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Well, gentlemen I come bearing ill news. The junkyard 13B i found is TOAST!! It seems that part of the coolant gallery in the front iron actually broke away, blowing out the inner coolant seal ring in the process and completely ruining the engine. The entirety of the inside of the keg was rusty. I've yet to take the pieces to Garagelife to get seen by an expert, but I'm pretty sure they're FUBAR. The attached pics will show the extent of the damage. It seems all I'll be able to save are the tension bolts, the stat gears and maybe the E-shaft. I also made the idiotic mistake of dropping the engine off of the stand (just don't ask) and straight onto the rear of the E-shaft so that may be bent now.
There really doesn't seem to be much I can use from the 13B, but there has been another development: I've recently picked up a set of 12A irons that have already been bridgeported! Now I need some guidance from those who know (much) better than me. At this point I'm inclined to build a BP 12A and go racing as I have all the parts I need in the form of my tired 12a Pro-7 motor. But I'm also sorely tempted to build an SE style 13B with those plates and RX8 internals. II don't have any of the 13B rotating assembly parts or housings What would y'all do? is a BP 12a worth it? Should I just save my money and build a 13B later instead?
I apologize, for some of you have already seen pretty much this exact post made in my thread about 12As Vs. 13Bs but I have many more eyes on this thread and on that and I'd very much to hear all the advice and experience y'all have to offer on this!
Last edited by IMSAaspirations; 09-29-21 at 10:21 PM.
Reason: Poor grammar and spelling
Here are some pics of the destroyed engine. What do y'all think of the pre-84 (and RX8) engines having the coolant seals in the rotor housings Vs. the 86-02 engines having theirs in the irons? Is this mode of failure common?
The offending iron. A closer look of where it seems to have failed. How the rotors and irons looked Oil and coolant gunk in the coolant passage The type damage done to the rotor housings
Last edited by IMSAaspirations; 09-29-21 at 10:27 PM.
Reason: Added question
This failure mode of rusted out water seal groove is extremely common. shame that it destroyed everything, not just the irons.
I was talking with other rotary wizards on a related thread of mine and the consensus was they're not the biggest fan of this design element of the 86-02 13Bs but did appreciate their other advantages. Though I'm not particularly hopeful the rotors are salvageable, I'm going to ask Daniel at Garagelife what he thinks can and can't be cleaned and reused before I discard anything. At this point I'm wanting to build an SE style of 13B with the seals in the housing and some 12A irons I have, maybe even the BP irons! I'l let y'all know how it all pans out. In the meantime I have to take my daily to get repaired from getting rear ended and replace the oil cooler line in the racer. So much to do!
Depending on how much time you want to spend, you can hit the rotors with a wire brush on a grinder. They may be okay if the rust hasn't caused too much pitting near the apex seal grooves.
The housings may be usable if there's not a lot chrome missing.
I don't have experience with them, but companies like Goopy Performance and Chips Motorsports offer a "surface treatment" that smooths out the chatter marks. From their description it looks like a very fine CNC machining of the surface.
Since they do machine work, I would assume they could also cut coolant seal grooves into the housings so you can use them with the 12A irons. That might be the way to go if the housings and rotors end up being usable.
Depending on how much time you want to spend, you can hit the rotors with a wire brush on a grinder. They may be okay if the rust hasn't caused too much pitting near the apex seal grooves.
The housings may be usable if there's not a lot chrome missing.
I don't have experience with them, but companies like Goopy Performance and Chips Motorsports offer a "surface treatment" that smooths out the chatter marks. From their description it looks like a very fine CNC machining of the surface.
Since they do machine work, I would assume they could also cut coolant seal grooves into the housings so you can use them with the 12A irons. That might be the way to go if the housings and rotors end up being usable.
Well I'm not a man with a ton of free time intrinsically but trying to clean them up does really sound like something worth making time for. I think a healthy coating of WD-40 rust penetrator and some wire brush action would be a good idea. Getting the seals out and the surface cleaned sounds like it'd be worth the effort and time it'd take.
The rotor housings actually seem to be in pretty good shape actually. They're not very marked in any way, save a little rusty where the water pooled. They may be salvageable as is or with a light touching up.
