We see this all the time. We sell a cam kit that has been well received and after all the kits we have installed over the last 10 years, our failure rate is off the charts LOW!
When your engine has poked holes through so many lifters, there are two big issues. First, if the valve stems under the holed lifters are not flat, but mushroomed from the hydraulic plunger mashing the top of the valve like a hammer, the cylinder head will have to be removed and the damaged valves need to be replaced.
The other issue is the oil pump. Since this wear is due to insufficient oil and all that metal that used to be lifters and cam are now in the oil pan, the metal particles have been ingested by the oil pump. It is ruined and will have to be replaced and the oil pan cleaned out.
As for oil usage, the stock cams we have seen have an average life expectancy of 160- 180k. You are right in the middle of the averages, in our opinion. The best oil is NOT Castrol, in our opinion.
But, yes, with the wrong oil we've seen a few virtually new BRM 06 Jettas with cams worn out in 70,000 miles.
What is worse, we have seen some aftermarket cams that have worn out in as little as 17,000 miles. THAT IS SICK! The particular cam was an AMC cam from some poor Canadian fellow, but now, you can get some real CRAP Chinese cams for as little as $90. DO NOT EXPECT A $90 cam to last more than a few months!! Because of a aftermarket cam chamfer issue, we see most cams struggling to surpass 100k. Our replacment cam champ is past 440,000 additional miles.
There are two issues which cause premature wear. 1) Insufficent oiling and 2) incorrect cam lobe design. Our replacement cam kit takes care of both of these issues. Are we the cheapest? Heck NO! Does our kit last? You betcha! We have many that exceed 250,000 miles that when inspected, they still look like they are breaking in. We parkerize the cam and it will show very well how it wears in.
We correct the cam lifter oiling by modifying our cam bearings to increase oil to the cam followers and correct an engineering error for cam bearing oiling. It's the most elegant and effective way to correct two mistakes in design.
Other than that, we have replaced the torque-to-yield rocker and cam bolts with bolts that are 1/2 the price. The reason VW uses stretch bolts in this situation is as a convenience for the company in manufacturing process. We have our naysayers who say 'you can't do that!', but with thousands of kits sold and only 3 bolts broken, we have to disagree. Our bolts are similar to the ARP materials, with a moly additive, which allows the bolts to stretch and rebound. We have a different torque spec for them and they are completely reusable.
Check the valve stems. If they are damaged, feel free to call. This is repair is in our wheelhouse. Literally, we have repaired BRM, BEW and BHW cylinder heads hundreds of times in our shop, with great success.
