All things considered, reliability, etc. which of these 2 engine configs. is better an I-4 or an H-4. Will be car shopping soon and would like to know.
I-4 is easier to work on with less parts to eventually fail. The H-4 has two cylinder heads and everything split for two different sides.
But, this is kinda irrelevant. The real comparison is track record of reliability of the design they use, irregardless of the configuration. Both designs are proven, and with the right maker, shown to be reliable. Subaru has been building H-4 engines for decades with a long track record of reliability. And Honda, Toyota, and Nissan have all designed and built very strong, very reliable 4 cylinders even longer.
With so many factors to consider in a car purchase, I4 vs H4 isn’t that big a deal. If all other factors are equal, I’d go with an I4. Since all other factors aren’t equal don’t worry about it.
Yep, not important. More important is the car around it. Only H4 is a Subaru, so the big question is do you want/need Subaru’s awd, or is front wheel drive enough?
The I-4 is generally easier to service and maintain. The issue with opposed engines is that if a problem develops from the pistons on down this means the engine has to come out and the engine block split.
This automatically means a complete engine overhaul as the crankshaft has to be removed from the block halves, the bearings disturbed, etc.
With an I-4 engine this is not an automatic procedure and any workarounds are far easier if the point in time arrives where an engine must be torn into.
And for some oddball reason, Subaru cylinder heads are far more prone to warping than a conventional I-4 cylinder head even though the Subarus are much shorter. One would think that a stubby in length cylinder head would not warp at all except under extreme circumstances but not so.
Thanks for the input. A Subaru Forester is on my short list and I hadn’t heard about the heads being prone to warping.
Odds are you won’t have a problem with the Subaru. They have had a 30+ years history of head gasket problems and I’ve replaced more Subaru head gaskets than I can even start to remember.
While it’s not often done even by mechanics who should know better, the heads should always be inspected while off and my rough guess is that probably 90% of the heads I’ve checked exceeded the warp limit of .002 of an inch.
A few thousandths of an inch will generally pull back down some with head bolt torque but those in the .005 and up range could be very problematic if not surfaced.
You don’t mention what Subaru you are considering.
If it has the 2.2L(1990-1999) you have no worries. The head gaskets rarely fail and engine is very reliable in general. It has Honda/Toyota like reliability and durability.
2.5L(1996-2004) is not worth considering if reliability is in the sentence.
The recent ones I have no idea as there is no data. Turbo engines from Subaru are reliable.
Just enter the word “Subaru” in this boards Search window and read hundreds of threads started by not-to-happy Subaru owners…
Thats pretty much true of all models
“All things considered”, you want an I4 longitudinally mounted with RWD. That’s the easiest configuration to maintain and repair, much easier than a transversely mounted engine and even more easier than a transversely mounted V6.
That pretty much means a small pickup.
Your post would be more interesting if you were shopping fot an airplane.
FYI, “irregardless” isn’t a word. “Regardless” is a word, and “irrespective” is a word, and they both mean the same thing.
I only wish that car engines were as easy to work on as airplane engines.