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PostPosted: Sat Jul 25, 2009 10:59 pm 
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I received the e-Bay seat bets and they had 2” webbing not the 3” that they advertised so they went back. They will replace them with the proper 3” wide belts. They claim they knew of the problem. If so, why did they continue the auction? I guess I will never figure some businesses. Until then, I wait.

I got the muffler and resonator from Summit They were special order from Jones Muffler. and I received them in less than 2 weeks. Very good service. They were even shipped to Summit and then to me. The resonator and muffler housings and internals are very heavy steel, almost as thick as my .120” wall headers. I didn’t mic them so don’t take my word literally. They are very heavy duty construction. Should last long on the rotary mill. The muffler I chose was sans the inlet and outlet tubes. The openings were about 3-1/2 diameter so I had to reduce the size down to the 2-1/4”. Done deal. They will now await the re-assembly of the car for completion of the exhaust system.

I also received the 4-piece roll bar kit of my design from Roll Cage Components yesterday. This too, was less than 2 weeks from order to driveway. The steel tubes were just wrapped togeter and shipped. There was no "packaging" per se. Regardless, it was received in perfect condition. The workmanship was excellent and everything fit just fine. It is all welded in already. I’d give Jimmy a 12 out of 10 rating.
Attachment:
roll bar as received.JPG
roll bar as received.JPG [ 70.82 KiB | Viewed 2781 times ]


I finished tearing down the car and completed the final welding of all the tacked joints. WOW - there were a lot of welds to finish up! I started painting the frame. The painting is going slow. There are a lot of small surfaces to cover a min of 2 coats. I am about ¾ done with the painting. I still have to weld the control arms before reassembly. Here is a photo of the roll bar on the car.
Attachment:
frame with roll bar.JPG
frame with roll bar.JPG [ 66.98 KiB | Viewed 3072 times ]

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Chuck.

“Any suspension will work if you don’t let it.” - Colin Chapman

Check out my rotary build log: click here


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PostPosted: Sat Jul 25, 2009 11:11 pm 
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Now you know why powdercoating is so easy!

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PostPosted: Sun Jul 26, 2009 8:31 am 
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Yeah powder coat would be EASY. Anything you farm out for someone else to do is EASY. But then you wouldn't have the inch-by-inch inspection that finds the 1 missed side-weld on a tube. I did 3 times!

I'm not sorry I chose to paint. It is therapeutic (not).

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“Any suspension will work if you don’t let it.” - Colin Chapman

Check out my rotary build log: click here


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PostPosted: Wed Aug 26, 2009 11:24 am 
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Wow. A month has passed since my last post. In my absence, I have been reassembling the car after painting the frame. All temporary ½” heim joint bolts along with other suspension bolts were replaced with grade 5 bolts and crush-type stop nuts. The suspension is mounted, with the preliminary alignment set. I'll have to wait for all the stuff assembled and find a flat surface to do the final alignment. Until then, I have a roller again! I bought some 10-32 and ¼-20 rivnuts and all of the bolts to the frame, like scuttle frame, steering shaft frame and rear fenders; etc. were prepped for mounting using the rivnuts. I didn’t order a tool but made one using a piece of ½ inch threaded rod and some nuts. The scuttle sheet metal pieces are now together using the rivnuts too. The homemade tool worked out pretty well. I started running the hard brake lines and have only one more to go. Need to purchase more brakeline.

I started tearing the RX7's wiring loom apart. So far, I have maybe 5 pounds of wire removed with more to follow. That took 2+ days so far! I won't need the seat belt motors or sensors; the cruise control; the air conditioning, the headlight motors or headlight washers; a power antenna, the power windows and locks; etc. All of it makes for a very complicated wiring harness. During this process, I also found that the harnesses in the '91 rx7 were not common. If the car had antilock brakes, or a different sound system, or a electronic controlled suspension, etc. each would require a different harness to be used.

The biggest chore undertaken, was to attack the engine. This was one of the reasons I chose to go rotary power. I knew the engine needed repair and wanted to use this build to learn about rotary engines. Last weekend, I had 2 buddies over and we tore the engine down. The front eccentric nut was a BIT** to remove. It was originally torqued to only 80-98 ft lbs. Maybe some Loctite was used too. First we tried the impact wrench----nothing. Then we tried a breaker bar --- nothing. Then we tried a 4’ extension on my breaker bar --- I broke two Harbor Freight Impact sockets in the process. I had to resort to buying a new, short impact socket from Sears. It had a thicker wall and didn’t angle off the bolt head as pressure was applied to the bar. That socket, about 5 minutes of Mapp torch and the nut finally succumbed to our perseverance. The rear eccentric nut needed some extra effort. We bought a 2-1/8” socket (3/4” drive) to fit the 54mm metric nut (matched the 54mm within 1 thou). We added heat from the Mapp just in case. We applied the socket, a ½- ¾ adapter, my ½” breaker bar and the 4’ extension and placed a wool blanket over the whole thing in case there was flying pieces. On a personal note, we just about busted a nut. Not the one we wanted to remove from the engine. In the process, the breaker bar’s swivel-end broke in two. There goes a nice breaker bar! The remaining square end embedded itself into the ½-3/4 adapter. So I broke out the MIG and welded the adapter directly to the end of the breaker bar and tried again. We increasingly applied some pressure (about 200-250 lbs) at the end of the extension and rapped the back of the breaker bar with a 2 lb sledge. This time the correct nut finally let loose. It was originally torqued from 289-362 ft lbs!

