Tales from the Batcave (RX-7, rallycross, misc. stuff content)

Clutch disengagement issue completely gone after replacing the Centerforce clutch (came with car) with a nearly new stock-replacement clutch that came with one of the eleventy billion core engines I bought.  Checking the Centerforce disk on the transmission input shaft and spinning it, it had about 1/8" of runout.

Incidentally, the 4 puck disk that I bought has a small amount of runout... on only one of the paddles.  Erk.  I don't feel too comfortable with trying to bend it straight.  I'll worry about that later.

Drivetrain vibration completely gone!  The trans mount was not only sagged, but completely broken.  When I put the 12A in, I bolted the mounts in with the trans mount cockeyed way to the right.  New trans mount from Atkins got the height and angle right after I unbolted the engine and realigned those mounts.

And now.  A sight that made me really happy when I got back to the garage from work.

December 2016:

June 2021:

The implication is that the '81 is now a running, driving vehicle!

Also, teh R fits in the "park" spot, not just the "work" spot.

Didn't have time to stop for photos during the process.

Changing oil, and trans fluid again.  Oil looked good, no shinies.  Trans fluid looked nasty with metal again, and then this popped out.

This has been grinding around in there a loooooooong time.  So, I can assume that the other two bolts surrounding the mainshaft in the bearing plate are loose.

But the trans isn't racking.  Huh.  Sounds like a blender, though.

The goods:

Got nearly 20mpg driving down and partway back, including the rallycross. (Currently luxuriating at chez Evan, alternately enjoying airconditioning, a shaded porch, and Polish liquid refreshments)

Nothing broke.

Trans never popped out of gear.

Handling is really good, and I never felt like I could not keep up with the steering.

I have a cute kitty in my lap demanding attention.

It never overheated.

The bads:

A/C compressor clutch/hub bearing is dying, occasionally making horrible grinding sounds.

I have a cute kitty in my lap demanding attention, making it really hard to type.

Right rear brake is binding.  The wheel was black with dust when I got to the site.

The engine feels... soft.  It has no oomph below 4000 and runs out of breath over 6.  I may be putting the header back on.

The carb randomly sticks before closing, holding the revs up.  Only happened a couple of times.

It flooded massively before parade lap.  I had the idle mixture waaaaay off, will feel better when I get a wideband on the thing so I can see what is happening tune-wise.  May be related to the soft feel.

It never overheated but it was getting up to the middle of the gauge after one or two of the runs. Thermostat opens a little below quarter.  Need to quantify the temp gauge.

IT REALLY NEEDS NEW DAMPERS. And bumpstops in the front.

All in all, the car looks like a winner.  Debating buying new tires or continuing to use the ancient (2007?) Silverstones with a buffing and Track Claw.

OMGLOLHAHAHAHAHAHAHAHA

Went to go set the timing with Evan's timing light because I don't have one and set timing by the "stab distributor in by eyeball" method.

THIS WHOLE TIME.

I HAVE BEEN DRIVING.

WITH NO LEADING IGNITION.

OMGHAHAHAHAHAHAHAHA!!!!!

"Geez this engine feels soft."  "It doesn't make any power down low or over 6000"

Yes, it pulls to 7500 with alacrity now, on leading only. 

Had a funny moment that led to the opportunity to discover this.  Was driving along I-71 north, and I heard a loud belt squeal.  Huh, something must be locked up on that Prius coming by in the left lane.  (I was only doing 80, so people gonna pass)  Noise kept on going after the Prius left.

E36 M3!  That's me!

With visions of an air pump locked up because the inlet has no hose on it yet, I booked over to the right berm as soon as I could get a break through a line of trucks.  Still heard it with the engine idling.  Jump out, open the hood....  all the accessories are turning? 

IT WAS THE CICADAS.

Didn't hear them before today.  Yow, they are LOUD this season.  I don't remember them being nearly this loud the last two broods.

So, of course, I had to minimize my time exposed to danger by going all out when re-entering the highway.

Pete. (l33t FS) said:

IT WAS THE CICADAS.

We noticed them too in OH. I even heard them in the rain with the windows up and A/C on for a short part of the ride home. Way louder than the Indiana ones....

I only heard them near Chillicothe and that part of I-71 a bit north of Columbus.  Absolutely nothing here by the lake.

