BMW (finally) publishes S65 Rod Bearing Clearance Specs

[Green-Eggs]

Originally Posted by Assimilator1

I've seen the same specs as you posted in the op on BMW's AIR, their is no clarification of what that con rod play refers to (I could post a screenshot of that if you want, but their is no more info, so not much help).

But going by Paul G's data, whatever BMW's conrod play refers to, it is not rod bearing clearance.
Other people believe it to be something else based on similar data layouts for other BMW engines, I'm not sure what though (I've PM'd one of the to ask).

OK, so here's the takeaway from this: this spec was cited at the BE Wiki with a link to the source. Once questioned as inaccurate, the "BE is evil" cheerleader hailed this as a "mistake." However, as you're now confirming, this wasn't a mistake at all; in fact BE wiki cited it correctly and provided the link (which is now dead). One guy, and hailed by the cheerleader, assumed it refers to rod side clearance. However, rod side-clearance is 10x larger than this value, and neither wanted to admit their mistake in making the wrong assumption.

Now that the link is dead, yes please post the screenshot.

[PaulGros]

Originally Posted by Green-Eggs

OK, so here's the takeaway from this: this spec was cited at the BE Wiki with a link to the source. Once questioned as inaccurate, the "BE is evil" cheerleader hailed this as a "mistake." However, as you're now confirming, this wasn't a mistake at all; in fact BE wiki cited it correctly and provided the link (which is now dead). One guy, and hailed by the cheerleader, assumed it refers to rod side clearance. However, rod side-clearance is 10x larger than this value, and neither wanted to admit their mistake in making the wrong assumption.

Now that the link is dead, yes please post the screenshot.

I don't believe anyone is questioning that the information WAS there (I saw it, but never saved it). What I believe is being questioned is that it related to the bearing clearance. The wording is ambiguous at best, but was taken by some to relate to bearing clearance, yet this wasn't explicitly stated and nor was it clear.

If data is put out there it SHOULD be scrutinised and questioned. Afterall, none of us are perfect and can make an error or misinterpret information.

[PaulGros]

Originally Posted by Assimilator1

I've seen the same specs as you posted in the op on BMW's AIR, their is no clarification of what that con rod play refers to (I could post a screenshot of that if you want, but their is no more info, so not much help).

But going by Paul G's data, whatever BMW's conrod play refers to, it is not rod bearing clearance.
Other people believe it to be something else based on similar data layouts for other BMW engines, I'm not sure what though (I've PM'd one of the to ask).

I remember seeing this and it was far from clear what it related to. As the link is dead I can't revisit and check, but I do remember at the time wondering if they were referring to small end clearance. Basically, it didn't appear to relate to either bearing clearance or rod side play, it was too small for either.

[Assimilator1]

I've attached the screenshot I've got of the rod bearings (and one for mains JFYI).

As I mentioned it's no clearer than the link you had Green eggs.
The person I PM'd earlier thought it is axial play, I've no idea myself.
Dumb of BMW to be so vague!

Originally Posted by Green-Eggs

OK, so here's the takeaway from this: this spec was cited at the BE Wiki with a link to the source. Once questioned as inaccurate, the "BE is evil" cheerleader hailed this as a "mistake." However, as you're now confirming, this wasn't a mistake at all; in fact BE wiki cited it correctly and provided the link (which is now dead). One guy, and hailed by the cheerleader, assumed it refers to rod side clearance. However, rod side-clearance is 10x larger than this value, and neither wanted to admit their mistake in making the wrong assumption.

Now that the link is dead, yes please post the screenshot.

I don't think the numbers were thought to be a mistake, but what the numbers meant, bearing clearance or rod side clearance, or small end clearance??

[PaulGros]

Originally Posted by Assimilator1

I've attached the screenshot I've got of the rod bearings (and one for mains JFYI).

As I mentioned it's no clearer than the link you had Green eggs.
The person I PM'd earlier thought it is axial play, I've no idea myself.
Dumb of BMW to be so vague!


I don't think the numbers were thought to be a mistake, but what the numbers meant, bearing clearance or rod side clearance, or small end clearance??

