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Thread: Kevs Rotary Sled (Revival)

  1. #1
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    Kevs Rotary Sled (Revival)

    You might have noticed that I haven't really done much work on the Hako for a few months. Part of the reason for that is that I am doing stuff for the er...German car, but the other half of the reason is because I've been working on recommissioning a car that I haven't driven in a few years.


    I bought it in 2006, in pretty ratty condition from JaPerformance (they were about to cut it up). It's a 1986 HC3S Luce Rotary Turbo Royal Classic.


    My initial plans were just to lower it on some big rims, and turn up the boost for a laugh and drive it around until the motor popped But then, I kinda got carried away and just ended up restoring the whole thing. New paint, suspension, motor, transmission and diff (a brand new Mazdaspeed 2-way, no less)


    That's my friend John Edwards building the motor, which he did on a Saturday with Leon Prgomet (who sadly passed away a few months ago).


    If it kinda looks like a mid 80's 929...that's because that's exactly what it is. But Mazda made a couple of thousand with the 13B Turbo and automatic transmissions, and this is one of the very few left in running condition.


    It's the Royal Classic version, which means limo-spec, with pimptastic velour interior.


    And heaps of ridiculous options, like reclining rear seats...


    ..and a fridge.


    This served as my daily between 2006 and 2009. I loved it, even drove it to Melbourne one time (a 2000km round trip!). It might seem a strange combination to have a luxo barge with a turbo rotary, but oddly it all worked really well. The rote is super-smooth, the upgraded trans had a nice, loose convertor and a nice shift kit, so it gathered speed in this seamless surge, which really suited the whole luxury/comfy vibe.


    The turbo was rebuilt with a T04 compressor, the trans had a mild build, and the stock exhaust replaced by a 3in dump and catback, but it was my daily, so I kept it at stock boost. In that trim, she puts out 240hp and does 15.2 over the qtr.


    It even got on the cover of the Drive section of the Sydney Morning Herald once.


    Then in 2009, she started acting funny and threw a transmission warning light. I pulled the code, and it said throttle position sensor, so I swapped in a new one at somewhat of an exhorbitant expense. Oddly, this made it even worse, and at the time, the Hako was just about getting on the road again with the rebuilt engine, so I just put the Luce in storage and forgot about it for a few years.


    And even on a half-dead battery, she fired up no worries at all, so the motor is still in good health.
    http://youtu.be/k9tCAaS4biM

    But to be perfectly honest, I've really neglected the car for the past few years, and have my work cut out to return it to its former condition.
    Hidden Content Originally Posted by datsunfreak
    No Kev, you are eating a duck fetus.

  2. #2
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    Re: Kevs Rotary Sled (Revival)

    Now for a minor service and bit of a poke around.


    First an oil change...the old stuff didn't look too bad, but I'd been taking the car for a run every now and then, and TBH, it's pretty much had an oil change for every tank of gas in the past 3yrs.


    Brake bleed...which also didn't look too bad for 3yr old brake fluid.


    Suspension...ah, well yes that looks bad The front suspension clunks and bounces terribly, (and you'll note that the shock oil is meant to be on the *inside*, not coating the outside :lol. The front shocks were still working well in 2009, but I guess after I parked her up, the remaining oil must have leaked out with the gas pressure.


    One thing I can eagerly address straight away is the chrome trim on the front of the bonnet. As you can see, it's attached (or at least...used to be...) by flimsy plastic brackets. So the approved HC 929 process for opening a Luce bonnet is to pop the catch, and then lift the bonnet from the sides. Do what seem natural and lift from the chrome strip, and it'll come off in your hand IIRC these were already unavailable from Mazda 5yrs ago, so thankfully the broken chrome strip was saved, and now I can repair it.


    This is a perfect job for my favourite, QBond


    First you carefully put the bracket back in position, and sprinkle some of the Qbond black power onto the broken part.


    Then you put on a couple of drops of the special fluid, and psssscht...it sets rock hard. You can also see where I sprinkled on some more powder and the bottom of the bracket is just perfect for the powder to build up.


    And literally within seconds it sets rock hard and you can lift up the whole piece by the bracket.


    Fixed!


    The years haven't been too kind though. The dash developed some small cracks...


    And a little 5c sized bit of rust on the c-pillar door opening has festered somewhat. Not toooo bad though (I hope!) and when I remove that trim, I should be able to treat it and arrest it.




