Rotary Madman

Hey all,

I've got an intermediate Iron I am half interested in using but it has pitting on the apex & corner seal surface on the exhaust side of the housing.

I assume this to be a bad housing but... I was wondering what life I could expect out of a stock motor with it? will it last 70K or so? I don't expect FD3S motors to go much longer than that anyway. I understand this will erode the corner, Apex & possibly side seal but I am curious by how much? Is it realitivly quick or after many miles?

I wont be running any modifications on this motor other than a DP, RB exhaust, and maybe an HRS intake, but other than that I'm leaving this motor stock.

THANKS FOR YOUR INPUT.

clykins

iTrader: (1)

I can't answer your question, but I can tell you I would not go through the trouble of rebuilding an engine with an intermediate housing like that. I would look for one in the classified section. I would bet you could find one for a very reasonable price. Good luck.

diabolical1

iTrader: (3)

hey Madman, welcome to the board.

I don't know how much help this will be, but here's my input. if you're concerned if the engine will fire and run, then it probably will. in my seminal days of porting, my hands were nowhere near as steady as they are now and the damn porting grinder used jump and dance all over the face of housings at times when I wasn't paying attention to edges, speed and positions. I honestly don't remember any of them looking as deep as your photo, but my point is it would work in a pinch and if you plan to fooling around with engines often, you kind of develop a sense of permanent "temporary-ness" (if that makes sense ). my point is I've built and driven on a lot of less-than-perfect engines for extended periods of time before I got "good".

that said, if your plan is to build and keep it going as long as you can (and your post indicates that you're more in line with this plan), then I think it would probably be worth the extra time and money to replace it now and build on something closer to perfect. just know that there are no guarantees though.

I hope some of this helps you.

Rotary Madman

Hey guys,

Excellent response Diabo. Despite your justified assumptions, longevity is a concern but not the ABSOLUTE goal. I just don't want to be rebuilding after something like 10K miles. I guess I'd be happy with 30K or so but would expect closer to 40 or 50.

Maybe it'd be best if I informed everyone of my project goals.

Currently I have 5 REW motors in varying conditions all in need of rebuild and am planning on rebuilding as many as I can. I have 2 torn apart now and am anxious to get one back together before I strip 3 more down and fill my garage with the parts. This is my first 3rd gen build and I would rather make my mistakes now instead of later. I was excited about this housing because it has ground smooth intake runners. Not polished or ported but smoother air flow for sure than stock. I'm not interested in Porting for my intended purposes for this car. But a side note: I do feel porting/polishing helps with stock turbo's since you can't just add boost to get power after a certain level.

Right now I am putting together a stock motor. I see the intake ports as bonus to get a little extra out of the stock turbo's at roughly 12 psi or what they can handle efficiently with minor upgrades (PFC,DP,Exhaust, & Intake). This motor will be to smog my car because I live in the worst car state, CALIFORNIA. I'm not a tuner but I am planning on playing with my car a bit but this will be my first experience with the complexities of the 3rd gen. I'm not so concerned about longevity as long as it isn't ridiculously low which is what I am trying to gauge from experienced members.

I have also toyed with the idea of running 1 set of Atkins seals and one set of RA seals in the same motor just to add some good research and validity or disagreement to the arguments throughout the RX7 community. Maybe a fun side project.

I don't mind experimenting but I want to make sure I have a theory and good brainstorming before testing.

ASIDE: I plan on using my absolute best parts for a planed T-78 single turbo build.


My argument for using this iron.

In my mind the apex and corner seal will have sufficient support with these small blemishes and I compare this to a bridge port or something of that nature where the apex/corner seal isn't 100% supported while riding over the bridge and the motors seem to be fine. wouldn't this have the same effect on a more minor level?

Looking forward to the debate!

1950884

I'm new to rotarys, but can't you machine it smooth?

Rotary Madman

Yes you can. This is a budget build and this may actually be too deep to fully machine and keep everything withing tolerance.