Worn Camshaft Lobe at 200k miles

[Bimmer Nut Ed]

One lobe looks like the picture below, and the lobe right next to it is a little less worn. The rest of the lobes look like new. Now whats with that. I know it's been a while since I adjusted the valves, not exactly sure how long it's been, but I don't see how this could happen even if the valve adjustment was off a bit. Either the rocker would be loose, and noisy, or if it was too tight wouldn't you burn a valve. Would a too tight condition cause something like this.

I feel that the two lobes at the end of the cam were just oil starved. Could that be the case?

So, it looks like I'll be installing a new cam. Do you guys think it's worth it in a 200k miles m30?

http://crappie.com/1pics/DSCF0011%20%5B800x600%5D.JPG

[Bimmer Nut Ed]

Doh, my own message board, and I don't search it first!

Here's what I found doing a search. By Bill R:
"which lobes are dry and starving for oil and if the banjo bolts that hold the spraybar down are loose then it will also be obvious, if thats the case, the front lobes on the camshaft closest to the radiator are the ones first affected and they will have a noticable groove worn in them..."

So I have to check the banjo bolts. But I do know I replaced the bolts with the new ones. And just now when I try to move the oil bar, it seems solid as a rock. Could the bar be stopped up and the oil not getting through. Something I will certainly check.

[Bimmer Nut Ed]

"Another possibility is a clog in the cam oil sprayer bar. You've been in there to adjust your valves so you most likely saw it and know what it is. As a preventative measure, I'd pull that off and spray brake cleaner through it (wear safety goggles!). Once you're confident it's clean, use a blow gun (wear safety goggles!) and clear out any residual brake cleaner and reinstall."

yep, again, I should really use the search function. doh

Can I drive the car with those grooves in the cam? How long might it last? Now just looking for opinions.

[winfred]

it'll be ok for a while, its fairly common to loose a lobe or two at that mileage on a m30/m20 but not always the same positions from my experience, keep it adjusted and listen for any changes as it wears that may clue you to something bad. my favorite was a 190e turd mercedes motor that we sold years ago, it came back after a while running bad and clattering, pulled the valve cover and it didn't have one lobe left that would lift the rockers more then a bump. those old benz motors could eat valve train components like corn flakes

[Bimmer Nut Ed]

Thanks Winfred. Wifeys response when I told her about the camshaft was "is it ever going to end"! The M3 needs steering end links, the 7's got a check engine, the wheels on all them need changing out for the snows. It's always something.

But you know, when you go out and drive them, I got to say, it's all worth it.

By the way, I rebuilt the tranny on the 7 as you may remember just two months ago or so, and it works great (still). A job well done always makes you feel good.

[Bill R.]

Hi Ed, if the cam is too tight it will cause the lobe to wear, on a squirt or splash system like the m30 cam spray bar it depends on clearance between the parts to allow oil to get in to lubricate. If the valve is tight then no oil can get in between the rocker and the cam since the rocker will scrape it out of the way as it slides along the cam lobe.
If its really too tight then it will burn a valve especially an exhaust valve.
It might just be my old eyes but the picture of that lobe i'm seeing doesn't look bad, the lobe isn't flat and slight scoring is meaningless





One lobe looks like the picture below, and the lobe right next to it is a little less worn. The rest of the lobes look like new. Now whats with that. I know it's been a while since I adjusted the valves, not exactly sure how long it's been, but I don't see how this could happen even if the valve adjustment was off a bit. Either the rocker would be loose, and noisy, or if it was too tight wouldn't you burn a valve. Would a too tight condition cause something like this.

I feel that the two lobes at the end of the cam were just oil starved. Could that be the case?

So, it looks like I'll be installing a new cam. Do you guys think it's worth it in a 200k miles m30?

http://crappie.com/1pics/DSCF0011%20%5B800x600%5D.JPG

[Bimmer Nut Ed]

Thanks Bill. The lobe is scored, and so is the one next to it. It's worn down I'm guessing 1/2 mm. I'll try to measure it. Every single other lobe looks like new, no scoring at all, smooth as a babies bottom.

I'll likely not change the camshaft at this time. I'll adjust it, check and clean the oil spray bar, and just listen for issues as it drives.

I'm wondering if I could enlarge the hole in the spray bar just a tad to get these lobes more oil? I'll take a look see when I have the spray bar off.

[Jeff N.]

ah...the old time crew. :)

That's doesn't look too bad in the picture. Typical of that mileage...

Could you run some wire through the spraybar to make sure there's not some sludge in one part? Might be better than opening up a different sized hole.

Don't some people pinch the middle of the spraybar to ensure oil goes to both ends? I think my Jim Rowe MM bar is like that...would have to check.

[Kibokojoe]

I have a 535i and a 735i and have pinched the spraybar in both of them. May have been to late for the 7. I discovered that the front banjo bolt was lying in the valve train earlier this year. I tried to tighten down the valves as close as I could to reduce the clatter but they still clatter :(. Looks like a head rebuild is in the future but for now my son just turns up his radio.


ah...the old time crew. :)

That's doesn't look too bad in the picture. Typical of that mileage...

Could you run some wire through the spraybar to make sure there's not some sludge in one part? Might be better than opening up a different sized hole.

Don't some people pinch the middle of the spraybar to ensure oil goes to both ends? I think my Jim Rowe MM bar is like that...would have to check.