wally13b

Hey everyone, I bought an s5 RX-7 turbo II with a dead motor for cheap and took it to myself to disassemble it and go for a rebuild. Before I even started tearing down the engine, I did a compression test on it to see if the seals were at fault: it resulted in the rear rotor still being relatively strong with 90 psi on all three faces, and the front rotor with 60 psi on two faces and 90 psi on the last.

Now we come to the disassembly and inspection of the engine. I found out the front rotor had an apex seal groove that opened up due to a blown seal (see pics below). Now I'm wondering if there's any way of fixing that one groove (I've heard the most plausible way would be to prep it for 3 mm seals).

Link for images: Front Rotor - Imgur

Thanks a lot for the help!

misterstyx69

iTrader: (142)

I'd junk that rotor,as the groove is not exactly straight and in the long run the 3mm seals would cost you as much to put in as the engine rebuild would.
You can't just cut the rotors for 3mm and go for it,.They need to be done with precision.

RotaryEvolution

iTrader: (30)

it could be repaired but i wouldn't suggest it for a first time build. basically peen the metal back into place with a solid corner seal in place, ream the corner seal slot and file the apex slot to spec.

Claytons91

yeah I wouldn't use that rotor. How do the housings look?

BeBopsama

Yeah unfortunately that rotor is a door stop with a groove like that. I'd say the housing is probably shot to hell too if that happened. About to tear my engine apart again and really hoping my front rotor and housing are in usable condition >.<

wally13b

Thanks a lot for the input guys, the rotor really does look like s***. I'm currently shopping for a good one now, and I took the time to take some pictures of the front housing for a damage check. Some scratches are pretty deep in there, what do you think? I also happen to have cracked coolant jackets in my front iron...this rebuild is becoming expensive but I gotta do it. I assume there's no real way of fixing the missing parts of the jackets on the iron?

Thanks again everyone, pictures in the link below!


Housing and Iron - Imgur

Sgtblue

iTrader: (16)

No...no practical way to repair the grooves in an iron. And that housing is toast too. Make sure that the rotor weights of the replacement are within tolerance of your good one, or buy a matching pair.

RotaryEvolution

iTrader: (30)

the rotor housing is toast but there is a practical way to save the iron but not while including shipping.

i charge $75 to repair each wall break but shipping to and from usually costs $100, so that's $175 to try and salvage an iron that you can usually buy for less used with shipping included. the repairs are usually only done on irons that are ported or on engines i'm working on in the shop, so it's cheaper to repair them versus replacement if the iron is in good shape otherwise. i also have never had a repaired wall subsequently re-fracture regardless of the rumors of it being sketchy to work with cast iron. used irons are usually $75 for 6 port n/a and up to $175 for REW/cosmo irons, 20B being the only other exception as they run from $300-1500 used so repairing them has quite an advantage.

misterstyx69

iTrader: (142)

hmmm..

Sgtblue

iTrader: (16)

Did not know this...obviously. And good to hear since they will become harder to find over time.

RotaryEvolution

iTrader: (30)

salvaging parts is going to be a necessity as time goes on, i think myself and John at Goopy are probably the leaders in reconstructive surgery.

it makes me wonder what some shops will do once parts are NLA.