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Post by BikeTuna on Sept 9, 2016 9:03:47 GMT
Following from Skuzzles Ultimate guide thread, the best engine would be to have a mk2.5 1.8vvt bottom end, with a mk1 1.8 top end, and fit forged rods.
I've got the opportunity of selling my 2.5 and buying a mk1 in the right colour with the right mods, but with a 1.6 short nose, so am looking to find out a bit more about how I'd make a block like this in the shed and chucking it in this mk1.
2 sets of questions here really...
Firstly, building an engine like this on the bench is the opportunity to go for a fully 'built' engine, but I don't have the mega money that these engines usually end up costing. The rods are clearly the weak point, but if you are that far apart in the block are there any other weak points that would be worth doing? Are there any other mods that really are worth spending on or is it that after the rods the £/bhp ratio drops off and you are only just scraping for ponies/willy waving?
Secondly, the process of swapping the blocks, I've done an engine swap on the drive before, but it was mostly plug and play. Apart from physically swapping the block and plugging in a ME221, is there any other known surprises along the way, like the loom having wrong plugs, fuel feed on the wrong side etc?
I guess a component list would be handy, I'll guess that I'll need a 1.8 TB as the 1.6 would be too small, is there any preference on the mk1 1.8 setup or the 2.5 setup? what about manifolds, would the 1.6 short nose one fit or will I need a 2.5?
A lot of questions I know, especially considering I don't even have the car, but if this isn't a viable option then I wont buy the car at all. I'll also mention that the future plans would involve forced induction of some kind, prefereably a Supercharger.
Cheers!
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Post by Vindi (Russell) on Sept 9, 2016 15:59:48 GMT
Have a read through the Flying Miata tech guide, there's nothing super difficult but you will need to change quite a bit of wiring, sensors and the fuel feed around
Russell
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Post by tropical on Sept 9, 2016 16:15:26 GMT
I don't know if it's a typo in your original post but the 1.8 and 1.6 engines are totally incompatible, the blocks are different lengths, different bore spacing etc. I can't think of a single component that could work on both engines except sparkplugs and flywheel.
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Post by Rickster on Sept 9, 2016 16:54:10 GMT
IMO you are over complicating this why are you so sure you want rid of the vvt Is it because you are going FI or because you want a mk1? In its standard form the mk2.5 is worth having. Otherwise just get a Mk1 and do whatever you want to it Either a 1.8 or the 115hp 1.6 Long nose? Swapping heads and blocks is never simple because of the ancillaries - one bolt hole in a different place can be a PITA!
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Post by BikeTuna on Sept 10, 2016 13:13:08 GMT
It was a typo in the original post...
The point is that I want to change my mk2.5 to a mk1 as I think it's better looking, doesn't have the rusty rail issue and can take a towbar. I've seen one that has a good shell, the right colour and a lot of the mods i want, but it has (in Skuzzles opinion ) the wrong engine to go FI with.
Skuzzles post says the best engine to FI would be the mk2.5 1.8 vvt bottom end, mk2 1.8 top end and forged rods, and I'm trying to get an idea on what's involved other than swapping the blocks.
If it looks like within my abilities I might have this mk1, and if not then I wont and wait for maybe a mk1 with a 1.8 instead.
Does that make more sense?
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Post by wannabe on Sept 10, 2016 17:12:43 GMT
IMO I think it's a shame to kill a 1.6 SNC if it's not dead - there aren't many left now, surely! - but point taken that if you're investing ££££ going turbo, you don't want to blow it all up and pay it out again on a new lump. Do it once, do it right, and all that.
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Post by Vindi (Russell) on Sept 15, 2016 12:39:52 GMT
I don't know if it's a typo in your original post but the 1.8 and 1.6 engines are totally incompatible, the blocks are different lengths, different bore spacing etc. I can't think of a single component that could work on both engines except sparkplugs and flywheel. You're not thinking very hard then. I bought a bare Mk2.5 Sport engine, swapped the head off a Mk2 and used all the ancillaries and wiring off my Mk1 1.6 engine. The only extras I had to buy was a Mk2 inlet manifold and a Flying Miata TB adaptor. Russell
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Post by tropical on Sept 15, 2016 13:56:31 GMT
My point was 1.6 and 1.8 actual engines/manifolds/heads being absolutely incompatible which was completely ignored originally. Surely the easiest thing to do if you want a mega power FI build just start with a good mk2 engine and forget the mk2.5 block bracing, you won't need it and if the rods where being made with inferior materials to save cost then what else may have been also? I think someone pushed a 1.6 to over 600hp/9000rpm before the crankshaft finally let go!
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Post by BikeTuna on Sept 16, 2016 7:35:30 GMT
I think this is going to end up being a no go for me, I found the flying Miata guide to the 1.8 swap and it looks a fair bit more involved than I was hoping it would be.
I've done engine swaps on the drive before, but with wiring differences and all sorts this looks more project than weekend bash, and I can't take a car off the road for that kind of time.
I think I'll end up keeping the 2.5 for a bit and seeing how far it goes before the VVT or the rods become an issue
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