    But the initial report was that she runs well enough. The front suspension feels like it's about to fall off though, so the big items to address will be the throttle position sensor issue, and the coilovers. There are lots of other small jobs, and of course a proper detail....
    Hidden Content Originally Posted by datsunfreak
    No Kev, you are eating a duck fetus.

  3. #3
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    Re: Kevs Rotary Sled (Revival)

    This is really a job that's been overdue for 3 years. Here we go. I always get a kick out of popping the Luce bonnet and seeing that iconic FC intercooler there. It's such a part of the car that I never had the heart to fit that ARC top mount that I had. Back in 2008/9, nobody I took the car to, had any ideas about why the trans was playing up. But in the past few years I have had some theories I've wanted to try out.


    Remove the IC, and you expose the throttle body, and the TPS.


    As you can see, the TPS consists of two spring loaded fingers, which extend as the throttle opens.


    And here is the first clue. They have different markings on them. One is for the engine ECU, and the other for the trans ECU.


    And now we measure the resistance. The radiator-side sensor has very low resistance when the throttle is closed. 0.3Ohm.


    And when the throttle is floored, it increases to 4.8Ohm...and how does this compare with the other one?


    As for the firewall-side one, when the throttle is closed, it registers 5.8Ohm. In other words, its resistance at idle is totally different!


    And so the penny drops. I quickly swap the fingers from side to side.


    And refit the unit into the car, and as you can see, the wiring is a little kinked and doesn't look like it's in the right order. All the while, I'm thinking,...shit, is it really going to be that simple?


    Well, I guess it's a life lesson that sometimes, it just is
    http://youtu.be/B8xfGMpTd0g

    It's FIXED No trans warning lights, the kickdown works, the manual shift works, the ECO/PWR button works, everything is as it should be.

    2008 is a long time ago, and I can't remember why I fitted the TPS in that order. Maybe I based it on the markings on the old Luce TPS, maybe I just based it on where the wiring seemed to want the sensors to sit. But as to why this worked, I think the answer lies in the way the throttle works the two TPS fingers:


    The TPS at the bottom of the pic works on a crescent-shaped cam, whereas the one at the top of the pic works on a lever/arm sticking out of the throttle spindle. These will work differently on the two TPS's. So at say 30% throttle, the cam might allow its TPS to extend 5mm, whereas the other TPS is worked off a lever and might have extended 10mm. Since both TPS's emit a different resistance curve, this would send conflicting messages to the engine and trans ECUs.

    If, say both TPS's worked off the same crescent, then it wouldn't matter what order you installed them in. This sounds familiar, I think this is what I had in my head when I installed them....I didn't count on the "gearing" of each TPS would change depending on which position they were in, though which affected the part-throttle sensor readings (it was always ok if you floored it though, and now that makes sense). But for what it's worth, it's now fixed.
    Hidden Content Originally Posted by datsunfreak
    No Kev, you are eating a duck fetus.

  4. #4
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    Re: Kevs Rotary Sled (Revival)

    Well flush with the relative success of the transmission fix, I confidently plunk the ass of the Luce into the air for the rear-to-front shock swaperoo. I have some spare shocks, but they're too short, so I had this hare-brained idea that I could swap the (relatively long) rear shocks to the front, and then install the short spares to the rear...and then just fudge around with adjustment until it was all vaguely driveable.


    G4 is no longer supported, so getting replacement G4s was out of the question. First the parcel shelf has to come out. It weighs about 8kg, since it has sound insulation on the underside that's about 2ins thick, plus all the gubbins for the air purifier and fridge. You'll also note that the aussie sun hasn't been too kind and there is some fading.


    And with the shelf gone, you can see the innards of the fridge and air purifier, and of course the original champagne colour that the car was born with.


    Grimy, but not leaking!


    And this is basically the shock that needs to go in it. I had a vague recollection that the rear shock was one inch shorter than the fronts, and so the new shock should be one inch shorter than the existing rears. But they would still screw down enough into the lower part to be safe and strong.


    The damn thing was pretty rusted on though, even with the locking collars loosened, I had to resort to the vice, and hammering with a punch to rotate the shock free from its base. Damn crap G4 quality


    And the result....FAIL. Oops, they're the same length as the spare one?


    Hmm...serves me right for not having a build thread that was detailed enough to note things like this (no, wait...). But the end result is that I had no choice but to put it all back together again....hmmm. To be continued.
    Hidden Content Originally Posted by datsunfreak
    No Kev, you are eating a duck fetus.

