rxsumo

We have used the 3.0S for weddings in the past...so happy to assist if required

It been a quiet few weeks on the car front, as the RX3 isnt living at home right now..... A couple of longish dyno sessions, including one with a engine analyser, and finally a break through on the engine miss problem. The good news is the we think we now know was is causing the high rpm misfire, the bad news is that the engine is now in pieces. In the first dyno session, the guys sorted the fueling, and got close to the correct timing, but ran out of time to look at the misfire, and at that stage they didnt have access to the engine analyser to see what was actually happening with all of the electrics. Its had assumed that the engine state was okay, as while the engine had been built for 7 years, it hadnt done a lot of kms, and had been built by a top NZ rotary engine builder, who specialised in old school PP engines. Between the dyno sessions, the compressions were checked and there was quite a difference in front to rear compression pressures, however the variance between the pulses on a per rotor basis were within Mazda tolerances. We hooked into the second dyno session on Tuesday, and after a couple of hours of diagnostics including swappng the distributor and igniters, and the coils, it was concluded that the electrics werent the cause of our issue, so it was something else. We did a couple of runs just observing the engine, while the misfire occurred, and it became apparent with the exhaust header colours while running up, that the rear rotor was lazy. So the air cleaner was removed and the main jets checked, and swapped front to rear, and the engine run up again. At that stage we saw that there was a huge fuel standoff on the rear rotor when the misfire occurred, at that stage the issue was isolated to a mechanical problem. There was only likely to be two possible reasons for the standoff, blocked/bad exhaust, or internal engine issue. So we dropped the exhaust off the headers and run it up again....and that run was interesting....it was unbelievably loud, and the HP was halved, so from a high of 150hp at 7000, it was around 80, the fuel standoff reduced somewhat, but the misfire was still there. So now there was only one possible outcome....engine out. We pulled the motor down yesterday, and think we have nailed the rear rotor issue. One of the apex seals, was extremely tight, and wouldnt move freely throughout its full movement range. We also found that there were excessive side seal to corner seal clearances on both sides of the rotor, so that probably wasnt helping the overall compression pressures.

Some pictures from the Sportimages website...

Video now up.....

Its been a few weeks since the last update, and the car has had its second outing at the track, and its now got a best time of 1:25.18, so we have taken 2 seconds off the lap times, and hopefully more to come. Since the last update I've really been focusing on getting the engine running right, although we have done a couple of the small tidyup tasks. I managed to score another "correct" white rim early grille off one of the fellow Mazda sprint competitors, so the car now has a grille with the grille emblem mounted. The leaking RHS wheel bearing seal has been replaced. Also repacked the rear muffler, which was virtually empty, which has quietened the car down heaps. I've spent hours trying to sort out the misfire issue, which didnt go away after the reworking of the fuel delivery system. So after chasing a over pressure - and subsequent carb flooding issue, and replacing the fuel pump and regulator, and the needle valve in the carbie, we have learnt something...... Holley fuel pressure regulators must have fuel being sourced from a straight pipe.....no elbows on the inlet, otherwise they dont work.... Anyway we got to the track, and after all the work on the fuel system, the misfire was still there. Time to back the timing off, we eventually got the car running cleanish, but the timing marks are way off "normal", which leads me to suspect that the dissy might be one tooth out, or some other timing issue, potentially created with the conversion from twin to single dissy. With the timing that far advanced, I suspect we have been lucky that we havent detonated the engine. Anyways its on the dyno this week - hopefully to sort out all the isses for once and all. Got some in car camera stuff for anybody that wants to go for a ride in the passengers seat at the track. The sound quality is crap....like some of my lines....but here you go..... Practice Run 1 Run 2 - got the quick time on the 3rd lap Run 3 Run 5 - wet

Will do, I thought I had the cameras sussed for the first outing...but didnt Will have them sorted for the next track outing

Been a little busy over the last couple of weeks, mainly wiring and cosmetic sort of work. Found it had 12A headlight buckets, which is why the car looked a little crossed eyed, so now it has 10A ones back in so the headlights fit in the correct position in the headlight bezels. The car now has a WOF, and is registered, so now we should be able to road test the car, to see if we have got rid of the fueling issues. The fuel system is now sorted - hopefully. The fuel lines already had 3/8 lines, but heaps of potential restrictions, fuel filter...the fuel lines were using the original position, so the lines came out of the pump and immediately went up, and it was a little messy around the banjo. The fuel pressure was too high for the IDA...set for 7psi instead of 3 psi So now there is 1/2 inch feeders from the tank to the filter and to the pump, it then drops to 3/8 to the carbie, we have removed the return lines, and now fitted a pressure guage. So the boot plumbing looks a little nicer now And the slightly tider engine bay... I've fitted the carbon fibre air box, its a little modern, but it came with the car - so the price was right , and I can get a cold air feeder to the carbie via the headlight pods The Paddy Hopkirk wheel fitted, with the correct screws and trim ring

Some more bits arrived this week... A brand new ignition assembly from my friendly Mazda dealer The old ignition was a little shagged, and the key wouldn't stay put in the hole And it has geniune Mazda keys I had a Paddy Hopkirk steering wheel, which is actually a Motolita, which came off an old BMW, that I wrecked, as the wheel was fitted to the BMW in 1974, its got to be the right period piece for the car. I managed to score a fitting kit for it off Ebay, which also showed up.

