Mx5 Rocketeer V6 Conversion Project

[Lewis's Friend]

I thought I'd share my next project. Partly because I love reading other peoples project threads and thought I should contribute, and partly to document the work as I go along, otherwise I tend to forget all the work I've done!

Anyway, to set the scene a little, I sold my previous fun car and was looking about for what to replace it with. I had a TVR S3C, which I really liked. However, I'd had it for almost 3.5 years, and just fancied a bit of a change and a bit more speed.

The TVR:
IMG_2233 by Jon Fellows, on Flickr

IMG_2215 by Jon Fellows, on Flickr

I wasn't sure what to replace it with, as in one way it suited me down to the ground. I did consider other TVR's, but they are fast becoming more money than I can spend easily, and I can't have a Chimaera because too many of my friends have them!

So the hunt was on. I considered classic American, but in the end concluded to have a classic that was still fast by today's standards was again too much coin for my wallet. So I carried on looking.
I researched Mazda Rx7 FD's, but really I prefer larger displacement engines than turbos and boost (sacrilege to my JDM mates!). I always came back to liking the TVR formula of small drop top with a (relatively) large engine.

I then saw a review in EVO magazine of a mk1 Mx5 that someone had thrown a Jaguar V6 into. Now I had experience of this engine from my old Jaguar XJ, and I liked it, so became rather interested.

Essentially Rocketeer make a kit to put a Jag V6 into a mk1 or 2 Mx5. You provide the base car, and engine and a few ancillaries. Everything else is part of the kit. This includes custom front subframe, wiring loom, ECU etc etc. It sounded perfect for me, as its an interesting project but didn't need any fabricating skills (of which I have none!).

So I set out to get a base car for the build. Obviously the most important thing (and hardest) would be to get one with as little rust as possible. With that in mind I found what seemed to be a perfect one from a (as I thought) well respected seller. So I trekked up north and bought this fine machine:

IMG_2515 by Jon Fellows, on Flickr

This is just after I picked it up. I had some reservations about it, but I had come so far it would have had to have been truly awful to give up at that point. This is why you never buy sight unseen, even if you think the seller is trustworthy...! Lesson well and truly learned...

So I drove back almost the length of the A1, which highlighted a few deficiencies in the car. Off the top of my head, some of these were:
-Driveline shunt
-Vibrations above about 60mph
-Blown speakers
-Windows not working
-Horrible judder in reverse
-Oil leak from the engine
-Dodgy immobiliser

So I got home safely, which was a start I suppose. Jacked the car up, and immediately wished I hadn't. So much rust...!

IMG_2518 by Jon Fellows, on Flickr

IMG_2519 by Jon Fellows, on Flickr

IMG_2526 by Jon Fellows, on Flickr

It was rather dispiriting, but having decided the only thing to do was carry on, I decided to make the best of it, and turn it into a good base car, even if I'd hoped to buy one like that out of the box. Ah, well, one lives and learns.

A taster of The Rust:
IMG_2530 by Jon Fellows, on Flickr

IMG_2552 by Jon Fellows, on Flickr

These use to help hold the front bumper on!
IMG_2566 by Jon Fellows, on Flickr

These don't really do the scale of the rust justice. However, and it is a big however, I could see no rot. Just masses of surface rust. So the great strip down has begun. Suspension components are coming off, rear subframe, diff and fuel tank out. Components powder coated, brakes refurbished, bushes changed and a full underside clean up and seal.

Getting to the shock bolts, and deciding to strip the boot out for good measure...
IMG_2570 by Jon Fellows, on Flickr

Diff out, and subframe being removed
IMG_2571 by Jon Fellows, on Flickr

Subframe out
IMG_2572 by Jon Fellows, on Flickr

And the back all stripped down
IMG_2573 by Jon Fellows, on Flickr

Just the fuel tank to go, and the back is stripped
IMG_2574 by Jon Fellows, on Flickr

And that takes me to the present. The front suspension still needs to come off, all the bushes removed and the components sent away for powder coating.

