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I've been chasing a lack of performance gremlin in a Senior Standard Eight.

The engine starts, idles and runs fine at low and high speed; it just lacks the performance it had.

I have a long test hill I use for a run at 40 - 45 mph to check the engine and cooling system periodically.

I have to keep my foot in it more during this run, and the engine is running cooler than it used to, pulling this hill.

Here's what I've done / measured:

Replaced points, condenser, and plugs.

Measured compression on all eight, 95 - 100 psi.

Fuel pump pressure, 2 - 2.5 psi.

Point gap set at .020", timing set at 9?. Checked operation of the mechanical advance in the distributor.

Fuel level checked in the DL Type 51 and it was right around 7/8" below the top face of the bowl.

Swapped out the DL 51 with a borrowed carburetor, no change in performance.

The rebuilt engine has about 2500+ miles on it.

Just after the rebuild, I set the tappet clearance to .004" on all, adjusting when hot and running.

Do you think it would be worth checking the tappet clearance again?

Adjusting the clearance holding three tappet wrenches and a feeler gauge is not the easiest task, especially on an updraft setup.

Has anyone used the attached method to adjust the tappets, vs. adjusting them with the engine running?

I've also heard some people just adjust them cold, .008" on the intakes and .012" on the exhausts. Once everything warms up they're supposed to end up right around .004".

Any thoughts or comments would be appreciated.

Interesting valve bulletin I ran across attached also.

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Have u tried checking the compression when engine is fully warmed up???

Sounds like timing, hopefuly ignition and not valve timing.

Hi 32:

This is a tough one. I might start by checking the dwell variation with a meter. If it changes more than 2 degrees when the motor speed is raised to 1500 rpm the distributor needs to be overhauled.

I would also check the spark using an adjustable tester available from NAPA. It should have at least 20Kv cranking volts.

Note as well that Packard released a service bulletin recommending addition of a grounding pigtail for the distributor to remedy a weak spark condition due to the tower.

When you are timing the motor I assume you are removing the starter with the engine running and using a timing light powered by a 12 volt battery. The points also need to be synchronized. That can be done using the timing light.

Next check the motor vacuum. If you have a leak that could cause a problem.

Hope this helps.

Hi All,

Thanks for the comments and words of wisdom.

I have not run a hot compression test, it is next on my to-do list.

I checked the dwell and it was steady. With the points at .020" I would expect a dwell around 28 - 32. I was reading around 38 - 40. Maybe I was a little off on the .020" setting.

The distributor was re-bushed, it is nice and tight. I'm going to dial indicate it to re-check. Dwell holds steady at fast idle.

My test of the secondary from the coil give a nice fat, snappy, blue spark, about 3/8" long. I'll look into the NAPA tester.

To make it easier timing I made up a degree plate that is permanently mounted to the timing cover case. The 0, 5, 10, and 15 BTC marks on this plate correspond to the timing marks on the flywheel. A white line on the vibration damper allows me to set the timing without removing the starter each time.

I did have an intermittent problem with the distributor a few years back. A heavy ground wire from the distributor casting to one of the distributor hold down bolts corrected the problem.

Points have been converted from the dual Northeast setup to the single point conversion plate currently being sold. Synchronization was done using the timing marks.

Good point on the vacuum test. This needs to be done, maybe both cold and hot, along with the hot compression test.

One other point worth mentioning. Previously when starting the motor cold I would get some slight tappet tick until she warmed up, after about 10-15 minutes. Now when I start it up cold I don't any tappet tick, tick.

I wondering if the clearance closed up? Hot compression check should tell.

Checked the timing chain, thru the access plug, not much play.

Still scratching my head.....

You mention a variety of changes u've made to the engine in terms of timing marks, single points system etc etc. WHAT change was last made BEFORE the lack of power problem ensued???

What about a restricted exhaust -- That might make it lose power under load although not sure about the engine running cooler if it did have a restriction.

All the changes listed, points, timing marks, etc. existed before the loss of performance.

Restricted exhaust, possible, will verify this when I run a check with the vacuum gauge. No changes were made to the exhaust system, prior to the loss of performance.

I had a similar problem in one of my Packards, it turned out to be a blocked fuel filter. I suggest that you see if a previous owner has installed a modern filter near your fuel tank. if nothing found, I would suggest that you conduct a flow, pressure and volume check on your fuel deiivery system.

Pressure test was done on the pump (stock Stewart Warner Type 407 mechanical), 2 to 2.5 psi.

No in-line filter, other than the brass screen on the fuel bowl.

Will check flow / volume.

Could have a restriction in the line to the pump.

Originally though it may be a blocked passage in the carburetor but swapping them didn't help.

Where's Gus when you need him....

gus-stories.org/

Thanks.