Pagoda SL Group
W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: BarryD on October 04, 2015, 00:22:30
-
When Jon and I removed the valve cover for a valve adjustment, we noticed two issues: First, there is some pitting on the camshaft. second, the valve cover seemed pretty dirty for a car that uses detergent oil. Can anyone provide some insight regarding:
1) Is this camshaft ruined? Could it be ground? Could I get another XX thousand miles from it if I do nothing?
2) Should the inside of the valve cover be cleaner? The valve cover from Jon's car was certainly cleaner!
3) Is there a way to easily verify that oil is getting to the camshaft?
Here's some background:
- The car was rarely driven from 1995 to 2002. The car did not move from 2002 to 2011.
- We replaced all the seals in the oil filter canister prior to driving the car.
- Since resurrecting the car, it has been driven about 1500 miles.
- Before driving the car, oil was changed, Next oil change was after about 200 miles. I use 15W-40 Rotella oil.
Thanks, Barry
-
To me, both dirt and camshaft condition may be the result of poor maintenance before the car was resurrected (bad quality oil, not changed etc.)
1500 miles since resurrection is not a lot. It will take more than that for detergent oil to clean up all that dirt.
To check if oil is getting on all the cam lobes: crank the engine with the cam cover and spark plugs out. You should see a continuous oil drip on the cam lobes. The one towards the sprocket will be the last one drip as it is the furthest in the circuit.
Check if some of the lobes have been flattened: Measure the lobes height with a caliper across the camshaft. All exhaust should be the same and all intakes should be the same. Also check the condition of the rocker arms. usually their contact surface goes before the lobes. If the only damage is that pitting, you may still be able to drive the car for quite a while. Use good oil with the required zddp contents and monitor regularly.
-
Detergent oil isn't like a bar of soap - it won't remove old deposits. It will keep loose dirt in solution so that the oil filter can remove it or it gets drained out during oil changes.
-
The deep pitting is unusual. Not really a sign of wear. May have had water mixed with the oil then allowed to set for a long time. Electrolysis corrosion can cause this kind of damage. Probably can be used without much consequence at this point. Put a camshaft on your wish list for the future! Clean the valve cover very well. K-1 kerosene will work fine. Dry it completely before installation. Best not to disturb any sludge on the cylinder head. Large chunks may be loosened up and may clog some oil passage if disturbed. Best just to do one or two more oil changes (sooner than normal) to "melt" the sludge gently away. Always change the oil in the fall before winter storage. In this way condensation and oil contamination are not left to do damage in the engine during it's winter slumber.
If the pitting issue causes accelerated wear, you will hear the valve adjustment get much louder again. I suspect you will not have any issue anytime soon. Cams can be re-built/re-ground. It is important that these cams are case-hardened again after re-building. They are "nitrited" (case hardened) from the factory. They will not last long otherwise.
-
Many thanks for these replies. The depth of the worst pitting on the camshaft is 0.1016 mm (0.004"). I measured two intake lobes at 39.62 and 40.44 mm respectively. The one exhaust I measured was 40.233 mm. When we adjust the valves this weekend, we'll measure them all.
-
On many camshafts I measured both intake and exhaust cams had the same lift, but I can't confirm it's also the case on these engines.
If one lobe measures below the others then closely inspect the tip of the lobe to see if there are signs of flattening. usually one can feel/see a ridge where the cam enters into contact with the follower, when there shouldn't be any.
-
Normally, if the cam is worn through the hardened surface it should be replaced. It will wear quickly after the hardened surface is breached. You can see the difference in the metal. The hardened surface looks like chrome. The unhardened metal is a darker grey. Radically worn and flattened areas on the cam lobes and rocker arms result once the breach occurs. In your case it does not look like the damaged areas are from wear, but from corrosion. I would proceed to use it. It looks like most of the case hardened area is intact.