If you have never worked on a rotary, the inside is a work of art. There are two rotors. Each has to be sealed for the pressure of combustion. This means a total of 45 pcs are used to seal each rotor! In a normal piston engine there are what 2 or 3 compression rings per piston? 3 Apex seals, 6 side seals, 6 corner seals, they are all multi part systems. That number doesn’t even count for the oil seals which add another 8 pcs per rotor. According to the service manual, everything can be measured and reused if it meets spec. But you have to remember exactly where each part came from and replace in the same position.

Upon tearing the engine down we found the source of the problem, One or two of the apex seals on one rotor decided to take a “vacation”. While on “vacation” they tore up the rotor and the rotor housing before finally leaving the exhaust port. This may have been due to several missing oil control o-rings. My guess is the root cause of the vacation was due to excessive caked up carbon from the oil leak. The other rotor and housing is in perfect condition and can be reused in spite of it missing only one of the four rubber oil rings. So now I have and engine in pieces spread across the garage and have to decide whether to find a good rotor and housing to rebuild the engine, or to find a used engine somewhere. The problem with used rotaries is that you really don’t know the internal condition unless you do a compression test. My engine had about 45# on one rotor and “zero” on the bad one but still ran enough to start and drive in the parking lot. Most sellers don’t take the time to measure that. So the hunt goes on. Anybody who knows of a good S5 NA rotor and housing, feel free to contact me.

That’s it for now. Work will not continue until I have a different engine or rebuild this one. There is no room to move in the garage.

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Chuck.

“Any suspension will work if you don’t let it.” - Colin Chapman

Check out my rotary build log: click here


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PostPosted: Fri Sep 25, 2009 11:30 pm 
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Hello Chuck

I am north of you a little bit in southern Wisconsin and have plans to use the same drivetrain. I have raced an RX-7 in Midwestern Council for a number of years. I don't know if you are aware of this, but Mazda motorsports has a terrific support program for Mazda racers. Both stock and competition parts can be had at significant discounts. If you plan on autocrossing your car, you would be eligible. I don't think it would help you on your quest for a new rotor and housing as even with a discount the parts are pretty $$, but for gasket sets, seals, bearings and the like they can't be beat.

I would like to come down and look at your build sometime if possible.

John
johnfromwis at yahoo dot com


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PostPosted: Sat Sep 26, 2009 9:02 am 
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John, come on down! Well not right now. There isn't much RX7 to look at, at the moment. The engine is in pieces and the tranny is out of the car etc. Once I locate a housing, the engine will be put together and then it is a matter of an hour or two to have the powertrain back in it's home. At that time, the RX7 packaging into the chassis will be done. I think you'll be happier to see it in this state.

Unless you are down here for some other reason and just want to stop off and say hi. You are welcome anytime.

I wasn't aware just how far down the ladder in racing Mazda Motorsports went. It is some good info. I'm not sure if I will get into "Autocross" I may do some parking lot stuff and maybe a HPDE or two.

I have everything(?) I need to put her back together. New apex seals side seals corner seals gaskets etc.I got them from Atkins.

Chuck

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“Any suspension will work if you don’t let it.” - Colin Chapman

Check out my rotary build log: click here


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PostPosted: Sat Sep 26, 2009 9:12 am 
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Chuck, when you broke the eccentric nuts loose, how did you brace the engine? That was a ****load of force.

My engine supposedly had a recent rebuild before I bought it, but it has been idle so long that I want to open it up for an inspection before I start it again. I'm a little leery about getting those mothers off.


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PostPosted: Sat Sep 26, 2009 9:36 am 
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Pete, the engine was on the HF engine stand using an Atkins adapter plate. My big problem was with the front eccentric nut. The small one! We broke 2 impact sockets in the process. We drilled a 1"x1/8" steel bar to fit across two pressure plate bolts on the flywheel. Inserted a extension tube, and braced it against the engine stand frame. That, a MAPP torch for about 5 minutes on the bolt and a seriously long breaker bar. The front nut is sealed with Loctite and silicone sealant. The heat brakes it down. Of course we covered it all with an old Army blanket to act as a shrapnel blanket if it came to that. Fortunately, it finally succomed. Don't try this with anything but a short 6-point heavy duty impact socket.

