DIY - V8 or I6?

[ncfitton]

I am looking for advice on whether the V8 or the in-line 6 turbo is easier for a home mechanic to maintain. Main criteria are ease of work, availability of parts, price of parts. Thanks for your input.

[Pig Farmer]

From my experience, the S65 V8 requires less maintenance when compared to the N54 I6. I can’t comment on the N55 or BMW’s newer I6 engines. Both engines have their own issues, but the S65 fairly bullet proof aside from the throttle actuators, Idle Control Valve, and rod bearings. The N54 is plagued with the high pressure fuel pump, electric water pump, charge pipe failure, vacuum leaks, and carbon build-up. The N54 produced amazing power some days, and felt lethargic other days. It was complete hit or miss. The S65 is very consistent day-to-day and much less finicky. Other than the oil change kit, the cost of parts and fluids are basically the same.

[Yoko22R]

Originally Posted by Pig Farmer

From my experience, the S65 V8 requires less maintenance when compared to the N54 I6. I can’t comment on the N55 or BMW’s newer I6 engines. Both engines have their own issues, but the S65 fairly bullet proof aside from the throttle actuators, Idle Control Valve, and rod bearings. The N54 is plagued with the high pressure fuel pump, electric water pump, charge pipe failure, vacuum leaks, and carbon build-up. The N54 produced amazing power some days, and felt lethargic other days. It was complete hit or miss. The S65 is very consistent day-to-day and much less finicky. Other than the oil change kit, the cost of parts and fluids are basically the same.

Having owned both the n54 and presently the s65, this description definitely hits the nail on the head.

[roastbeef]

natural aspiration is just less complicated.

[rcracin]

Originally Posted by roastbeef

natural aspiration is just less complicated.

Yup, turbo cars by virtue will always be more complicated because they have more parts. More parts = more potential failures.

[pbonsalb]

I have had both an N54 and an S65 for the past 9 years and done all the work on them since 2014 when the CPO warranties expired. I like them both a lot. I tend to do a lot of preventative maintenance, whereas others wait until something breaks. I would say both have been very reliable. There is a set of known issues for both. Take care of them or make sure they have been taken care of by a PO and you should have few surprises. With 146k on the N54, I plan to do the turbos soon. I consider that to be comparable to the rod bearing change I did on the S65 at 60k in terms of complexity and time. The S65 has the usual bolt on mods and the N54 has only a JB4. The S65 is faster but mine is a 6MT and you have to work it to extract the maximum performance. A DCT would be way easier. The N54 is auto, which works great with the turbo.

I’d say any BMW motor from the last 10 years will be complex to maintain long term. The easiest would probably be something like a naturally aspirated N52 with a manual trans. Not sure when the last of those were made, maybe around 2010. But an N54 or S65 is so much faster. I like power so I’ll pay extra and do more work to have it.

[ncfitton]

Thanks to everybody for your input so far. This helps me a lot and is much appreciated.

[tdott]

I would agree that I prefer to work on an S65 over a S54 or N54.

[Bimmer Barney]

I've had N54 and S65 and I do all my own maintenance and repairs.

S65 costs me about $800 more per year to maintain but is much easier and much more reliable and than my N54.

[Richbot]

I've owned a couple of M52 cars, a couple N54's, an N55 and this S65 thing. THe S65 has been the least troublesome of all of them. And very easy to repair and diagnose so far. My M3 is 25,000 miles away from being the highest-mileage BMW I've ever owned - now at 125k. My E36 got to 150k before I sold it, the rest were all double-digits when sold. All gave me a lot more issues than this car has.

The NA N-series engines may be the biggest nightmare of all - none of the performance, most of the complexity of the turbo engines just with new and exciting failure modes

[pbonsalb]

I am at 146k on my N54 and 101k on my S65. Both are more complex than my S52, but I had that motor fully built and put a turbo on it to make it as complex as a newer motor.

[Scrippy]

I have both and the V8 is waaaaay less finicky IMO. I maintain my cars well but the turbos still went out in my 335 leading me to rebuild and replace. Both engines are basically 10lbs of shit in 5lbs bags, space is very tight. I find it easier to do things on the V8 but the price of ///M goodies is higher so pick your poison. I will say that you can achieve higher numbers for less cash with the N54 though. I like the smoothness of the turb6 but prefer the rough noise and power the S65 offers. In summary the N54/N55's are stressed trying to do what the V8 just does. Heat soak is very prevalent in the turbo 6 setups. Your first mods should be intercooler and oil cooling, then go wild.

[Denny347]

I cannot compare turbo to NA, I came from my N52 330i to my S65 but as a guy who does his own repairs, I can say that the N52 was pretty cake to work on and so far, so has the S65. Granted I've only changed out the plugs, t-stat, and alternator on the S65. I changed the VCG, OFG, PCV system, serpentine belt/tensioner, plugs, coils, on the N52. None of it was complicated. I've always liked the simplicity of NA engines.

[Scrippy]

Own a S65 & N54. They are the same.....10lbs of shit in a 5lb bag! No room anywhere and you have to disassemble 6 things to get to the one issue lol. Replaced my turbos and all lines/gaskets without removing subframe. That'd be the worst for N54 I suppose. The S65 has things like TA's or idle control valve failures but those are easy fixes. Like I said....booth motors ask you to completely undress them just to look in their mouth, so flip a coin if you don't already understand the M3 is what you want.