Packard Forum Index » V-8 (1955-56)

The 1955 heads are lower compression, and shorter, 1/2" reach spark plugs are used, where the 56 has 3/4" reach.

The 1955 main bearing caps are less beefy, and the bolts are shorter.

The retainer for the timing chain cover seal is smooth, where the 1956 is knurled. I understand this change was made due to some of the sommth ones spinning loose. Even with knurled ones, I always drill thru the retainer and cover, and install three, evenly spaced screws and selflocking nuts. They are behind the vibration dampner and only visable with a flaslight.

Most may already know this, but the 1955s have a collar behind the cam retainer plate that floats with the cam and allows a steady stream of engine oil to pump onto the tinming chain and gears. Late 1956's have a collar that is pressed onto the cam, and only allows a squirt of oil each time a hole in the collar lines up with the oil galley; one squirt per revolution, versus a steade stream. This was one of the factory's fixes for low oil pressure.

Joe H

"Late 1956's have a collar that is pressed onto the cam, "
What leads u too believe that???? I have seen NO such PRESSED on collar. The collar is different on LATE 56 but NOT pressed on.

The collar in any Packard V8 is niether pressed NOR floating. It is PINCHED between the cam and the gear. Remove the gear and slide off the collar. The LATE 56 Collar is different from all other collars ONLY by a flat that is ground on the OD of the collar. The late 56 plate is different from all other plates by the way the oil grooves are cut.

I would have dig out a collar and look at it to refresh my memmory but it is possible that there is a relief or champfer cut on the ID of the collar to accomodate the radii at the machined shoulder of the cam. Otherwise, the collar MIGHT wedge at the radii of the cam and give the impression that it is pressed on.

Keith -

Attached is a pic of the late design plate and spacer, with a paperclip showing a drilled passage that would otherwsie be invisible to the casual viewer. I had posted this image at another forum, sometime ago, to help clear up some confusion as to which parts were which, but I bet they threw the baby out with the batwater on that one, too.

Someone else had posted a similar pic of the early design parts that they had removed from one of their cars - perhaps you. If so, please post it here as a visual reference for all in this more permanent site.

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"The collar in any Packard V8 is niether pressed NOR floating. It is PINCHED between the cam and the gear."

You are right, float is wrong; pinched is correct, guess I need to refer to my notes more often before speaking off the cuff. Also, IIRC, the difference between the thickness of the (thicker) collar and the retainer plate is what determines camshaft endplay.

As for the collar being pressed on or not. The early ones practically fall off, but I have never been able to remove one of the later ones. I recall using putty knives, screwdrivers, etc., but never succeeded. I just figured they were either heated and dropped on, or pressed on, but what do I know.

Hey, cut me some slack, I am just a new guy :)

Joe H

Another diference between early and late V8s (don't know exactly when they started) is the addition of oil shrouds on the valve springs. I once had a set of heads come back from the machinist with them installed upside down, and I did not notice it. Of course wee know that upside down they do absolutely nothing, but if installed correctly, they deflect the oil from dripping directly on the valve spring and seal.
With that set of heads, the engine fouled a plug on the left front cylinder in about 5,000 miles. I used a rope snaked thru the spark plug holes to hold the valves in place to remove and re-install the shrouds, one cylinder at a time. What a pain it was, but it taught me to check the shrouds after that.

The early V8s must have had major problems with plugs fouling until they came up with that simple fix.

Joe H

Something else that needs to be known is AMC, Studebaker, and Packard oil pans. This is an AMC pan that's currently on e-bay right now. This is exactly like the one that came off of my 320 that was originally in a '55 Hudson Hornet. I know for a fact that the AMC will NOT fit in a Packard chassis, and probably vice versa. The oil pan will hit the steering linkage on a Packard chassis, and the indentation on the AMC pan towards the rear is to clear the steering linkage on an AMC chassis. That being said, I know that if you used a Packard oil pan on the earlier Stepdown Hudson chassis, it would clear. A nice, useless piece of info for me to share.

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