1.6 to 1.8 upgrade

Technical Area Engine, Transmission, Exhaust etc
2

Ok i see a lot of 1.8 MK2 engines for £3-400 on a well known internet auction site.

My 1.6 mk2 has done 170k as of today, and they havnt been easy miles, I’d like some more power, and this seems like an obvious choice… My 1.6 needs a cambelt and blows blue smoke on start up so I would rather spend the money on a new lump, than bolting my stable door after my horses are dead…

Are we talking bolt in with a few changes, or will i need to spend the same again in parts to get it to fit

If google is my friend my 1.6 had 109bhp from the factory and the 1.8 has 145… 35bhp is a good lump more in anyones book!

 

Ta

 

Ed

3

Lots of silly little changes as certain things are on the other side of the engine. It would be better to get an MOT failure, move over all the bits you need then scrap the 1.8 Mk2 body. Otherwise you would be searching for all sorts of little bits.

4

Flyin’ Miata sell a conversion kit: http://www.flyinmiata.com/index.php?deptid=&parentid=&stocknumber=04-70500%20%201994-97 

And have a how-to writeup: http://www.flyinmiata.com/tech/1.8_conversion.php

Note that this conversion is for a 1990-'93 1.6.  Don’t know if the later 1.6 raises any extra problems.

5

The kit is engineered to fit any of the 1,8 engines into a Mk1.

There will be silly changes on the Mk2 that will cause problems, I assume.

 

6

 That won’t be relevant

 

The early 1’6 uses different sensors,

You will need the ecu from the 1.8 to run properly, so a wreck/scrapper would be the best option

7

 Well, instead of just assuming it’s too difficult, how about exploring what the actual problems would be?

The big difference between Mk.1 and Mk.2 1.8 engine sensors is that the cam angle sensor was changed to a crank angle sensor.  I don’t know which is fitted to the Mk.2 1.6 but whichever it is ought to be a straight swap over to the new engine, don’t you think?  There’s the VICS and possibly VVT to deal with too, but neither is a showstopper and both those are issues with a swap into a Mk.1 too.

Can anyone think of a reason a Mk.2 1.8 engine cannot be run by Mk.2 1.6 ECU and its sensors, because I struggle to think of one?

8

Unless you’re doing this for the fun of the project, it really seems rather more effort than it is worth when 1.8 mk2s are ten a penny…instead of spending £400 on an engine, plus a few hundred more on other parts and tools, plus days of backbreaking work, why not just chip in yours plus a few hundred for a good 1.8?

9

 Now that’s a very practical point. :slight_smile:

10

ok, my car is a cheap runabout it’s scruffy, dumped on coilovers, base spec and noisy as hell, its worth bugger all on a good day, its just not worth buying another just for the engine. I’ve got an lsd coming for it this weekend i just plan to have some good fun in the car for a while, mainly sideways… 

I have my own garage restoring classic cars, all the tools ramps and hoists i could need, I’m sure the mechanics of the job could be done in an afternoon, however what i need to know is what bits will work and what won’t, the engine is available for cashpoint money, so that is simple, i don’t even know if it will bolt up, are the mounts the same? manifolds? ecu? wiring? clutch? flywheel? are the blocks the same? heads?i dont know…

If its just makiong brakets and a downpipe and slotting in a new ecu then i’ll do it, if it needs days of headscratching and custom parts, new clutch etc then i have more important projects, but if its quick and easy to gain a quarter as much power again then yeah, i’m up for that… sorry for the lack of punctuation and paragraphs, my phone and this forum dont seem to get on… thanks ed

11

 Engine will bolt straight up to the gearbox.  All Mk.1 and 2 gearboxes and engines are compatible. 

Most of your other questions are answered in the link I provided to FM’s writeup on putting a 1.8 into a Mk.1 1.6. http://www.flyinmiata.com/tech/1.8_conversion.php

 

12

Ok seems good, I’ll get looking for a cheap 1.8 lump, my lsd and callipers are getting delivered tomorrow so need to get that little project sorted first…

have a pic of the old bus looking grubby and well used…

 

 

13

10mpg

I reckon the best way to do the project is.

  1. Not to look at a 1.8 car before starting the project to check all those stupid little differnces there will be! That is the job of posters here to advise on.

  2. After asking on this MX5 forum and finding no one who has done the same job, sail on regardless.

  3. Do not look for a scrap 1.8 that will have any special parts you may or may not need that will be no dearer than buying just an engine.

There are a good number of differences that both myself and Ricahard Nicol have advised there will be but neither of us have a 1.6 handy to advise you on re detail but as you are far too busy to look at a 1.8 we await your report on the problems of changing the engine.

Good Luck!

14

Well that’s pleasant…

I have listened to all the advice given, all the important stuff seems to have been covered, i.e the wirings pretty much the same, the engine will drop onto the mounts and bolt up, all the potential ‘differences’ seem to be minor things, like throttle body nounting brakets and alternators, all par for the course stuff when swapping engines, and having an engineering workshop to hand i cant see any of that presenting a problem, I dont need the car as a daily drive it’s a third or fourth car to me, so i can happily wait a week or two if there’s a snarl up…

have trawled my local scrapyards and there are no Mk2 or mk2.5 MX-5’s of any description, so that’s out, i dont know anyone with a MX5 so thats out…

I resent the attitude that says, ‘no-one on here has done it so you’d be better off not trying it’ I’ve rebuilt 1930’s race cars from tea chests full of rusty parts, I have done engine conversions on everything from 600bhp Nissan Sunny Pulsars to 60bhp Morris Minors, if you’re to scared to try something different think outside the box and problem solve then that’s your loss, not mine. making a 1.6 4 pot MX-5 a 1.8 is hardly the stuff of legend, i can do it, no problem, i was just trying to acertain the degree of difficulty involved.

A superb forum I’m an active member on, has a posting rule that goes along the lines of ‘if you have nothing pleasant or constructive to say, say nothing at all’ this works in real life too…

Tbh considering this is a specialist forum you lot seem to know sod all about your cars, my last two toy cars (911 SC and TVR Chim) had specilist forums stuffed with people who knew their cars inside out and took pride in knowing the answers to difficult or complex problems, and given the chance to help another enthusiast on their way actually helped, rather than make sarcastic comments, maybe this forum is a bit chippy, i dunno,  thanks to all that have genuinely helped I think I’ll just get on with it in my own time and way now.

My LSD has arrived today as have my new callipers, i was going to ask advice on fitting that, but I’ll probably get told it’s impossible without having a whole MX5 there to transfer a couple of inconsequential brackets from…

have fun guys…