1UZ engine swap

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Might as well start the build thread now, as I started stripping the engine down pending it's lift out in the next few days and the arrival of a 1UZ

I'm always pleasantly surprised at just how much room there is in there!

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Thasalorraengine!

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Fastdruid said:

Did you work out exactly what year engine it was?

They're a bit tricky to date, the easiest way is probably the date printed on the HT leads but of course that relies on them not having been replaced...

Not yet, but it's non vvti, that much I do know.

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came with ECU, wiring still intact, plus MAF sensor on a section of the intake pipe

Really does look like there's everything there I'll need initially

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VladD said:

Does Clare/Claire do this as a standard(ish) kit or is it bespoke for each person? Any idea what the cost is likely to be?

IIRC it's £350 for the subframe. It's a 'blank' so will have brackets for mounting it to the chassis and suspension. It doesn't include engine mounts, I'm not sure it even has mounts for the steering rack (as the rack often has to move a little on these projects). You'll need to fabricate those mount points yourself

I'm happy enough doing the welding and could probably fabricate my own subframe if it came to it, but it seems pointless to reinvent the wheel when there's a suitable product available 'off the shelf' so to speak

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Had a spare hour or so last night between putting the wee man to bed and the light going.
Got the gearbox and some other extraneous bits off and the engine is looking much more compact now.
It also has an aircon pump attached and while my car doesn't have aircon, I'm tempted to see if I can source the pipe work and HVAC components to make it work, that's assuming the engine will fit with the pump attached.

I also note the cruise control mechanism on the throttle linkage so I'm tempted to have a look into the feasibility of implementing that too.

Next task is to get some suitable bolts so I can mount the engine on the stand. The ones that attached the gearbox are too short, and being a fine thread, I don't have any in my boxes.

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Fastdruid said:

Have you got the cruise control motor? I think I may have one spare if not.

I don't but I suspect I'm also missing the cruise control ECU, most of the wiring and the control stalk, so it's not something I'm fussed about right now

Might be a nice-to-have once it's all in and I've worked out what space there is

I'd be more interested in getting the air con working first

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Fastdruid said:

Air-con should be pretty easy, just connect the compressor to the existing MX-5 system. Piece of cake.

mine didn't come with air con as standard, that's the additional caveat

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ikarl said:

feef said:

Fastdruid said:

Air-con should be pretty easy, just connect the compressor to the existing MX-5 system. Piece of cake.

mine didn't come with air con as standard, that's the additional caveat

Haha, you don't like doing stuff the easy way huh....much respect!

If it was easy, everyone would be doing it :P

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Got the new engine on the stand and have started stripping it down to check sensors, fix a few bits that were damaged when it was removed from the donor car, and generally give it a tidy up

In the meantime, I've been pondering gearbox options and doing some ratio calculations

Stock MX5 box and diff would be good for a theoretical 138mph top speed, and cruising at 70 would be at 3100 rpm : That gearing seems a little short for my liking

A 350Z box with the MX5 diff would see a theoretical 178mph top speed, and cruising at 70 would be at 2400 rpm.
There are also plenty of folks out there making adapter plates for the 1UZ to the 350Z gearbox. However, I believe someone has already done a 1UZ/350Z combo in n MX5 and that's reason enough for me to look for an alternative



However, the curve-ball here would be to use a transaxle, which would mean I wouldn't have to worry about the engine/gearbox mounting so much as there's a torque-tube/driveshaft between them, and dropping in a Porsche 944/968 transaxle would give a theoretical top speed of 150 and cruising at 70mph would be at 2800rpm.
There's also the case that although the 1UZ is all aluminium compared to the MX5's cast iron block, it is still a little heavier (around 45kg if I'm right), so using a transaxle (and losing the spare wheel which lives in the boot) would maintain the weight distribution. Part of me is also thinking it might be easier to modify a linkage than ensure an entire gearbox lines up with the gear shift location on the transmission tunnel

The majority of 944/968 transaxles don't have an LSD (some did have, but they are expensive and rare second hand) but there are LSD kits out there for the normal versions, so would be an upgrade path for the future

Hmmm

A transaxle MX5 hasn't been done before, and that's reason enough for me to consider it

Thoughts?

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Fastdruid said:

Good luck!

The path less travelled is far more grief and expense (trust me, I'm half way down it).

yeah, but I'm an awkward, contrary bd when it comes to things like this If I'm going to do a job, I want to do it properly and 'my' way

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Scratch that idea

On the 944/968 it seems the tube that the driveshaft runs through is structural, and attaches the engine to the gearbox as well as providing a mounting point for the shifter linkage

I think that's a step too far

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VladD said:

feef said:

Scratch that idea

On the 944/968 it seems the tube that the driveshaft runs through is structural, and attaches the engine to the gearbox as well as providing a mounting point for the shifter linkage

I think that's a step too far

Alfa 75 and Alfa 90 have a transaxle according to Wiki. Not sure how available they are though.

