I started my mx5 journey fairly arse about face when I decided I wanted to rebuild an engine, having never done so before. I've done engine swaps and some repair work but never fully built my own. So I had a look round and found a suitable VVT to use.
I wanted to essentially just rebuild make slightly better, clean everything up and lap the valves etc. Spec was pretty much stock besides some forged rods in case I decide to go FI in the future. Overall the engine seemed to be in good condition, fingers crossed. I did the work and added a baffled sump plate as well to help with track work. Once that was pretty much done I started to hunt for a suitable car to drop the engine into.
I picked up this 99 NB recently which seemed to be relatively rust free in the right places and having had some recent welding and paintwork. It's by no means perfect but I wanted the car to build a track focused machine from so seemed to fit the bill.
The engine seemed to have a big misfire (more on that later) and after compression testing seemed very low on compression on the middle two cylinders Vs the others. No real matter the engine was a Bp4w Which was useful as I was thinking about using this head to play about with a skim, porting etc for another rebuild.
I used the car for a few short trips, the PAS was leaking badly, the misfire didn't seem to get any better and the brakes were also binding on the front left.
First job really was to pull the old engine, I removed the head first up to have a look if there was any visible reason for compression loss but couldn't see anything.
It was only when I got round to the coil pack that I could see coil 3 was in 2's slot and vice versa. Likely cause of misfire found!
Anyhow I already had a fresh engine and so the bp4w was on its way out.
An afternoons work later and the vvt engine was in place and ready to go. Everything buttoned up and she started second go after having realised the coil pack was plugged in the wrong way.
Everything looked good until I saw a cascade of oil coming out the front of the block. Disaster.
Much work later and having cleared the alternator out of the way I could see the oil pump had cracked and was leaking catastrophically. An expensive and time consuming mistake to say the least.
Another day later and I had the engine pulled and back on the stand. In undoing everything I had somehow left the old mushed up o ring in place as well as the new o ring leaving them no room, tightening down obviously resulted in the crack. Lesson learned.
I've ordered a boundary billet gear pump to replace it which should be here on Tuesday so fingers crossed I can have it back together and in the car for then.