mx5cartalk.com

Hi all

I'm looking at buying a 1989 or 1990 MX5 and I'm hoping to do a B6T conversion from a 323/TX3. I have just finished rebuilding my B6T so I'm not interested in any other form of engine conversion.

I've searched this forum and others but have failed to come up with much detailed info on actual B6T conversions from a 323/TX3. I'm wondering has anyone attempted this conversion in an MX5 and if so what difficulties you found and any other info that will help make this conversion a success.



The following is a list of issues I can think of with the conversion;

1. I will need to unbolt and remove that front engine bracket used in the east/west configuration
   
2. Possibly use the MX5 sump
   
3. Possibly use the MX5 left and right engine brackets and mounts
   
4. I'll need to use the MX5 crank angle sensor (maybe need some work as the slot in the end of the cam is slightly different between MX5 and 323/TX3
   
5. I'll be running full aftermarket engine management so the crank angle sensor and AFM aren't an issue
   
6. I'm hoping I can use the MX5 intake manifold
   
7. I'll have to make a custom exhaust manifold
   
8. I'll use the MX5 flywheel

you might as well start out with the 94+ 1.8L MX-5. stronger diffs that can handle turbo power, swapping in the good LSDs is much easier & the 1.8L models come with bigger brakes too. in which case, might as well go the 1.8L BPT.

i'll let others explain the rest


howdy, by the way.

I will need to unbolt and remove that front engine bracket used in the east/west configuration
Yep

Possibly use the MX5 sump
Yes definatly will have too might need the mx5 oil pick up as well

Possibly use the MX5 left and right engine brackets and mounts
Yep thats a given make sure you get all the parts (quite a few to them) about 4 main parts each new ruber mounts are 75 bucks for the set from mazda i think from memory


I'll need to use the MX5 crank angle sensor (maybe need some work as the slot in the end of the cam is slightly different between MX5 and 323/TX3
Yes what is done to your head? anything special? if its nothing out of the ordinary why not just use the mx head asuming its in good condition? or swap all your valve train and cams from one to the other?(not sure if this works havn't seen it done)

I'll be running full aftermarket engine management so the crank angle sensor and AFM aren't an issue
pretty sure with aftermarket engine managment you will still need crank angle sensor? but i cant be sure


I'm hoping I can use the MX5 intake manifold
Yes should bolt on your injectors will fit

I'll have to make a custom exhaust manifold
there are some around that might suit your aplication be it from AVO SMB greddy/ or ebay ones


I'll use the MX5 flywheelnot sure wether you had to but it might be easier as youll be using the mx gear box just incase there is any difference



Other problems you might incur

there is a couple of welsh plugs you will have to change

a fair bit of removal and refit of mx5 specific water lines (mainly down pass side of engine) to and from back of head etc

new oil lines etc all the usual stuff that would normally be done in a turbo/upgrade

Check you pulley profiles to make sure they are the same
some are different depending on year of manufacture

basicly if you have a running b6 in an mx and a B6T on the ground between the two motors you should have everything!

Thanks guys!

Howdy SuperMazdaKart the B6T is the only option since I just spent big buck$ on rebuilding it, that's why I've opted for an early model MX5, that and the fact they're a lot cheaper


lowmiata...

• The head is extensively worked so I'll be using the complete B6T
• I realise I still need the cam angle sensor I was just pointing out it'll need some slight work for fitment
• I will be using the MX gearbox so that's why I said I'd use the MX flywheel
• I dont think the water and oil lines will be a huge issue since I'm using the complete B6T but as you said since they're both B6 and will be sitting on the floor beside each other it should just be a matter of swaping some bits and pieces here and there.

It can be done and has been done, theres a bloke here in adelaide that i know of whose done it to his NA and is currently helping with a third for a local club member being very reliable and powerful..

I may be able to find some photos...

I had a chat with him before i did my turbo (like a yr ago) but he 'was a little bit hazy' on details... made it sound like there was a huge amount of things to change i dont believe he used MX motor components, i think he made the B6T fit in as it was.. I seem to remember he had some big issues with the intake manifold, making it fit in the engine bay... rewelding bits and pieces.. i cant quite remember..

But it can be done.. and good luck with it!!

Well seeing as you've already got the B6T block, I suggest that you buy a lunched B6 from an MX-5 and swap everything onto it. Then there's no messing about with engine bits and pieces. The most you'll have to do in terms of major changes is punch out the welsh plug from the front of the head, and put the thermostat housing neck there instead.

My history? I put a Familia (BPT) engine into my NA8. But the reason was not for power, it was because the BPT was a cheap replacement for my BP, which I ended up rebuilding with forgies, B6T rods, etc etc. Fitting a whole B6T engine with the wrong manifolds, mounts, sump etc etc was just not going to happen, so a lot of parts from the original BP engine had to be put onto the BPT.

For info on what I did, check the Engine swap threads here: http://forums.sabretooth.id.au/index.php?f=4

Thanks guys!

sabretooth I've read your thread before, a member on another forum posted the link to me the other day. It was helpful with a number of things, thanks.

Well at least it's looking more and more like it's do-able without having to make massive modifications. That was my major concern since I need to use the B6T long engine that I've already dumped so much cash into.

If anyone else has more info keep it coming

I've done similar mate.

I used teh mx5 block and slotted the B6T internals in using teh mx5 head.

I've also used teh B6T turbo cams in my MX5 head before, never had any fitment problems with CAS, but you'll find it delivers the best usable power with teh MX5 intake cam and the B6T exhasut cam, seemed to build boost a bit quicker for me.

I have a full set of MX5 engine mounts if you're intersted, rubbers in good cond etc.

PM fordetails.

Thanks for the info Sean. I've actually fitted aftermarket cams to my engine already Also there's probably not much point in grabbing the mounts off you as I'll just use the ones of the MX5 engine in the car, I appreciate the offer though thanks.

Anyone else got any info?

just go get your MX-5 already

Doing that this weekend My engine will be finished Friday I believe it's in the process of being dummy built now.

PSI-JET I am curious as to how you will get your car engineered and how much that will cost.

Shouldn't be too much of an issue for engineers. I'll do a brake upgrade and make sure everything else is A1 and it meets EPA requirements. It's B6 DOHC to B6 DOHC with the obvious addition of a turbo so engine wise there's no issue, it's just the turbo that will be looked at.

I sold my previous engine to a mate who put it into a KC Laser wagon which none of the KC range ever had a turbo option and it cost him $500 for the engineers without any dramas.

Hopefully it's as cheap and easy for me

PSI-JET wrote:Shouldn't be too much of an issue for engineers. I'll do a brake upgrade and make sure everything else is A1 and it meets EPA requirements. It's B6 DOHC to B6 DOHC with the obvious addition of a turbo so engine wise there's no issue, it's just the turbo that will be looked at.

I sold my previous engine to a mate who put it into a KC Laser wagon which none of the KC range ever had a turbo option and it cost him $500 for the engineers without any dramas.

Hopefully it's as cheap and easy for me

Brakes should be fine as you have 4 wheel discs.