About a year ago I picked up an 87 RX-7, naturally aspirated nothing special, I just like the idea of the rotary. Its different and that is fun, but I've never worked on one so I want to ask a few questions before I just dig in and hope for the best.

First question - Is it absolutely necessary to replace the apex seals during a rebuild? My budget for this little project is seriously limited and apex seals are a bit expensive as far as parts go so if its feasible to reuse them that would be good news for me going forward.

Second question - Is it common that these engines be seized after sitting for an extended period of time? For all I know this car hasnt run in ten years or more, and it is seized.

Last question is about reverting the motor to be run with a carburetor. I read somewhere once that they were notoriously difficult to keep tuned - is that true? How difficult is it to make the switch? You may be wondering why I would want to seeing as how fuel injection is more efficient and all, and I will tell you. I am a tinkerer and among the things I tinker with are hydrogen generators. It is really annoying to deal with computers and hydrogen because of those pesky O2 sensors and carburetors simplify that. Any thoughts on making the switch to a carburetor would be appreciated.

 

Hard seals include apex, corner and side seals. All have minimum specs set out in the Factory Service Manuals...at least they are in the 3rd Gen Manual of which I’m most familiar.
I’m not a pro builder by any means, but even IF the hard seals are reusable IMO you should replace the respective seal springs. Housings and irons or side plates, just like blocks and cylinder walls are wear items too. There are also journal bearings and oil control rings that can be reused depending on condition. Soft seals like coolant seals cannot be reused.
If your engine is seized it’s hard to say how feasible a “budget” rebuild will be.
There are videos available out there that will give you an idea of what you’re contemplating.

 

Thanks for the reply. I have been sort of dreading pulling the engine to take it apart since finding that it was seized, and I've been rebuilding the engine in my truck for a distraction so the rotary has been out of sight out of mind for a bit. I will be having some down time at work here in a couple months and the rotary has started calling out to me again.

What do you figure the odds are that this engine is stuck for some reason other than someone did something foolish with it? lol

 

Just from lurking on here for a while, it seems pretty common for an engine that's been sitting for a few years to be no good. Full rebuilds are SOP for cars like yours whether it's because the engine's seized or the coolant seals are leaky or whatever. I understand your budget constraints, but I think it would be worth your while to replace all the seals while it's convenient. Good luck with whatever you do!

 

I'm guessing the water seals went and the PO let water sit in the engine and rust out.

I hope not though. Good luck.

 

Dear lord, please let it be a pile of money locking up this engine

 

What a wondrous thing that would be!

 

That would be most unfortunate indeed.

 

I get what you're saying, and for the most part I do expect to have to replace all the seals, I've found what appear to be decent rebuild kits for around $350 but they don't include apex seals which seem to cost almost as much by themselves.