Pulled 77 3.0 Liter Turbo engine: Marks on camshaft

[Simon930Berlin]

Friends,

We have pulled the engine for a proper service and reseal, and looking at the camshaft clinders 3 and 5 have marks on the cam lobe, but not on the rockers. One is from the exhaust, one from the intake side.

Has anyone seen this before, should I replace the camshafts? Any idea of a probable cause?

Thanks as always for your advice!
Mileage on the wholem car is less than 60K

[356911930]

It looks like you need to have your camshafts welded and reground. You will need to have the rockers resurfaced at the same time so that they can wear in together.

Rahl

[Simon930Berlin]

Weird there is no marks on the rockers, no?

[dap930]

It is possible that some of the the camshaft spray bar holes are plugged from coked oil from unfiltered return oil from the turbo sump drain. This is something that will need checked out if synthetic oil has not been used in the engine.

[Simon930Berlin]

What I found here on Pelican (the almighty resource) is what I clearly think is my wear pattern: Cam Damage

I have only run the Porsche approved 10W60 oil, since last adjusting walve play (whilst exchaning all plugs and ignition cables) about 10K miles ago. And of course regular oil changes at least bi-anually, as I take the car on 20m stints on race tracks every now and then.

Now I would think the Porsche Classic Oil should be designed to prevent exactly this kind of damage, as it results from lower levels of ZDDP in modern oils, which as an ingredient is less required in modern engines. (For a deeper dive on ZDDP I found this, but it doesnt answer my main question: Ultimate Motor Oil Thread or Why we hate CJ4/SM oils)

My question to the pros would be: Is this wear likely to have happened in the last 500 or 10.000 miles? How quickly does a camshaft deteriorate when showing these wear patterns?

All input is much appreciated!

[Simon930Berlin]

Originally Posted by dap930

It is possible that some of the the camshaft spray bar holes are plugged from coked oil from unfiltered return oil from the turbo sump drain. This is something that will need checked out if synthetic oil has not been used in the engine.

Will check as we pull the camshafts!

[JJK78-951]

Finishing up one at work like that... Went ahead and got new cams, new rockers and new rocker shafts. Definitely check the spray bars... also would recommend adding the rockers o-rings for extra protection. It could have happened since you last checked, but could just be that you didn't see that damage on that particular lobe last time...

[faapgar]

If you look at the second picture of the rocker lifter face you see a line of wear that is horizontal about 40-60 thousandths from the bottom.That is a sign of the end of life for cams and rockers.Not enough zinc in the oil in the past.Ciao Fred

[bpu699]

just went through the same...

Grind cams, $450
Grind rockers and rebush, about $300 or so

Take apart entire motor and rebuild it while you are in there especially to clean out spray bars (which did have crap in them)... $$$$$$$$$ and about 2 years of my time

[T77911S]

probably loss of oiling.
I would check the spray bars for blockage.

I would also be concerned it is coaking from the turbo that has come lose.
happened to me.

[Simon930Berlin]

Hello,

so the solution propsed now is to grind down, and adjust rockers for the new diameter - is that valid?

Thank you, gods of engines

[xabwest64]

Guys,

You need to remind that these engines were designed to work with mineral oil back in the days. Full synthetic oil is not suitable for these since the oil layer left on every parts will be too thin when engine is stopped. Every start up you will get wear. Better use semi-synthetic with recommended grade/visco. Well known issue with 3.2 engines as well.

[Simon930Berlin]

Originally Posted by Simon930Berlin

Hello,

so the solution propsed now is to grind down, and adjust rockers for the new diameter - is that valid?

Thank you, gods of engines

I know too little about engines, but I like my car to be in top notch condition. No reason to spend some money, and not get it done right.

Now if I understand the solution correctly, the idea is to grind down the lobes that are affected (the two cylinders in the middle) and adjust the rockers to the new rotational diameter.

To me this sounds a bit like a hack, is this the way to do it? Should I get new unmolested camshafts? Its a 3.0 Turbo Carrera not for nothing, that I would prefer to be in as-engineered-condition, driving it, but keeping it as originally designed.

And I will surely switch to semi-mineral oils, if not all mineral oils moving forward. Seems crazy this happened with the suggested Porsche Motor oil, used exclusively in the last 4 years or so...

[JJK78-951]

If the money is not an issue for you, then yes I would spend the extra needed to get new camshafts and new rockers, rocker shafts too, RSR O-rings, timing gears etc. anything you can get to while you are down that far. Do it right, it will be worth it in the end.
Good luck!
J

Originally Posted by Simon930Berlin

I know too little about engines, but I like my car to be in top notch condition. No reason to spend some money, and not get it done right.

Now if I understand the solution correctly, the idea is to grind down the lobes that are affected (the two cylinders in the middle) and adjust the rockers to the new rotational diameter.

To me this sounds a bit like a hack, is this the way to do it? Should I get new unmolested camshafts? Its a 3.0 Turbo Carrera not for nothing, that I would prefer to be in as-engineered-condition, driving it, but keeping it as originally designed.

And I will surely switch to semi-mineral oils, if not all mineral oils moving forward. Seems crazy this happened with the suggested Porsche Motor oil, used exclusively in the last 4 years or so...

[Simon930Berlin]

Ouch, that reads like a 10K message

Originally Posted by JJK78-951

If the money is not an issue for you, then yes I would spend the extra needed to get new camshafts and new rockers, rocker shafts too, RSR O-rings, timing gears etc. anything you can get to while you are down that far. Do it right, it will be worth it in the end.
Good luck!
J

[WPOZZZ]

Hi Simon, yes, you can go all out and get new cams/rockers from Porsche...if available. What I did on my old 3.4 turbo was to sent the cam and rockers to Elgin Cams in California for a regrind. When returned, they were in brand new condition. Both methods are good, but regrinding is more economical. While you are in there, you could up the grind to an SC/sport cam.

[pmax]

Originally Posted by Simon930Berlin

What I found here on Pelican (the almighty resource) is what I clearly think is my wear pattern: Cam Damage

Here's another for comparison
Intake rocker? cam lobe wear opinions

And of course regular oil changes at least bi-anually, as I take the car on 20m stints on race tracks every now and then.

How much track time is that ?

[pmax]

Originally Posted by Simon930Berlin

What I found here on Pelican (the almighty resource) is what I clearly think is my wear pattern: Cam Damage

Here's another for comparison
Intake rocker? cam lobe wear opinions

And of course regular oil changes at least bi-anually, as I take the car on 20m stints on race tracks every now and then.
...
Is this wear likely to have happened in the last 500 or 10.000 miles? How quickly does a camshaft deteriorate when showing these wear patterns?

All input is much appreciated!

How much track time is that ?

[JJK78-951]

Originally Posted by Simon930Berlin

Ouch, that reads like a 10K message

Just finishing up one at the shop now and actually bill is a lot more then that but heads were also sent out etc. Cams themselves are Webcams and think cost about $1000. Rockers run about $80-90(each) if I recall correctly so that portion not so much if you are "already in there", just extra parts cost... these prices are shop cost prices but usually you can get close to the if you shop around or go direct to the manufacturer.

Cheap. No, but then again you are talking about a $100K+ car all day long so dropping $20K to make sure the engine is right is a small price to pay!

[Simon930Berlin]

The car gets around 30m of tracktime every month, and regular hot drives on mountain roads and highways. Its moved properly, not above 3K rpm until warm, cooldown rounds when driven spirited, etc.

Its not my first turbocharged car, I learned the hard way with a Delta Integrale

Originally Posted by pmax

Here's another for comparison
Intake rocker? cam lobe wear opinions



How much track time is that ?