I had no idea one could have the water seal channels machined into later irons! That may be something to consider. However I do have set of BP 12A irons already, and I may be able to salvage the E-shaft and rotors, I'm almost inclined to spend that money on so GSL-SE housings and make a 13B that way. This method of failure being a possibility makes me want to use the other style of irons in order to avoid it. This on this, y'all??
New GSL-SE housings would be the way to go. Even though I have a pair in a box it slipped my mind they're still available.
you'd need to port them for the bridgeport but that's all compared to the work required for the used housings.
New housing surface is better than material removed from a used housing.
i just checked, and i'm used to Mazda USA having between 2-15 GSL-SE housings, but they have 86! that is more than they had had in a decade
13 pairs of fenders too, crazy
Well I guess that'll be my next big step! Having the exhausts ported doesn't seem like to big an endeavor to make it all work so I'll just chock it up to being part of the engine build.
Lately I've been busier than a 2-peckered billygoat trying to get my car prepped for this weekend's test and tune out at Chuckwalla in-between and after shifts at work. I don't own a trailer so the logistics of getting it there need some figuring out but it'll be well worth it!
Hello all! I hope you've been well and that the holiday season has been treating you well! It's been a while since I let gave an update on the progress I've been making. Firstly a rather minor thing: one of the oil cooler lines failed at the AN fitting. Upon start up one day it spewed like an arterial bleed from the fitting at 80 PSI on startup and absolutely coated the engine compartment and driveway. I shut off the engine immediately and was lucky enough to avoid any damage. Though that was a relatively minor break, it jeopardized the big thing I had planned... I FINALLY GOT MOZU TO THE TRACK! I was able to get the oil cooler ones fixed and get to Chuckwalla on the 22nd of October for a test and tune and turn laps on track. I met up with Carl and a couple others involved in racing these old RX7s and the were instrumental in helping me shake the car down and make sure I had it ready to run. I can't thank them enough! Regrettably I don't have many pics or videos from the track day as I was so focused on driving I didn't really remember to take any, but I'll upload a few that I have soon. There really haven't been any big mechanical updates on Mozu. The track day showed the car is rung well and ready to race, so nothing has really been done otherwise. Brandon at Rotary Engineering Santa Barbara has finally released the Group C kit he'd been working on and an IMSA or group C car is still my ultimate goal, but that's a ways off at this point. My attention has been focused much more on the daily lately and that's where I hope to make good progress in the near future. As things progress I'll be sure to keep y'all informed.
Hello, gentlemen! I come now with transmission lube questions! After having done some research I've decided that I'm going to change the fluid in the transmissions in both the racer and the daily and refill with Amsoil Severe Gear 80w90. My research here on the forums also lead me to an interesting trick. I believe it was Kentetsu that saids he runs 1qt proper gear lube and 1qt ATF in his trans based on an old trick the Datsun racers did back in the day. Does anyone else do the trick? Does anyone else see a point to it? I believe the reasoning was to add some detergent into the lube, and that would make sense for 40 year-old oil technology compared to today's modern chemical concoctions we put in our machines. Is it still a relevant trick? If it's still a useful trick is it street-safe or more motorsports oriented?
Hello, gentlemen! I come now with transmission lube questions! After having done some research I've decided that I'm going to change the fluid in the transmissions in both the racer and the daily and refill with Amsoil Severe Gear 80w90. My research here on the forums also lead me to an interesting trick. I believe it was Kentetsu that saids he runs 1qt proper gear lube and 1qt ATF in his trans based on an old trick the Datsun racers did back in the day. Does anyone else do the trick? Does anyone else see a point to it? I believe the reasoning was to add some detergent into the lube, and that would make sense for 40 year-old oil technology compared to today's modern chemical concoctions we put in our machines. Is it still a relevant trick? If it's still a useful trick is it street-safe or more motorsports oriented?
if you put regular gear oil in these things they don't shift very well when its cold, the ATF trick fixes this. i would think though that a good synthetic is just a better option for a track car though
I have read a few places that GL-5 gear oils typically have sulfur/phosphorus to improve the extreme pressure performance. Similarly, the sulfur/phosphorus tends to damage brass synchros. Other sources indicate that most newer GL-5's may use less (or no sulfur/phosphorus). This is all from internet chatter, so YMMV. That is why I use Redline's MT-90 in the tranny and 75-90 GL-5 gear oil in the diff on the racecar. Not sure if it is really necessary, but seems safe enough. Performance has been good too, with no gear failures or poor shifting.
