29 replies to this topic

[jcm32517]

Hi
First post so apologies if its in the wrong section.
I have a 1993 mk1 1.6 longnose crank which needs a new engine due to the woodruff key being absolutely mullered by someone previous
My question is which engine swap should I do? More power obviously!! Is there a definite list of which engines fit which models?
I have searched but the information is confusing and I'd like the easiest swap possible utilising my wiring, ecu etc .
Any information greatly appreciated
Cheers
John
A picture of the car as we all like pictures

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[Bol]

Same answer as before. If you want to use everything you’ve already got, you need to do a straight swap. It’s then different for each of the other oem engines - but doable, particularly if you can get the ECU, loom etc from the donor.

[Zed.]

 I'd like the easiest swap possible utilising my wiring, ecu etc .

 

just about anything will fit, whats your budget & mecanical / bodge level?

easy like-for-like is another 1.6, the 1.8 is popular (but needs a lot of ancillary parts as 1.6 & 1.8 engines are different lengths as a start!)

@carl s has a good writeup of his 1.6 - 1.8 swap (with photos  )

 

https://www.mx5nutz....22586&p=4480193

obviously theres easier with the earlier mk1 1.8 engine as in FM's guide (you don't have to buy their stuff to convert...)

 

https://www.flyinmia..._conversion.php

 

or the posh version...

 

https://www.flyinmia...isc/1.8swap.pdf

 

add a supercharger or turbo?

 

then theres honda k20 or k24 4 cylinder, honda k30 v6, gm's LS v8 engines.............

 

Rich.

[Zed.]

Ah, the Ignore function  

again  


Rich.

[jcm32517]

Same answer as before. If you want to use everything you’ve already got, you need to do a straight swap. It’s then different for each of the other oem engines - but doable, particularly if you can get the ECU, loom etc from the donor.

Same answer as before?
I appreciate the easiest route is Same engine as I already have, is the 1.8 worth the hassle over the 1.6?

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[Bol]

Sorry, I miss read your post and thought I’d responded to you about it before.

I’m not sure I’d go to the hassle of swapping from 1.6 to 1.8 for the sake of 15 horses. Maybe for the vvt, but that’s even more complicated. I’d be inclined to go like for like then turbo or supercharge.

[jcm32517]

I'd like the easiest swap possible utilising my wiring, ecu etc .

just about anything will fit, whats your budget & mecanical / bodge level?

easy like-for-like is another 1.6, the 1.8 is popular (but needs a lot of ancillary parts as 1.6 & 1.8 engines are different lengths as a start!)

@carl s has a good writeup of his 1.6 - 1.8 swap (with photos )

https://www.mx5nutz....22586&p=4480193

obviously theres easier with the earlier mk1 1.8 engine as in FM's guide (you don't have to buy their stuff to convert...)

https://www.flyinmia..._conversion.php

or the posh version...

https://www.flyinmia...isc/1.8swap.pdf

add a supercharger or turbo?

then theres honda k20 or k24 4 cylinder, honda k30 v6, gm's LS v8 engines.............


Rich.

Thanks for the info, the original plan was always to turbo the car, but I was trying to get everything tip top first!
The 1.8 swap seems a lot of hassle for 200cc and maybe 15-20 bhp ? I don't think its worth it..
My mechanical bodgery is ok , nuts and bolts no problem but diagnostics and the clever stuff not so much

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[jcm32517]

Sorry, I miss read your post and thought I’d responded to you about it before.

I’m not sure I’d go to the hassle of swapping from 1.6 to 1.8 for the sake of 15 horses.

No worries, confused me as well
I don't think the gain is enough for the 1.8 swap, as ever more power is not an easy gain... I think I'll just look for a decent 1.6 engine and throw that in.... then sort the turbo later..
I may try the loctite fix first and see if I can bodge it until I have more free time.

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[Bol]

The alternative is to get your bottom end rebuilt with new bearings and honed crank (if it needs it). Will be a similar cost all in and at least you’ll know you’ve got a decent engine. I got a low mileage used one when my woodruff key was fubared and ultimately regretted it. The new engine had a dodgy oil pump and I ended up having to rebuild the bottom end on that one. If I’d stuck with the original I’d have saved myself about a grand. Different story if you can fit it l yourself though. I can’t.

[Zed.]

 

 

I'd like the easiest swap possible utilising my wiring, ecu etc .

just about anything will fit, whats your budget & mecanical / bodge level?

easy like-for-like is another 1.6, the 1.8 is popular (but needs a lot of ancillary parts as 1.6 & 1.8 engines are different lengths as a start!)

@carl s has a good writeup of his 1.6 - 1.8 swap (with photos )

https://www.mx5nutz....22586&p=4480193

obviously theres easier with the earlier mk1 1.8 engine as in FM's guide (you don't have to buy their stuff to convert...)

https://www.flyinmia..._conversion.php

or the posh version...

https://www.flyinmia...isc/1.8swap.pdf

add a supercharger or turbo?

then theres honda k20 or k24 4 cylinder, honda k30 v6, gm's LS v8 engines.............


Rich.

