ncsugrad2006

Long story short, I am rebuilding an N62B44 for my 545i. The engine I bought out of a junk yard, and once I got into it I found someone had been through the heads before I got it.. (the whole story is a LOT longer, but anyways)

Straight to the point.. The N62 engines have different "tolerance classes" for their rocker arms. Is there a way to figure out which "tolerance class" is supposed to be used for each rocker arm in the N62B44 (545i) engine? All the manuals just say to make sure to put them back in the same spot, which is fine and dandy, but I wanted to see if there is any way to actually check and make sure they are right. In my case I want to be sure an idiot mechanic didn't put them in the wrong spots prior to me getting these heads.

I can't find anything on it online.. Does an entire head have the same "class" or are they all mixed up? On these heads they are all either 2 or 4 I noticed (clarification: each head has both class "2" and class "4" rocker arms). I have them separated out how they came out, so I can put them back in how they came out. Would like to check them though if possible.

BMW also calls them "roller drag levers" FYI

Here is how they were arranged in mine--works out to most likely 16 of each (2 and 4). I had one I couldn't find a number on, will look closer later. I am going to check my "old" heads to see if they have multiple classes per head or not tomorrow.

ncsugrad2006

I'm guessing no one knows then..?

I had a few messages with a BMW master tech on another forum this morning that at least made me feel a little better.

He stated that on the N52 engine (valvetronic) they regularly replace the lifters due to some sort of issue (ticking maybe? not sure). When they do that, they used to have to order specific tolerance class rocker arms to replace exactly what came out of the car, but now when they order the replacement parts BMW does not even ask which classes they need, so ultimately it seems that they don't matter. They just put one class back in the whole engine.

I would assume they mean SOMETHING, but maybe it's just an over engineered thing like usual

Burim87

I am having the same issue basicly, how did the assembly work out for you, i noticed on real oem rocker arms 4 are 42 gram in weight and 1, 2 , 2A, 2B and 3 are all 41 grams some are connected to the VVT system but the amount doesn't add upp with 4 of 4's on each cam so it's hard to tell wich ones should be in place on the springs that are on the cams driven by VVT motor