Cam Wear?

[Santawillis]

Hello,

 

After getting the car running again, electics sorted, and a few shakedown runs I am finally adjusting my valve lash! After a quick look in the valve cover, it did become apparent that my cams are "blemished", for lack of a better term. 

 

Should I begin saving for some new cams? Am I worried for absolutely no reason? 

 

Appreciate you all, happy that the weather is finally turning back into spring for us up North after 4th winter.

[Mike Self]

Is this an OEM BMW cam, or a quality aftermarket like Schrick or Alpina?  Or is it a re-grind?  Hardening quality on regrinds can be chancy, but OEM and good aftermarket cams should be good for a long time, presuming good oil pressure and no oil starvation to the head.  M30 engines (basically an M10 with two more cylinders) have a reputation for worn cams, but I've never seen a good explanation as to why.  M10s, on the other hand seem to have very long-lived cams.

 

Can you feel wear with your fingernail between the portion of the cam lobe that's wiped by the rocker arm pad and the un-wiped section?  If you can't, the wear probably isn't enough to worry about.  If there's galling (pitting) that could be from a number of causes--bad oil, oil starvation, poor cam lobe heat treating etc.

 

mike

 

PS--when adjusting your valves, check the adjuster disks for flat spots.  They do that...and you can buy oversize adjusters if you run out of adjustment.  

[Son of Marty]

I'd stock pile a new cam and rockers, the black spots in the enlarged photo are the back side of the hardening and at some point it will wear through and the lobe will go flat shortly there after. Only run a high zinc motor oil and never run the same rockers on the new cam they will have bits of the hardening stuck on the faces and ruin your new cam.

[Santawillis]

@Mike Self and @Son of Marty finger nail does not catch on anything on the cam itself, unfortunately I have no history on the car and what cam they used on their top end rebuild. Car sat for unknown period of time and I have been slowly getting it back on the road.  I have been running Liqui Moly classic 20W50 for the first two oil changes. Blackstone oil results have given me a good amount of zinc but not sure if it's sufficient. 

 

Thanks for the advice on the valve lash adjustment Mike!!!

 

 

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BMW 20W50 Oil Change Kit - 11421258038KT1 | FCP Euro

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BMW 20W50 Oil Change Kit - 11421258038KT1

 

Rafael

76 2002-240303 (1).pdf

[tech71]

3 hours ago, Santawillis said:

Should I begin saving for some new cams? Am I worried for absolutely no reason?

How does it run?

Pretty much have to remove the head  to get new rockers installed so if it runs ok I would drive it a bit before making any decisions.

Your oil sample is not great, did you follow labs recommendations on a new air filter and close inspection of the cooling system? A pressure test might be a good idea. Relatively high levels of lead and copper as well.

Whats the engine compression? May want to start saving for a fresh engine, makes no sense(false economy) to install a fresh cam/rockers into a run out engine. Sorry

Castrol does sell a "Classic" High Zinc 20-50, I buy it on Amazon. Haven't seen it as an "on the shelf" item.

Edited April 6 by tech71

[Santawillis]

It's running well I would say! A bit of blue smoke on hard acceleration 

But like others are saying it's probably from a tired bottom end and piston rings. Video from a separate question about the bubbling from the radiator. 

[tech71]

8 minutes ago, Santawillis said:

Video from a separate question about the bubbling from the radiator. 

Did you figure that out? Pressure test time for sure.

Good news is a worn M10 engine can run for a very long time but if coolant is finding its way into your oil, well thats not good.

Edited April 6 by tech71

[Son of Marty]

You can get a test kit to check and see if combustion gases are present in the coolant.

[Santawillis]

It happens sometimes when the car is cold, once it warms up it tends to go away. The Blackstone labs result did show some sodium present but I am not experiencing any coolant loss. We had to get the coolant system flushed several times and I am guessing it was from using the same funnel in the early days of getting the car up and running. Pic of the smoke.

[TobyB]

It's going to take more pictures of the lobes to tell you much about the cam.  But that one pic doesn't look... normal.

 

Drive the car this summer, and keep an eye on the lash.  I've taken apart motors with cams that looked good and

rockers that were a mess, and  I've made a cam with round lobes out of a bumpy one, and the rockers were fine.

So just run it.  And if things look questionable, yes, start scrounging up parts for a rebuild, a new motor, an LS swap,

whatever tickles your fancy.  Because these motors are, in fact, pretty tough IF you don't let them overheat much.

 

t

in for Cummins 4BT

[Santawillis]

16 hours ago, TobyB said:

It's going to take more pictures of the lobes to tell you much about the cam.  But that one pic doesn't look... normal.

 

Drive the car this summer, and keep an eye on the lash.  I've taken apart motors with cams that looked good and

rockers that were a mess, and  I've made a cam with round lobes out of a bumpy one, and the rockers were fine.

So just run it.  And if things look questionable, yes, start scrounging up parts for a rebuild, a new motor, an LS swap,

whatever tickles your fancy.  Because these motors are, in fact, pretty tough IF you don't let them overheat much.

 

t

in for Cummins 4BT

Here are some further pics of the lobes, love my silicone valve cover. Please don't look at my failed header paint too long! 

 

A birdie told me it was going to be in the 70s tomorrow in Chicagoland! 

[tzei]

The cam is dead. I bet rockers are dying too.

[TobyB]

yeah- oh, yuk. 

 

Get the Hardly Davidsunn 2400 zddp oil and run that until it dies...

 

...because that cam, I agree, is not ideal.  My version would be saving

up for a winter rebuild of another engine.  

 

Having watched others run some pretty horrible cams, though, you might get 

some fun out of it this summer.

 

t

 

[tech71]

On 4/6/2024 at 12:15 PM, Santawillis said:

it did become apparent that my cams are "blemished", for lack of a better term. 

Galled is the term I would use,  wonder what the wear pads look like. Thats lack of proper lubrication for whatever reason.

Bottom ends probably in similar shape. Still, you may get some miles out of it yet with proper life support.

All part of the 02 journey.

My 76 is a similar story and has a tired engine, smokes a bit and has an annoying rattle (think it's my timing/oil chain) but it too, still runs pretty strong. Funny thing is I have a fresh, replacement engine sitting here, it's been ready for over a year and still not installed. I just keep driving it and working on other stuff 😉

 

 

Edited April 8 by tech71

[Santawillis]

Thank you everyone for your insight! Current plan is as follows in order.

 

1 - Adjust valve lash, maybe retorque head bolts? @TobyB what are your thoughts on that?

2 - Find new engine to prep, just like @tech71 

3 - Drive the "crap" out of the car with the current engine

4 - Once the current engine goes "poof" install new engine!

 

Looking forward to this adventure, and I'll keep you all posted on the progress!