Packard Forum Index » Post-War (1946-54)

I have a '49 Custom 8 with the 356 and am trying to figure out if the oil filter is plumbed correctly for a hydraulic lifter engine. Service Letter Vol. 22 No 14 from December of '48 has instructions for the filter installation on the Eights and Super Eights and has a diagram. It shows the upper side port of the filter (they call it the inlet) connected to one side of the oil pressure sending T, the other side of the T that goes to the block via a little "pigtail" is removed and the bottom port of the filter (the outlet) is hooked up there instead.
My current set-up has the upper port going to one side of the T with the sending unit, the other side of the T has the pigtail going to the block and the bottom port of the filter goes to a fitting at the oil pan.

I tried to find inlet and outlet markings on my oil filter canister but can't read anything near those ports. It looks like a stock set-up but according to other posts it's not uncommon to have the plumbing on these incorrect or backwards.

Can anybody tell me if the above Service Letter applies to the 356 engine and is indeed correct? I'm asking because I'm getting what sounds like lifter noise and after exploring other causes it may be due to insufficient pressure to the lifters due to an incorrect filter set-up. The somewhat strange thing is that the lifter clatter almost goes away entirely after driving the car about 15 minutes.

Ron

I do not believe that particular letter is applicable to the 356 engine for the simple reason that Packard had some noisy lifter issues in the early 40s that was traced to low flow and pressure lost thru the filter. I am not even sure it was correct for the later non 356 engines with hydraulic lifters because some of the same concerns were still applicable on the 288/327 blocks.

There were several bulletins for the 356 engine revising the filter canister to try and control the issues with full lifter flow thru the filter. A plumbing revision was made for 42 and this bulletin mentioning the "fix" with the plumbing rerouting was issued in 43. On earlier engines Packard suggested the mechanics install another tee so the pigtail could be added to feed the lifter gallery directly and there would be another outlet available to feed the filter. There was an orifice on the feed line to the original filters to farther restrict the amount of oil thru the filter so the lifter gallery would get a stronger flow. Later canisters with the side inlet and bottom outlet had the restriction built in. On the 40 and 41 356 engines mechanics also had to drill a hole in the block so the filter could drain into the crankcase. Believe the port into the crankcase was standard from 42 thru 50.

Aside from eliminating the second tee used on the early engines by changing to the 4 way fitting on the 42 and later engines, that final plumbing fix with the bypass flow dumping into the crankcase was to the best of my knowledge carried thru on all 356 engines and was standard with all engines 51 thru 54.

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Thanks for your input. I have that earlier Service Letter I just thought it would have been superseded by the one I referenced. But you must be correct that it just refers to solid lifter engines. I must be reading the diagram incorrectly in the Vol 22, No 14 letter because that hook-up just doesn't make any sense, it's just a loop between the sender and the filter.

If the sketch in your post is correct then my setup is essentially backwards, my bottom port of the filter goes to the block just above the oil pan and the side port goes to the block oil gallery via the pigtail. The other difference is that they swap the definitions of inlet and output ports on the filter. So I'm still confused as Hell.

Yours sounds correct. The early filter with inlet on the bottom is shown in that 1943 article.

The bottom port on the block with the sender and 4 way fitting is the output of the pump. The top port is the feed to the lifter gallery. On postwar filters the inlet is on the side and the outlet is on the bottom so your car should be letting most of the oil go directly from the bottom port via the pigtail into the top port and to the lifter gallery. A small portion of the oil -- approx 10-15% or so -- goes to the filter inlet on the side of the can and the clean oil out the bottom drops into the crankcase.

On that later vol 22 bulletin where they show the plumbing the entire supply to the lifter gallery is going thru the filter just as it did back in 1940 when the 356 hydraulic lifter issue started. That route is satisfactory for solid lifters because other than the valve which admits oil into the timing chain area at the front of the gallery there is no appreciable loss. Not so with hydraulics.

The earlier issue found was with hydraulic lifters continually losing oil and needing volume and pressure to keep pumped up, along with the loss thru the valve into the timing chain area to keep the chain lubed, there was just not enough flow to do that with all the supply going thru the filter -- particularly if the filter started to get clogged. That is why they went to the pigtail to divert most flow to the lifters with the filter getting a minimal amount to just do the bypass cleaning.

I don't follow. You say , "most of the oil go directly from the bottom port via the pigtail into the top port and to the lifter gallery." But my bottom port goes directly to a fitting just above the oil pan. My side port goes to the pigtail to the gallery on the side of the block.
In any event, you think it's plumbed properly?

I don't have a good photo showing the actual tubing but here is a drawing detailing flow for a factory install on a postwar hydraulic lifter 356 engine. The same is used on 51-4 engines with factory filter. The pigtail is feeding the lifter gallery the majority of the oil supplied by the bottom port. Orifices in a fitting connecting to the tubing going to the filter or in the center pipe inside the filter allow only a reduced amount of oil to flow thru the filter. This is the typical bypass filter system Packard used.

If your tube plumbing is different then perhaps you could post a photo or drawing showing the install so we can see the difference. It may be OK but there is always the possibility someone has done something different.

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Oh, I didn't realize that was a four-way fitting that the sending unit was on. Now it makes sense! Yes, that's the set-up I have so I guess I have it correct. Now I still have to figure out why I'm getting what sounds like tappet noise. Thanks a lot for clearing this up for me.

Could it be missing the orifice at the inlet of the filter?
John

The symptom here that begs for an explanation is the OP's comment that the lifter noise goes away after about 15 minutes, by which time the oil is thinner and pressures are probably lower, especially at lower engine speeds. So what's the explanation for that observation?

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Good point. One possibility might be too much clearance between a lifter and tappet body letting the oil leak out before the lifter is filled and it is taking a long time to get enough volume in the lifter to pump it up. Another might be dirt or a bad ball valve in a lifter that can't seal very well with the same long time needed to fill the lifter.

If it is more than one that is noisy, possibly the overall pressure or volume is low due to wrong weight oil, wear, or sludge blocking the pickup. Another possibility is the timing chain valve is stuck and too much oil is bleeding past the valve into the timing chain so it is taking more time for the lifters to fill. Any aeration if there is too much oil in the crankcase could also be an issue.