SME = Subject Matter Expert, ie somebody that’s knows a lot about Mx5s or even a professional engine builder!
Thanks for all the help and advice folks, now does anyone have a 2.0ltr engine going spare 
ahem… 2.5L conversion… ahem…
If you buy a 2.0 you’ll have to strip it to check it isn’t going the same way, then you’ll need the matching wiring loom, ECU, clocks, lock set etc.
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[quote=“alben, post:20, topic:129142”]
I think that I’d be looking for a decent lowish mileage 2.0 from a write off with a known history.
[/quote],
After all if you buy a used car you don’t take it to pieces and make sure it’s all OK - Or maybe you do?
I agree, if you buy a used car, especially one with low mileage and history, why would you strip it down?
Now if it was sold with know engine issues then that would be a different story but that’s not what I’m after .
I’m a bit confused as to why the 1.8 is classed as the “runt of the family,”?
There seem to be plenty on the roads and available for sale, surely if the 1.8 is serviced and maintained ie oil charged etc then the engine is as good as the 2ltr (obviously less BHP).
Also if I do buy a 2ltr and then “have to strip it to check it isn’t going the same way,” does that mean the 2ltr has same known issues a 1.8 may have and isn’t reliable?
What does low mileage and service history have to do with anything? You’ve just proven the low mileage thing wrong and it might as well have had FSH for all that’s worth too.
The engines have a problem, the whole range from 1.8 up to 2.5.
Don’t just talk about it, go out and find a 10k miles engine if you can and see what they’re asking for it.
Engine issues here: http://www.duratecnc.co.uk/?p=146
Elsewhere on there you’ll find info on engine specifications.
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Rich,
I do not own an NC nor do I intend to. I do own 2 early models, one a ‘93 1840cc engine, the other a 2002 so called “Sport” (cough) which pretty much shares the same bottom end, but with the so-called VVT head. Now, as far as I can recall, there was a street corner rumour, the later cars’ bottoms were a tad beefed up. Never the less, I can tell you the Mk1’ bottoms had a reputation for oil control ring cracking.
I should point out that these engines were the old school iron-block alloy head engines and have no relationship at all with the apparently cheesy NC mills…most of which seemed to go on with no issues to high miles but as usual…enough go pop and that’s when the bad reputation starts to get reported and you cannot blame folk much for that.
The reason why I’m posting is the 2002 Sport’s mill had now clocked 107.7 thousand miles, many quite brutal in my hands, and most the worst possible in my wife’s hands with 7 mile round trip school commutes until she retired 6 years back. It burns no oil, compression is as it left Hiroshima or near as dammit, and when the oil gets dropped annually or every 4,000 miles, it’s only just going black-ish light brown-tan colour. The trick, I think, with any so-called “Sports” car twincam which you have to assume has at one point in it’s multi owner life…is Oil…oil…oil. At the least annual, or 5k max while ensuring weekly dipsticks are done.
Now my Mk1.
I blew the original at Croft 7 years back…oil control rings cracked. I’d never heard of it.
Got an G’teed oil-tight low miles ( about 60k) out a write off from a trusted source, in it went in about 7 hours total with copious amounts of tea and bacon butties.
Since then, it’s had it’s backside ripped off the limiter often over my local glen back roads and is 100% bob on.Same story oil wise as the other 5. Annual 4/5k change outs always with OEM filters.
I’d rather have either of my engines than a weekend garage queen’s with 31k on it that never has the bonnet lifted. That kills them quicker than a lot of people think.
I’m pretty sure my Sport’s engine will soldier on for another 100,000.
Long after I’m gone!
I am sorry about your issues, but I urge you to read Duratec’s link. It’s all to familiar for many I would wager. Hope you get sorted. On balance, your answer is getting as close you can to installing a decent mill out a whatever. Been there, done it.
Another professional and well respected OC Forum Guru who does mill installs in Paul Roddison Racing. Have a chat. Top bloke by all accounts.
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If you’re intent on DIY then I would suggest:
Take your engine out and check the crank. If it’s ok then carefully buy another 1.8 engine.
Strip that and rebuild it, if it needs a crank you’ve got one. If it doesn’t you’ve got one to sell.
If you build it and treat it properly it’ll serve you for the rest of your days.
Outside of this issue they are actually very good engines.
I’ve had 5 early 5s in the past and never so much as a hiccup out of any engine. In fact my last one was a Mk2.5 1.8 VVT with 130+k on the clock. It didn’t use any oil and ran like a dream.
I just fancied a change from replacing sills and front chassis legs so bought this mk3 with engine issues as a challenge.
That said I will probably have one or more early 5s again soon as its become a habit!
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Okay, so just thought I would update all on my mk3 with knackered rings and piston.
After many cold and wet days working on the drive I have replaced 1 x piston and a full set of rings.
All bores gave been honed out (DIY job) and engine reassembled.
Today was the big turn the key day and what a relief when it’s started, no knocking, rattling or smoking. In fact it ran really smoothly.
Just been for a 20 mile road test and it’s starting to clear the oil in the exhaust system and everywhere else now but it hasn’t used any oil yet.
I have a 300 mile weekend away trip planned tomorrow so fingers crossed!
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Fingers crossed you’re sorted, good job👍
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take it easy and remember you are basically back into “RUNNING IN” mode for the next few k.
also for best running in remember to let the engine warm up fully before moving off!
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Good for you! Just remember to keep the oil level topped up and check on a regular basis. Just drive normally, no lugging in high gears and keep the revs to a reasonable level for the first 500 miles or so.
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Good luck with the trip.
May I suggest an oil & filter change after it, and basically regard this 300 miles as a bedding in jaunt and maybe change up tgo higher gears a wee bit more than you ( or I!) would like.
Alright for me to spend your cash from my keyboard but I suspect you know what I mean.
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did it survive?
Oh yes. Running like a dream.
In fact it’s now done 2000+miles since the rebuild and I’ve just got back from a long weekend driving around Snowdonia adding another 500 miles.
Oil is checked weekly and has not budged from when it was filled.
No knocking, rattling, smoking or anything to cause concern.
In fact I would quite happily now look to buy another mk3 with knackered rings and repeat the exercise since I have all the tools now and the weather’s better.
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