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Subaru Boxer Engine Pros Cons
I just visited the Subaru site and looked at the way they build their Boxer engine. What are the pros and cons of this design? And if it is such a good idea why don't other manufacturerss do likewise (patented, how long has Subaru been doing this)?
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Subaru Boxer Engine Pros Cons
I don't think they have a patent, Porsche and Ferrari (among others) have both sold boxer engines.
My relatively uninformed opinion follows.
Pros: (pretty much off the Subaru web site)
Low CG
Better engine balance
Less intrusion into passenger compartment in crash
Cons:
More difficult to uniformly lubricate cylinder walls
Difficult to fit engine and suspension in the same space
I wonder if they will last as long as a more upright design
as the miles accumulate due to lubrication issues.
In the Subaru implementation they should have used a timing
chain instead of a belt.
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Subaru Boxer Engine Pros Cons
From a mechanical point of view, the biggest advantage other than those listed, is the lack of vibration.
The boxer configuration means each pair of cylinders balance each other, as one moves so does its mate, balancing each other out.
As for the timing chain, that's another controversy, I'd rather have a belt than a chain.
Best of luck.
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Subaru Boxer Engine Pros Cons
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As for the timing chain, that's another controversy, I'd rather have a belt than a chain.Best of luck.
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Why is that? The belt is quieter but beyond that I see only disadvantages.
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Subaru Boxer Engine Pros Cons
Any time you have a moving (especially turning) part in an engine it needs to be balanced, and the more it weighs the more work it is to get it balanced.
A timing chain weighs a lot more than a belt, so it is more parasitic losses due to imbalance and extra weight to turn it.
A belt or chain is a wear item, it only has a limited life span and will need to be changed, granted the chain has a longer life, but I would rather change the belt and know it's fine then wait for the chain to hand grenade the engine.
Best of luck.
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Subaru Boxer Engine Pros Cons
Good arguments Murf.
You haven't convinced me, but good arguments nonetheless.
I'm an advocate of changing the timing chain with every valve job  and exchanging strength for marginally better balance in this application doesn't seem like a good trade to me.
But belts work fine, they're just a PIA/expensive to change. If all engines with belts were non-interference I'd feel a little better about them.
Anyone know if the Subaru is an interference engine?
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Subaru Boxer Engine Pros Cons
There have been plenty of auto builders over the years utilizing the boxer engine. VW is one that comes to mind immediately, I froze in one just like everyone else up north
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Subaru Boxer Engine Pros Cons
I forgot to mention, that car "feels" like it has two more cylinders than it actually does.
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Subaru Boxer Engine Pros Cons
Ken, I hear what you're saying, but with todays modern materials the belts are far stronger than they need to be.
Bear in mind though, a chain is only 'supposed' to have the same life expectancy as a belt. It's just people don't worry about chains. Early belts gave the concept a bad rap because of breakage or skipping teeth on a bad backfire and then causing the 'interference' part to rear it's ugly head.
Best of luck.
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Subaru Boxer Engine Pros Cons
Murf, if what you're saying is correct then you have to wonder why manufacturers continue to specify a 75k-100k maintenance item to change the timing belts. I've never heard of a maintenance item for chain replacement but I agree that changing one when the mileage is >100k and the engine is otherwise going repairs (water pump, front seal, heads off, etc) would be a good idea.
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