1990 Mazda Miata MX5 - service

[MiataMark]

Went to the Mazda dealer to try and get a thermostat and radiator cap, typically they don't stock them but can order. While I was there had a look at the new MX5 RF (the targa version?) £30K! The inside was all leather and fancy dials a big step away from the basic MK1, driving position felt similar though.

In the car park took this;

Not a huge size difference really considering the age gap.

Great to be driving round hood down, snicking through the gears, revving to 7,000rpm. Just makes me smile

[MiataMark]

Yesterday I did a slipkndgrip (slipngripross ) track day at Thruxton, great day well organised. I was interested in Thruxton as a circuit as it’s a bit wider and potentially safer with more run-off than Castle Combe, although as it’s faster that’s probably debatable. I have driven Thruxton before once at a launch event for the Ford Mondeo (original) and again at a corporate event I orgainsed which culminated in driving a Ferrari 355 round the circuit.

I started off bright and early and had a nice drive trough the country with the top down and arrived very early despite getting lost at the end. Made ‘camp’, signed on, noise check (82dB must try harder) and briefing.



Did the 3 sighting laps and realised that I had no idea where the racing line was and there were no friendly cones showing turning in points and corner apexes.

So got some instruction from Andy, 3 laps with him driving and 3 with me. Good to get independent confirmation that the car handled well, unless he was just being polite. I can’t recommend going out with an instructor enough, it showed me the lines and gave me confidence.

In a low powered car Thruxton is a pretty much a flat out circuit all 4th gear apart from two 3rd gear sections. Out of the pit lane keep to the left for the first corner (Allard) then up to the complex, brake hard and down to 3rd turn right clip the right curb then left and clip the left curb (not too hard or it lifts the inside wheels). Later in the day I was getting a bit of a slide for the initial turn. Swing right then left to hit the apex for Segrave, drift left and change up, then pretty much flat out for the next few corners. A bit of a dab of brakes for Church and then keep left and foot hard down, maxed out at about 100mph, tried 5th but nothing to be gained. Then the chicane, aim for the loudspeaker down to 3rd (I did try it in 2nd but ended up right on the limiter) turn right in the middle of the track (that took some getting used to) clip the right curb if feeling brave, then the left curb (if feeling brave) then the final corner clipping the curb (if feeling brave). I’m not sure I ever got the chicane completely right and had my only 2 incidents there, first I lost confidence between the first 2 corners braked and locked up sliding onto the run off. The second I braked when I shouldn’t have and had a small spin in the middle ending up on the run-off area. Gave the stewards something to laugh about.

Far too many words but I didn’t have anybody to take pictures, here are some from Facebook.







The whole day was well organised and very friendly, there were some other very fast cars present, e.g. race prepared E92 M3’s. I did meet up with a fellow MX5 driver , Andy, (MK2.5) which was good to share some ideas. But I didn’t feel out of place and the low numbers combined with the length of track meant that there was the opportunity to get some clear laps in.

Car was superb throughout no issues at all, although the tyres took a bit of a hammering, at least it shows I was trying. They are standard mid-range tyres that I bought in case I wrecked them and they'd done 2 previous track days.




Conclusions;

• New front brakes were very good (probably not ideal bedding in procedure), although the pedal is a bit spongy now
  
• I’ll do more slip and grip events, in fact will book Castle Combe for August
• I need a better seat, harnesses and standard seats don’t work
• Still need to think about stiffer roll bars and/or stiffer front springs
• Need to think about track biased tyres
• More power would be good :-)

A good day, of course the weather helped, even if I do have a sore top of my head. This was one of the reasons I bought the car in the first place so it's great to start using it again, I can see it becoming more track focused.

Mark

p.s. I'm thinking of calling the car Joseph....

[skodacious]

Great write up and car looks purposeful! 😎

[johnthesparky]

Tyres show you were having fun

It looks good out there, what was the tent for?

[MiataMark]

Jul 6, 2019 13:46:36 GMT johnthesparky said:

Tyres show you were having fun

It looks good out there, what was the tent for?

Much fun was had

Tent was just somewhere to put all the stuff I took and mostly didn't use (tools, oil etc) and my picnic which I did It was also good to sit in during the lunch break out of the sun. Garages were available but for an additional £30 and I'm a skinflint.

Trackday was £155 and I used pretty much a tank of fuel (~£40) but probably did ~100 miles on track.

[slipngripross]

Thanks for the mention mate. hope to see you again soon

[MiataMark]

johnthesparky made a comment in the  @quatermass (ex?) Naughty Corner thread about people posting what they have done but not the thought process or planning behind the work done.

