. How does it work? I have one stainless line coming off through a port on the lower left part of the rear iron. I figured it was for oil, but I don't know exactly. I notice everybody is talking about ATF, but that doesn't make sense to me as I imagine alot of RX-7's are manuals, and there is no transmission cooler. So, how does the oil cooler work? In the miata, the oil cooler is internal to the block and it exchanges heat with the coolant through a little plate by the oil filter. I imagine the RX-7 system isn't like this? All I have is that thick stainless line coming from the port. What am I missing?

 

The oil cooler sits in the front of the car just below the radiator. It has two lines that connect it to the engine. One is the line you speak of that connects to the port on the lower rear iron. The other connects at the lower portion of the front cover on the driver's side.

 

I was a bit vague. The power steering system uses ATF as the fluid. I neglected to mention it, my bad. Anyways, the power steering pump sits directly above the AC compressor and above the front oil cooler line. This line is the outlet from the engine, it's on the front cover on the drivers side bottom corner. The other one you identified is the outlet from the cooler, which goes to the rear iron and then up through the filter and to the engine.

The oil cooler on our car is a traditional oil to air type, there is no coolant involved in it.

The power steering system leaking ATF is obviously not good on multiple levels, but for me, the leak was very slow and happened over a long period. The ATF ate the rubber sections on my oil cooler line and AC lines, which of course puts you in a bit of a predicament. That's why I mention checking those lines is a good idea, either to catch a leak before it eats the lines, or if the lines are already compromised to catch it and replace before you lose oil pressure.

So to sum up, it's a good idea to inspect all those lines to ensure there are no leaks.