MZR carnage history
My engine reliability and configurations have been a hot topic among my friends and the broader MX5 community here in Norway :-) I have almost lost count myself so I thought I’ll make a post about it and some considerations on why the MZR engine has been such a bumpy ride compared to my 3 previous BP-powered MX5’s.
So here is a history lesson on MZR reliability in my ownership.
This is not my first rodeo..
| Engine | Service | Configuration | Cause of failure | Comment |
|---|---|---|---|---|
| L8-DE | 2012.06-2014.08 | MP62 SC | E85 oil dilution | Original engine 40K Km. E85 and red deposits on engine internals Blown engine Post mortem |
| L5-VE | 2015.03-2015.09 | MP62 SC, ID1000 | Oil overfill + Knock | Initial damage happened on the Nurburgring. Also optimistic ignition tables in MazdaEdit tune. Smoking is harmful, for your MZR engine that is. Engine rebuild part 1: Tear down and damage assessment Did a costly rebuild with forged internals, but got an incomplete POS piston kit with missing oil ring supports ruining bores.. |
| L8-DE | 2016.10-2018.06 | Stock, later SC | Small pulley, small engine, boom | Spare engine 120K+ beater engine Used in N/A form while messing with the engine rebuild. Saw some action on Nurburgring and Rudskogen. Need for boost in 2018 lasted 2 weeks before it blew up spectacularly in 200+ leaving 100m of oil and parts scattered along the road. |
| LF-VD | 2018.08-2018.08 | MP62 SC | Engine Knock | Knocked itself to death on the first pull.. The piston head combo was way too much compression. Shortest lifespan engine ever… first engine to not see track time at all. Also the cheapest engine at 4K NOK in a crate from Saudi Arabia… |
| LF-VE | 2018.09- 2020.06 | MP62 SC | Failed IAT sensor -> Knock | Best engine I ever had. LF-VE block with L5 head. Cheap short block from eBay. Saw probably 7 trackdays with SC in Norway, also TF and trackday at Nurburgring. Set the fastest lap on Rudskogen 1:37,8 and plenty sub 1:40 laps. Another one bites the dust |
| L3-VD | 2020.06-2020.10 | SC, ID1000 | Coolant in cylinder, warped head | New 2.3L Engine Pressure in the cooling system Another oddball MZR VD engine from ebay.co.uk. Mid COVID, so needed something fast. Worked out great… I later trashed the engine as I discovered that the several of the pres-fit piston pins had started to seize up and bend. Does not take boost at all. |
| L5-VE | 2021.02-2025.09 | Turbo | Over boost due to split boost signal line | Held up 4 seasons which is a record. Two first N/A + Esslinger Stg2. Then Fab9EFR kit on minimum boost |
| L3-VDT | 2026.04-current | Turbo | - | - |
So to sum it up: The same 2006 NC have had 8 engines, of 6 different engine codes and 4 different types of power adders in my 14 years of ownership. On average I have had an engine blow up every 1.75 years :-)
To set things in perspective, all my four previous BP-powered cars had zero engine problems. That includes the 323 GT-R, and a built 2004 MSM with GT3071. Both ran 15 psi at the track.
Why
It’s complicated.. and not complicated.
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I actually run my car on the race track, HARD, chasing lap times. On a good year 4-5 times. Some years even a pilgrimage to the Nordschleife as well.
Running a car 10/10Th’s on the track is not the same as doing some pulls on public road. Here is a graph of one full tilt lap @Rudskogen.
More than 60% of the 1.4x lap is WOT in high G conditions. A typical trackday is about ~20-30 laps.
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Mistakes were made.. Especially during the early years (2013) with OEM ECU reflash tuning. Huge step back compared to the the previous EMS’s I had used on the BP.
The reflash software, doc and community are now much better much thanks to speeps over at m.net who reverse engineered the whole ECU and making the free ROMDrop software https://romdroptuning.net
Though the first L5 I broke was due to bad ignition tuning and a sub optimal map for CLT/IAT temp compensation. -
The MRZ engines does not take boost very well.. If you look at my table of shame five of them broke with some kind of forced induction. ( The junkyard L8 had no chance of survival though :-) ).
Based on my own observation all MZR’s with a press-fit piston pin design will fail with boost. The pin bends or it simply seizes in the piston -> rod snaps –> party is over.
Even stock pre 2009 LF-VE tends to destroy themselves with no mods at all.
So any L8, pre 2009 LF-VE, LF- or L3-VD should stay N/A imho. -
The MZR platform in general seems to have less headroom for extracting more power out of stock components compared to the BP and other Mazda iron block engines. Stricter emissions, better efficiency, thinner rings and ringlands etc.
It’s designed to hold stock power and not much more it seems.
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