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Discussion Starter · #1 ·
Hi all,

I started my mx5 journey fairly arse about face when I decided I wanted to rebuild an engine, having never done so before. I've done engine swaps and some repair work but never fully built my own. So I had a look round and found a suitable VVT to use.

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I wanted to essentially just rebuild make slightly better, clean everything up and lap the valves etc. Spec was pretty much stock besides some forged rods in case I decide to go FI in the future. Overall the engine seemed to be in good condition, fingers crossed. I did the work and added a baffled sump plate as well to help with track work. Once that was pretty much done I started to hunt for a suitable car to drop the engine into.

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I picked up this 99 NB recently which seemed to be relatively rust free in the right places and having had some recent welding and paintwork. It's by no means perfect but I wanted the car to build a track focused machine from so seemed to fit the bill.

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The engine seemed to have a big misfire (more on that later) and after compression testing seemed very low on compression on the middle two cylinders Vs the others. No real matter the engine was a Bp4w Which was useful as I was thinking about using this head to play about with a skim, porting etc for another rebuild.

I used the car for a few short trips, the PAS was leaking badly, the misfire didn't seem to get any better and the brakes were also binding on the front left.

First job really was to pull the old engine, I removed the head first up to have a look if there was any visible reason for compression loss but couldn't see anything.

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It was only when I got round to the coil pack that I could see coil 3 was in 2's slot and vice versa. Likely cause of misfire found!

Anyhow I already had a fresh engine and so the bp4w was on its way out.

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An afternoons work later and the vvt engine was in place and ready to go. Everything buttoned up and she started second go after having realised the coil pack was plugged in the wrong way.

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Everything looked good until I saw a cascade of oil coming out the front of the block. Disaster.

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Much work later and having cleared the alternator out of the way I could see the oil pump had cracked and was leaking catastrophically. An expensive and time consuming mistake to say the least.

Another day later and I had the engine pulled and back on the stand. In undoing everything I had somehow left the old mushed up o ring in place as well as the new o ring leaving them no room, tightening down obviously resulted in the crack. Lesson learned.

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I've ordered a boundary billet gear pump to replace it which should be here on Tuesday so fingers crossed I can have it back together and in the car for then.
 

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Discussion Starter · #2 ·
Worth just saying as well, I'm coming from having worked on BMW's, mini's and some mercedes. What a joy the Mx5 is to work on. Bags of clearance almost everywhere, simple fasteners in logical sizes and electrical connections which are happy to plug and unplug without disintegrating in your hands. And a wealth of available parts too.
 

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Over-complicated pile of bits that oneday will be fitted to my '91 SilverShItBoX
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· Banish a little rust a day people
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Worth just saying as well, I'm coming from having worked on BMW's, mini's and some mercedes. What a joy the Mx5 is to work on. Bags of clearance almost everywhere, simple fasteners in logical sizes and electrical connections which are happy to plug and unplug without disintegrating in your hands. And a wealth of available parts too.
You say that but every bolt will disintegrate in your hands or by itself if left in the weather, rust gets at everything resulting in a never ending cycle of repairs, they leak frequently, and yeh used parts are being horded by a few individuals who charge silly prices and drive them up from everywhere else
 
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VVT swapped NA & TD04 turbo NB
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You say that but every bolt will disintegrate in your hands or by itself if left in the weather, rust gets at everything resulting in a never ending cycle of repairs, they leak frequently, and yeh used parts are being horded by a few individuals who charge silly prices and drive them up from everywhere else
How many hard tops would you like? $1600 rare as rocking horse shit m9
 

· Banish a little rust a day people
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£1900, plus $300 delivery m9
 

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Over-complicated pile of bits that oneday will be fitted to my '91 SilverShItBoX
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VVT swapped NA & TD04 turbo NB
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Discussion Starter · #9 ·
I would like a hardtop at some point. Seems like the going rate is £450/£500?

Engine is back in now with a boundary pump and seemingly working nicely. Had a bit of difficulty getting it to run well but turned out to be the old nb1 coilpack not being well. I've now wired in the nb2 vvt coils which seem to be doing the job for now.

Vvt is obviously not working at the moment so I'm thinking about doing a standalone me221 or the like in order to be able to bring vvt back online.

In the meantime I've now added an LSD. I picked up a second hand Black line diff and have swapped that into the stock casing. I know it's a Chinese knock off but it was up for a reasonable price and seemed to be worthwhile. Can always change it if it does fail. Only driven it locally but seems to lock up well and is doing the job with no additional noise or issues so far.

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Next thing on the list is brakes. When I bought the car the front left caliper was seized so expect the fronts need to be rebuilt or replaced and so would like to add new discs and pads all round with braided lines.
 

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The asking rate is £450/500, from what I've seen the going rate is still £350ish (still up over the £280 I paid 2 years ago).
 

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The asking rate is £450/500, from what I've seen the going rate is still £350ish (still up over the £280 I paid 2 years ago).
I paid £275 and had a free car with it😜

I sold mine for £750
you saw that one coming🧐

Where's the best place to buy?
look evrywhere, just don't expect somewhere like forums or fb to be a cheap source as evryone wants a hardtop (to keep or sell for profit £££)

they're out there, ebay badly listed or spelt is a great search direction;)

Rich.
 

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facebook is shit for them, there's a few breakers on the larger groups seemingly trying to buy everything up and charge a tonne for it so beware.
 

