Go Bottom

Subaru Boxer Engine Pros Cons

View my Photos
DennisCTB
Join Date: Nov 1998
Posts: 2707 NorthWest NJ
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2008-02-12          151270


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)?



Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



Subaru Boxer Engine Pros Cons

View my Photos
kwschumm
Join Date: Feb 2003
Posts: 5764 NW Oregon
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2008-02-12          151273


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.
....


Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



Subaru Boxer Engine Pros Cons

View my Photos
Murf
Join Date: Dec 1999
Posts: 7249 Toronto Area, Ontario, Canada
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2008-02-12          151275


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. ....


Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



Subaru Boxer Engine Pros Cons

View my Photos
kwschumm
Join Date: Feb 2003
Posts: 5764 NW Oregon
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2008-02-12          151276


Quote:
Originally Posted by Murf | view 151275
As for the timing chain, that's another controversy, I'd rather have a belt than a chain.Best of luck.


Why is that? The belt is quieter but beyond that I see only disadvantages. ....


Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



Subaru Boxer Engine Pros Cons

View my Photos
Murf
Join Date: Dec 1999
Posts: 7249 Toronto Area, Ontario, Canada
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2008-02-12          151277


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. ....


Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



Subaru Boxer Engine Pros Cons

View my Photos
kwschumm
Join Date: Feb 2003
Posts: 5764 NW Oregon
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2008-02-12          151285


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? ....


Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



Subaru Boxer Engine Pros Cons

View my Photos
cutter
Join Date: Feb 2000
Posts: 1307 The South Shore of Lake Ontario, New York
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2008-02-12          151287


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 :) ....


Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



Subaru Boxer Engine Pros Cons

View my Photos
cutter
Join Date: Feb 2000
Posts: 1307 The South Shore of Lake Ontario, New York
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2008-02-12          151289


I forgot to mention, that car "feels" like it has two more cylinders than it actually does.

....


Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



Subaru Boxer Engine Pros Cons

View my Photos
Murf
Join Date: Dec 1999
Posts: 7249 Toronto Area, Ontario, Canada
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2008-02-13          151303


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. ....


Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



Subaru Boxer Engine Pros Cons

View my Photos
kwschumm
Join Date: Feb 2003
Posts: 5764 NW Oregon
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2008-02-13          151307


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. ....


Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



Subaru Boxer Engine Pros Cons

View my Photos
Murf
Join Date: Dec 1999
Posts: 7249 Toronto Area, Ontario, Canada
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2008-02-13          151311


Ken, I honestly believe it's a combination of legalez and a fear thing.

A lot of auto companies got stung really badly by timing belts. At first they weren't specifying them as a 'wear item' and so it was under warranty, so was all the other parts that got munched up when they broke!!!

The interesting part is that almost every timing belt out there is made by the same company these days, so we can assume they are all made to the same standards and with similar materials, etc., however, depending on what it goes into, it is scheduled to be replaced at between 30k miles (yes 30, Volksy diesels and some small Ford gas engines) and
about 100k miles.

So the way it works is, the car companies gamble that more people will give them $$$ from belt changes, than will make warranty claims if they let go before scheduled replacement points.

However, a friend of mine has a fleet of compact pickups and cars, he NEVER changes the timing belts at recommended points. He says only about 1 in 25 of them ever go before he gets rid of the vehicle at about 300k kms (180k miles). His drivers are not gentle on the vehicles.

Sounds like a case of over-caution to me.

BTW, the Subaru engines are about 50/50 interference design and non-interference.

Best of luck. ....


Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



Subaru Boxer Engine Pros Cons

View my Photos
kwschumm
Join Date: Feb 2003
Posts: 5764 NW Oregon
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2008-02-13          151325


Thanks Murf. I'm not too worried about belts, since many of our vehicles have had them, but still prefer a chain. Maybe it's all in my head. I've had chain issues too, an old Opel wore through the chain tensioner every 50k miles or so and fixing that was every bit as bad as changing a belt. Still, the chains give me a warmer, fuzzier feeling. ....


Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



Subaru Boxer Engine Pros Cons

View my Photos
phxmotor
Join Date: Feb 2012
Posts: 2 Pinecrest CA
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2012-02-20          182470


Subaru made noninterference engines only before 1997. All 2.5s since they 1st appeared in 1995 have been interference. 2.2's and smaller have always been noninterference, until 1997. In that year even the 2.2's became interference.

As far as reliability, these engines easily last 300k, Twice that many if things are fixed as they wear. They are on par with the best Hondas and Toyota powerplants.

As far as chains vs belts; You can now have your warm&fuzzy feeling because brand new Subarus have chains. Their 6 cyl engines have had chains for many years. Just dont expect 30-35mpg. These vehocles are more a tool than a fasion staement. All awd Subarus are more akin to a Jeep in practicalty.

Their wonderful driving characteristics are just a bonus. I believe the move to chains will prove to be wonderful if the head gaskets stay intact. If not, be prepared for a once commonplace (almost universal) head gasket replacement. If it does happen dont be surprized. It is quite normal even after the factory has claimed one supposed fix ater another. If you do buy one just be prepared for a simple and always sucessful head gasket job. Ease of head gasket replacement is one of Subaru's strong points.$300 if you do it yourself, 13-2300 if a shop does it.