Once that was done we attacked the rear nut in a similar process. We only broke 1 breaker bar during that process. The 3/4" drive Sears chrome socket worked well here.

With my first rotary rebuild still in process, I am far from an expert. I would think you would be able to just peek into the exhaust port and push on the apex seal with something soft to see how they react. If they move and return freely, I would think you are good to go. Is there anything wlse to be worried about?

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“Any suspension will work if you don’t let it.” - Colin Chapman

Check out my rotary build log: click here


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PostPosted: Sat Sep 26, 2009 10:49 am 
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rx7locost wrote:
With my first rotary rebuild still in process, I am far from an expert. I would think you would be able to just peek into the exhaust port and push on the apex seal with something soft to see how they react. If they move and return freely, I would think you are good to go. Is there anything wlse to be worried about?


It ran crappy and I never got a good compression test. Good point on inspecting through the exhaust port, will definitely do that first and maybe decide differently.

Thanks for the details about the nut removals. Your infprmation will save me a ton of time and frustration if I get into it, I'm sure.


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PostPosted: Sat Sep 26, 2009 2:13 pm 
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A flywheel lock is the cleanest way to immobilize the engine but doesn't work if serious torque is involved. We used a long piece of 1.5 x 1.5 x .25 angle iron. Drilled two holes that would align with two of the flywheel bolts and there you go. It reacts against the floor so you can put a LOT of torque on it the center nut. We did bend that Craftsman 3/4" drive socket wrench (the kind that has a round sliding bar through the wrench end. I'm having a senior moment and don't remember what they are called.) Of course that was with a four foot pipe on it. After doing it this way for several years and disassembling engines a dozen or so times, I broke down and bought a "super" air impact. That baby will put out about 500 ft-lbs, doesn't require any locking of the eccentric shaft and is much less stressful of both you, your engine and its cradle. Pricy though, about $150 for a Chinese brand, IIRC.

The later 13B used the front as a sealing joint so it was sealed and torqued so much. The second time you take it off will be a lot easier :wink:.

The rotaries are very sensitive to getting water into one of the combustion chambers. The problem is that it not only ruins the end plate (either front or rear) involved it also ruins the center plate. I have had the rust ground down with some mixed results. Grind takes of the nitride hardening of the cast iron surface. I'm not sure that it matters a whole lot given the seasonal nature of our cars though. Another source of problems is the chrome plating on the rotor housings themselves. There are acceptable limits for the flaking, though. Mazda published a rebuild manual that uses a fairly simple set of criteria to judge the go/no go status of parts. It should be available through the rx7club, if not I could sent you the pdf.

That being said, if the motor will turn, that's a good thing. Lack of compression can usually be fixed pretty cheaply. The main culprits are the obvious, the apex seals, but also the less obvious side seals on the rotors which serve as the "piston" rings for the rotary. Once you have them apart they are much more simple to reassemble that any other engine, IMHO. We build a part that bolts onto the left fron of the front housing (using the air conditioner studs) and slipps into an engine stand. It orients the housing so you can stack the rest onto it like building a wedding cake but pivots to allow the assembly of the oil pan, front accessories, flywheel, etc.

As I mentioned, my son and I have been racing (or trying to race) for the past 6 years and have gone through a bunch of engines in that time. I still think its cheaper to buy a whole engine that to try to build one out of pieces. I have a little bit of land with a barn, though, so I can accumulate extra cars and engines more easily that most people.

Improving the breathing of a rotary is relatively easy. IIRC, Racing Beat and other Mazda parts suppliers sell templates that can be used to grind larger ports and dramatically increase the horsepower of these little motors.

Sorry to keep rambling.

Good luck,
John


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PostPosted: Wed Oct 07, 2009 9:46 pm 
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I finallly scored a good rotor housing. I had a false start and bought a housing that was not as described. That took a while to straighten out. Finding a specific part used takes some patience. I received my 2nd housing today. It is just as good as the one good one from my original engine. Unfortunately, it is a turbo housing so I'll have to change out the exhaust port and plug the coolant passage to the turbo. Not a problem. I've got the exhaust port from the original engine. I'm pumped! Saturday is the day to reassemble the engine. I plan on getting the engine together, the tranny attached and the pair in the chassis.

I can regain the garage and progress can begin again.