However, I have just driven the Rocketeer demo car, and loved it so there is motivation there! Also just agreed to put a deposit down for the next build run.

Hopefully this will be of interest to some of you out there. We'll see how smoothly the rest of the build goes...

[Lewis's Friend]

davebem said:

Olivera said:

Um yeah where is the rust there? As far as old cars go I can see pretty much zero rust, apart from a little bit of surface corrosion.

Yeah its not bad at all, no more rust there than a 5 year old ford focus. The bumper brackets are bad though.

In terms of the rust, as I say, it’s not rotten at all which is good. But it will be tragic in not very long at all if not dealt with all over! Hence the strip down, which is not something I wanted to have to do - engine swaps are much more fun!

Also, the pictures don’t quite do the rust justice. But you’re correct, it could be loads worse.

[Lewis's Friend]

finlo said:

HustleRussell said:

You call that rust?

Is there a weight penalty with the Jag engine? Jag V6 seems a strange choice.

Jag V6 is Ford/Mazda all alloy tiny little thing with the added bonus of VVT.

There is pretty much no weight penalty at all. The Mx5 lump is iron block, whereas the jag v6 is ally.

The demo car is making about 260bhp, and was great to drive. It felt very similar actually to my mates Chimaera.

[Lewis's Friend]

Cambs_Stuart said:

Great idea and thread. Following with interest. I had a ST220 which had the alloy V6. It was a great engine, revvy and made a superb noise.
Until it decided to eat it's own crank bearings.
What kind of gearbox and diff are you using?

Cheers. I really liked the engine in my XJ, but obviously a totally different application.

Before driving the demo car I wondered if it would be a bit too refined, if that makes sense. But no worries there!

The gearbox and diff are kept from the Mx5, and should be good for the power. I’m looking to change the diff though, as 1) it’s got loads of backlash in it and 2) I want to change to a 3.6:1 ratio. On a standard Mx5 that can be a bit low geared, but should be ideal for the v6. That’s the theory anyway! It’s a Torsen LSD.

[Lewis's Friend]

AyBee said:

Looks fun Having just had a quick look at their website, which kit are you going for?

I’m going for the ‘they provide everything’ kit, as I don’t have the skills to do anything else!

It is expensive, and I can understand why people might think why not just buy a faster car out of the box?

My reasoning is that I’ve never done an engine swap, and quite fancy ticking that off, the small roadster/big(ish) power really does it for me and the rest of the car is a bit of a blank canvas for me to mess with over time.

I held of ordering one until I drove the demo car though, as it’s quite a big investment for me. But I was very happy with the test drive so went for it.

[Lewis's Friend]

pstruck said:

I've been thinking recently that I really need a project. Having had a couple of Mk1 MX-5s in the past my thoughts have been homing in just such a project. I have done zero research yet, but am definitely interested in the idea of an engine transplant, so I will be reading your progress with interest. If you're happy to share outline costs then that would be interesting and helpful also.

The kit is basically £7k, and to that you need a base car (and mk1's seem to be going up in value quite quickly) and an engine. Rocketeer can provide a crate engine I believe, but I will probably be trying to get one out of a wrecked Jag S-type. As the gearbox is not needed from the Jag, you can take the engine from an auto as someone has mentioned on this thread. They seem to go from between £300-500.

There are then a few bits you need to get hold of, like a second mazda 1.8 throttle body.

I have started a spreadsheet to track costs - to be honest I think it will be quite pricey, but then I'm keeping track of tools bought as well. My new impact wrench is my new favourite thing. A total lifesaver!

[Lewis's Friend]

Drew106 said:

I'll be watching this one with interest. I bought a Mk1 last year which I've been tinkering with since.

Had a look at the Rocketeer cars at the national meet in Gaydon back in September. Awesome bit of kit.

I plan to add a bit of power to mine in the near future but will likely go the usual turbo route.

