ok, so i have both. the only difference i see is that the intake on the intermediate iron is quite a bit larger... the whole "block" that i took apart looks better than the r5 i took out of the car... and the front iron on the r5 has a groove from what is believed to be a corner seal spring...

i guess my question is since i plan on porting anyways, does it really matter which ones i use? one of the housings has a small "chipped" area on the y iron motor, whereas the r5 motor had quite a bit of "chipping" so i plan on using those housings anyways.

 

anyone?

 

Basically there are two types of R5 castings. Early R5 engines had short ports in the intermediate plates, while later ones had tall ports like a Y casting. I don't know exactly when they started nitriding them, but I don't believe any the short-port R5 castings were nitrided. I could be wrong though. Ask Jeff20B; he knows all about the different castings for the irons and rotor housings.

You should probably use the Y castings, since they are nitrided and from your description it sounds like they have less step wear.

 

lol step wear doesnt even describe it...

 

Do you know how to check for nitriding?

 

color of the main casting? gray = nitrided, black = non-nitrided? either way, the housing in the pic looks pretty hosed

 

no i have never checked for nitriding... the y housings look way better, ill have to snap a pic of them but they look like gold compared to the r5 in the pic

 

I'd be interested in seeing a side by side picture of the center housings to see the difference in the height of the ports.

I don't think I have ever seen a "short" port housing, but maybe I have never seen a "tall" port........

 

Just use the Y plates. They're in better shape anyway. The R5 plates sound like they're early castings and probably not nitrided.

Let's see some pics to confirm.

 

ill snap one when it gets dry out lol theres a huge difference..

 

r5 on the left, y on the right.

 

i still have to clean them up but the spots on the y plate are just dirty spots, not gouges.

 

aww wook at de cute wittow port on the R5

 

haha thats kinda what i thought too

 

That's the size of an NO or GSL-SE or S4 NA intermediate plate. I don't build any R5 engines with tiny ports like that. The ones I build have tall ports/runners and are nitrided.

 

can you tell if the y plate is nitrided or not from that pic?

 

All Y plates were nitrided unless j9fd3s knows something I don't.

 

sweet!

 

The 2 R plates I have sitting around are the tall ones

 

and they "R" nitrided. https://www.rx7club.com/attachments/...ess-repu12-jpg

 

so basically all 12a plates were nitrided?

 

It'll be interesting to see if the seating surfaces for the water seal O-rings have any pitting or corrosion. I haven't been looking in a couple of months, but I've torn down three 12A engines and have yet to find a set of irons (or even a single iron for that matter) that does not have pitting and/or corrosion that is beyond tolerance.

I'd be interested to see what condition yours are in when you polish that surface up.

Just checked my Y and R5 plates and they're both the same port size. Just wish I could build with 'em.

 

idk, lol i havent done that yet... what is the "tolerance"?

 

According to the book, the fretting (corrosion/pitting) cannot exceed 0.07 mm from the inner edge of the inner O-ring (water jacket O-ring seal) inward toward the center, and cannot exceed 0.07 mm depth beneath the seating surface of the O-ring.

0.07 mm = 0.0028 inches.

Sucks because they looked fine until I cleaned them up with the scotchbrite pad on a drill like Aaron Cake did on his video.

Hope yours turn out ok!

Glad I checked the FSM tonight too, because I just found where it said that the irons can be resurfaced, but not to exceed 0.18 mm (0.007 inches). It has an asterisk next to it tho that says "less than 0.10 mm (0.004 inches) in case with 80 degree C sprayed layer". I take that to mean if the irons are nitrided you cannot resurface them past 0.10 mm.

Again, I hope yours turn out ok when you clean them up!

 

what video are you referencing? I would like to watch it... as of right now they don't seem to be bad, but u never know till u do it the right way lol