One of the conclusions from the tack day was that standard seats don't work with harnesses and that I need a competition (race) seat. This does have a few issues though, as SWMBO uses the car the seat needs to be adjustable and also for MOT some testers don't like seats that are non adjustable. The harnesses I bought (Sabelt and I'll admit to being influenced by the name and the look) don't have push button release which is also dubious for the MOT. Also SWMBO wouldn't tolerate using harnesses (no sniggering) and they're not the best for day-to-day use anyway.

So what seat to buy/use, there's not a lot of room in a MX5 for the harness and seat belt lower mounts and I'm concerned about how the shoulder belt will work with the 'wings' on most race seats. I could just swap in a race seat when I do track days. While mulling this over I composed, but didn't post, a long post for the Question Section.

I had a trip to Staffordshire planned and a short (OK 2 hour) detour on the way home took me to Wrexham and Demon Tweeks, to get some advice, except this happened...

Well that went well sat in few seats talked to the assistant and bought a seat (Sparco Sprint);
   will it fit - don't know
   will it work with the inertia reel belt - don't know

   can I fit it to the seat runner - don't know.

p.s. to left is my wife's preferred seat (it cost, a lot, more than my seat!)

So much for planning

Think I might be breaking out the welder to sort out mounting it. Current thinking is to use the seat belts day-to-day, arrange the harness eye-bolts so that I can 'easily' detach the lower harness straps when not on track...

In other news, below is further evidence of how hard the tyres were working on the tack day;



The lumps of rubber were stuck to the wheel rim, and because I'm a poseur...

Won't be for a while before I attempt to mount (in the car) the seat, any advice on marrying the seat to the runners would be welcome. I do have a set of MX5 specific side mounts.

[johnthesparky]

That’s almost the same research I did with the (possibly) new seats for the Fug

We did sit in them last weekend and admire the exhaust though, so they have been useful even though we haven’t checked if they’ll fit yet

[MiataMark]

Booked another track day at Castle Combe this time, slipandgrip again.

Just popped down to the body shop to sort out getting the under-sealing done and pulling out to come home it's not running right :-( I think the exhaust manifold to down-pipe joint has blown. Could this be an excuse to buy a cheap tubular manifold...

[ChasR]

If you do buy a Tubular manifold, be careful.

I had one on my MX-5 and it was near impossible to pass the MOT. Granted, it had a decat, but considering it had the 3.5% emissions rule apply to it, it should have passed. However, it would struggle to get under.

Other cars of a similar vintage like my 944 Turbo with a decat passed the MOT fine here.

In the end I put it down to the one wire lambda sensor. With the sensor moving so far downstream on a 4 branch, they can't really help up effectively ;there is a good reason why Mazda put them right in the top of the exhaust manifold.

A wideband sensor in addition to wiring to go to the ECU feed so as to give it a narrowband signal is one way around the issue, as those sensors are heated.

[MiataMark]

Jul 15, 2019 16:51:20 GMT ChasR said:

If you do buy a Tubular manifold, be careful.

I had one on my MX-5 and it was near impossible to pass the MOT. Granted, it had a decat, but considering it had the 3.5% emissions rule apply to it, it should have passed. However, it would struggle to get under.

Other cars of a similar vintage like my 944 Turbo with a decat passed the MOT fine here.

In the end I put it down to the one wire lambda sensor. With the sensor moving so far downstream on a 4 branch, they can't really help up effectively ;there is a good reason why Mazda put them right in the top of the exhaust manifold.

A wideband sensor in addition to wiring to go to the ECU feed so as to give it a narrowband signal is one way around the issue, as those sensors are heated.

Interesting although I started to lose comprehension towards the end :-)

Mine is early enough not to have a cat at all, the lambda sensor on the manifold I found on eBay looks to be in the same place as on the standard Mazda one. This is just a cheap stop gap set-up if I go this route. Things are different with tubular manifolds that have longer initial runners (I'm sure that's not the right description)

Ultimately I want to fit an ME221 ECU which would hopefully be easier to map for both emissions and performance. Probably be able to use a wide-band sensor as well, I'd quite like to fit an AR meter.

This is a more tubular manifold and the sensor boss is much further down the exhaust (it's also 3 times the price)

Mark

[cjl1281]

Just read through this, absolutely love MK1 Mx5's great little sports cars. glad to see people like yourself keeping them on the road and I shall be looking forward to see how it progress'. I owned a little mariner blue MK1 a couple of years ago as a summer project, safe to say it didn't go well should've kept it though miss it quite bad.

[MiataMark]

Jul 15, 2019 17:22:02 GMT MiataMark said:

Mine is early enough not to have a cat at all,

Correction all MX5's have a cat, although the imports are smaller. I haven't checked mine yet as it's back at the body-shop having the under-seal put in the front arches. Won't get much of a chance to do anything this weekend, exhaust or seat related, as I'm going to a horse show on Saturday and Sunday is work to pay for it all.