Chuck "but the Mazda goes hmmmmm" Schaefer

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“Any suspension will work if you don’t let it.” - Colin Chapman

Check out my rotary build log: click here


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PostPosted: Tue Oct 13, 2009 7:24 pm 
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The engine is back together again. I had a few mis-steps but nothing insurmountable. I did have one "huh?" moment. The oil o-ring between the front iron and the alloy front housing had 2 designs. Things didn't look right on Saturday so I went to the net and found a link to Mazdatrix notes on assembly. Unfortunately their site was unavailable on Sat so I couldn't see the details. Sunday I found the site was up but I couldn't follow their instructions. The correct o-ring for an S5 is supposed to have a Teflon ring surrounding it to help support it from blowing out from high oil pressure. But I must have an earlier front housing that had a smaller counter bore and couldn't fit the Teflon ring. The Mazdatrix site said to just use the o-ring and to eliminate the thick gasket. But if I used the o-ring supplied, it was sloppy in the hole and too thick to use without the gasket. I ended up running out and getting an o-ring that fit well and had the right amount of "Squish" if I replaced the thick paper gasket with Ultra Grey silicone sealant.

I used an 80/20 STP/oil mix as an assembly lube. I have had good success in the past using this. I had used straight STP years ago on a rebuild of my MGA engine. That engine sat for about 20 years before firing up.

I did have one problem on one rotor. After installing the side seals and corner seals, I assembled the rotor to the iron, Everything was fin until I tried to install the apex seal. One of the corner seals had rotated and I couldn't push the apex seal all the way down. I had to remove it and re-install the side seals etc. Other than that the engine block went together well. I was amazed at the "WHOOSH" sound when you turn the flywheel by hand.

I got the eccentric shaft trick done. I had to lap off the spacer by .001" to set the eccentric play to the minimum play.

I also found I had to assemble the water pump housing before installing the front pulley. If I had the pulley off the pulley hub, it probably wouldn't have been an issue. As I am writing this now, I think I could have separated the pulley from its hub instead of removing the hub. Oh well.

Had another problem that when I had everything together, before tightening up the front eccentric shaft bolt, you are supposed to tighten the bolt, then remove it and measure the distance from the shaft end to the pulley hub flange. This is a way to verify that you haven't slipped the Torrington bearing and trapped it with the spacer. Well I did it and the measurement was too much. It took me two tries to finally realize that I was checking it with the eccentric shaft in the vertical position. Every time I loosened the bolt, the shaft would drop about 1/16". Once I saw that, I lifted the eccentric shaft by hand and measured in spec. I realized I had it assembled right all along.

Most all of my faux pas were beginner’s mistakes. I know how to avoid them now. Actually, looking back on the re-assembly, it went amazingly smooth for being such a strange engine to me. Having one rebuild under my belt, I'm sure the second rebuild (heaven help me) would go much better. They say you are not an experienced rotary rebuilder until you rebuild the same engine for the 2nd time.

The engine/trans assembly is back in the car. From what I can tell, I am now back where I was before I tore it down for painting. All the hard brake lines and flex lines are made up, bent and in place. I should be able to fill it up with fresh brake fluid and bleed the system. Then I’ll check for leaks. Then I’ll attack the wiring!
Attachment:
rebuilt engine.JPG
rebuilt engine.JPG [ 216.19 KiB | Viewed 2021 times ]

Attachment:
rebuilt engine 2.JPG
rebuilt engine 2.JPG [ 213.88 KiB | Viewed 2331 times ]

Attachment:
brake lines 2.JPG
brake lines 2.JPG [ 222.67 KiB | Viewed 2017 times ]


That is it for now. I’m still hoping to have a runner by the end of this year. But this rebuild delay has set me back.

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Chuck.

“Any suspension will work if you don’t let it.” - Colin Chapman

Check out my rotary build log: click here


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PostPosted: Tue Oct 13, 2009 7:58 pm 
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Your engine certainly looks all business; very nice work!

I'm looking forward to your startup.


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PostPosted: Wed Oct 14, 2009 2:14 am 
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Looks great! :cheers:

Rod

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PostPosted: Thu Oct 15, 2009 8:02 pm 
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Thanks for the compliments guys.

I got the fuel lines run from the rear up to the front today. I still have to find a TIG welder to finish up the intake plenum. I still have to figure where to run the wiring from the front to the rear. Down the tunnel seems like the most logical approach. I wanted to run the fuel lines first and work the wiring around them.

I found a home for the two coil packs and will mount them tomorrow, just to get them out of the way and say they are done.

Thinking of running a lawn tractor-type battery to save some weight. I haven't found a good home for it yet. The logical places are in front of the scuttle, up on the shelf or in the rear. up on the sculttle will be where the heat is seeing as the exhaust runs out the RH side of the engine. Any of you rotary guys have any comments about this?

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“Any suspension will work if you don’t let it.” - Colin Chapman

Check out my rotary build log: click here


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