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

The dispersants in detergent oils keep particles in suspension that are too small to be filtered. This prevents deposit formation on rings and valve guides.

So the only problem with detergent oil is when the motor has never used it and the crankcase is full of sludge. In that case the pan needs to be dropped and the sludge cleaned out.

Yes full flow filtration is better, but GM and Chrysler were building motors with bypass filtration well into the detergent era. VW as well didn't use anything. You can always stick a good sized magnet on the bottom of the oil pan, but if the car sits for a week almost all of the particulates will fall to the bottom anyway.

I wouldn't let a lube bay mess with the bypass filter if equipped unless they can explain why it should be torqued to 15-18 lbft.

For those Packard motors the 10w-30 should go a long way to preventing valve sticking.

Good Morning Brenda in Long Beach...In my humble opinion, since you have found a mechanic that you like/respect, I would use the same person for everything that you don't wish to do yourself. That way they become familiar with your Packard and you become a bit more important to that person as a percentage of their business.

Since my favorite ship is the original Queen Mary, I wonder if you have driven your Packard down to the Queen for lunch? Ernie

I believe you need to use oil with ZDDP in it (Zinc). From what I have been reading, the zinc helps the oil stay on the metal and bearings during the time when the car is not in use. So that when you start the engine after a prolonged period, the oil is still in place on critical components and there is less chance of engine wear. In the day, ZDDP was in most oils but was eliminated in most modern oils due to its damage to catalytic convertors. Since you don't have a catalytic convertor, I believe you are better off with zinc in the oil rather than not.
Most oils for diesel applications have zinc in them. A lot of enthusiasts use Rotella T4 which is a multi-weight and has the zinc in it. I have spoken to Technical support at Shell and Castrol and they both recommend multi-weight oil with ZDDP for older cars

Multi grade oils were introduced in 1951, detergent oils a few years earlier. From the fifties through the eighties 10W30,multigrade, detergent oil was the default choice in every garage and dealership. Chances are, any car made from the early fifties up has never used anything else.

Zinc additives came in also in the early fifties to get over some excess wear problems in the earliest OHV V8s. The high performance, short stroke V8s put more pressure on their cams and lifters than the old flathead and low performance OHV sixes, resulting in excess cam and lifter wear. The ZDDP additive cured this.

Now that OHC engines are the rule they are backing off the ZDDP. This does not matter to a flathead engine like the Packard straight eights and sixes although it might to the OHV V8s.

So the short answer is, use a good name brand 10W30 and don't worry about it. You can use a synthetic if you want to spend the extra money.

Do not listen to knotheads who say all old motors need good ol' non detergent straight 30 oil. They don't know what they are talking about. Taking their advice will do more harm than good.

Rusty,

Amen

Can't the same be said about all this ZDDP stuff?

I think Rusty did imply that the ZDDP is not so critical for the flathead eight engines like our Packards in the thread above. And it is more important for the OHV V8s.

One question that remains is in regard to the ZDDP helping to prevent dry starts. The message from the oil manufacturers is that the oil sticks to the bearings and other metal over time better with zinc than without. This is supposed to help when the car sits for a some time. It supposedly protects against engine wear upon start up.

If it is in fact true, then it is probably better to have ZDDP than not.