  5. #5
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    Re: Kevs Rotary Sled (Revival)

    With a couple of weeks over christmas, I really had to get my ass into gear, and start fixing the Luce. So it starts with picking off the massive pile of leaves and twigs on top of her and giving her a good tub. I really am a bad custodian, the paint was actually mouldy in parts


    But while the paint is chalky as hell to the touch, it still does look ok. When I detail the car for real, my claybar is going to get nuked into the D-dimension tho :lol:


    The main thing I have to do is fix the front coilovers, but while the nose is in the air, I figured I'd use up some of the spares that fell out of the woodwork when I did the garage cleanup a few weeks ago.


    An oil and filter change...FUN LUBRICATION FACT: the 13B uses the same small oil filter as MX5.


    Then new plugs. I don't always drive a rotary, but when I do, I prefer NGK B8/9EGV.


    The plugs are buried on the side of the engine, which might have been easy to reach in an RX-2, but in the Luce, there is aircon and all kinds of crap in the way. On the right you can see the MX5 oil filter, which is quite easy to reach, with enough space for you to just grab it and spin it off by hand.


    New plugs are sorta like platinums in appearance, but are normal copper plugs. Normally, rotary plugs are bespoke to the 13B and cost $50ea, but when the engine was rebuild John Edwards machined the rotor housings to accept normal sized plugs. These are $12ea.


    Old ones were in good shape with little wear (they are normally really worn away by 10,000kms). Heaps of crap on them though, which speaks of not enough long hot drives and too much starting and shuffling around the driveway. My schedule is that I change the plugs every 7500kms, so I think these haven't done more than a few hundred kms.


    The battery was also in poor shape, so I figured I'd treat the Luce to a new one.


    The Luce's engine has got good compression, I think, because even with the old dead battery that could only spin the motor weakly, it never had an issue firing up, so with a brand new battery, it's all good.
    http://youtu.be/XTEkTcF2ePI

    The other thing I found were a set of pads, so on they go...


    Which is a good thing, because the old ones were pretty marginal


    And then we bleed. The Luce has speedbleeders, so this is easy to do by myself...and it also seems that I have run out of the cheap stuff, so the Luce gets Trust Dot 4.


    One snag though...on one side the caliper has evidence of a leaky seal


    So off it comes, and I'll get it rebuild at Chatswood Brake and Clutch.


    Once the brakes are sorted, I'll hop onto the coilovers...
    Hidden Content Originally Posted by datsunfreak
    No Kev, you are eating a duck fetus.

  6. #6
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    Re: Kevs Rotary Sled (Revival)

    The passenger side caliper seemed to be ok, but I decided to be safe than sorry, and so I dropped both front calipers at Chatswood Brake & Clutch for rebuilding.

    So that left me some time to work on the coilovers, which you will remember are shot at the front. I'd taken the dead shock and the spare shocks to a shock rebuilding joint to see if the guts of the spare could be put into the dead one. There was a notion that I might be able to disassemble them, and extract an insert that lives inside, and just swap them over. So the first step is to try to prise off the end caps to the old dead shock.


    Turning them with a stillson/plumbers wrench didn't do jack, so I made this handy dandy tool, out of a strap of steel, with two bolts tapped into place to act as lugs on those holes in the end caps.


    But the caps were screwed on so tight that the lugs sheared right off. Hmm...could be that they are corroded on. The coilover bodies are steel, whereas the end caps are aluminium. So over the years I think there has been differential corrosion and that powdery corrosion has built up in the threads of the end caps. So they are not coming off for nobody.


    The idea switched to maybe using the longest of the spare shocks, which is a whole 4ins too short, but if I screw the shocks into the blue bit halfway, then it's only a 20mm ride height drop. Hmm...nah. Seems dodgy.


    So I moved on, and one of the things I've been dreading, is to check the cowl area for rust. The Luce is actually remarkably good for rust, but it's been sitting for a very long time with a pile of wet leaves and twigs built up over the wiper area. So there's bound to be wet crud under there. So off comes the wipers and I'll remove the plastic cowl panel for a look see.


    First sign...hmm, actually very good, no rust at all under the cowl panel. The paint under there has held up perfectly.


    And poking inside the cowl box where the wiper mechanism lives, is good too. No signs of rust.


    I could only check the driver's side, because there isn't an opening hole on the passenger side. Then again, leaves shouldn't be able to fall into the passenger side (there's no grille on that side) so that's prolly ok too. This is the view looking towards the a-pillar on the driver's side. Any water falling into the cowl box exits through drain holes at the a-pillar, so this is where you could find build up dead leaves and hence rust.


