[yupetc]

Spring is inside the sprocket in your first picture. Parts 4 and 5 both have coil spring in it. It's a VANOS adjuster unit. Oil pressure goes in and out of that thing by means of valve actuation from the VANOS actuators, it's there to change the timing phase in a backward "retard" movement during higher RPM when engine is under load. Intake and Exhaust sprockets have different degrees of this phase shift angle; I mentioned in some other threads, don't remember the numbers. But if you get a chance to open up this sprocket, you'll find a coil spring under the plastic cover. If you open it further by removing 4 bolts, you'll see the oil chambers and see how the oil can fill the chambers to turn the sprocket. Spring is there to coil it back once the oil is released, back to normal timing when that happens. This isn't new knowledge, you can find more info about this in those N55 PDF's.

[wheela]

Originally Posted by yupetc

Spring is inside the sprocket in your first picture. Parts 4 and 5 both have coil spring in it. It's a VANOS adjuster unit. Oil pressure goes in and out of that thing by means of valve actuation from the VANOS actuators, it's there to change the timing phase in a backward "retard" movement during higher RPM when engine is under load. Intake and Exhaust sprockets have different degrees of this phase shift angle; I mentioned in some other threads, don't remember the numbers. But if you get a chance to open up this sprocket, you'll find a coil spring under the plastic cover. If you open it further by removing 4 bolts, you'll see the oil chambers and see how the oil can fill the chambers to turn the sprocket. Spring is there to coil it back once the oil is released, back to normal timing when that happens. This isn't new knowledge, you can find more info about this in those N55 PDF's.

Thanks for explaining again! I know about vanos and what it does, and that it runs on oil pressure from the vanos solenoids, but I never knew HOW it used oil pressure to advance/retard the valve timing. But everything you explained makes sense I know this picture is from the s55 tech doc, but as it shows the content is the same as n55 and I had this screenshot handy from posting it recently in a different forum.

[Dynamics99]

To clean the cylinder head can I use a brass brush with purple power? I used a plastic scraper and it got decent amount off but there is still carbon/gunk around the valve edge area (not the valves but the big ciruclar area where the valves go). Ive read on LS1tech forum to not use scotch brite.

[TinCanSailor]

Posting this pic of our recently removed rod bearings with 85k miles. Hoping the wear reference can help others trying to decide when to do their bearings.

We do 5k mile oil changes using LM 10-40. It is my daughter’s car and will say that she has driven it hard. She likes to take off quickly and allows the car to sit and idle for long periods of time.

We recently dealt with the OFHG after a belt broke which thankfully did not get ingested at the crank. I’ve dealt with M car rod bearing issues and at 85k miles felt the time was right to change them out.

[yupetc]

Originally Posted by Dynamics99

To clean the cylinder head can I use a brass brush with purple power? I used a plastic scraper and it got decent amount off but there is still carbon/gunk around the valve edge area (not the valves but the big ciruclar area where the valves go). Ive read on LS1tech forum to not use scotch brite.

As long as it's brass brush, you'll be okay, I've done this way too many times and valve seats are still sealed fine as long as you lap the valves well enough.

And on scotch-bright, I think they are referring to the green variant, that you better not use. The blue variant scotch brite will be fine. The packaging will say non-scratch on the blue variants.

[yupetc]

Originally Posted by wheela

Thanks for explaining again! I know about vanos and what it does, and that it runs on oil pressure from the vanos solenoids, but I never knew HOW it used oil pressure to advance/retard the valve timing. But everything you explained makes sense I know this picture is from the s55 tech doc, but as it shows the content is the same as n55 and I had this screenshot handy from posting it recently in a different forum.

Exactomondo, amigo.

[yupetc]

Originally Posted by TinCanSailor

Posting this pic of our recently removed rod bearings with 85k miles. Hoping the wear reference can help others trying to decide when to do their bearings.

We do 5k mile oil changes using LM 10-40. It is my daughter’s car and will say that she has driven it hard. She likes to take off quickly and allows the car to sit and idle for long periods of time.

We recently dealt with the OFHG after a belt broke which thankfully did not get ingested at the crank. I’ve dealt with M car rod bearing issues and at 85k miles felt the time was right to change them out.

That's some babbit wear, and about all she wrote. 85k miles seems soon and judging from the oil you're using, I reckon you're suspecting some oil consumption excessively and having such higher vis oil helps with oil retention and piston sealing? OEM rod bearing gaps are usually on the thinner side, so those aren't really the right oil vis for the bearing gaps unless you've made some aftermarket changes; but from the pics it doesn't look that way because I couldn't identify aftermarket coatings nor some tri-layer manufacturing witness marking. Either way, good to hear you're pulling it sooner than later to observe for excessive wear. As I've mentioned in earlier posts, N55 rod bearings aren't the problem, it's the pre-set of bearing gaps and the oil starvation which will toast the bearings relatively sooner. Playing safe is always better, but no everyone dares a weekend DIY on these bearings on a regular basis. Motor on, folks!

