So I knew I would not be looking at the prettiest engine when I finally got it apart to rebuild it, but this is not what I was expecting....I guess it's what I get for a $800 TII.

But this is my first RX-7, and therefore the first time ive tried rebuilding an engine and I dont know if I can reuse many of these parts...so if the engine experts out there could give me a quick run down that would be excellent.

We'll start right off with some pictures:

Housings:







Rotors







What I do know:
The housings and rotors are completely shot, I dont know how it happened because i bought the car with the engine blown, but the housings and rotors will definitly be spending the rest of their lives on a bookshelf.

It is the plates that I dont know if i can reuse or not, and it would be very helpful to know if i need to look to replace them too. I've run my fingernail across them and pretty much all 4 faces i can just barely catch a fingernail on.

So what is the deal with the plates? Reusable?

 

Couldnt upload all the pics in one post...here are the plates:














So it would be really helpful if I could get a few opinions on how these look / what I should do to test them.

And obviously I am going to need new rotors and housings, and possibly plates, so if someone could point me in the direction of where i can get them....or maybe a whole new engine? I've looked at possibly putting in a JDM engine, but i dont know how easily they go into a USDM car.
Is it possible to just use the short block from a JDM engine and mate it up to the USDM tranny, intake, wiring harness that I already have?

Many thanks in advance...
--Nick

 

"folds hands and prays" please dont let my engine look like this

 

Those irons dont look to bad. Looks mostly like normal wear. Make sure the grooves arnt to deep and make sure you check for warpage and check the edges of the water jacket seal for cracks. clean out the groves of you seals to get a better look. Its hard to see the edges or how deep the grooves are in the pics. The rotor and housing are trash.

 

You have some deterioration around the water seal there in the lower left hand corner of the picture. I wouldn't use it.

 

Thats just what I got for my TII

except i was a noob and paid $2600, because I thought it just had issues....

I rebuilt my engine myself using different housings, and it ran great for like a month. Then I got a mysterious coolant leak and I'm having Rotary resurrection rebuild it again.

all I can say is good luck.

 

looks like you got some new paperweights....

 

The irons would probably be fine once lapped.

 

Where can I send them to get lapped?

 

damm, everything looks pretty jacked up.
I would use anything from that motor...easy as that..

 

Does corksport still have cheapo JDM short blocks?

 

So I cleaned out the o-rings and the plates look to be fine to me except for the small scratches on the center edges of the plates face. The intermediate and rear housing look ok to me, however the front housing I can feel a groove with the tip of my fingernail but I cant catch my nail on it.

So here are my questions:
Is there a better way to check the plates?
Should I reuse the plates? (or at least the rear and intermediate, and trash the front)

Where should I get replacement housings, rotors, and possibly irons?
OR
Should I trash the whole thing and get a replacement engine?
And if so, should i get USDM or JDM?
The tranny and intake parts are in good working order so I dont really need a long block, so can i just get a shortblock?
Where should I get any said engine parts from?

 

Side plates look good.
Of course, rotor housings and rotors are just expensive pieces of metal now.

What I would worry about the side plates is the water jacket groove / wall.
Clean that inner o-ring out and carefully inspect that thin wall between the combustion chamber and coolant passages.

Personally, I wouldn't lap the irons - you have to worry about end play and changing the spacer after that.
I wouldn't trust any machine shop to take care of this job, as it deals with precision and tolerance.
Lapping the irons also gets rid of the nitrided surface, and it's not easy to recreate that hardness.
People tend to overemphasize lapping used irons - I'd rather throw away out-of-tolerance crap and get better used ones over lapping.


-Ted

 

oh god this makes me scared to pull my engine on monday.

 

Atleast you will have some nice bookends and a good story when people ask.

 

If there's doubt, don't use them. Mine were borderline, too, so I spent $800 and a few months on a rebuild, and the engine just barely made it through the breakin period (500 miles) when I floated the dipstick.

 

I've done a little poking around on the interwebs and it looks pretty cost prohibitive to try and get any kind of replacement motor...so it looks as though i am going to be looking for new housings and rotors (and possibly irons). Is there anywhere special I should look for these other than ebay and posting a WTB in the 2nd gen For Sale forum?

 

And also what of those parts are interchangeable from s4 turbo to s5 turbo? I believe the s5 rotors are different, but what about the housings and irons? can i substitute them? or is it possible for me to use s5 rotors? or if i get both s5 rotors and housings?

 

I agree. Though I have less experience, I don't trust lapping either. The FSM specifies what makes an iron good or bad. Use those numbers and procedures.

You can get a machinists straight edge and use feeler guages or use a stepped wear gauge.

I use a magnetic base dial gauge with a flexible arm (like the kind you use for end play). I set a small square of newspaper page between the housing face and the gauge with the arm bent so the gauge comes back to the housing surface. Then I rotate the base (the nespaper lets it rotate easily and without scratching) so the gauge head goes back and forth over the seal groove. It actually gives pretty accurate and consistent readings.

 

It's easier to stick within your series. The rotating assembly needs to be balanced. If you stay within your series and get rotors that are the same weight as your old ones, you don't need to worry about rebalancing.

Rotor housings are basically the same with some improvements on the S5's coating irons I don't know about on TII's, but I'd imagine they are slightly different as they are on NAs.

I would try and replace each rotor with the same weight stamp rotor that came out if possible. Figure out which was front and which was rear and replace it with the same letter so they will match the front counterweight and flywheel counterweights. If you've got two of the same rotor, it's easier.

I put S5 rotors in my S4 engine... but it was the whole rotating assembly out of a factory balanced block: rotors, flywheel, front CW.

I don't know if everyone is that **** about it. Some will probably say it doesn't matter as long as you stay within your series and no more than two rotor weight letters apart between your two rotors. I like to play it safe.

 

With weight stamps, iirc, the factory specifies you can be within two letters (A to C, B to D, C to E). Obviously matching perfectly like A to A or C to C is ideal.

Send a private message to Rotary Resurrection. He sells off his NA stock all the time, and he's got enough experience to know what makes a good iron. You may find them cheaper through someone else, but not by much, and you can be pretty sure that if it came off his shelf it's in good condition.

 

oh **** what happened to your engine?