As far as block reliability, the 4 cyl truely feels like a 6 cyl and it will last indefinatly as long as it is never run without oil. Rod and mail bearings never ware out unless they run out (or very low) on oil. If they do develope bad bearings, the bottom end of the engine can not be repaired. In therory yes, in reality, no. Head gaskets and waterpumps are eminantly fixable, but a bad bottom end makes the short block a throwaway.

But as far as "Citroen like" high quality engineering and quirkyness Subaru engines are among the most logical, reliable, and long-living machines ever built. The definative proof is this: google 'airplane engines subaru'. The $20-$30k engines are often made with 4 and 5 year old engines with verified low hours. To have this style of engine available in an affordable car (especially coupled with awd) is a real treat. ....


Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



Subaru Boxer Engine Pros Cons

View my Photos
auerbach
Join Date: Sep 2007
Posts: 2168 West of Toronto
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2012-02-20          182474


That configuration is a bit more costly to build, which explains its unpopularity. As to longevity, Consumer Reports lists owner-reported repairs for all Subaru engines as "much better than average" (its highest rating). So even if it IS an interference layout, you needn't worry.

True: When mine was rear-ended a friend took the engine for his home-built aircraft. ....


Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



Subaru Boxer Engine Pros Cons

View my Photos
Murf
Join Date: Dec 1999
Posts: 7249 Toronto Area, Ontario, Canada
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2012-02-21          182481


The use of a Subaru engine in an aircraft has very little to do with dependability, reputation or quality.

It is the only widely available, currently produced, horizontally opposed engine.



Best of luck. ....


Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



Subaru Boxer Engine Pros Cons

View my Photos
DRankin
Join Date: Jan 2000
Posts: 5116 Northern Nevada
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2012-03-04          182626


ok.

Somebody tell me what an interference engine is.... ....


Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



Subaru Boxer Engine Pros Cons

View my Photos
kwschumm
Join Date: Feb 2003
Posts: 5764 NW Oregon
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2012-03-04          182627


Quote:
Originally Posted by DRankin | view 182626
ok. Somebody tell me what an interference engine is....


If valves can hit the piston when the valve timing is off (like when a timing belt breaks) it's an interference engine.
....


Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



Subaru Boxer Engine Pros Cons

View my Photos
hardwood
Join Date: Dec 2002
Posts: 3583 iowa
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2012-03-04          182628


My Brother in law had a Suburau, I don't know what year, model, etc., but any way after the warranty the head gasket, (gaskets), went bad. He was persistent in his request, (requests), till they agreed to replace them.
Then for some reason the replacment gasket, (gaskets), went bad again about a soon as he drove it home, the folks at Subarau didn't want to discuss it. I don't know what he did with it but it dissapeared soon after and he got a different brand.

Frank. ....


Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



Subaru Boxer Engine Pros Cons

View my Photos
DRankin
Join Date: Jan 2000
Posts: 5116 Northern Nevada
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2012-03-04          182633


Many thanks, Ken.

We had a 1982 Suby purchased new in Anchorage. That car/engine combo was nothing short of amazing. I once drove it in snow so deep the snow flowed onto the hood and broke like a wave around the windshield.

Once, when my 5000+ pound van broke down, the Subaru pulled it home 4 miles with a tow strap. This was on a -0 morning and up a steep ice covered highway.

When we wore it out we bought a Justy. Not even the same car............ ....


Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



Subaru Boxer Engine Pros Cons

View my Photos
kwschumm
Join Date: Feb 2003
Posts: 5764 NW Oregon
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2012-03-04          182634


Nice to see you on here again Mark.

It's funny, I drive a 4WD Tacoma and my wife drives an 07 Subaru Impreza. In snow the Impreza is amazing, the Tacoma not so much. Even in 4WD with studded snow tires and a few hundred pounds of sand in the bed the Tacoma isn't even close. Now if the Impreza had more ground clearance it would be perfect. In the next year or so Subaru is supposed to come out with a new Impreza version called the XV Crosstrek with much more ground clearance and we may trade the old one in for one of those.
....


Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



Subaru Boxer Engine Pros Cons

View my Photos
DennisCTB
Join Date: Nov 1998
Posts: 2707 NorthWest NJ
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2014-09-09          191054


I just bought the 2014 Crosstrek please read my review

http://tractorpoint.com/forum/subaru-autos/191056/1/2014-Subaru-Crosstrek-Review.html ....


Link:   2014 Subaru Crosstrek Review

 

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



Subaru Boxer Engine Pros Cons

View my Photos
chuckles
Join Date: Jul 2003
Posts: 88 Eastern PA
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2014-12-11          191602


Couple more things on the Subaru Boxer now with the ultra thin oil 0W20 weight they had some oil consumption issues. Also some head gasket and ring issues on the 2013 Impreza, supposedly resolved in 2014 models.

If you need to do a valve job the engine has to be removed on Boxer style blocks.

I think the low center of the engine does help with stellar crash ratings.

These are high revving fun engines though! ....


Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo


   Go Top


Share This







Member Login