Oh and I'll see your rust and raise you this...

Wow, that puts it in perspective!

[Lewis's Friend]

It’s not cheap, but then you’re also paying r&d costs, plus a profit for them. Of course some will think it’s not worth it - fair enough.

Having driven it, and not having the skills to do that kind of conversion myself from scratch, to me it’s worth it.

I do recommend viewing their website though for more details, plus photos etc. It gives you a better idea of what’s on offer.

[Lewis's Friend]

Robmarriott said:

I see it has two throttle bodies and they're fairly far apart, the MX5 uses a cable throttle so how does the nearside throttle operate?

I have to say, I'm not sure. Whatever method, it seems to work! I'm guessing a second slave cable, but I'll let you know when I get it.

[Lewis's Friend]

Dr G said:

Bookmarked and will follow closely.

I had no idea such a conversion existed until a few minutes ago.

I think even if you did happen to stumble upon a freakishly clean MK1 you'd still want to do a fair amount of preventative work under there to protect your investment. Putting all that time and money into the car only to then be afraid of getting it wet or dirty would be a terrible waste. Properly sealing and protecting the underside will pay off many times over in terms of durability, peace of mind, and ultimately your enjoyment of the finished product.

That was the idea - no point spending on the conversion and fitting it to a rust bucket. Even though I do enjoy Roadkill on youtube...

[Lewis's Friend]

Escy said:

I saw the car throttle youtube video of this and thought it looked fantastic. I'm looking forward to seeing how it pans out for you. Is all the working going to be done on the driveway?

Cheers - it will all be done on the driveway. Sadly I don't have a garage I can fit a car into, so outside it is!

[Lewis's Friend]

Olivera said:

HustleRussell said:

I have to say the financial side makes no sense to me. Say you spend two grand on the donor Mazda and Jaguar bits, and seven on the kit. You're in for nine grand, and at the end the car still has the interior and exterior appearance of a grand's worth of mx-5. You've still got a tired hood, suspension, brakes etc to contend with. I'm sure I'd a lot of fun and part of the fun is in the journey but ten grand opens up a lot of fun car options.

Indeed. I like the kit too but realistically it's going to be a 10k+ project to do everything properly and to the high standards of the Rocketeer kit. I honestly think I'd go for an MX-5 NC and the BBR Super 200 or 225 kit instead.

I do understand that point of view, but I did the sums and it was worth it to me.

I wanted to do as much of the work myself as I could, which this kit allows but also takes away the bits that I don't have the skills to do.

In terms of alternatives for the price, there isn't really very much that meet my criteria. After considering all types of things, from amercian classics to jap stuff, my list of things I wanted eventually came down to pretty much this:
-roadster (I like the roof down, despite my amazing ability to burn in direct sunlight)
-small; the better to use little back roads
-'enough' power - subjective I realise but I wanted there to be a decent step change from my TVR (circa 150bhp)
-NA - I just prefer larger displacement to forced induction (though I am willing to compromise on this and have large displacement AND forced induction!)

The above is pretty much a TVR, but as said, I can't have a Chimaera as too many of my friends already do, and anything else is out of my reach! This seemed to tick every box. That said, I can see why others would not want to go down this route.

[Lewis's Friend]

Escy said:

Did you consider a MR2 Roadster with a 2GR at any point?

I have to say I didn't, but the mx5 only came to mind initially having seen the review of the Rocketeer Demo car in EVO.

[Lewis's Friend]

Thanks for all the positive comments anyway chaps - I'm pleased that its of some interest to people.

Some minor updates from today - I managed to get the front suspension stripped down. At one point there was a mild flurry of snow, which seemed a bit off when I was trying to work!

The front hub knuckles totally defeated my ball-joint splitter that I bought for the purpose, so I hit them with the biggest hammer I had, and that freed them off.
IMG_2579 by Jon Fellows, on Flickr

Angle grinder required at one point...
IMG_2580 by Jon Fellows, on Flickr

And the front suspension off.
IMG_2581 by Jon Fellows, on Flickr

Next I'll start getting the bushes out, before sending all the parts out for powder coating. Nice and easy!