    With that pleasant surprise out of the way, the wipers get sanded and hit with etch primer, while they're off.


    And a fresh coat of VHT roll-bar black to make them nice-nice again.


    The Advans have been dropped off to get some 205/50-17 Michelin Pilot Sports and 235/45-17 SP Sports mounted that I had stashed away, so the Luce should have good rubber all the way round soon.


    There still is the question of what to do about the coilovers though. Gotta think about it some more, but I reckon those shocks are rusted solidly together and I won't be able to get the apart anytime soon.
    Hidden Content Originally Posted by datsunfreak
    No Kev, you are eating a duck fetus.

  7. #7
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    Re: Kevs Rotary Sled (Revival)

    The rebuilt calipers came look great!


    The reason for the sudden fluid leak was pretty obvious, one of the pistons was badly corroded. The seal (ie glorified rubber o-ring) is fitted into a groove in the caliper, and the piston slides in and out of it. So as I pushed the piston back to accommodate the new pads, the corroded section pushed past the seal and the jagged edges tore it. Hence the fluid leak. But we got 2 new pistons now.


    I also got me some new rubber boots to fit into the caliper bracket.


    After a good bleed...I got 99 problems, but brakes ain't one (suspension accounts for about 92 of them tho)


    Another little bonus...as I was fitting everything back up, the ABS sensor on one wheel just fell off :lol: The wiring was toasted...and now I think I know why the ABS hasn't worked for years (it worked for most of 2006, tho!) It'll be easy enough to solder on new wires in place.
    Hidden Content Originally Posted by datsunfreak
    No Kev, you are eating a duck fetus.

  8. #8
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    Re: Kevs Rotary Sled (Revival)

    Finally...I found a replacement shock locally at K-Sport. K-Sport are made in the same Taiwanese factory as G4 was, so they are interchangeable, but are a black colour instead of chrome tho.


    And they managed to supply me with the same 50mm "Type D" shock as the dead shock, so it's a perfect fit in the old G4 hardware.


    So on it goes, with the new caliper and pads. You'll notice I also fixed the broken ABS sensor wire in the background.


    With everything buttoned up, I ran a whole 500ml of fluid through the whole system. Yeech...better out than in I guess.


    The new Michelin Pilot Sports, they're 205s on a 7in rim, so there is a tiny bit of stretch


    Hmm...maybe the front needs to go down about 10mm?


    But the great news is that Luce drives magnificently. The front end hasn't been so tight and planted in years, and no more front end clunks over bumps. And rather embarassingly, the ABS is working for the first time since 2007 :lol: (bloody hell it was as simple as a broken wire)

    The reason for the difficulty with the suspension is because it's all custom. There isn't actually any coilover kit available for HC Luce, except for some Korean kits which are quite exxy (the HC 929 was sold there as the Kia Potentia until 2001). The HC doesn't quite have the same suspension as FC RX-7. In this pic you can see FC shocks on the left (G4 and Tein) and they are both 4ins too short. The one on the right is a mix and match setup that G4 (which used to be handled by Just Jap) was kind enough to put together for me.


    I then got strut top plates laser cut out of 8mm steel, and that was the last piece of the puzzle I needed to get the hybrid setup into the Luce




    It's good to know that I can still get parts for it, and interestingly, K-Sport also sell an airbag kit that will screw into the existing coilovers.
    Hidden Content Originally Posted by datsunfreak
    No Kev, you are eating a duck fetus.

  9. #9
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    Re: Kevs Rotary Sled (Revival)

    After this, the maiden voyage went quite well....oh look a rotary at a petrol station


    The suspension was pretty transformed with the removal of that dead shock, so no more clunking soundtrack as you drive. The ride height has settled during the drive (the earlier pic was just off the jack) so the wheel gap has re-awesomed itself.


    Brakes work good too, and the ABS is still working, so I think that busted wire must have been the issue all along. The only issue was some strange squealing noise when I accelerated from standstill, and when I got home, the drive belts for the oil metering pump and alternator were pretty loose, so I tighten them in a hope that it'll fix it.


    But a few days later the belts didn't seem quite so tight anymore, which means I think that they're on their last legs and are getting stretchy. So...new belts...JDM yo, Bando brand.


    As you can see, the 13B has quite a few...one for power steer, a/c, alternator (which also drives the water pump and fan) and the air pump. Now the air pump is a weird rotary thing...it takes fresh air from the airbox and pumps it into the exhaust manifold. The official reason is to pump in fresh oxygen to help the exhaust charge get a more complete burn once it leaves the rotor housing, but in reality what it really does is inject fresh air to dilute the pollution in the exhaust, so the pollution readings aren't quite so catastrophic Some nice design there by Mazda: the water pump and fan are driven by two belts, the air pump and the alt belt. So if one snaps, you still get to limp home with a working water pump and radiator fan.