Jul 16, 2019 22:54:49 GMT cjl1281 said:

Just read through this, absolutely love MK1 Mx5's great little sports cars. glad to see people like yourself keeping them on the road and I shall be looking forward to see how it progress'. I owned a little mariner blue MK1 a couple of years ago as a summer project, safe to say it didn't go well should've kept it though miss it quite bad.

Thanks, they do look nice in blue. I'm sure your Spitfire will be a worthy successor even if they don't handle as well (I've had a Herald 13/60 and a Spitfire 1500 in the past)

[MiataMark]

Ummm, investigated the exhaust today, bad there doesn't seem to be anything wrong (it would have been a relatively easy fix), good I seem to already have a tubular manifold of sorts.




So I still have an issue, the engine runs but it's surging, sounded like exhaust issues but nothing obvious. Might be the Idle Speed Control Valve... I have remembered that there is a primitive diagnostic port need to to investigate that next. Needs to be fixed by 12:Aug!

I did take off a wing mirror and get it into primer to paint satin black and started on removing paint from the front bumper.

[MiataMark]

First the engine issue, I didn't explain it very well, as you accelerate it isn't smooth feels a bit like a blocked EGR (which the car doesn't have). Will investigate the Idle Speed Control Valve, hopefully a good clean will sort things out or see if i can bypass it.

While messing about with that I started on the paintwork, using a medium sanding disk it was fairly easy to get through the bad paint. I need to get back to the plastic (light orange). I also dismantled the passenger door mirror and gave it a quick rub over then some primer (I only had zinc primer) will get some Satin Black to finish it off.

Need to get some flexible filler to fill i the holes from the badge as well.

[MiataMark]

So no faults showing that should rule out the Idle Speed Control Valve, but not necessarily the Idle Speed Air Valve. This is a valve bolted to the side of the intake manifold that is operated by the heat of the coolant, it has coolant running through it.

It's the block in the middle with 2 small hoses at the front.

Took it off an despite the manual saying that water would come out not much did, anyway gave it a clean and a good squirt of carb cleaner and out it back on. The water level in the radiator was a bit low so topped that up. Did it cure things, not sure did it make a difference yes.

So that leaves me with it could still be the Idle Speed Control Valve, expensive at ~£300 to replace or the air valve, ~£25 secondhand tested. I have a suspicion that not all is right with the cooling system, it seems to be losing water. Although there was no sign of contamination when I checked the oil before the track day I am starting to wonder if there might be a HG problem.

So next step is to check oil, compression check, cooling system flush...

A question I have, I want to fit an ECU (ME221) if I do can I get rid of a lot of the additional plumbing (e.g. the Idle Speed Control) as it will be controlled by the ECU?

[MiataMark]

I dropped in at the garage that did the MOT to ask for advice, on hearing the car the mechanic instantly diagnosed miss-firing, which kind of makes sense. So Thursday evening I ordered new plugs and plug leads from Moss.

This morning I decided to take out the existing plugs etc, the first came out no problem. A bit of oil round the thread but they looked good colour wise (older Haynes manuals always used to have a useful colour photo of spark plugs explaining what the different colour of deposits meant) and good gap.



I couldn't get spark plug 2 or is it 3 out, the plug spanner wouldn't catch on the hex part of the spark plug. At first I thought it was a build up of oil, but after a lot of frustration I actually looked down the spark plug hole and some dip-stick before me had left part of the rubber insert from a plug spanner in the hole hoiked that out and removed the rest of the plugs. All looking good except #1 (or 4) which was sooty obviously not firing.



Had to go out for lunch and the plugs/leads arrived while I was out (ordered Thursday evening delivered Saturday afternoon, good service). Anyway stuck them in and connected them up. The lead are Jackson Racing 8mm leads and the plugs NGK. Using the BNMAC/@quatermass measurement of power as the leads are RED I reckon that's added at least 100bhp...




So time for a test drive, but before that. When I first got the car I had a T R Lane roll cage fitted by T R Lane and got them to put a threaded insert in the middle of the top bar (would probably fail MSA scrutineering now) for a camera mount. MrSpeedy made up some 10mm to tripod thread adapters, but I've never tried it out. I've got a Canon G7 compact with video capability, a wide angle lens and an old tripod head..



Which resulted in this...



Car is now running well, more interesting videos later, maybe (need to try and sort out the wind noise)...

Track day booked for 12:Aug at Castle Combe, need/want to fit my new seat by then, and then try and keep it working for RRG and the BNMAC stand (must remember to book ticket).

[MiataMark]

So how long should it take to fit a seat, couple of hours maybe... it took me the best part of a day and a half! Not helped by not having the correct bolts, bent mounting hardware and it just being incredibly tight space to work in.

