Video: What went wrong with the MX-5’s Barra!

In this episode of Carnage, Scotty pulls the heart out of Lightning McBarra to see what went wrong

Videographers: Matt Hull

If you’ve been keeping a close eye on our blistering Barra-swapped MX-5, you’ll know that it went dangerously close to running an eight-second PB before things went a bit south.

In a recent episode of Carnage, Scotty had the little Mazda out at a test day at Heathcote Park Raceway, where the MX-5 set a new best of 9.26@147mph. That was bloody awesome, but unfortunately the fun got cut short when the car came back from a run with Bubba Medlyn at the wheel and the Haltech iC-7 dash showed 0psi of oil pressure.

While it didn’t rattle itself to bits or throw a leg out, we knew something was seriously wrong, and there was a good chance it’d done a whole pass with no oil pressure. Scotty’s main suspect was a broken oil pump, so in this episode he gets to work finding out what went wrong.

Much to his amazement, dropping the oil and cutting open the oil filter didn’t reveal the shiny glitter from eaten bearings that we’d expected – unfortunately we can’t say the same for the 1JZ in the Trolvo!

That may have been a good sign, but to check the oil pump properly, the engine still had to be pulled. As you can imagine, pulling a donk as hefty as a Barra out of the little Mazda’s engine bay isn’t exactly fun, but after a bit of fighting, the big Ford mill was free.

Scotty wasted no time in tearing it down, and as soon as he lifted the sump, we found our culprit. The oil pump itself was fine, but the oil pressure relief valve for that pump had unwound itself and was just sitting in the sump. That meant all the oil pressure was dumping straight out of that port rather than feeding the engine.

While it was bloody tempting to just throw the engine back together and send it, even without any bearing damage we were still at the limit of this stock-bottom-end LPG combo. The compromise solution that Scotty’s cooked up to get the Mazda back on track is a bloody ripper, but you’ll have to wait for a future episode of Carnage to see that. Stay tuned!