Thanks for the info, the original plan was always to turbo the car, but I was trying to get everything tip top first!
The 1.8 swap seems a lot of hassle for 200cc and maybe 15-20 bhp ? I don't think its worth it..
My mechanical bodgery is ok , nuts and bolts no problem but diagnostics and the clever stuff not so much

Sent from my SM-G960F using Tapatalk

 

the bonus of a 1.8 conversion is 240cc & more torque, the ~15hp is minimal but the torque is aparently very noticeable  

I'm staying with the 1.6 (for competition class reasons) but goin diggin&fiddlin for shitz&giggles

 

but then I'm not doing the conventional mx5 'thing' either

Rich.

[Zed.]

I have a 1993 mk1 1.6 

90 or 115 hp?  

Rich.

[tony100]

Surprising that a long nose crank keyway is going bad, is there 8 slots on the pulley?


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[Zed.]

Surprising that a long nose crank keyway is going bad, is there 8 slots on the pulley?

Excellent question  

they can fail if badly assembled, like everything its down to the mecanic or fitter....

Rich.

[jcm32517]

Yes 8 slots on the pulley, car and engine seem in fairly good order lots of history etc.. the engine has always struggled with power below 3k revs sluggish etc..
I was hoping the cambelt had been fitted incorrectly and a belt change would sort it..
Unfortunately the bottom was loctited in and the key way is definitely splayed, im yet to get the woodruff key out to see the full extent of the damage.

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[jcm32517]

I have a 1993 mk1 1.6

90 or 115 hp?

Rich.

115 according to the vin plate but drives like a 90

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[Zed.]

 

 

I have a 1993 mk1 1.6

90 or 115 hp?

Rich.

115 according to the vin plate but drives like a 90

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before you condemn anything check the crank - cam timing, if both cams are out it can do horrible things....

 

Rich.

[tony100]

Surprising that a long nose crank keyway is going bad, is there 8 slots on the pulley?

Excellent question

they can fail if badly assembled, like everything its down to the mecanic or fitter....

Rich.

Yeah thought I'd ask - it is interesting that quite a few of the non-short nose engines suffer with the issue.

I got a SNC engine and I abuse it regularly... Seems fine to me

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[Zed.]

 

 

Surprising that a long nose crank keyway is going bad, is there 8 slots on the pulley?

Excellent question

they can fail if badly assembled, like everything its down to the mecanic or fitter....

Rich.

Yeah thought I'd ask - it is interesting that quite a few of the non-short nose engines suffer with the issue.

I got a SNC engine and I abuse it regularly... Seems fine to me

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20-something years of repairs can take their toll, the longnose (bignose) can suffer the same workmanship as the earlier shortnose although the earlier engine can seem to fail for fun...

 

interestingly the snc failures seem to be mostly something of legend now so either it was the rumored bad luck or machining tollerances that caused replaements as the suviving cranks seem to be reliable  

I've a snc (lightwieght sports crank according to Mazda  ) engine in my 1990 Eunos, the timing gear was stripped off when I bought it for waterpump replacement but the crankshaft was (is) in perfect condition   

I also have another snc spare  


the snc / lightwieght sports crank is exactly that, a bit lighter than a later longnose (bignose?) item so should be slightly quicker revving than a later item  


now, I'm trying to get brave enough to build my drysumped engine around the lighter crank  

Rich.

[tony100]

Surprising that a long nose crank keyway is going bad, is there 8 slots on the pulley?

Excellent question

they can fail if badly assembled, like everything its down to the mecanic or fitter....

Rich.

Yeah thought I'd ask - it is interesting that quite a few of the non-short nose engines suffer with the issue.

I got a SNC engine and I abuse it regularly... Seems fine to me

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20-something years of repairs can take their toll, the longnose (bignose) can suffer the same workmanship as the earlier shortnose although the earlier engine can seem to fail for fun...

interestingly the snc failures seem to be mostly something of legend now so either it was the rumored bad luck or machining tollerances that caused replaements as the suviving cranks seem to be reliable

I've a snc (lightwieght sports crank according to Mazda ) engine in my 1990 Eunos, the timing gear was stripped off when I bought it for waterpump replacement but the crankshaft was (is) in perfect condition
I also have another snc spare


the snc / lightwieght sports crank is exactly that, a bit lighter than a later longnose (bignose?) item so should be slightly quicker revving than a later item


now, I'm trying to get brave enough to build my drysumped engine around the lighter crank

Rich.

Yeh my front crank seal needed doing and the keyway looked mint. Not touched it since. No need.

I've wondered if there is an uprated bolt (arp?) That would fit the crank but I've not been able to figure that out yet. Nor of it's even worth doing.

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[Zed.]

I've wondered if there is an uprated bolt (arp?) That would fit the crank but I've not been able to figure that out yet. Nor of it's even worth doing.

 
one of the common bolting-failures seems to be around the crank splitting between the threads & the keyway, the thinnest section of the nose.
 
I'd happily use an Allen-bolt in place of the origonal Mazda item, cheaper than an ARP replacement?
Allen bolts are usually high-tensile and available in several rates above the average 8.8 grade with 10.1, 12.9 & 14.something if you'd need such?

Rich.