I would be leery about using my own mix of gear oils.
if you put regular gear oil in these things they don't shift very well when its cold, the ATF trick fixes this. i would think though that a good synthetic is just a better option for a track car though
After having thought about to more and done a little more reading up on it I'm of the same opinion you are. It seems that a good quality synthetic oil should be more than enough under racing conditions. I may try that ATF trick for the daily however. When it's cold the trans seems to grind a bit going up into 2nd and up into 3rd, but after it warms it shifts perfectly fine. That trans has 290,XXX miles on it so I'm trying to keep it going as long as I can!
Originally Posted by Carl
I have read a few places that GL-5 gear oils typically have sulfur/phosphorus to improve the extreme pressure performance. Similarly, the sulfur/phosphorus tends to damage brass synchros. Other sources indicate that most newer GL-5's may use less (or no sulfur/phosphorus). This is all from internet chatter, so YMMV. That is why I use Redline's MT-90 in the tranny and 75-90 GL-5 gear oil in the diff on the racecar. Not sure if it is really necessary, but seems safe enough. Performance has been good too, with no gear failures or poor shifting.
I would be leery about using my own mix of gear oils.
Carl
I've noticed the same chatter in regards to GL5 formulation, but the FSM I have for both 82 and 83 specify 80w90 GL4 or GL5 oil for the trans so I was gonna get some, though I was ,or worried about the oil weight. The more I thought about that, though the less it seemed like 5 units if weight measure probably wouldn't make the much of a difference in a race than it would the street. I'm unsure if I need the 80w for the street car or not. Also Michael says that the redline lasts about a weekend's worth of racing, do you hav that experience as well? Or is something lek 16 hours of hard running about what one can expect from trans oil under racing stresses?
I'm wary of mixing myself but that's why I like to check with y'all!
I saw the same thing in the FSM, implying (maybe) that sulfur/phosphorus are not such a big problem. Mike mentioned that to me too when I saw him earlier in the week. For the race car, I do just change all the fluids after a weekend of endurance racing. I don't know if it is necessary, but it is the equivalent of 4-5 sprint race weekends and the fluids are not that expensive so why not. Mike has blown up 3 diffs in the last 5 or 6 outings. Positive it is not from old fluid :-) He seems to have some other set-up problem that he has not yet worked out. I haven't worked with him on it yet, so I have no idea.
The only transmission failure I have had in 20 years was when I was using Redline Shockproof Lightweight (or something like that). Probably not related to the gear oil. Most likely just an old transmission. It was the original one from the factory. Saying this though probably just jinxed me. Dang!
I have read a few places that GL-5 gear oils typically have sulfur/phosphorus to improve the extreme pressure performance. Similarly, the sulfur/phosphorus tends to damage brass synchros. Other sources indicate that most newer GL-5's may use less (or no sulfur/phosphorus). This is all from internet chatter, so YMMV. That is why I use Redline's MT-90 in the tranny and 75-90 GL-5 gear oil in the diff on the racecar. Not sure if it is really necessary, but seems safe enough. Performance has been good too, with no gear failures or poor shifting.
I would be leery about using my own mix of gear oils.
Carl
ive read that too, but most of the oils you can get are GL4 AND GL5, so its more chatter than anything practical.
Hello Gentlemen! Yes yes I know I've been gone for more than a year now but that's simply due to life getting busy and pulling my attention every which way but towards my RX7s. I'm still here, I still have the race car and I still daily the 83 GSL. I've done nothing to the car since I last posted but am currently prepping it for the University of Vara later this month! All I'm doing really is swapping in a passenger seat and moving the battery so "prepping" may not be the right word.
Since everyone on this forum has good (read slightly offbeat but in a positive way) taste in cars y'all may appreciate where my automotive attention has been lately; I bought a 1967 Lotus Europa in August and getting it running and driving has been taken most of my free time as of late. The lotus is my personal (very) long term project as my old man and I share the race car as a seat time car more than anything, but I'm still committed to building an IMSA car out of it, unless I can find a real IMSA racer laying around.
09-29-21, 10:20 PM
