Pitting on cam lobes

[Scott Stephen]

Hi, im really starting to wonder about my '93 940T 2.0 Auto

The car has 139K and when i had it the turbo was knacked. (Les is currently rebuilding it for me

I pulled the cam out today to replace the valve hushers under the tappets. The clearances by the way are pretty much well within tolerences, Anyhow, the cam has some pitting marks on 3-4 of 8 lobes. Im wondering if this poor girl has suffered oil starvation at some point as this would not help the turbo either (When i bought the car the oil level was below the minimum)

Should i consider replacing the cam or should i live with it, if anyone else has seen this pitting then please let me know, i just can help thinking though that if oil starvation was evident then id be seeing scoring on the lobes and the bearings in the head for which there is none!

ta, scott

[Les, slight limp]

More likely to have suffered from extended periods between oil changes if this turbo is anything to go by, i'd change the oil and filter a couple of times early, about 1000 to 1500 miles max, any good dino oil, it would be a waste to put synthetic in for those amounts of miles, i have found castrol gtx high mileage to be good at shifting any crap that's in there but i'm quite sure in your line of work you know whats best, everybody has different opinions on oil and rightly so.

Volvo cams are very hard wearing and if there was a problem with the cam you'd hear it.

[Alec Dawe]

I'd be tempted to live with the cam as well. The pitting might be caused by acid build up in the oil if the change intervals were neglected, but unlike Ford Pinto cams which would wear through the case hardening as soon as look at you, I think the Volvo cam is much better made, and will probably cope, especially if you keep the oil change regime up to date from now.
Obviously the pittiing won't get better, but it shouldn't get worse, and even in the very worst case scenario, if it does start to deteriorate badly, it'll make that fact known by the clattering noises you'll get, but it will still run, and if won't effect the rest of the engine, so I'd be tempted to leave the cam for now

[malb]

I suspect that the pitting is caused by acid from neglected oil changes or moisture uptake from lots of very short duration runs, engine never heating up enough to boil off crud accumulating in the oil.
As with others, I wouldn't panic about it unless it is also showing rust. In that case, I would rather replace it than grind iron oxide off it while running and have it go through the rest of the engine

[RollingThunder]

Hi Scott,

If you want a replacement cam, I have a couple in my garage - all T profiles - which is the correct one for your engine. I'll see what condition they're in at the weekend - you can have the best one for £10 plus the cost of postage in you're interested.