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

I have a chugging knock in my 1951 300. It sounded like it came from the front or passanger side of the engine. I consulted the manual, ran the engine without the number one spark plug, and the knock disappeared. I am thinking that I have to replace the main bearings, at a minimum, on the first cylinder. I will not remove the engine since I do not have the space in my garage. Any suggestions as to the safest way to raise the engine and support it during the operation will be appreciated. Also any advice regarding the bearing replacement will be useful. I appreciate all the responses to my Ultramatic Questions, it seems to be working better now after the adjustments.

Dear Casey:

The usual set up used was a bar across the fenders that would suspend the motor same as they use for many modern cars. You could make something out of pipe and/or angle iron.

However, I doubt the noise alone is sufficient diagnosis.

I would test a light body oil 10w-30 in the motor and see if the oil pressure is abnormally low (the oil light should come on at idle) and the noise should change. Worn main bearings usually have low oil pressure. The manual says that main bearing knock is a higher speed noise.

Also, if a piston ring is broken that would show up in a compression test.

Don't rule out the fuel pump for which the cam is tied to number one (I think). If you kill #1 that changes the engine speed as the fuel pump action takes place.

Good luck.

I am not familiar with the 51 Packard. However most all cars of that vintage can allow for pan removal without lifting the engine. I know the 55 and 56 V8 model Packards can allow for pan removal without lifting the engine.

If u must lift the engine then use a cherry picker or differential hoist or some other suitable lifting device just as u would if u were going to remove the engine completely from the car. Once it is lifted to the desired height then support the engine by placing somekind of wooden blocks between the engine mounts and the frame.

I would be very leary to support the engine across the fenders of the car. It weighs about 1000 pounds and i'm nt sure te fenders will take that kind of weight without denting. More modern engines are rather lite and the support acrosss the fenders is often used. I've never used it. I always block between the engine mounts.

Does the service manual indicate that the engine has to be lifted????? What does the manual say about supporting the engien??????

Keith, on the 51-54 straight eights you have to jack the motor off it's front mounts just to get enough clearance between the crossmember and the pan to even get at the front oil pan bolts. Very tight clearance.

I used a 2x4 piece and a floor jack to raise the motor using the front crank pulley.

Thanks for the tip Kevin. I've often placed a block of wood under the oil pan (block of 2x6 or 2x8) big enuf to spread the load to lift engines witha floor jack. Every engine i've tried it on the method works just fine. Just need to make sure the block of wood is thick enuf (at least 2 inches like a 2x4 which is really 1.75" thick) and wide enuf to span broader than the width of the pan. THis is important to be broader than the width of the pan so that the rigid sides of the pan carry most of the load.

Keith, you can do that also on the straight eights, but if you are trying to get the pan off, then the engine can't be supported by the pan itself.

Tim,
I appreciate the info. What I have in the engine now is Rotella 10w40. The oil pressure at idle is 35psi. The noise dissapates as the engine speed is increased. I'll get under the hood and check the gas pump. I rebuilt the pump earlier this year, maybe I'll get lucky and a loose pump may be the problem.
Thanks.

Dear Casey,I too have a 300. I had to lift the engine to remove the pan.I have a question for you.Have you taken the pan off before?Do you or anyone out there think your noise could be a lifter?There was 1/4 inch of sludge in my pan when I took it off.In hindsight my getting the car to the painter most likely saved my engine.I did note that if my engine oil level was at or nearer the top line (If you know what I mean.)other than in the middle, my oil light was less likely to come on.With the exception of in very hot weather.(And I had better not shut her off!)But that is not the topic here I digress.In fear for my engine after the inital pan cleaning.(And anything else I could get at.) I have continued to quick dump my oil to clean it out.(Three times.)I cant tell you the oil pressure but the light used to come on alot more often than it does now.I too thought I needed a bearing job.And I will but not yet.I use straight 30 wt.With some additive from time to time.I have not posted for some time and I am reluctant to do so here, but here it is. B

Brian,
I did clean the pan when I first got the car. I did not remove it but dropped down the back end and cleaned out (as you did), about a 1/4" of gunk. I re-tightened the fuel pump, and really listened to the engine and the sound is more like a chug than a thud, I also noticed that the exhaust gasket is leaking at the #1 cylinder. Perhaps I shall replace the exhaust manifold gasket and see what happens. Brian I appreciate your imput.
Casey Rog