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Discussion Starter · #16 ·
Quite a bit to update on since the last proper post. After having sorted the diff which has so far been great, the next things were to look at hardtop (the soft top in place was badly leaking and broken), sorting the brakes and lines, and then looking into beginning the power mods, namely getting the right things in place for ITBs.

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I managed to find a hard top in the right colour, it's a bit scabby but it'll do for what I'm looking for. May even consider wrapping as well.

At the same time I did new disks and pads (roddisons) all round, with braided lines. I managed to destroy the line going across the back axle so also ended up replacing that with a braided item as well.

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Following this I'd ordered a Jenvey kit from Bofi, which seemed to take an age to arrive so decided to tackle the front wheel bearings which had been squeaking, and fitted an AEM wideband in readiness.

Ahead of the ITBs I'd also ordered an ME221 which i'd fitted and managed to get running, albeit without VVT activated, and was running pretty averagely given the basemap.

Then this kit arrived:
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Fitting was relatively straight forward with exception of the throttle linkage which took a bit of tweaking to get working. all other bits a direct swap save a bit of soldering on air temp and TPS sensors.

The next things was to try and get it running, which was quite a quick process once I'd figured out the right fuel plumbing! - New video by thomas whatley

I managed to get it going, but without the SPS idle valve which I'm still waiting for, so instead using a vacuum line setup to harvest vacuum for the master cylinder.

The next thing that was frustrating me was the wiring loom, so decided to strip it back and re-wrap for the best positioning given the new setup

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Following that I had an issue with the ME221 melting one of the chips, still not exactly what caused this, the car worked and ran fine still but obviously wanted it checked out and fixed. I wonder whether it may have been alternator related as I after running a couple of times switched to an NA item.

That left me chasing a parasitic draw for ages, before finally figuring out it was to do with the 12v switched feed.

The next thing on the list was replacing the ancient 14 inch alloys, which I managed to with a set of Japan Racing items.

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It now looks fairly hilarious on it's suspension so I'm looking at getting a set of Meister Clubraces, and looking forward to getting the ME221 back so we can finish off mapping and enjoy some summer driving!
 

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Discussion Starter · #17 ·
Lots of updates to follow this and quite a few new parts. After the Me221 was replaced we got to mapping, but the car was very down on power, and I was beginning to feel fairly disappointed. Kept logging and checking and logging more but nothing we did seemed to make it much better. Eventually took the decision to replace the original engine damper pully with a Fluidampr and a new 36/2 trigger wheel. Firstly was quite surprised at how much difference the trigger wheel made to engine response, but that also highlighted the fact that the timing was way off with the old trigger wheel. With the base offset suddenly in the right place the car came alive and actually made good power. Still not properly dyno'd but Virtual Dyno shows c.160bhp vs. the previous 100 or so with timing out.

Anyway, after that was sorted I spent quite a bit of time just using the car and driving, then felt confident enough to take it for it's first track day at Brands. Car performed very well, but was starting to get a bit hot on some of the longer runs, and the tyres were far too much for the stock suspension, to the point I could barely lose traction, so wasn't necessarily the most enjoyable trackday, but good to spend time on track nonetheless. Levels of body roll a bit of a joke!





After the track day I decided I needed to firstly replace the original radiator, work on better seating and suspension, and make some tyre changes to something slightly less fully track orientated.

In the mean time I found a set of Cops a local guy was selling so took those, then created a loom from scratch to go full sequential cops, which really tidies up the engine bay, as well as the black crackle painted valve cover.





That was followed by a new seat, with associated mounts, new coilovers from meister and new drop links then new set of wheels/tyres to make the most of it all.



Before Suspension





After, could still add a bit more drop, but already catching the exhaust slightly on middle of the road speed bumps.







The suspension really transformed the car, I was massively surprised how much more compliant the car is, especially on slow speed damping. Puts my R56 Cooper S to shame and makes it a really nice drive.

In the background I've been slowly gathering bits to rebuild a new ported/polished head and am now getting close. Could probably start a thread alone on that as getting the head ready for the cams has been a long process, but I'm close now having finished the grinding/machining work. Just need to get the lash caps right now, then we should be ready to fit. My only concern at this point is the oil return holes being nowhere near the placement of the original cams, so not sure whether to just chance it and hope that'll be low pressure return, or whether I should try and open those up?





 

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Some nice progress here, you obviously has a reasonable budget to play with as there's some tasty bits going into your build. Are you going to add any body reinforcement? I found plenty of improvement when adding roll bar, chassis bracing and even the delrin door blocks.

Ben
 

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Discussion Starter · #19 ·
Yeah I've been wanting to get one of the GCfabrication roll bars for a while, but have been tossing up going for a full cage instead. I've seen a few come and go second hand so may bite the bullet and order one but they seem to have a longish lead time at the moment.

I'm also considering chopping out the original chassis rails and replacing them with thicker items as one of them is more like a pancake than it is a chassis rail. Not sure whether to prioritise that or sorting out all the rusty suspension arms and bushes. Got a small bubble of rust on the rear wing as well which I need to start addressing.
 

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Discussion Starter · #20 ·
Slightly disappointing but not totally unexpected. Accidentally left the exhaust bung in so not sure what that was worth, and was having some weird fuel issue on the way there at very slight throttle, so perhaps something going on. AFRs on the dyno spot on though so the remote tuning did it's thing. Pulls nicely all the way to redline as well.

Thought I'd do a compression test when I got home just to check things over and was bang on 175psi for all four so nothing too bad, but equally not amazing there. Tossing up whether to redo the block when I finish building the new head now just to make the most of things while the engine is in bits.

 
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