Packard Forum Index » V-8 (1955-56)

WHile u're at it having the oil pressure gauge installed it will be a good diagnosis to have the oil FILTER replumbed to feed from the BACK of the engine at the oil pressure sending unit tap.

If pump is bad, but showing good oil pressure then the lifter noise should go away by plumbing the oil filter as indicated above. It won;t fix the pump but it will help to determine that the existing pump is worn.

Why is it a good idea to have filter connected at back of engine?? Pls give full details

Packard V8, I'm not so sure that's a good idea, though I have no personal experience with it. It may result in an improved %-age of the oil being filtered, but I'd think that removing the filter from it's factory location could have the effect of lowering the oil pressure throughout the system. My thinking in saying this is that the filter is essentially a final restriction, after which it's just a gravity dump back into the crankcase. Removing the restriction may lower pressure.

Not to steal any of Keith's thunder, but since he and I kicked this around, offline, some years ago, perhaps I can provide some insight until he is available for further comment.

IIRC, the underlying notion is that any air introduced into the oil stream by the pump builds up in the main gallery, which extends, vertically, to the top of the block. The OE pressure sender/switch taps into that passage.

Trapped as it were, the air builds up (actually, down), until it begins to escape into one of the lifter galleries - thus starving the lifters for oil.

By replumbing the feed for the oil filter as Keith suggests, the air is redirected to the filter cannister, where it is released, harmlessly, through the outlet plumbing.

Keith might have been looking at replumbing as a possible solution to the problem, initially, but has since recommended this as a means of identifying aeration of oil as the problem.

Aeration isn't the only cause of of reduced oil pressure, but - aside from foaming that results from overfilling - its confirmation points to the oil pump as the problem. If its nothing more than a matter of wear at the driving shaft and bore, that can be solved by the approach used by the late Bob Aller (and others), which involves installation of a bushing and truing or replacing the shaft.

The stock Packard oil pump gear case is about 3in higher in the sump than the Olds HV oil pump with adapter. This is because the original pump had the vacuum pump assy on the bottom. So -- due to oil level, if there's air being sucked into the oil to cause the potential aeration problem described above, the new Olds pump would eliminate it.

IMO, relocating the oil filter is just a band-aid, just like the late cam plate is a band-aid. If the oil pump is worn out and/or the clearances have opened up, only a new, bigger volume oil pump will solve the problem of low oil pressure and it's symptom of clacking lifter(s).

BTW, even with an overhaul to tighten the crank & rod bearing clearances, you cannot easily do anything about the cam bearings and lifter-to-lifter bore clearances. Hence, only more oil volume is the only real solution.

For those who haven't seen it, here's the Packard V-8 Club website from 2006 explaining the Olds HV oil pump fix:

1956packardpanther.com/PV8C/PV8C_OHVOPA.html

Craig

looking over Kevin's engine build, why did you guys put in expansion plugs in the front lifter gally holes that go to the cam plate?

i don't see anywhere that they are required and if put in place seems like they would render the oil grooves in the cam plate useless.

as seen in this picture.....i removed them and HH agreed as well.

Hank

To my knowledge from selling engine parts, driving V8's for many years and personally disassembling many v8 engines for parts, bearing wear and low oil pressure is not a significant problem. Lifter to bore wear/excess clearance is not a problem either.

I have a '56 Caribbean I bought in 1963 that had a brand new engine (long/short??) block installed in it when I got it. I drove it until 1970( still have it 5699-1080 VMV)it had lifter noise problems which I do not recall what I attempted or succeeded in solving.

Ths new engine certainly did not have clearance problems and know the oil pressure was up to specs, checked with mechanical gauge

BH in the post just above gives a good explanation for why i recommend the replumbing of the oil FILTER. However i mite make one minor or insignificant correction to the following statement:

"Aeration isn't the only cause of of reduced oil pressure, but ..."

Pressure reading ata gauge is independent of air, oil or any mixtyure of air or oil.

Bottom line:
In the Packard V8 there is an AIR TRAP SPACE directly below the oil sending unit of about 2". replumbing the filter bleeds off the air before it can pass to the rest of the engine.

And as BH and Craig indicate the replumbing of the oil filter is only a diagnostics or 'band-aid' fix for the SYMPTOM of a worn oil pump. NOT a fix for the pump.

However, there is a secondary lifter noise that seems to occur independent of the low speed lifter noise. The secondary noise comes in at about 2700 rpm (about 70 mph)almost without fail. The filter replumbing eleminates that.

I've been running the replumbed oil filter now for well over 15K miles AND the Olds conversion oil pump kit in my 56 Exec. No problems at all.

Somewhere on this website i posted pictures of a DISECTED block i have with a tracing of the oil gallery at the top of the block which causes the air trap.

air trap area inside of turquoise box. Red lines indicate oil gallery.

If replumbing the oil filter causes some skepticism for oil pressure issues then perhaps a round slug of aluminium with a very tiny hole thru it would act as a 'filler' for the air space area to prevent air from bilding up.

Either way, IF the pump is found to be worn (90% chance it is the problem) then the Olds oil pump conversion is the best AND cheapest AND easiest and most long term answer.

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