It survived its first outing at Manfeild - just! I managed to run a best time of 1:27:24, which is rather slow for the car, but we were having issues with a major misfire in 3rd and 4th gears, which meant I was off power for most of the straights. See it did get to the track... I managed to lose the air cleaner on the second to last run, probably due to the misfire vibration. But had an awesome day, the car has a really good balance, really good tractability, and is really nicely setup. When we had power (in 1st and 2nd gears), the car was magic. So the to do list..... New Air Cleaner (and probably a cold air box) Upgrade the fuel system (my PP guru reckons I'm running too smaller fuel line) Get the tail lights painted, the correct candy apple red Rebuild the oil cooler mounts, on Saturday morning when doing the timing I spotted the oil cooler floating, so patched it up for the weekend. Get the car WOFed, and registered, once I get the Motorsport Authority Card back from MNZ Work out why the fuel gauge doent work Get a new battery Build some brake ducts for the front

Now I've had a chance to get the car out of the garage, and get some photos, it's time for its own page. This is how the car looks now. I've just spent last weekend reinstalling the close ratio gearbox, race diff, and the fast steering box. The car was also missing the centre dash console, along with the factory guage set, so a new one of these arrived in from the States early last week. So this weekend was to restall the dash centre, the factory gauges, and the additional guages, the heater controls and get the centre console in. I also had to get the decals on. So the interior looks like this now, a vast improvement on the gaping hole SO the car is a 1972 Mazda RX3 Coupe, that has spent the last 15 or 20 years as pretty much a dedicated road legal race car. When I first encountered the car, it was owned by some members of MREC Tauranga, and was running a 13B J Port, and was a class winning car at Taupo at the time. It eventually found its way to Wellington, and was repowered with a 13B Turbo, and the usual Supra box. The previous owner had acquired it as a rolling shell, and had decided to go 10A PP. So the specs.... Driveline: 10PP running around 180hp. Mazda factory 4 speed close ratio gearbox. Mazda factory 4.9 competition diff, with a Mazdaspeed race spec LSD. Suspension: Front is coilovers, with Koni adjustable shocks, and Knightsports Camber adjusters. Wilwood 4 spot calipers, with Wilwood rotors Mazda Factory race steering box - 2 turns lock to lock Rear is cart springs with lowering blocks, and as per Group 2, two forward control arms Brakes are series 2 RX7 - adapted to fit the RX3 handbrake setup - pretty much like the Group 2 setup Mazda 626 RWD swaybar Body At the moment Savanna lower nose cone Aftermarket Fender flares Savanna rear bumper Savanna Geniune accessory Bobtail Savanna GSII rear quarter badges. Body parts at hand.... Savanna Race two piece front Splitter Savanna Race single piece front Splitter Savanna Race rear blade spoiler Savanna Race Group 2 Fender Flares The plan..... I want the car to run either of the two Race fronts, and probably the two piece front spoiler. I'll also have another boot lid done so we can set either the blade or the bob tail. I need to get some molds taken of the fender flares, and then they will go on the car, as well has having the guards chopped out. Then we will look for some 9 or 10 inch wide rims for the car. At the moment I'd like a set of 15 x 10 Watanabes, although depending on price I might also look at the similar Panasport 2 piece rims. The idea is to keep it as a period race car kept pretty close to the Group 2 specs. Ultimately the car will probably end up with a 12A PP, as that is pretty much how the Japanese cars run in the day. The only real difference is the period Japanese cars ran a gutted interior, no bumpers, no headlights and a megaphone exhaust. So we have a few tidyup items to do before its first outing in a couple of weeks. Finish off tidying up the dash wiring Fix a leaking radiator overflow pipe Replace the Fire Extinguisher Gets some numbers made up for the car Get some towing eye decals Time the engine, as its a little retarded at the moment. Discussion Link

All good, the steering box is 2 turns lock to lock...apparently the are like hens teeth to find

Actually wasnt that hard, the race car is really tidy, and we werent using the RX3 that much. I decided that rather than spend a heap of money developing the Mustang for motorsport, I would be better to do a deal on the race RX3, and use the money to restore the Cosmo instead. Yeah, found a house with a garage thats has the same square metreage as my old house and garages combined....all good

One of the guys on Ausrotary did a single batch of early Mazda under bonnet stickers...I was lucky enough to get a set before he decided not to make any more.

