The life and times of Miata #338

The package showed up. It was my stock Miata radio that's more than 35 years old that was modified by Jeff Anderson (RIP) over 25 years ago. I sent it out to have the dodgy channel looked at and to be serviced. It came back with all of the caps and incandescent bulbs replaced (old parts included) as well as a new drive belt for the tape deck. Brandon was impressed with the fact that the tape deck worked at all. Even the lighting was in pretty good shape with just one or two bulbs out. Maybe not totally necessary, but call it preventative maintenance. Brandon couldn't find a problem with the bad channel and it seems to be okay now, which makes me think I had a bad connection at the back of the unit.

The CD player didn't work when I sent it out. Instead of fixing it, he installed a hidden Bluetooth receiver inside the head unit that hijacks the CD input. The lights still work on the player so it looks stock but I no longer need to use my little Bluetooth-FM adapter thing. It looks good. The Jeff Anderson modifications are still in place.

When reinstalling the interior, I wasn't happy with the shift feel due to the new heat insulation being compressed by the center console. I removed one of the pieces and it's better. I'll evaluate again after I get on the road.

Since I had the car on the lift for all the fluids, I decided to swap out those upper shock mounts and front bumpstops. All four mounts had definitely started failing with the rubbing left front being the worst. That's it on the left in the picture, you can tell it's a 1.6 part from the short studs. The other is a slightly slipped 1.8 part. The gap between the top part and the rubber beneath shows the slip, it should be in contact. I've been playing whack a mole with these by taking the best I can find in my parts stash, but they keep continuing to degrade. Now I have four new ones in place.

Interesting detail change between the 1990-93 and 1994-97 units that I'd forgotten about - the spring perch is less aggressively contoured on the early ones.

This will raise the ride height slightly. Once the car is off the lift and settled, I'll take a measurement and see where it sits. It will definitely help with the rubbing - not because the ride height is higher, but because the bumpstop location had moved up with that slipped upper mount and thus maximum compression put the wheel higher up into the wheel well. 

The surgery was a success. I drove the car to work yesterday and not a single rub. I'm very happy with the ride quality. I suspect it's sitting a bit higher now and I'm a bit uneasy with the stance for my survivor stock-ish car - the wheels look a little more aftermarket than I'd like in pictures - but I can't complain about the function. I need to spend more time looking at it from a distance :)

The bad channel is back on the stereo. I may do a back to back test with my other stock one. It's possible I do have a bad speaker and I missed it because I had the headrest speakers too loud. It's not really noticeable unless I've got the balance and fader set to drive just the one speaker. The Bluetooth modification is nice enough, although I got a pop out of the speakers when I turned the car off. Hmm.

I also picked up a new accessory. A local(ish) Miata owner was selling a factory tonneau cover that he'd had for years and never installed. The price was right so I decided to buy it for my hoard, as I still have the one I picked up in the 90s. I have no expectation of needing it anytime soon, but they haven't made these in decades.

This must be newer than my other one, this warning isn't on the other. But it's an important one. If you try to open the door with the mirror snap in place, something's going to be heavily stressed.

For the first time, I own a Miata with functioning AC!

I am very excited about this for the summer. I know the little 1.6 will get dragged down by the compressor but this will extend my happy driving weather considerably. My coworker Kyle did the system fill for me, and once I replaced a bad o-ring and tightened the fitting properly it all went perfectly. So happy.

I've been driving FM's new 2024 Miata a lot recently. Partly for evaluation, partly to help break it in, partly because I have to do some network investigations on it and in large part because I can. It's funny, compared to a 1990 in good shape it almost feels synthesized. The controls don't feel mechanical, they feel like they're running a simulation. The engine noise is very subdued and doesn't change character much (at least, not below 6k which is where I'm keeping it for now). Even the leather on the wheel feels too smooth, with no indication that it's organic. Weirdly, the worst part of the car is the ride quality at city speeds, it doesn't soak up the surface like 338 does. It does deal well with uneven surfaces at higher speeds, though.

I'm not looking for rough edges, just that little bit of friction/noise/vibration that tells you it's a machine. Like when you adjust the HVAC controls on an NA, you can feel you're moving doors via a cable. Or when you move the turn indicator stalk, you can feel the contacts clicking into place - especially on the non-airbag cars which have much beefier contacts and better tactile feel than the airbagged ones. I'm still trying to come up with a good way to explain it, but the engagement level is just lower. Of course, the new car is very capable and definitely faster and it's quite possibly the most engaging new car available to people who work for a living. It's just that I'm comparing it to one of the sports car icons.

