Wow, it cracked both sides? How would you repair this? I'd have a spare empty shortblock you could have for shipping.

Once again, more proof that this is the best damned forum on the planet. Two offers for free blocks. Fuck yeah, Miataturbo.net.

Sorry man, that sucks. weird.

Tried the dump a bunch of solvent down my holes trick. Started with a bottle of AC Delco X66P because I had it laying around. Followed it up with some acetone. I'll post up again in 5k miles to see if it made any difference.

Sorry to hear about what's happening to Hakan.


How about Supertech pistons?

"Removing squirters, lower oil temps"

Whoa, that would mean that same amount of heat is what, going from the piston to the block? Hotter pistons more prone to detonation.

Car is properly back on the road, so first (cautious) update...

Engine and transmission cracks were expertly repaired.
Block is sleeved, has ACL bearings and no oil jets.

It has been almost a couple of thousand miles since first crank.
30 weight non-synth oil for the first two oil changes, and non-synth 10w40 till I hit the 1000 mile mark.
I used Shell HX8 Ultra 5w40 after that, and have been driving/enjoying it since.

The engine never once asked me where the oil jets were. Just purrs along nicely.
One noteworthy observation involves oil temps. Seems like it runs just a little HOTTER.
Like, 5 to 8 degrees (C) hotter than before.
I am used to seeing 89-90C on the gauge, now I consistently get 95+C.

Maybe that oil mist from the jets was cooling on its way down to the pan.
I mean, that's the only thing I can think of.

I left bearing clearances on the high side of the specs, so I'm getting 22-24 ish PSI at idle with a fully warm engine, but anything above idle is pretty high.
I often hit 90 PSI during driving. Steady cruise at low rpm with warm engine is never below 60 PSI.

Have not had the time to do a compression test yet.
Engine is more responsive, but that is expected.

I am happy to answer any questions I may have overlooked posting about.

That is a lot of oil pressure. VVT pump? Shimmed relief valve or standard?

"A lot of", as in, good or bad?
It's a standart aftermarket pump:

https://cimg8.ibsrv.net/gimg/www.mia...11ca30b3c6.jpg

I just shimmed the relief valve with one washer.

There is no way I would have shimmed the pump, those levels of high oil pressure are not improving anything, just wasting horsepower and raising oil temps. Given your oil pressure measurements I question why you're running a 40W oil, I don't think it's needed.

Also curious how the block was repaired.

To be perfectly honest, I bought an aftermarket pump because I was really pressed for time.
So, I just wanted to be perfectly sure, that's why I shimmed it with just one washer.

Transmission cracks were simply ground and welded. I found a really good welder, he did a great job and I paid him about 8 or 10 bucks for the whole thing.
Engine was tricky.
I asked the welder (who is a machinist) to turn a solid steel bar that would fit perfectly in the bearing housings in the block. Think of it as a cylindrical crank, bolted in the mains.
Then the crack was ground in a V and welded from both sides, and ground smooth to level the surface.
I had him make that steel bar to prevent any distortion during welding.
It worked like a charm, and subsequent line bore checking verified no distortion.
That guy charged me 50 bucks.

Sleeving the block and all the machine work came to about $250, including the crack repair.

Hell, runs great now..Plenty redline runs so far.

What he said. Your high pressures are raising your oil-temp by converting your engines hp into heat.

I don't think you need to change anything, but next time you tear into the engine, my suggestion would be to undo the changes.

I guess I could always un-shim the pump.
Or, maybe go to 5w30...

That's cool how it was repaired, sounds like a soild repair. And cheap relative to our money! Just getting a machinist to make that steel bar you needed would have been 100-200 bucks here.

Do you know what sleeves were used by chance?

If it were my car I would run 10-30 motor oil and go from there. That's easy to change and should drop the oil pressure some and increase the oil flow to the bearings. I run 10-30 in my motor on my car and have had excellent results for years, never had a bearing problem before. Have seen many boost and RPMs. I do run a large oil cooler for last few years though and I think that is a good idea if you are racing and boosting a miata to have a good oil cooler.

Sleeves were custom made. They are good at that kinda stuff.

Plugging the jets probably reduced the oil flow needs significantly, raising pressure overall. The relief is at about 60psi stock. 90psi creates excess heat, as mentioned. It also puts excess strain on the pump and may possibly cause additional wear, but that's speculation.

There's no reason to work it so hard. Flow protects the engine, pressure is simply a measure of the resistance to the flow. The main and rod bearings are not sealed and pressurized, but rather volume flow protected.

Ahh, sensibility speaking here. There are various sorts of journal bearings and it is typical for engines to not require oil pressure to "lift" the shaft in the journals. Rather, the presence of the oil, and rotation, create the film needed to keep the parts separated.