Personally I would take that as small end clearance as all other data relates to the conrod and not bearings. Your second screen grab specifically mentions bearing clearance for the mains, I would expect the same terminology to be used for conrod bearings.

[omgzirra_exe]

Originally Posted by spammysammich

On this forum. At least 3 in the two years I’ve been part of it. One in Brazil and two in the us. Parse for bore scoring and loss of compression. Any ethanol. I do not believe our fuel systems were meant to be used with ethanol mixed fuel. I hope I’m wrong but the time frame in which these engines were created predates wide spread adoption of ethanol blends.

ive been on full E85 since 2019 lol MMV, for others.

injectors are cheap to replace anyways.. and take less than 2 hours.. so i would chalk it up as a replacement item at 100K if not sooner. but most injector failures come with some type of debris being stuck.

[Assimilator1]

Originally Posted by omgzirra_exe

ive been on full E85 since 2019 lol MMV, for others.

injectors are cheap to replace anyways.. and take less than 2 hours.. so i would chalk it up as a replacement item at 100K if not sooner. but most injector failures come with some type of debris being stuck.

What do you mean by 'debris being stuck'?
Debris in the injector? If so, how do you know this?

[omgzirra_exe]

Originally Posted by Assimilator1

What do you mean by 'debris being stuck'?
Debris in the injector? If so, how do you know this?

usually if you suspect a injector failure, the first thing you should do is get them flow tested, now this doesn't really "dictate" a dirty injector but it can lead you to follow the fuel system and go from there.

the first culprit would be dirty fuel from fuel pump, to then fuel filter not catching the dirty fuel and other jazz.

i actually had a friend who had a fuel injector cause him issues, car basically wouldn't start and if it did it sounded like a rod was thrown.

after inspection, one injector was stuck open, was it because it failed? or dirty? who knows.

[Assimilator1]

Got ya, although the fuel filter will catch any significant debris before it gets to the injectors, unless it's torn or damaged somehow.

[PaulGros]

Originally Posted by Assimilator1

I've attached the screenshot I've got of the rod bearings (and one for mains JFYI).

As I mentioned it's no clearer than the link you had Green eggs.
The person I PM'd earlier thought it is axial play, I've no idea myself.
Dumb of BMW to be so vague!


I don't think the numbers were thought to be a mistake, but what the numbers meant, bearing clearance or rod side clearance, or small end clearance??

Just for info, here is an example of data error from BMW (well in this case BMW MINI). If you look at the wear limit for the mains its a clear typo at 0.700mm

[Green-Eggs]

The first post has S65 data from TIS. Paul's post has tidbits of highly credible, yet unverifiable information about S65 clearance from the original bearing blueprint. Here's a third source for S85 clearance, also from TIS.

Here's what strikes me about this S85 spec: The S85 specs are presented in the same exact order as the "disputed" S65 specs. This tells me that the S65 specs were intended to convey bearing clearance, not something else. However, it also becomes more likely that the S65 version is inaccurate because we know that S65 and S85 share the same crank journal, rods, and bearings. I also notice that these are quite a bit different than what Paul claims are actual BMW specs (0.026mm - 0.062mm).

More muddy waters to wade through.

[PaulGros]

Originally Posted by Green-Eggs

The first post has S65 data from TIS. Paul's post has tidbits of highly credible, yet unverifiable information about S65 clearance from the original bearing blueprint. Here's a third source for S85 clearance, also from TIS.

Here's what strikes me about this S85 spec: The S85 specs are presented in the same exact order as the "disputed" S65 specs. This tells me that the S65 specs were intended to convey bearing clearance, not something else. However, it also becomes more likely that the S65 version is inaccurate because we know that S65 and S85 share the same crank journal, rods, and bearings. I also notice that these are quite a bit different than what Paul claims are actual BMW specs (0.026mm - 0.062mm).

More muddy waters to wade through.

One is production specification from myself. Bert knows where I acquired the information, please feel free to check if the drawing was provided to me and is in my possession - or ask for verification on what I posted.

The second is service information. It's normal for a "wear limit" to be given in this information, hence the higher max clearance.

Far from muddying the waters, this gives clarity on clearances and supports the data I have provided i.e. nominal 0.046mm as per other BMW engines.