A buddy who would otherwise have helped with all this is, sadly for the project, going traveling around the world soon. But in lieu of physical help, I have stolen a lot of his tools to help with the project, including a press to help with the bushes!

[Lewis's Friend]

TwoStrokeNut said:

It's been mentioned a couple of times before.

OP, did you look at Claire's work over on MX5 Nuts? That's a lovely sounding V6 conversion with the ITBs.

http://www.mx5nutz.com/forum/index.php?showtopic=2...
https://crapengineering.weebly.com/

I confess I hadn't seen this - looks like a cool project.

Originally the Rocketeer car was tested on ITB's, but was changed to allow for better low speed road manners I believe.

[Lewis's Friend]

A quick update. I've carried out stripping all the bits off that are getting powder coated/painted and getting all the bushes etc. out.

It's been quite pleasant working in the garden...
IMG_2585 by Jon Fellows, on Flickr

The only bit I struggled with was getting the rear hub assembly apart. I had to admit defeat eventually and take them down the local garage to put on their big press - they came apart easily after that...!

So now I'll be taking all the bits in for blasting and finishing. Hopefully they'll be back before Christmas - we shall see...
IMG_2591 by Jon Fellows, on Flickr

[Lewis's Friend]

Kitchski said:

Completely unrelated to the Mazda (which I wholeheartedly approve of, and am watching with interest) but your S3 was lovely!

Cheers - I did really like that car. But it was time for a change and I'd done all of the jobs I wanted to on it (particularly the interior refresh, which I very much enjoyed doing).

I think the MX5 should also be a decent wedge faster which is another thing I was keen on. Though that said, the TVR was quick enough and loud enough to always bring a smile to my face.

[Lewis's Friend]

A small update, as work is still slowly going on on the project.

I've now stripped the car down as far as I'm going to (I think!), with the removal of the fuel tank. Now there are just a few small details to look at, like drilling out snapped off bolts, welding a couple of new studs in to replace sheared ones etc, and its ready for me to start cleaning up and getting ready for treating and undersealing.

So here it is with the tank out
Image.png by Jon Fellows, on Flickr

Image-1.png by Jon Fellows, on Flickr

Sadly, the prevailing weather conditions this weekend meant I didn't get a great deal done - cowardly I know. It looked quite nice though!
Image-4.png by Jon Fellows, on Flickr

And lastly, I've taken delivery of what will hopefully be the heart of the new and improved MX5! This is a long way off to be fair, but I was phoning around breakers, and this came up at what seemed a reasonable price, so I went for it. Definitely not going to have much done to it any time soon, but its nice to have it anyway...
Image-3.png by Jon Fellows, on Flickr

[Lewis's Friend]

anonymous said:

[redacted]

It is... A friend and I went halves on it a while ago to practice doing up a car from the ground up (the theory being we couldn't make it worse!). We did some welding, undersealing, new brakes and lowered it along with some extremely tasteful cosmetic mods!

There is a build thread for it here if its of interest:
https://www.pistonheads.com/gassing/topic.asp?t=14...

[Lewis's Friend]

Kitchski said:

Lewis's Friend said:

It is... A friend and I went halves on it a while ago to practice doing up a car from the ground up (the theory being we couldn't make it worse!). We did some welding, undersealing, new brakes and lowered it along with some extremely tasteful cosmetic mods!

There is a build thread for it here if its of interest:
https://www.pistonheads.com/gassing/topic.asp?t=14...

Ah yes! I remember that thread! Thought I'd 'watched' it but seemingly not. Did you sell it in the end?

No, I've still got it. Though I'm just waiting for some decent weather to give it a wash and take some attractive photos of it and put it up for sale. I've found that three cars just means one of them gets totally ignored...!