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I actually think the boxer engine design while better than VW and P for strength I think the Japanese company missed a few things and allowed an oil consumption flaw in it's design.  Head gaskets being another area as well. 

I think there is some mention of some other boxer engine manufacturer using oil when put under strain. 

Subaru has had problems also with different metals causing electrolysis issues and they have a need to have a really good ground strap for the motor. 

I had heard of this before ..... See this post. 

"

You’re seeing some fairly good answers but they’ve left out a very important factor, the electrolysis issue. This is what Subaru had so much trouble understanding. When a flat engine stops all of the liquids (oil, un-burned fuel, etc.) falls downward. At the intersection of the different metals there at the bottom, along with this fluid mixture electrolysis occurs. To lower this effect Subaru improved the grounding straps, even adding additional one in some cases, to their engines.

This is why with a Subaru you should change the oil at 3,000 to 4,000 miles, your transmission fluid at 30,000 miles and your coolant every 3 years. This is to reduce the conductivity of these liquids. Also on a Subaru keep the ground post of your battery very clean so it has the best contact. So, conduction mixed with dis-similar metals mixed with corrosive chemicals was a problem it took Subaru a long time to understand the physics of in their particular case, it was quite elusive (and they are smart engineers too)."

BTW, some forums on 996 say oil consumption of 1 quart USA per 600miles is acceptable.   I really wonder if the boxer design is the issue and the higher performance and temperatures sometimes on those heads when they stop and the coolant is stationary and hence more cylinder head heat occurs. 

I love the torque of the engine and the driveability and it seems we have to live with the oil consumption.

I have been looking at the numbers for a Subaru EJ25 piston to cylinder wall clearance.

.003" seems to be the number. This seems high to me and could be the source of the excessive oil consumption.

I recall that we used to try for .004" to reduce drag on the pistons. It was expected that with that much clearance, there would be excessive oil consumption and a tiny amount of smoke from the exhaust.

Many new engines only allow .002 to .0025 clearance. I suspect that the Subaru oil consumption may be from this seemingly excessive amount of clearance. It's possible that Subaru discovered a need for this clearance that we are unaware of.

Any one else have an opinion ?    To me, this kind of excessive oil consumption is not acceptable.  Probably Total Seal rings would eliminate the problem. Only problem is....total disassembly to install a set................Bruce

Forged pistons are used for increased reliability at least in turbos and in some NA builds you could inquire of Outfront they used to be called Outback motors. 

I had enquired from LachutePerformance.com and the cost of doing a NA 2.5L was not for the faint of heart and they continued to press to do a turbo as the cost is the same for a much greater output.

Having torn down, literally, hundreds of these motors now I can tell you that aircooleds observation certainly lends itself to the issue, coupled with the fact that the ring grooves have virtually zero tolerance.  What we see most often is the rings are stuck in the ring grooves fully compressed and caked with carbon/oil/sludge build-up.  We actually been able to free some up with a kerosene soak on the engine, with mixed results.  But that's just one of the inherent issues with these motors... There are at least 3 other "unconventional" things we do to the motors to improve longevity and performance, but I can't give away all of my secrets... LOL

I struggle to buy the "flat 4's all do it" argument, or the electrolysis. As Allen said above, Bruce noted, and Carey confirmed-- oil consumption is primarily an engineering and machining issue, and there's no good excuse for it.

I'm more tolerant of stuff like this with Type 1s-- because the design is almost 90 years old, and VW's Sainted German Engineers never designed them to make 180 hp with 94 mm cylinders. The makers of those cylinders just feed a tiny market with what amounts to small-batch runs of imperfectly designed and machined parts. It's up to individual builders to worry about piston clearance, whether or not the rings are gong to get gas-ported, etc. The Type 1 is typically hot-rodded on a tight budget, to within a mm of just flying apart... so there are bound to be issues. It's baked in the cake.

But this thing with the EJ motors (to say nothing of the Porsche M96/97 failures) coming from a mass manufacturer, shady enough to say that a qt/1200 mi is normal, or that there's nothing wrong with an IMS failure at <50k mi is just inexcusable. These are giant companies with huge R/D budgets, who apparently decided that these engine design and manufacturing flaws were good enough for who it's for.

I really can't imagine how this would all be going down if it were Ford or GM we were talking about. Detroit-bashing has reached a point where people don't even think about it, they just kiss the blarney-stone, and move on. It's taken as a matter of faith that German and Japanese cars are "better" by every metric, and that nobody is the world could ever hold a candle to their superior engineering.

There is no perfect platform. 

Last edited by Stan Galat

I just love how nobody responded to my comments about the head gaskets. The Subaru gaskets are junk. Period. There are better gaskets out there that don't disintegrate and leak. 

But that is totally different from the oil consumption issue. I agree with Stan completely, the excess oil consumption is unacceptable. 

Danny, there are some tech shops specializing in Subies that have pretty much licked the head gasket issue using other companies head gaskets.  I read this site below comments years ago and I think they use six star but there are other companies as well. 

I do not think the issue is not as prevalent today but cavitation is a problem if coolant goes from a liquid to vapour it looses it's cooling effect.  Using Evans coolant helps too as it does not go to a gaz state so it can continue to cool the head. 

Others ways to prevent flash heating the heads seem to be to make sure you idle for a bit after a hard run.  The extreme guys have a circuit that runs the aux pump until the temp drops. 

 

https://allwheeldriveauto.com/...-head-gasket-repair/

I'm generally not a blue fan-- but this blue is way better than most others I've seen. I was a little worried with the fist picture, but this shot really brings out the gray in the color, and I like that a lot. I tend to think little-bitty cars look better in serious colors, as opposed to bright hues, but everybody has a different idea. 
 
I know you are set on red for the leather, but I'd (humbly) ask you to consider a nut brown (not tan, but a real brown)-- something similar to what Marty put up last week.
 
If it were mine-- I'd do black leather and never look back... but that's me.
 
You do you, @Lane Anderson.
Last edited by Stan Galat

I know this isn't the proper forum for this Subaru oil consumption issue so here's my last bit of info.  I was looking in at the Subaru specs again today. Besides having nearly double the piston side clearance of a VW the maximum allowable piston ring end gap is .040". The top ring was .010" to .020 as an OK tolerance. The oil rings are are considered within spec at .020" to .030" and no more than .040" ! VW is about .015" to .002" .  With this kind of clearances, no wonder they use oil !  I wonder why Subaru allows such wide open spaces ?...............Bruce

Lane Anderson posted:

I have to admit that I’ve started looking at some darker browns as a possible alternative to oxblood.

I'd encourage you to continue in that vein. Aesthetic choices have to be something you (and not anybody else) love-- but almost every brown compliments the blue where oxblood (depending on how red it is) can very easily fight it for attention (in my opinion).

"Oxblood" is a catchall and can be anything from mahogany to almost brown (with red overtones). IMHO, the more red it is, the worse it would look with blue (which sounds pretty strong, I know). Also, I would factor in that the longer an oxblood leather sits in the sun, the more washed out it will get and the pinker it is going to look (almost always).

Get what you want, Lane-- but you asked for opinions, and there it is.

Last edited by Stan Galat

 

Another thing to consider is that a coupe ain’t a Speedster.

Lighter colors make the interior of a small, closed car feel roomier. I think this is why most headliners are lighter colors.

We went with a light tan interior on our Mini Cooper, and it makes a huge difference (most of them have all black interiors).

For me, Oslo blue over tan really pops.

Just saying.

 

Last edited by Sacto Mitch

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