TxGoat wrote:
If you have had the head off the engine, did you carefully clean the block and head surfaces, paying special attention to areas where the head studs go into the block? All surfaces right up to the studs need to be clean and flat. Studs and stud holes in the head must be free of rust and scale. A new gasket should be used, and the head should be installed and the nuts tightened in the correct specified pattern. It's best to tighten them with a good torque wrench in 3 stages of about 1/3, then 2/3, then full recommended torque. Then, after filling the engine with water and running it for 15 or 20 minutes at light load or idle, it should be stopped and allowed to cool down, then the nuts retorqued to spec with the engine cool. At that point, I'd go for a short drive of a few miles at lower speeds and avoiding any hard pulls, then let it cool down again and again check all nuts for proper torque. Do any checking and tightening in the correct pattern and do not exceed recommended torque.

TxGoat wrote:
"Vacuum is nice and steady, that is, needle does not flutter."

That's good news. That indicates that your valves are sealing and holding compression, at least at idle.

Valve noise is normally a clearance issue or a lifter issue, and may not affect valve sealing.

Valves can somtimes work well at low speeds, even if some noise is present, but fail work well at higher speeds due to sticking issues or weak springs or both.
Driving the car at moderate speeds for a few hundred miles can resolve sticking issues. Weak springs need replaced. Rust pitted springs need repalced. If an old engine has one or more weak springs, it's usually best to replace all of them.

TxGoat wrote:
Putting new lifters on a used cam may not be a good idea. Mixing the positions of used lifters on the cam may not be a good idea. If you continue to have issues, I suggest removing all of them, keeping them in order, and take them apart and clean and inspect them. Do not mix parts from one lifter to another, ever! Hydraulic lifters have a limited range of function, and need to operate within that range, which typically requires an initial adjustment. Factory procedures and specs would need to be followed. The lifter needs to be able to expand when the engine is cold to maintain proper valve clearance, and collapse slightly as the engine warms up to maintain proper valve clearance. A stuck, bottomed, or topped out lifter plunger cannot do this.

I'd want to run the engine several hundred miles at moderate speeds to allow the fresh oil and Marvel oil a chance to clean up the lifters, rings, etc. Any cleaning effect will occur when the engine is warmed up and running. I'd keep the engine speed down, with road speeds in the 45-50 MPH range or less. Longer runs are better than shorter runs. The idea is to get the engine warmed up and running, and the hot oil circulating. Runs lasting an hour or more are best. If you have an oil filter, I'd start with a clean element. Correct any missing or other tune up issues. You want the engine running on all cylinders.

Fish'n Jim wrote:
Considering the mileage and unknown condition, I think you're over reacting.
It's stable and doesn't appear to cause issues. Maybe a bit of fine tune might help but if it's working, accelerates, I wouldn't mess with it.
It's a stroked low compression engine, so may not match the "published" levels of more modern ones and wear is a factor. ie, close enough if no issues.

UR using a compound gauge so zeroing is crucial to accuracy. I'd check with a different gauge, if suspect.

JeromeSolberg wrote:
I have had some struggles with noisy lifters, and I haven't quite resolved them, but here is some insight I have learned from the experience of another member of this site:

There is the specified clearance for the lifters, IIRC it is 0.030-0.070, but don't quote me on that. It can be measured with the little gage that may be purchased from Max Merritt or Pacific Northwest Packards, or the lifters from Kanter have instructions on how to disassemble a lifter to turn it into a gage.

The poster reported the same issue that I have had, and others do - that the lifters were quiet when cold but one (in his case) lifter was noisy when hot. He replaced the lifter a couple of times to no avail, but finally measured the clearance and found it to be tight, and then after having the stem ground shorter to put it within range, the problem went away. He believes that the lifter needs enough clearance to be able to "pump up", and when the engine gets fully warm is when the clearance gets smallest.

My problem, I believe, is that when I measured the clearance for a number of the valves it was on the low end. It may be that, because it is not easy (for me at least) to do this measurement, that it actually was/is below. It is also true that because of valve recession the clearance can get tighter over time, which may be the crux of the issue - since it was on the low end, after running for a few hundred miles it went below the tolerance.

So the moral of the story is - it may not be your lifter (though if you take the head off to check, it may make sense to replace the lifter at that time), it may be valve recession has caused the clearance to tighten up. Most machine shops can grind the valve stems, my understanding is that it needs to be done carefully so that the valve stem end is still flat and perpendicular.

TxGoat wrote:
I'd try setting the initial timing at 10 or 12 BTDC. If you have a worn timing chain and distributor drive gear or out of place timing marks, that may get it closer to correct. If it kicks against the starter when warm, back off just a little. I've had very good results using Marvel Mystery Oil in older engines with gummy lifters. A good 10W30 detergent oil is beneficial, also.

TxGoat wrote:
That sounds low to me for an engine idling in neutral. Is the gauge known to be accurate? Does the engine idle well and run well? Is the gauge connected to true manifold vacuum, and not a port on the carburetor? I'd expect a Packard 8 to run on the high side of the normal vacuum range, 20" plus or minus, at low idle of 300-400 RPM. Timing can affect vacuum, as can any engine loading, or extreme wear. An extremely worn engine would be an obvious oil burner. A stretched or slipped timing chain might cause low vacuum.

JWL wrote:
Kevin's advice is good, so long as it's not brake fluid leaking. The brake system should be number one on your list to repair and restore. Then steering and suspension. No joy if you can't stop and steer safely.