Potential Cause of rumored GR86’s blown engine? Seal packing(RTV) was peeled off

[Dadhawk]

Originally Posted by Petah78

I could be wrong on this but I think the real danger of too much oil is the oil hitting the rotating assembly causing aeration (cavitation).

That's basically what I meant by frothing.

[NoHaveMSG]

If you line up the dipstick with the top of the dipstick tube you will get a pretty good idea of how far it goes into the engine. The crank is not much larger than the crank pulley. There is room to run more oil if you want, first gen guys have been doing it.

Here's a pic of an FA20, tip of dipstick is marked with an arrow since it is kinda hard to see.

[ZDan]

IMO, RTV partially blocking the oil pickup tube cross-section, or even worse a li'l booger of RTV partially blocking a critical oil passage to a bearing, is a much much worse scenario than dropping oil pressure on some turns. Not saying that's the definitive cause of the failures we're seeing, but critical bearings *never* getting adequate oil supply is obviously a worse case than them occasionally not getting adequate oil supply.

I had my pan and pickup tube inspected, some RTV was indeed found. They removed it and also replaced the screen. Honestly the amount they found doesn't look as bad as other cases I've seen. But my big worry is if there's RTV in an oil passage somewhere...

NJMP Lightning on Monday/Tuesday! I'm running 5w30 synth and will add 1/2 a quart to maybe a quart and hope for the best, fingers crossed...

[Spektyr]

Originally Posted by ZDan

IMO, RTV partially blocking the oil pickup tube cross-section, or even worse a li'l booger of RTV partially blocking a critical oil passage to a bearing, is a much much worse scenario than dropping oil pressure on some turns. Not saying that's the definitive cause of the failures we're seeing, but critical bearings *never* getting adequate oil supply is obviously a worse case than them occasionally not getting adequate oil supply.

I had my pan and pickup tube inspected, some RTV was indeed found. They removed it and also replaced the screen. Honestly the amount they found doesn't look as bad as other cases I've seen. But my big worry is if there's RTV in an oil passage somewhere...

NJMP Lightning on Monday/Tuesday! I'm running 5w30 synth and will add 1/2 a quart to maybe a quart and hope for the best, fingers crossed...

It makes the most sense to me that there is no single smoking gun. It's not the RTV, and it's not the high-speed turns alone. It's things in combination. Certain kinds of RTV blockages that don't cause trouble normally, plus a high speed turn, maybe very slightly low on oil... it all adds up to a motor grenade.

Potentially, all the focus on the RTV is causing a lot of the problems we have with getting the manufacturer to take it seriously because they're certain that alone isn't what's causing the problems. If we keep looking for one cause, and they follow suit, and they can prove to their satisfaction that RTV alone can't be responsible the natural assumption is "user error".

Maybe.

[gcmak]

A pretty comprehensive video covering some real-world testing done.

[NoHaveMSG]

Originally Posted by gcmak

A pretty comprehensive video covering some real-world testing done.

Pretty similar to what I see on my first gen. My car is a bit worse being on super 200 and with aero. I don't have my logging setup working yet. Still can't properly register rpm signal.

[gcmak]

Originally Posted by NoHaveMSG

Pretty similar to what I see on my first gen. My car is a bit worse being on super 200 and with aero. I don't have my logging setup working yet. Still can't properly register rpm signal.

The video includes an FA20 car for reference.

[NoHaveMSG]

Originally Posted by gcmak

The video includes an FA20 car for reference.

I skimmed through the track video the first time. Watched in full at lunch. I do think you guys are right, the FA24 oil system is more prone to surge. I think the best way to track wear though is going to be checking UOA's and seeing if any bearing material is popping up in the oil. It is hard to say what level of surge these will tolerate before it starts really wearing bearings. I do see similar levels in my first gen to your second gen video, but the track I frequent has a lot of elevation changes into turns or during turns. I can't look at the gauge the whole time I am driving obviously, but looking at video I can see the gauge about half the time. I regularly see down into the 30's in long corners. The lowest I have seen is 5psi on a hard elevation transition in the middle of a left right combo.

[autosenses]

So it seems a slight over fill of oil might be beneficial? If so, by how much? 5.5 max fill?

[BioRebel]

So then the issue might be due to the rate at which the pressure recovers when going through left->right complexes.
Does anyone have a picture of an FA20 with the pan removed for comparison?

EDIT: Thanks for putting this together, and like I said in the other thread I'm eagerly awaiting the results. I've been waiting for a good solution to this problem to show up first. Here's hoping this is it.

[FrickingReallySlow]

Originally Posted by Dadhawk

That's basically what I meant by frothing.

FA20/24D has a baffle on the upper oil pan that separates the rotating crankshaft from anything below. We know the capacity of the oil pan itself. Then you just need to add the volume between the lip of the lower oil pan and the baffle plate on the upper oil pan and you know how much oil you can "safely" add without chance of aeration.

But once you start your engine, probably half the oil is already sucked out from the oil pan anyways and into the heads etc so chance are aeration from crank is pretty low.

[Arthur-A]

So that means it can be overfilled by more than 1 quart safely?

[NoHaveMSG]

Originally Posted by BioRebel

So then the issue might be due to the rate at which the pressure recovers when going through left->right complexes.
Does anyone have a picture of an FA20 with the pan removed for comparison?

EDIT: Thanks for putting this together, and like I said in the other thread I'm eagerly awaiting the results. I've been waiting for a good solution to this problem to show up first. Here's hoping this is it.

I'd have to find it but there are pics of the FA20 and FA24 inside the oil pan. The FA24 is slightly different in the way the oil pickup gets oil up into the timing cover and then the oil pump, it's more direct then the FA20. I would also have to find the thread but I believe the upper oil pan is more open to the timing cover. I think KillerBmotorsports had a thread with pictures on it. I don't fully recall.

Edit: I guess I could have just looked at their thread right next to this one

[BioRebel]

Originally Posted by NoHaveMSG

I'd have to find it but there are pics of the FA20 and FA24 inside the oil pan. The FA24 is slightly different in the way the oil pickup gets oil up into the timing cover and then the oil pump, it's more direct then the FA20. I would also have to find the thread but I believe the upper oil pan is more open to the timing cover. I think KillerBmotorsports had a thread with pictures on it. I don't fully recall.

Edit: I guess I could have just looked at their thread right next to this one

Yeah, thats what I wanted to know, if that gap towards the front was present in the FA20. But it sounds like the slope towards the front of the FA24's pan is also a contributing factor.
Maybe Subaru's fix will be an OEM UEL that gives more clearance to the pan lol