Running bearings
 

Hey guys long time no post:p

Don't spend much time here but I'm inspired to try get boosted again. Long story short my mr2 I boosted with an old celica engine. Basically using junkyard bits, old subaru turbo and I slapped it on megasquirt. Basically didn't see an issue short of driving it till it threw a rod.

However after getting the AFRs all sorted and no detonation to be heard I went racing and on 2 motors ran the journal bearings. First motor had been to the moon so I put it down to that but the second one was a good low km engine out of an old road car N/A on stock ecu it was fine, a day on the boost juice and it dies. So I stopped till I had the time to diagnose. It's been out back for months and it is making me sad cause I have no racecar for the weekends.




Soooooo I'm just looking for a spitball on what could be causing this issue. First guess would be oil starvation but why? My turbo feed is from the head I tapped off the oil pressure switch port. I have both a gauge and a light and the oil pressure seemed mint. Only other thing I can think of is the frothy return oil is getting picked up when the car is really revving and air is getting to my bearings. Also thought detonation might be flattening out the bearings but the failure seems too fast for that plus ringlands are fine and motor sounds strong can't hear dick all bad noises.

So was thinking maybe change my return line to have a small catch tank type setup intergrated with the valve cover breather with a vent/filter on it. Also maybe something I'm missing and will look noob. Thoughts?

your boosting and using nitrous on a stock n/a motor?

Only boosting no clown juice lol. The rods are the same as the gen 2 3sgte I should be good for 400hp if I want, I'm only on 10psi on a small turbo so shouldn't even blink.

did you use a restrictor on your turbo oil inlet? did you ever check the oil pressure with a mechanical gauge?

Yep I used quite a small restrictor via using a banjo bolt with quite a small hole for the feed, no oil buildup in the drainback and no smoke out the tail either. The gauge is mechanical and has it's sender next to where the oil light plugs in. Which is why I'm kinda stumped:confused:

Might have to really his square one and redo the drainback with a catch for the blowby as well as redo the timing to 10 degrees across the board and run it while recoding my gauges with a camera and datalogging a bunch of runs on my laptop. I have an A/F gauge, oil pressure, water temp and the ability to datalog and nothing unusual shows up but I KNOW it has to be something to do with the setup given the motor was fine before all this. Unless I'm the unluckiest guy in the world which wouldn't surprise me either:rolleyes:

I don't want to spend the $$$ on drysump either, that makes no sense when the stock oiling system is fine except for an evil wizard that imma kill when I find it.