    First, before I work on belts, I always unhook the battery. It's very easy for a spanner or something to slip off a fender and fall on top of the starter, and when that happens the motor will crank. Even if it only does 1/4 of a revolution, that's enough to trap your fingers in the belts.


    Now, there are two ways that belts are tensioned, and the 13B has them both. The nice way is a tensioner that is tightened/loosened by turning a bolt. Once the tensioner is lowered, the belt goes slack and can be removed.


    Two of the belts look like they can only come off if the fan is removed, but in reality you can wiggle the belt past the fan blades.


    This is the other kind of belt tensioning...the alternator is on a sliding bracket, so I use a long screwdriver to lever it upwards (and make the belt tight) while I tighten the fixing bolt.


    With this kind you also have to loosen/tighten the main mounting bolt on the other side.


    Et voila...new belts! For the record, they are all the same as FC, except the power steering belt is shorter. I guess there must be less clearance in a Luce, so the power steering pump and a/c compressor locations are swapped compared to an FC.


    Next job is to replace the other front shock. The other day, I replaced the really dead shock on the passenger side, but the driver's side still looked good, with no leak. But if you went over a speedbump, you could tell that there was a little bit of a difference from side to side...I dunno if this is due to the driver's side being worn, or because of differences in valving between the G4 and the K-Sport. But anyway, I'll change it so that the front end is a matched pair.


    Struts are easy to change


    Roughly 45mins to get to this stage.


    The last thing for today is to remove the Blitz boost gauge from the steering column. The light doesn't work anymore, and TBH it isn't needed since the motor is capped at 6psi and doesn't spike. When I first got the Luce, the plans were to screw up the boost to the max, and then drive the thing until it blew up, and so I fitted the boost gauge. But then I had the motor rebuilt, and kept it at stock boost, so there isn't any reason to have a gauge. Looks much cleaner without it.


    With the new tyres, it's still got good fitment Interestingly, what I thought was an rear wheel bearing noise is gone. I guess it must have been related to the hard old tyres being a little flat spotted from sitting in one spot for so many years. With the new Dunlops, it rolls quietly, so I reckon there's actually no issue there.




    And we're done...mechanically this is as good as she' gonna get, and I would say the Luce drives as well as it did in 2007 when the resto was still fresh.
    Hidden Content Originally Posted by datsunfreak
    No Kev, you are eating a duck fetus.

  10. #10
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    Re: Kevs Rotary Sled (Revival)

    One last job was the rust spot in the C-pillar. There was always a little bit of a rust spot in the c-pillar, mostly behind the chrome trim. But just the same, it's gotten worse while the car was in storage, and the paint in the area is a little bubbly and you can see rusty water coming out from that area. The question is...how bad is it?


    Well, only one way to find out, and removing the trim starts with removing the rubber door seal, which has plastic pop studs at each end, but is just squeezed into a channel on the underside of the trim


    With the rubber seal out of the way, some screws are revealed...


    But the trim is also bolted to the c-pillar sheetmetal, and that means that the interior trim has to come off to access the bolts. BTW that metal panel at 11'o clock in the pic is the Yakuza Plate that tried to take my pinky finger...as I pulled it free of its plastic studs, it damn near sliced the thing off


    At first the rust doesn't look too bad, after scraping off the loose stuff.


    But further scraping with a wire brush exposed a few pinholes....Oops.


    But if you look from the inside, the paint seems to be intact, so it's all on the outer surface.


    The first step is to treat the rust with rust converter, which chemically attacks the rust and converts it into this inert black substance. Then I give the surface a rough sanding, and then wipe off the residue with a tack cloth, and then wipe the panel with prepaint solvent.


    Then we bog...as me mate Edd China would say...a golfball of filler, to a pea of hardener. Then you mix it all until it's a uniform colour. Funnily enough, in 20yrs of working on cars, this is the very first time I've dabbled in bog, so this is all very interesting.


    ...within 5mins of mixing, it goes into a soapy sort of consistency, and you can peel chips of it off the board I was using. So once mixed, it starts to harden and you have to work fast.


    Proof of the Yakuza Pinky Finger Rite of Passage..
    Hidden Content Originally Posted by datsunfreak
    No Kev, you are eating a duck fetus.

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