Anyway, out with the old and a quick check to see if the new seat would bolt onto the existing runners, close but not close enough.





You can buy adapters from various sources but at anything from £50-75 not an option. I did but some custom MX5 seat mounts some time ago, which are listed on eBay at £63, so the first option is to go with fixed seats.



This shows how cramped it is. So I bolted the mounts to the seats after estimating what mounting holes to use. Put then into the car and couldn't get the bolts for the mounts to floor to line up. It's also incredibly tight at the back to get access. After taking the seats out and trying to mount the seats to floor after much messing about realised that they were bent out of shape (my fault) tried thee other pair I had much better.

But can't fit the floor bolts with the seat in place, so bolt front of seat in place and then bolt mounts to floor, then spend ages getting the rear side bolts in place. Everything fitted up and I realised I'd got the lap belts upside down. I'd moved them around to get the eye bolts lined up so that the snap brackets could clip over them.



So out with the seats (again, I lost count of the number of times the seat was in and out), decided to raise the rear of the seat a bit which gave more clearance to access the rear floor bolts. Eventually everything mounted.



Looks good and feels much better, although now they're not adjustable SWMBO can't drive it also it may be an issue come MOT time. Longer term plan is to make some adapter mounts to attach the seat to the runners. I think a U shaped 'tray' will work. There's something missing from one of the runners anyway so it moves about so I need new runners.



In other news, I painted up a wing door mirror in satin black, looks better than having it left in silver just need to do the drivers now and paint the quarter light frame.

Attacked the paint a bit more, bought a surface disc from screwfix but it's a bit too aggressive. Stripped one of the headlight covers down to mostly metal.

Sprayed with matt black, shows up the uneven surface so I think that needs to go down to bare metal all over. The car now looks like it's wearing an eye patch

Track day 12:Aug and then RRG, then I'll get on with sorting out the body work.

[MiataMark]

Not sure this will satisfy MOT rules for seat adjustment...



To be fair I did ask a MOT tester about this and his comment was "...if there isn't an adjuster there I can't fail it for not working..."

At least now one of the seat bolts is a high-tensile one (I really can't be bothered to take the seat out yet again to change the others over, they're hidden down the side and a real pain to change). Driving the car yesterday I think the back of the seat needs to come down a bit and could do with being a bit further back but I'll try it on the track first. Longer term I really need to get the seat fixed to the seat runners, there are brackets available but a) they're expensive and b) they don't allow any height adjustment.

In other news in preparation for RRG I got a custom printed T-shirt



I also got a long-sleeve one for track days that mandate covered arms.

[MiataMark]

Without wishing to tempt fate too much, still not broken after another track day!

Slipandgrip 12 August Castle Combe slipngripross these are really good events friendly atmosphere and reasonable price. The numbers are lower than some track days so more track time and importantly for me not being passed all the time.  Unfortunately I'll be away for the September day, might have to risk the weather in October.

So a track day in August at Castle Combe should be fine, errr maybe not, misty and damp start to the day so waited for the track to dry out a bit. Got a couple of good sessions in and some more instruction from Andy to show me the proper lines. I did find the first run out a bit intimidating but after learning the lines felt more confident and actually felt like I was getting it right. Obviously slow and needed to get out of others way a lot.

So lunchtime and rain and more rain, eventually though I thought I've paid so I should go out, I was fine but twice managed to spin getting out of the way of faster BMW's. One went past and there was so much spray I couldn't see anything! Was running maybe 20mph slower and with the hood up and helmet on got very 'steamy' inside.

SWMBO was on photographer duty (the normal photographer obviously that a scabby MX5 wasn't work taking photos of, it's not as if he was wasting film!). An example of SWMBO photography skills is this fine example of a shot




Some slightly better examples are;







That last shot shows some of the standing water that was around for some of the time.

And a video of a lap (lap time is ~1:40 not sure how good that is for a standard 1.6 engined MX5), think I got the lines quite good on this run.

I was hitting about 100mph (on the speedo) before entering Avon Rise (before Quarry) and some fairly heavy braking into Quarry and Tower/Bobbies. 

Conclusions;
- instruction is great for building confidence
- I'm getting used to Castle Combe
- I need better tyres (Nankang NS2R?)
- I need more power!
- Car was/is remarkably reliable (que breakdown soon)
- I really should try and get it one colour.

Oh and the seat was much better although it's a pain to get in and out of, newly painted wing mirror wouldn't stay in position though.

Some interesting cars there, a pristine 209 1.9 GTi, a new Honda NSX lots of Honda's and a clutch of very quick and loud BMW M3s.

Next stop RRG and the BNMAC stand...