It's still pretty fun to take up a twisty road on a sunny February day with the top down and the seat heaters on.

Excellent.  I've always believed air conditioning in a Miata is basically a requirement, and I'm at 9,200ft where it's a lot cooler than Junction.  I'd guess I most often use it with the top down at stop lights, where I don't need the power anyway. With the way the 1.6 kills the compressor at full throttle, it's not too much of an inconvenience.  The thing I hate the most is that it manages to re-engage between shifts, and the rev drop with a lightweight flywheel and the drag from the AC is just too much.

Hmm, I have an idea for a new product.

It needs a blip shift except it has to work with or without the brake applied, or program it like a BMW that hangs the revs between shifts.

Blip shift is what heel-toe is for :) This is not a drive-by-wire car you can program. I'm thinking of something to prevent the compressor from engaging during a shift. 

I'd obviously buy such a thing!  I think it'd be nice even without a lightweight flywheel, but the lightweight flywheel is what makes it really annoying.

Time for a 338 update!

Berck, I have an idea for how to implement this, I might cobble one together and send it to you for evaluation :)

338 got roped into product development support, kinda. We had some new wheels with a fairly aggressive fitment that needed to go on our 1991 R&D car called Pepper. I was doing suspension work on the car and wanted to roll the fenders before the tires got here. 338's fat daisies have the same width and tire as the new setup, so with the addition of some spacers they were used for fender clearance testing. This paragraph is really just an excuse to post the always-popular max travel picture.

This is also a good indication of how important the correct offset is - 5mm made the difference between "no problem as long as the mounts haven't collapsed" and "wow, that front fender needed a lot of rolling".

Here's Pepper and 338 hanging out in my garage and driveway. People are going to start wondering if I collect these things or something.

338, one of the oldest Miatas, also met one of the newest with FM's new ND3 R&D car and the two of them took shifts in my garage. I have to say that the ND is missing the organic feel of 338, and the ride quality was such that I actually checked with a Mazda engineer to confirm they hadn't revalved the Bilsteins for the ND3 - it was much harsher than I remembered. Overall, the ND feels more like a simulation of the driving experience after so much time in a good NA. It's faster, sure, but it's missing something tactile.

i'd choose the NA every day of the week.

TIL there's such a thing as the Fat Daisies. I don't know when I'll have a road-going NA again but I sort of want to buy a set just to make sure I have them when/if I do...

I'd never called them Fat Daisies before, but it's totally the right name for them now that it's been invoked. I bought them for the same reason - wasn't sure I needed them, but just in case.

I just realized I'd posted ND3 driving impressions already. Too bad I'm not getting paid by the word. 

Nice.  Definitely happy to test your extended-a/c-pause device, but you'll probably want to do it in the next few weeks before I tear my car apart for the engine swap / turbo install.  I'm guessing I won't need an A/C disable at all once I get the turbo installed:)

Sounds like I'll be testing locally then :) This is not exactly a top priority project. And we are talking to SEMA about selling 1.8 swap turbos. 

Those round hole wheels painted a little lighter than the current centers would give a top down NA a Jag D Type vibe. They deserve to sell well if they pass your QC.

Keith Tanner said:

I just realized I'd posted ND3 driving impressions already. Too bad I'm not getting paid by the word. 

Wait, you're ​not? 

338 had an adventure today!

It's coming up on 36 years old, but it's never been on the track before. That wasn't Dad's focus and I have many other trackable vehicles. But today we were doing a product familiarization day. The plan was to give all of our customer service and R&D employees a chance to take the FM cars out on the track and check out all the various modifications. Not everyone gets a chance to be hands on with the R&D fleet, and we felt it was particularly valuable for our support team to have direct experience. One of the requests was for a car with Koni Sports and stock springs, since that's a combo that often gets recommended for people who want a fun street car without it being lowered and with excellent ride quality. Sounds familiar. So 338 got the invite.

We had three NAs, two with turbochargers. One of them was running Koni Sports with FM springs, which made for a good back-to-back combo. Another was running a more track-focused V-Maxx Track Pack suspension. By sheer happenstance (and because they're a good fun street tire), they were all on the same size Yokohama Flevas. We also had an NB, an NC and two NDs, ranging from a full aero turbo car to a bone stock ND3 with 637 miles on it. Other than the stock ND, the other cars were all on Toyo RRs and were set up for fairly high performance. We were at Grand Junction Motor Speedway with the track all to ourselves. 