Could you use one from an MR2? It's mid engined, so I don't know if that removes the feasibility.

I'd looked at the gear ratios on the Alfa 75 box and it would be somewhere between the stock box and the 350Z in terms of rpm and road speed

They aren't all that common, however, and I'm not 100% sure they'd handle the torque

The most powerful engine fitted to them was the 3L V6 in the 75 Cloverleaf (Milano Verde) but even then, it only made 184lbft compared to the 1UZ with 268lbft

The attraction of the Porsche transaxle was also the availability of LSD upgrades, whereas they are thin on the ground on the Alfa 75 box

I might still pop down to the Alfa Workshop in Royston and see if Jamie has or knows of any 75 gearboxes available, as I'm sure he'd have a better idea of whether it could handle the power and torque

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tr7v8 said:

feef said:

Scratch that idea

On the 944/968 it seems the tube that the driveshaft runs through is structural, and attaches the engine to the gearbox as well as providing a mounting point for the shifter linkage

I think that's a step too far

Yup it is a torque tube but can be cut down shorter. A guy built a Locost in the USA based on a 944 & did exactly this. There are dimensions on the web for the adapter to the bellhousing for the LS1 transplant into the 944.

I've also been looking at some of the weights involved, and the torque tube is a heavy lump

It's still under consideration, but I'm tending towards the Toyota w58 gearbox for simplicity, availability of parts and flexibility of shifter location

The 350Z box has a 'remote' shifter which is about 7" too far away from where it ideally should be

I know this could be modified and the distance cut down by 4" but it's still quite far out compared to how the W58 would sit

Plenty of time to think things through before a decision needs to be made however

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'Box sorted

I've got a Toyota W58 box en route to me

Bullet Performance in Australia also do a kit to mate the W58 to the 1UZ which they use in their MX5 based cars, so as a combination, it 'should' fit.

The W58 also has a few variations/options on shifter location so that shoud help.

Waiting for a break in the weather to get the engine and 'box out the MX5. While I can work on bits and pieces in the garage, there's not enough space to get the car in. :/

The W58 has ratios:
1st - 3.285:1
2nd - 1.894:1
3rd - 1.275:1
4th - 1:1
5th - 0.783:1

Keeping the MX5 diff (which has a final drive ratio of 3.636:1) gives the following road speeds at 6100 rpm:

1st : 40mph
2nd : 70mph
3rd : 104mph
4th : 133mph
5th : 170mph

Anecdotal evidence says the MX5 diff I have can easily handle the power and torque I'll be putting out, and it's more likely that the axles will fail before the diff.

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Gearbox arrives tomorrow.

Not heard back from Bullet yet, so will chase them this week.

I'm tending more and more towards running with the emerald ecu as it can support the stock crank trigger wheel with cam phase sensor to manage the timing. That would mean I could strip out almost all the stock wiring, and need only the TPS, MAP, crank, cam and air temp sensors to make it work.

It also means things are more flexible on the engine's rev limit. Stock the limit is about 6100rpm I think, but they can rev significantly higher than that and remain well within safe limits. The emerald means it can be mapped accordingly.

I still need to examine how to control the speedo. The stock speedo takes its signal from a pickup in the gearbox. Obviously that's not now an option. The emerald can drive the tachometer.

Got everything disconnected and unbolted now, even have the chains for the hoist bolted into place. Just need to get a gap in the weather that will coincide with some free time so I can lift it out. (Although viewing the image reminded me I need to remove the ARB)

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Don't you love ultrasonic cleaners

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Fuel injectors. The grubby one still has the rubber seals and grommets on which makes it look different.

I've got an overhaul kit on order which will replace all those.

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Fuel injector kits arrived, half of them are done

I've started fabricating some blanking plates to allow removal of the EGR valve and associated gubbins, but the motor on my milling machine has let the magic blue smoke escape so while I'm waiting for that to be repaired I'm resorting to cutting disks and grinders to make the plates. Not as pretty, but most of them won't be easily visible so I can live with that.

I've given all the top-end engine covers and manifolds a good clean and will be reassembling the top end hopefully later this week.

I need to get ahold of Bullet in Australia as I've not had an answer to my email yet, and once the engine is assembled, the project will be largely waiting on the gearbox-engine adapter kit

I can, in the meantime, get the old engine and box out the chassis, clean up the engine bay, maybe do some trimming and welding in there as well as clean up the corroded chassis legs, and sort out the wiring for the Emerald to work with the 1UZ.

I'll dig out a few photos shortly

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Got ahold of Bullet, just sorting out some bits and pieces with them and finalising pricing and shipping

As a result I've added a HiLux clutch master cylinder to the shopping list as that's the one that's compatible with the custom slave cylinder supplied with the Bullet kit

In the meantime, some progress has been made with a break in the weather and a friend with free time coinciding nicely, letting me get the old engine out

I also took advantage of having it out to inspect the damage to pistons 1 & 3

Yup, that's dead