[TinCanSailor]

Originally Posted by yupetc

That's some babbit wear, and about all she wrote. 85k miles seems soon and judging from the oil you're using, I reckon you're suspecting some oil consumption excessively and having such higher vis oil helps with oil retention and piston sealing? OEM rod bearing gaps are usually on the thinner side, so those aren't really the right oil vis for the bearing gaps unless you've made some aftermarket changes; but from the pics it doesn't look that way because I couldn't identify aftermarket coatings nor some tri-layer manufacturing witness marking. Either way, good to hear you're pulling it sooner than later to observe for excessive wear. As I've mentioned in earlier posts, N55 rod bearings aren't the problem, it's the pre-set of bearing gaps and the oil starvation which will toast the bearings relatively sooner. Playing safe is always better, but no everyone dares a weekend DIY on these bearings on a regular basis. Motor on, folks!

I sincerely appreciate the feedback on what ya see.

[Dynamics99]

Okay, I cleaned the cylinder head surface and put it on. I did not torque anything down due to losing the cylinder head washers which are the bigger size of the two. I'm missing four washers and I'm sure they are in the garage somewhere. They are $10 per washer on FCPEuro. Any chance I can go to a hardware store and match it? Not sure what steel grade they are but that's outrageous pricing.

[yupetc]

Originally Posted by Dynamics99

Okay, I cleaned the cylinder head surface and put it on. I did not torque anything down due to losing the cylinder head washers which are the bigger size of the two. I'm missing four washers and I'm sure they are in the garage somewhere. They are $10 per washer on FCPEuro. Any chance I can go to a hardware store and match it? Not sure what steel grade they are but that's outrageous pricing.

I wouldn't risk getting those washers out there, you're not only dealing with material grade, you're looking for an exact dimensional match in metric denomination, too. And they will greatly affect how deep you're torqueing the thread in and how far a span the washer helps to clamp down. I don't know, it it were me, I wouldn't go for alternatives.

Let me look in my garage after work, if it's just a few pieces, I may be able to locate some.

[Dynamics99]

Originally Posted by yupetc

I wouldn't risk getting those washers out there, you're not only dealing with material grade, you're looking for an exact dimensional match in metric denomination, too. And they will greatly affect how deep you're torqueing the thread in and how far a span the washer helps to clamp down. I don't know, it it were me, I wouldn't go for alternatives.

Let me look in my garage after work, if it's just a few pieces, I may be able to locate some.

I'm going to clean my garage tomorrow to find them lol. A bit frustrating when the garage got messy again cleaning and putting the head back on. The crankshaft counterhold tool got delivered though.

[Will_460cs]

Originally Posted by TinCanSailor

Posting this pic of our recently removed rod bearings with 85k miles. Hoping the wear reference can help others trying to decide when to do their bearings.

We do 5k mile oil changes using LM 10-40. It is my daughter’s car and will say that she has driven it hard. She likes to take off quickly and allows the car to sit and idle for long periods of time.

We recently dealt with the OFHG after a belt broke which thankfully did not get ingested at the crank. I’ve dealt with M car rod bearing issues and at 85k miles felt the time was right to change them out.

I f anything I think yours look better than mine I posted on

https://www.e90post.com/forums/showt...572184&page=15

At 69k. one long service based on CBS with BMW. Oil analysis was green.

[yupetc]

Originally Posted by Dynamics99

I'm going to clean my garage tomorrow to find them lol. A bit frustrating when the garage got messy again cleaning and putting the head back on. The crankshaft counterhold tool got delivered though.

I found 3 of those bigger washers. So if you need any from me, just PM me. I'll be happy to help. I also have 3 smaller washers in case you need those, too.

[Dynamics99]

Originally Posted by yupetc

I found 3 of those bigger washers. So if you need any from me, just PM me. I'll be happy to help. I also have 3 smaller washers in case you need those, too.

Sent PM

[Dynamics99]

So, I got the cylinder head torqued away. Working on the oil pump and retrofitting the m3 oiling system. Ran into a fitment issue on the chain guide. Since I have an older style leaf spring tensioner the diameter will need to be enlarged to fit the S55 oil pump since the later chain tensioner with the hydraulic plunger has cat ears to fit the n55 or s55 oil pump veins. So I have grinded away some material and need to work on clearing those veins. Another forum member had done the same thing but no pictures were posted. I will keep test fitting after removing material little by little to ensure a tight and secure fit for the gear and the e-torx screws.