Packard Forum Index » V-8 (1955-56)

Had a bad feeling in my gut all day. Took my car to a show only about 14 miles from my house. right before i pulled in, the engine began to make a bad whacking noise. i goosed the engine a few times and the noise went away. I figured that shes 52 years old and, while it did concern me, i shrugged it off. after the show i re started, and everything seemed ok. i made it about a mile down the road and the tapping resumed but worse, and a rev did not help. The noise was a sharp metallic rap that seemed to be coming from deep under the lifter valley cover. if I put my hand on the valve cover, i could feel a sharp pulse that was in time with the noise. throughout all this the engine ran perfectly smooth and maintained perfect oil pressure.

i had the car towed home on a flatbed.

please help!

could a lifter be stuck??

maybe take the cover off and inspect.

thats what i was thinking. sticking or completely collapsed

"Whacking noise", "metallic rap"; those are the words people use to describe a spun rod bearing. I'd drop the pan and pull the rod bearing caps for inspection.

I concur. If it continued to run smoothly, it is unlikely to be a stuck lifter/valve. My bet would be on a bearing. Probably spun or simply worn out. You were right to be cautious and have it towed. I have seen a 40 that was running perfectly and within about 5 miles threw a rod through the side of the block. It's relatively cheap to check the bearings and not so cheap to repair/replace the block.

Rod knocks don't usualy go away. Start the engine and just let it idle. Remove one plug wire ata time (and put it back on before moving to to the next wire) and listen to see if the knock goes away or greatly diminishes.

This sounds like a lifter noise problem. This is a typical problem on OHV Packard V8s due to the inadequate oil pump. There has been quite a lot of discussion on this subject if you look for it. The most drastic solution is a larger Oldsmobile oil pump, they sell an adapter for this. There may be other things you can do without tearing your engine apart. Hope some of the real experts chip in on this.

Since it's a V8 it's most likely lifter noise DUE TO WORN OIL PUMP and not necessarily bad lifters. This was most common among the V8's.

Try filling the crankcase 1 quart over the full mark on the dip stick. If that helps or doesn't, then run an oil line from the BACK of the block at the oil pressure sending unit to the oil filter and disconnect the original filter feed line at the front of left head and plug the head.

This does NOT correct the oil pump fault but should eliminate or greatly reduce the symptom (lifter noise) if that's what it is.

I have a 55 400 and have experienced much the same problem. There would usually but not always be lifter rattle on starting which would go away as the car warmed up and was revved a little. This would also sometimes come back at idle. Last time I started the car i got the same rattle which suddenly began to sound like something more serious. I shut the engine off and am now wary about starting it again.
Reading about the shortcomings with the standard oil pump I figured this may be oil starvation and I am getting a Melling conversion kit from Craig which I will fit and try again with fresh oil when I get time.
While the oil pan is off I intend to look at the bearings but I don't really have enough experience to know what I am looking for. I also intend to remove the valve covers and see if anything is amiss there.
Any advice would be appreciated.

You really need to do some of the checks mentioned in this thread before you buy anything. I am leaning towards checking the bearings, let us know what you find.