Itinerant Air-Cooled

My '78 Westy has always had a little hydraulic valve clatter when starting its cold engine. The clatter went away after it ran for a few seconds.

Lately, things have been much worse:

If I start the engine and only run it briefly at low RPM (like backing it out of the garage and/or moving it around in the driveway), the next time I start it I find that a lifter has completely bled down and it takes a full 10-15 minutes of driving at speed to get it to pump back up.

The same thing happens the morning after a hot highway drive.

The lifters were new when I rebuilt the engine around 30K miles ago and the oil and filter have been changed every 3-4K miles since the rebuild.

Do I have a worn lifter that is bleeding down prematurely, or is there something wrong with the oil supply to the lifters that is not feeding them properly at low rpm or when the oil is hot and thin?

I have not yet determined if it's the same lifter bleeding down every time or if it's any lifter whose valve is open when the engine stops.

Thoughts?

Thanks!

I have a nearly identical issue, but with fewer miles...post up if you find a cure.

Thanks!

To get some of the questions out of the way, what oil filter and oil are you using?

Are you running stock lifters and camshaft or are they by someone else (like Webcam or something).

Mine are new stock lifters, 20w-50, Mahle filter, black.

Have you performed a cylinder drop test to see if it's the same cylinder every time? If it's the same, you have narrowed the culprit down. If a different cylinder every time, you know you have a system-wide issue.

Is the case a solid lifter "dual relief" case?

Robbie

Stock camshaft and lifters. Whose I do not know (supplied by the dude who messed up the first rebuild). Castrol 20w50 oil. NAPA Gold oil filter. I have not tried to isolate it. What is the cylinder drop test? It is a hydraulic lifter GE case. Only one relief valve.

Thanks!

vwlover77 wrote:Stock camshaft and lifters. Whose I do not know (supplied by the dude who messed up the first rebuild). Castrol 20w50 oil. NAPA Gold oil filter. I have not tried to isolate it. What is the cylinder drop test? It is a hydraulic lifter GE case. Only one relief valve.

Thanks!

Ya want a temporary cure?

If your lifters are set at 1 1/2, now adjust them to 2. If your lifters are adjusted to 2, now adjust them to 1 1/2.

Engines like to stop at the same place, usually the highest compression cylinder with a little recoil backwards.
Check the position of the distributor rotor and pulley mark, and see if you can tell us the typical stopped position of the engine.

Lifters have little check balls/discs that are supposed to seal the pushrod oil supply escape under the pressure of the open valve. Sometimes, they don't. Some have dumped a Marvel Mystery Oil solvent in the oil supply 100 miles (or ten minutes, I can't remember which) before the oil change to see if that will un-clog the ball/disc.

Me? I'd drive it more frequently.
Colin