Well after 15 years or so of ownership , I've decided to trade the RX3 in, but all is not lost, there still is a RX3 in the garage. The new car is a 1972 RX3 Coupe, that has been around the MREC for many years, and has a heap of different motor and box combos from a 13B J-Port to a 13B Turbo, and now a 10a PP. The car has a heap of Mazda factory parts, including a 4 speed close ratio box, 4.9 LSD, factory fast steeering box, and all the fibreglass bits to build a Group 2 lookalike, with both types of front and rear spoilers When I was in Tokyo, I managed to score a set of the correct fender flares for the early body shell. The intention is to build it into a replica of the 1970's Mazda Japanese racers like this At the moment, I've just finished putting all the race driveline bits back in the car (the previous owner has started to turn the car back into something more road oriented), the next exercise will be to sort out the centre console which was missing when I got the car, and the centre dash wiring. Hopefully it will be ready for its first outing at round 1 on the Intermarque series. Once I find the money tree again, I want to get some moulds taken off the new fender flares, and get them installed on the car.....guard cutting time...especially on the rear, then to import some 9 or 10 inch wide Watanabes

I think thats what he paid for it, he also had to pay for the ferry, WOF and Rego, so he would have lost money on the car.

A mate of mine sold this a couple of weeks ago, so its interesting why its been sold again so quickly. Watch out for the LHS front hub nut loosening off. He also had all sorts of issues with the ABS and TRACS system, I'm not convinced that a wheel sensor would cause the issue.

Try Wim - multirotor on Ausrotor, he may be able to help. Glenn died earlier this year, and Rotarypower has closed up shop. I have another couple of mates that can build my engines, so one of them will probably do the job, eventually

They popped up on Ausrotor, and fortunately I managed to get to them before anybody else did. Hmmm, the price....would buy a nice daily driver, or around half what the original owner of the Cosmo landed it for. Glenn Munro had a full set of end plates (3) for one of these engines that he offered to me, I turned down in preference to spending the money on rotor housings, and they sold back to Japan for $11K, around 12 months ago. End Housings generally can be restored either by skimming or by a crowd in Canada that ceramic coat them, rotor housings cant, which makes the rotor housings pretty critical to rebuilding an original motor that will run.

The holy grail for a Cosmo Sport Owner with a stuffed engine, is to find some new rotor housings. A few weeks back a pair surfaced in Belgium of all places....and now they reside in NZ I was pretty glad to get them before they were snapped up by a Japanese enthusiast. These are unique to the CosmoSport 10A and as you can see they have a roughcast exterior, unlike the R100/RX3 smooth finish scalloped exterior. This will allow us to rebuild the original motor, although we will still probably run an RX3 10A, with stage 2 porting.

I can recommend Ashley Audio in Arthur St...for stereo work and alarms

Suspect there are 5 or 6 in the country at least. There was an Auckland dealer that sold two of them trough TradeMe, as well as somebody in Dunedin doing the same. Suspect none of them are actually on the road however. Engines are the biggest issue, mine has done a geniune 80K, and the motor is shot. Major cracks around the sparkplug holes due to bad water channel design causing hotspots in the housings. Rust would be another factor. You would have to be brave to own a R130, and drive it. The motor only shares Apex seals with the 10A, and virtually everything else is unique, at least with the Cosmo, you can transplant a later 10A, and actually drive the car without having to worry about motor failures. Our intention is to go do this path, fit a RX3 10A engine, and ultimately have the original L10B motor "rebuilt" and kept for originality purposes only. This way the car can actually be used.

The Cosmo hasnt moved much. I've managed to score a few NOS bits and pieces, engine bits and trim, over the last 12 months. We are in the process of buying a new house, and a few other priorities have delayed the project a little longer.

Well its been a while... Latest race trim - I grabbed some of Mike's old race tyres, shoved them on the Mustang LX rims that were lying around The latest bit for the car from Ebay. Factory HO Air cleaner, the car should have one of these from the factory. Returns the car back to cold air induction. If it was good enough for the Group A engines....its gotta be good. Had the Mustang back at the track in May. Got it down to a mid 28, which is only a second slower than Mike in the Pursuit car, and my M535i Its kinda had to concentrate on your line, with a cop car up your ass Only real drama at the track was me spinning the car, it gets a problem with tank surge when it has less than a 1/2 a tank of gas....the problem is real bad through the esses and into the hairpin....so bythe time you arrive at the hairpin, the engine has virtually lost all power....LSD unlocks...and spin time....

The Mustang is back from the panel shop ,so I spent the weekend reassembling the interior, and doing so other random stuff Look ma...no holes... The paint came out pretty good overall, we didnt want a flash shiny job, as it wouldnt match the rest of the car. I also got around to stripping the aluminium backing off the body mouldings, so hopefully they wont twist up and lift off anymore, and fired the mouldings back on the car. I scord a set of BBK springs for the front of the car, which gave me a similar ride height to the chinese "no name" springs, but were 1.5mm thicker in the spring wire, and had more windings, which should equal heavier spring rate.

checked in my old identicar....according to the information...probably provided by Ford in NZ both 1.3 2 door Sports ($3450) and 2 door GTs ($3515) were imported CBU in limited numbers from 1971, as well as the Mexico ($4131), and the RS1600 ($5097) looks like in '73 changed to 2 door Sports, and 4 door GT