[mbs xk8]

Hey all, I'm back with a project P38 I bought at an auction. I previously owned a 2000 RR and loved it. Now I have a 1998 white RR with 156k miles. Please don't lecture me about buying a RR with an unknown history. I'm a risk-taker - LOL.

I've just been able to get her started and the engine sounded great. Then about 5 minutes later, I started hearing a "knock." It seems to go away when the revs are increased.

The sound doesn't always happen. I turned off the RR and let it sit for about 10 minutes, and when I restarted it - the sound was gone and the engine sounded good again.

I'm also tracing an air suspension pump issue. It seems to pump for a few minutes, then it stops. I know I have a leak because she's sitting on her bump stops.

Any advice on the engine sound? Does she have a broken rod? (I found a cylinder head rolling around in the back of the SUV. It was really strange just sitting there. But the engine looks complete)

 

[RRToadHall]

A cylinder head does not just roll around the back of any rig. Just as you would know if you had a broken rod. If you were missing a cylinder head from under the hood you would have a 4 cylinder engine and if you had a broken rod you wouldn;t be able to run the engine.

 

[Imonlyaguest]

Sounds very much like the valvetrain. It might be a sign of low oil pressure but more likely rockers. It sounds like you have more than one that has suffered the sinking socket problem. A 98 may well be in the VIN range that was affected. Pull the rocker covers, remove the rocker shafts and have a good look at the cup in the rockers where the pushrods sit. You are looking for ones that have sunk into the alloy rocker. There was a Technical Service bulletin issued that highlighted this problem.

 

[mbs xk8]

Thanks for the help! I checked the VIN and I"m outside the range (my vin is WA397441)

I started the RR today to raise the suspension... and the engine was nice and quiet for about 10 minutes. Then that ticking started again.

 

[Ferryman50]

You also could run her until ticking starts, then take rockercovers off and run her again "to be closer to the ticking". Feel with your fingers over each rocker if the ticking is simultanious, check torque of the pedestalbolts.
As a plus you can watch if lubrication is as it should be.

 

[chris no 10]

How's the water/oil, I've had one that started quietly, but once warm started ticking, it was a slipped liner that needed the heat before it would start slapping. The fact it had a cylinder head in the back, does it need replacing ?. Has it been replaced?. ( look for new bolts ) it's a gamble buying any p38 unless you know the history, from an auction is being brave.. let's hope it's just a tappet not adjusting .. get a cheap stethoscope or use a screwdriver to try and locate the noise.