Most people were quite surprised by just how good 338 was on track. It would just swallow up berms that had some of the more track-biased cars hopping and it made mean little growly noises from the intake. I did warn everyone in advance about the Canadian-spec coolant temp gauge reading higher, but it never budged from the normal 12:30 position. The car was just fun, friendly and communicative, all the reasons we fell in love with Miatas in the first place. At least one person put it amongst their two favorite cars.

There was some surprise about how high the brake pedal sat - I've never noticed, but it was quite a bit higher than one of the other NAs that was suffering from too old brake fluid and too much turbocharger. Obviously, a great time was had by all and 338 came home showing no ill effects - although it did have some pretty noisy lifters partway through the day. A car you can comfortably drive to the track, drive as hard as you want with multiple drivers and then drive home? That's a proper sports car. Well done little 338.

When I got home, I had to give the car a bath to deal with some of the dust from the unpaved approach road and to clean the minimal brake dust off the wheels.

It was just warm enough that I very much appreciated the new AC system on the drive. It's not exactly going to freeze you out, but I was nice and comfortable. It's going to make the summer much more pleasant.

Still waiting to see if my photographer coworker got any good pics of little 338 on track. But in the meantime...

I was driving the car to work this week and was hearing a noise. A fairly quiet one, but with the hardtop on and windows closed you could hear it. It was road speed related, almost like something in a tire but not as high pitched. It sounded like it was from the rear. So I popped the car on the lift and poked around.

And found nothing. There's nothing that is making any sort of contact or potential noise that I can find, although I suppose a failing CV joint in the halfshafts might do it. They don't see much angle though. There was also a bit of a scuff from the rear brake pads so I readjusted the rear caliper (which were correctly adjusted) just in case. Then I reassembled and I shall reevaluate.

Also, I've heard people complain about how hard the AC compressor hits the 1.6 when it cycles on. And now I know that yes, it really does :) We've had some really unseasonal temperatures this past week so I was appreciating the AC even more.

I'm surprised that they didn't use a variable displacement compressor.  They had been around for a while by then, and were invented specifically to eliminate cycling for low displacement engines where the A/C torque is a significant percentage of cruise torque.

Hmm... I wonder if they geared it so short so flywheel inertia can take up some of that WHUMP when the compressor engages under highway cruise.  It's very noticeable on my similarly geared and powered RX-7 on the highway.  In city it's less noticeable because you're always shifting and accelerating/decelerating anyway.  And it probably cycles a lot less too, with less airflow.

In reply to Pete. (l33t FS) :

Maybe it was some of that "REAL sports cars don't have AC, so why bother" thinking as well :)

I'm sure you've seen more of these than me, but having worn out more than one bearing in more than one Miata diff, that'd be my bet...

In reply to Berck :

Pinion bearing? It's not rumbling but clicking, nothing like the sort of noise a wheel bearing makes. I was expecting to find something like a wiring harness touching the driveshaft balancing weight or something on a wheel. Have you had a failed bearing make that kind of noise?

 I don't tend to see worn out stuff as much as I used to see exploded stuff. Hmm. I know where there's a good 1.6 diff sitting on a pallet at work, I could try swapping it in and see if that makes a difference. I need to drive the car first and see if the brake adjustment made a difference. I might also break out the Chassis Ears and see if I can locate it. 

Oh, sorry, if clicking is the operative word, then no, I take it all back.  I was thinking whining.  My first failed pinion bearing was a rhythmic pulsing whine--not quite like a wheel bearing either, but not clicking.

I've been able to reproduce every failed diff noise with the car in the air.  Put it in gear at idle, let it spin up the drive train, then apply just a little drag from the parking brake...

I've also experienced failed Miata CV joint and it didn't click either they do on FWD cars--the symptom was vibration while accelerating in a corner.  It was easy to find because the boot was torn.

Doss the noise go away or significantly change character with the brakes applied, as if a brake pad was tapping around inside the carrier?

It could be some pad deposit on the rear rotors giving the pads a little pulse. That would track with it happening right after a track day with inexperienced drivers - at least once I saw someone come off the track and sit with the brakes applied on one of the cars. I think it does go away with brake application but the traffic wouldn't let me test it very much. I'll try to get out today and characterize it better.