Poked around with the car today.  Using the ultra precise method of dipping a mechanical temp gauge's probe in the radiator, I determined that a third of the way up on the gauge is about 195F and the halfway point (the highest I saw at the rallycross) is 220F.  So it is cruising down the highway at 195.  Not awful, not great.  The radiator is a bit crusty inside, and the coolant already looks like pea soup, so I may be flushing it out with some cleaner and trying again.

Love to get a NEW radiator, but the only thing available in 2021 is aluminum, and Prepared rules state that radiators are free except they may not weigh less than stock.  If it comes to it, I might add ballast to an aluminum unit, but I'd rather not.

Then went to diag the ignition system.  Weird that the leading ignition died, as the leading ignitor is facing the fan airflow and the trailing is tucked up next to the alternator, over the water pump housing.  Also weird that my trailing ignition seemed to be running at what should have been the leading's timing.

If you guessed right, give yourself a cookie: I had the leading and trailing connectors switched around.  That's why it was running not completely horrible on trailing-only: it was connected to the leading pickup!

Found an ignitor in my collection of stuff, lifted the alternator out of the way for access, connected the distributor up the correct way, and we have two ignition systems again for the first time.  Was able to pull another quarter turn out of the idle mixture screw, too.

Found the dyno sheet for the black car's old engine.

Found a pic of the Quantum from a particularly muddy Detroit rallycross.  I think this was from the epic mudfest that got Detroit region kicked out of Fowlerville.

I'm going with 'not fowlerville' given what appears to be my zx-2 behind ur quattro and I never made it to Fowlerville.

Adrian?

cghstang_chris said:

I'm going with 'not fowlerville' given what appears to be my zx-2 behind ur quattro and I never made it to Fowlerville.

Adrian?

Photo is from early 2010, so it appears you are correct.  I placed 4th in M4 behind Scott Harvey and Orion in 1st and 2nd respectively, out of something like eleven cars.

You won PF in a class of three.  Third place was ZB in his Golf.

Pete. (l33t FS) said:

All in all, the car looks like a winner.

It is a winner.  It's the 2008 Prepared Rear SCCA RallyCross National Champion car.

In reply to slowautoxr :

With this and the black car, I have two of the three RX-7s to have won a national championship.  Gotta catch 'em all!

No pics, but today was productive.  Seeing that Black Magic fans have gone from open straight-blade to shrouded S-curve style, I bought a replacement blade from Summit.  It rotates the other direction, so I had to pop the controller apart and switch the positive and negative leads around.

I also had to use a 5/16" shaft collar to hold the blade to the motor, because the older motors don't have the groove for the spring clip.  This entailed buying a 1/4" collar and drilling it out to 5/16".  The second one didn't get mangled in the process.  And since the hardware store closes at 8, and I've been working until 7:30-8pm this week thanks to being short staffed, this all took a few days worth of evenings to get done. 

When I put the fan in, I switched it around so the controls are on the passenger side, so I can adjust the fan temperature with the engine running, as the knob was really close to the A/C compressor on the driver's side.  This required extending all the wires, so in the process of doing that, I dug up some of that nice woven loom and did it all neatified.

Next up:  The compressor clutch.

Just kidding.  Next up, I pulled a bunch of coolant from the radiator and added three bottles of BG Coolant Flush and drove around.  Water temps now hover around the thermostat opening temp if driving at anything over 35mph.  I'll let it stew in there until later next week and then flush it all out with water, then go back to a cocktail of 2:1 coolant:water with a bottle of Water Wetter for seasoning.  I REALLY don't want to go to an aluminum radiator.

Things done today, no pics because I fail at taking pics lately:  Repaired the air pump that decided to start making horrible noises.  While the air pump was off, I replaced the MOP lines with the new ones I'd bought from Atkins, along with four brand new-in-Mazda-bags hose spring clamps.  Rotated the A/C compressor adjuster bracket 180 degrees so it won't foul the A/C fittings, and installed the R-134a adaptors.  As soon as I get my compressor clutch tools, I'll worry about that.

Also, after repairing the ignition system, apparently somehow the timing was way retarded.  Set timing to 4" leading with 8 degrees split, seems much happier now.  Between that and the repaired airpump the idle speed has gone from 800 to 1100rpm.

