[Boostedphil698]

I see a lot of guys on the N55 group pages on FB spinning rods on tuned N55's. I'm starting to question whether these engines can handle a tune or even PS2. Some guys spin them on 5w-40, but it really makes no sense at the end of the day. Thoughts anyone? Just want to hear some thoughts.

[Munchi435i]

Originally Posted by 435i_Phil

I see a lot of guys on the N55 group pages on FB spinning rods on tuned N55's. I'm starting to question whether these engines can handle a tune or even PS2. Some guys spin them on 5w-40, but it really makes no sense at the end of the day. Thoughts anyone? Just want to hear some thoughts.

First I'm hearing about "a lot" of reports about spun rod bearings on the N55.

Have you reached out to those individuals your taking about? I feel they would give you better insight since it happened to them. Ask them what mods they have and how aggressive they drive etc..

[F32Fleet]

What reports?

[5w20]

flame maps and burble tunes? lol

[Poochie]

Please humor us and just share some info on just one guy, with a spun crank hub, specifically on an N55 motor..

I would like to meet him; I'm sure he also has the original photos of Bigfoot riding a unicorn..

[Munchi435i]

the only mention upon some light research on "N55 spun rods" is with the E9x model years.

Post some links to what you consider "a lot" of spun rods or screenshots of the posts you're referring to

[imperfectluck]

435i_Phil you have to give us some concrete proof to elaborate on "some guys" for us to give our thoughts on.

[theEZV]

Originally Posted by 435i_Phil

I see a lot of guys on the N55 group pages on FB spinning rods on tuned N55's. I'm starting to question whether these engines can handle a tune or even PS2. Some guys spin them on 5w-40, but it really makes no sense at the end of the day. Thoughts anyone? Just want to hear some thoughts.

I see a lot of guys on the FB group pages talking about how the Earth is flat, so....

There have been a few posts/threads on N55 road bearings over the last few years, but considering the amount of stock/tuned cars that have passed through, they are few and far between. Apparently the 2014+ cars have the same bearings as the S55 and those guys are pushing 500whp+ with a simple "stage 1" tune, and we haven't heard anything on the rod bearings from them.

[Boostedphil698]

I'm not going to list every person who has spun a rod in the N55 group on fb but it's at least 1 post a day.

[perryo91]

Originally Posted by 435i_Phil

I'm not going to list every person who has spun a rod in the N55 group on fb but it's at least 1 post a day.

So anecdotal... why make such a click-baity title if you can't provide any evidence. joker

[Marlinman]

First off I don't think you can spin a rod. You either "throw a rod" or spin a rod bearing. Also, I'm on FB n55/tuned n55/bmw groups/racing bmw groups pretty regularly (many times per day), and there really aren't guys/gals posting that spin motor components every single day. It seems more common on there because of yahoos that buy a shit car and shit maintenance and don't change oil, tune it and send it that usually spin a bearing or throw a rod. Having said that, it isn't very common on the N55 and is much less common than other bmw motors (s65 or N20).

[zole2112]

Originally Posted by theEZV

I see a lot of guys on the FB group pages talking about how the Earth is flat, so....

There have been a few posts/threads on N55 road bearings over the last few years, but considering the amount of stock/tuned cars that have passed through, they are few and far between. Apparently the 2014+ cars have the same bearings as the S55 and those guys are pushing 500whp+ with a simple "stage 1" tune, and we haven't heard anything on the rod bearings from them.

Originally Posted by Marlinman

First off I don't think you can spin a rod. You either "throw a rod" or spin a rod bearing. Also, I'm on FB n55/tuned n55/bmw groups/racing bmw groups pretty regularly (many times per day), and there really aren't guys/gals posting that spin motor components every single day. It seems more common on there because of yahoos that buy a shit car and shit maintenance and don't change oil, tune it and send it that usually spin a bearing or throw a rod. Having said that, it isn't very common on the N55 and is much less common than other bmw motors (s65 or N20).

What Marlinman said! Lot's of yahoos on facebook, just saying.

[thejeremyman9]

Originally Posted by Marlinman

First off I don't think you can spin a rod. You either "throw a rod" or spin a rod bearing. Also, I'm on FB n55/tuned n55/bmw groups/racing bmw groups pretty regularly (many times per day), and there really aren't guys/gals posting that spin motor components every single day. It seems more common on there because of yahoos that buy a shit car and shit maintenance and don't change oil, tune it and send it that usually spin a bearing or throw a rod. Having said that, it isn't very common on the N55 and is much less common than other bmw motors (s65 or N20).

Lol, so accurate regarding the FB groups. The FB groups are so childish compared to the forums. I am not on the BMW ones but i am on 3000gt ones for my other car and its exactly the same story. People buy a used car with no service history, go romp on it, spin a bearing, and then part the car out. It's sad really.

