Packard Forum Index » V-8 (1955-56)

Hi,

Wondering what the best type of oil would be to put in a 352 V-8. The 1956 Clipper manual suggests using 10W-30.

Any recommendations on what brand of oil to use? Or weight?

The engine "had the heads redone, and new rings installed" like 10-15 years ago and within the last 20k miles.

It has an Oldsmobile oil pump if that makes a difference. Oil pressure is around 60-65 PSI at all speeds.

Edit: looking in the service manual it looks like the pressure should be 45-50 PSI. IDK how big of a problem it would be to have it higher, or if it could be caused by the oil being old. We put a fair amount of 15W40 in it just to top it off earlier too.

You'll want to add a zinc additive to the oil (ZPPD)for reduced lifter and cam wear.

I swear by Mobil 1. With that kind of oil pressure, likely you could back it down to 5w20. Stuff might be a tad tight and you want to be bearing on the oil film and not steel.

15W-40 is a low rpm diesel oil. With the Olds pump the primary drawback is excessive wear on the distributor drive and lost power due to pumping loss. With the stock pump it is not advisable given the pump is designed for 20w oil (ie distortion of the pump body).

Starting after the API SJ rating zinc levels were decreased. So for example, lawnmower oil that is sold as such is an SJ rating. Thus, the lawnmower makers want the zinc.

On the earlier Senior Packards I doubt the zinc matters because they have soft valve springs and rocker follower rollers. For the V-8 an oil closer to as built probably is a better fit if the car is being used for a lot of highway driving. As well, these modern diesels have diesel oxidation catalysts and particulate filters so the zinc content of those oils is subject to that consideration.

You can buy the zinc additives or SJ rated oils from firms such as Lucas and 10w-30 is a fair choice given Packard specified 20w for that engine.

Alright, will be asking for 10w30 and will be looking at zinc additives soon.

Thanks for the help everyone.

Risolone offers a zinc additive and Lucas has a full line of SJ rated oils with the zinc.

One of the reasons I don't like those heavy oils is because at least 40% of the power produced by an engine is used making it go round and round. So if you put heavy oils in that number goes up. Packard recommended heavier oils to control consumption due to worn rings so if the car isn't blowing smoke heavy oil is not needed.

In the ultra horsepower dyno cars we used the 5w-50 and they occasionally blew up. That oil had massive amounts of either viscosity improvers or pour point depressors. But those oils also were low zinc to protect cat converters.

Thanks Tim I will look them up before I get the oil changed.

I don't know when the oil was last changed but in 2017 the previous owner mentions using 15W40 Classic Car oil. Could explain why the pressure is so high.

packardinfo.com/xoops/html/modules/newbb/viewtopic.php?post_id=188532

Another option (and the one I use) is to buy CCCA Motor Oil from the Indiana Region of CCCA. The Indiana Region combined efforts with D-A Lubricants to produce an oil that contains ingredients, including ZDDP, to protect our old flat-tappet engines. For anyone interested, their web address is:inrccca.org/product/classic-car-motor-oil/

One other item is that 10w-30 will run cooler with less tendency for foaming than a heavier oil. Modern cars typically run in the 60-65 psi range using crescent type pumps, but I would put an oil closer to spec and see where that number ends up. The hydraulic lifters are calibrated for lighter oils as well.

I forgot to mention earlier but when I was driving home and got the engine properly warmed up, it was 40 PSI driving and 20 at idle

Vs. 60-65 for both when cold