It appears that I am registered for this weekend's Detroit region rallycross.

Time for the first "away game"!

Mary Shiloff wrote:

Bad news - with the prospect of 1+ inches of rain tomorrow, we have decided to cancel Saturday's event.

My fault, guys!  Sorry!

12.48 gallons to top off the tank after 323mi of driving to work and home and Batcave (well, wrong order).

Heh. Heh. Heh.  Better daily economy than the Volvo and it runs on cheap 87 and not 93.

One .020" clutch spacer liberated from an A/C compressor I replaced yesterday, 10min of vacuum, 8 ounces of ester oil, 45 minutes of vacuum, and 1.2lb of R-134a later, the '81 is refrigerating down to 38F vent temperature.

Major win.

GoPro died midway through the rallycross on the 5th.  Started the afternoon runs and it was not registering that a SD card was in it, so I figured the card was kaput.

Heh.  Nope.

I get out to the garage last night, open the door, and find this.

Um?

Appears to be heaving from the rusted out spot I thought I'd repaired earlier.  

Lovely.

Went to Dragway 42 with the '81 to see what it can do, since it has literally been since 2000 that I have driven a stock 1st-gen.

Short answer:  16.74 at 80.6 or somesuch.  The car ran 17.2 or so at 80 according to magazine tests.

Long answer: I only got one run because they were PAAAAAACKED, like eight million slick tire cars, and they were running some heads-up competition thing.  So I had no time to play with launch techniques or shift points.  The carb ran out of fuel a little past the 1000' mark in 3rd so I short shifted to 4th right before the 1260' lights.  (Or is it 1254'?)

Does burnouts really well, at least, for what that's worth.  Rear disks suck!

Swapped the RX-7 for the Volvo to find that something got in it somehow, even though all the windows were closed, and chewed on a coffee cup.  I'd been meaning to clean the interior anyway.

Also, jumping from a 100hp 2200lb car to a 25 year newer 340hp 3600lb car is a bit of a culture shock to say the least.

And now are the boxes!

What's in the booooooox?

Being nearly impossible to find low budget 13" rally tires, I rang up Rocky Mountain and went to buy four BR44s at mega discount closeout prices.  He said, well heck, I only have five in stock, I'll knock off another $25 if you buy that too.  Sold.  Also bought some new ultra aggressive rear hoops for the '84.

All seven tires cost me about what two Hoosiers would have been.  Shipping, however, was $230. Ouch.

Slightly annoyed that the website promised that the tires were not built on rally casings, and that the 13" tires were 155s The six BR33s that I'd bought had Black Rocket on the sidewalls.  The 13" tires are recapped Michelin 16-60-13 (kinda big) and the 15" tires are seriously, seriously stiff Dmack Grippa casings.  I believe spft sidewalls make for better grip, but options are low, and they are probably better than the hockey puck Silverstone tires I have now.

Heh.  I mounted these tires for a local rallycrosser in 2007.

they're... old

Previously, in the Batcave...

IT REALLY NEEDS NEW DAMPERS. And bumpstops in the front.

As delivered, the front suspension had "*shrug*" dampers up front and 8" Eibach 200lb springs, set to have about negative 3/4" preload.  Whatever three turns of the spring seats is.  I know this, because I raised the ride height that much.

I don't know if it was coil binding before, but it definitely was after the adjustment.  On road transitions in construction zones.  Clearly, I could not just ignore the problem.

$150 (ouuuuch) later...

Since that is probably too blurry, I acquired a pair of 225lb, 10" long Eibachs.  Why Eibach and not cheaper QA1s?  For one, QA1 doesn't make a 225, only 200 and 250, and I felt 250 would be a bit much but wanted more than the 200.  For two, they use a much higher grade of steel, so they can have thinner/fewer coils, so they have more travel for a given length/rate.  I'm probably still going to be running into coil bind, but I don't feel like hacking up another set of strut housings just yet.

As for the bumpstops...

Oh we in HD now!  Bilstein HD to be precise.  They have internal bump stops and beeeeeefyness due to the upside down design.

Another thing I did was, the upper spring seat was just resting under a stock seat.  This was eating up about a half inch of much needed height, so I cut the seat away from its inner sleeve, which is still needed for the coilover seat to interface with the strut top.