[Boostedphil698]

I was really just asking for people's thoughts. I wasn't trying to post "clickbait."

[Jvac]

Originally Posted by 435i_Phil

I was really just asking for people's thoughts. I wasn't trying to post "clickbait."

Been reading this forum regularly for 2 years. I consider it a fantastic repository of information about our platform. Many members are experienced mechanics and/or tuners and I can't say I recall any discussions that involved the issue you are referring that didn’t involve some high mileage, multi-owner car that's being pushed too far above stock and has a sketchy maintenance history. In other words there was more to the story than the poster cared to acknowledge. If this 'spun rod' was a common issue on property maintained f30s I think you'd be seeing more threads about it.

[thejeremyman9]

Originally Posted by Jvac

Been reading this forum regularly for 2 years. I consider it a fantastic repository of information about our platform. Many members are experienced mechanics and/or tuners and I can't say I recall any discussions that involved the issue you are referring that didn’t involve some high mileage, multi-owner car that's being pushed too far above stock and has a sketchy maintenance history. In other words there was more to the story than the poster cared to acknowledge. If this 'spun rod' was a common issue on property maintained f30s I think you'd be seeing more threads about it.

I am of the same school of thought as this. More often the not, the forums reflect the bad more than the good, so if there is a common problem it's all over the forums.

I have really only heard of spun bearings on N55 when people oil starve, money shift, etc.

[Boostedphil698]

Originally Posted by thejeremyman9

I am of the same school of thought as this. More often the not, the forums reflect the bad more than the good, so if there is a common problem it's all over the forums.

I have really only heard of spun bearings on N55 when people oil starve, money shift, etc.

I'm probably not getting the full story from the posters, like everyone has stated.

[Poochie]

Originally Posted by 435i_Phil

I was really just asking for people's thoughts. I wasn't trying to post "clickbait."

The N54/N55 has the same bolt, sprockets and friction plates, as every other BMW but it does not push enough power to spin the crank hub.

On the other hand, it literally happens every other day, on the S55, since it contains the identical part(s), as the lower output motors but pushing higher level of power.

Your typical N55, even tuned, doesn't overwhelm the crank hub bolt and plates to be an issue, as it is on the S55.

[AmuroRay]

I think crank and block harmonics play a role. The Forged crank my flex less, transmitting more of those harmonics to the block and crank hub.

Just a guess.

[VAF30]

Originally Posted by 435i_Phil

I'm not going to list every person who has spun a rod in the N55 group on fb but it's at least 1 post a day.

So Im on about every N55 group on FB and I dont recall seeing the last one? In fact in two years I can think of two and those were grenade motors that probably had different issues... LMAO .. one a day...

[XutvJet]

There are many cases of earlier N55s spinning rod bearings.

Beginning in the 2014 model year, BMW introduced the S55. In that same model year, BMW also started using the S55's rod bearings and forged rods in all N55s. It's pretty rare to hear of a 2014+ N55 spin a rod bearing. I've had read of a few cases, but it seems no more common than any motor and most of those cases are in more modified N55s. When you play with fire, expect to get burned. I'm speculating here, but the S55 rod bearings are likely more robust given the stock power levels of the S55 and it's ability to rev to 7700 rpms. Also, all F3X series 2014+ N55s began running superior electronic wastegates (EWGs) and larger turbos.

Rod bearings often spin because the piston gets hammered really hard during a predetonation event and that hammering drives the piston and rod hammer straight through the oil film between the rod bearing and crank. It could possibly be that since EWG's are better at controlling over-boost, which can lead to predetonation under high load situations, this improved over-boost control reduces the chances of a spun rod bearing. Of course in modified cars, that control and threshold narrows.

Just my theories.

[Boostedphil698]

Originally Posted by XutvJet

There are many cases of earlier N55s spinning rod bearings.

Beginning in the 2014 model year, BMW introduced the S55. In that same model year, BMW also started using the S55's rod bearings and forged rods in all N55s. It's pretty rare to hear of a 2014+ N55 spin a rod bearing. I've had read of a few cases, but it seems no more common than any motor and most of those cases are in more modified N55s. When you play with fire, expect to get burned. I'm speculating here, but the S55 rod bearings are likely more robust given the stock power levels of the S55 and it's ability to rev to 7700 rpms. Also, all F3X series 2014+ N55s began running superior electronic wastegates (EWGs) and larger turbos.

Rod bearings often spin because the piston gets hammered really hard during a predetonation event and that hammering drives the piston and rod hammer straight through the oil film between the rod bearing and crank. It could possibly be that since EWG's are better at controlling over-boost, which can lead to predetonation under high load situations, this improved over-boost control reduces the chances of a spun rod bearing. Of course in modified cars, that control and threshold narrows.

Just my theories.

I know about the bearing revision but I don't think the N55 has forged rods unless it's been confirmed. The N55 in the M2 has a forged rotating assembly I know that.