Correct oil

[Horstuff]

My hull card says it's an M 13299. I just got the boat and haven't fully investigated the engine, but it's a straight 6, stamped Chris Craft, blue, and sure looks like it would be the original.

What type of oil is correct for the engine? Also, does the transmission use a different type of oil?

[RRGadow]

If its a Hercule...the motor and trans share oil. We put standard 30W in ours.

[JimF]

There should be a brass tag on the manifold that indicates what weight oil. The brass tag also indicates what model engine you have. It may be missing. I have an "M" and it says 40 weight. Whatever the weight, I believe you should use straight 30 (or 40), not 30 HD. If you are running 30 weight and you find that your oil pressure goes down after running for a while and getting pretty warm, you might up to 40.

[JimF]

Here is a picture of an "M" engine. It is actually an MBL but it is similar

[Horstuff]

Jim,

That looks pretty much just like my engine, thanks for posting that. I have not looked for or seen the tag but I will look for it.

Sounds like the engine and trans use the same oil, right? Do they actually share the oil or just use the same type, filled in two different locations?

[Captain Nemo]

The engine and reverse gear use the same oil and there is a galley where they are connected. When you suck out the oil make sure you take the cover off the gear and suck the last quart or so out of there.
I would recommend a non-detergent oil if you don't have an oil filter because detergent oils suspend contaminants and gunk to the filter so, without a filter, all that is circulating thru your engine all the time. A non-detergent will just allow the crud to settle in the pan to be sucked out at the next oil change.

[maritimeclassics]

You may consider the use of Brad Penn The green one oil. This does not have the zinc and phosphorus removed that helps old engines last, here is the web site read for yourself http://www.penngrade1.com/

[quitchabitchin]

Here is the info from a website that explains the API Service classifications found on the back of oil containers. You can add ZDDP additive or use a heavy duty oil such as Shell Rotella T.



"If you are driving an older classic muscle car or hot rod that has an engine with a flat tappet camshaft, you should be aware of the fact that today's SM and SN rated motor oils contain much lower levels of anti-scuff additive called "ZDDP" (Zinc Dialkyl Dithio Phosphate). The level of ZDDP in current motor oils has been reduced to no more than 0.08% phosphorus to extend the life of the catalytic converter. Phosphorus can contaminate the catalyst over time if the engine uses oil, causing an increase in tailpipe emissions.

The lower ZDDP content is not harmful to late model engines with roller lifters or followers because the loads are much lower on the camshaft lobes. But on pushrod engines with flat tappet cams, the level of ZDDP may be inadequate to prevent cam lobe and lifter wear. In some cases, cam failures have occurred in as little as a few thousand miles of driving! This is even more of a risk in engines if stiffer valve springs and/or higher lift rocker arms are used.

To avoid such problems, you should add a ZDDP additive to the crankcase, or use an oil that meets the previous SL service rating, or use diesel motor oil or racing oil that contains adequate levels of ZDDP to protect the camshaft and lifters.

If you are installing a new camshaft in the engine, be sure to use the cam manufacturers assembly lube and follow the recommended break-in procedure. But you will still need to add ZDDP to the crankcase or use an oil that contains adequate levels of ZDDP for continued protection."

[Peter M Jardine]

The distinction between oils that have two ratings, in this case 10w30 versus 30W is that the former oil has a wide viscosity curve for use in colder weather. When the temperature is low, 10W30 has the ability to act like a 10 weight oil, so that the engine still gets lubricated. In warmer weather, it acts like a 30W oil. There is no effective lubrication difference between the two, except for the vicosity curve. Amsoil make an excellent high zinc content 10W30 synthetic that is intended for use in vintage engines. You can find it on their website. Here is their blurb on this oil. An excellent product.

FROM THE AMSOIL WEBSITE

Protects Flat-Tappet Cams
The lifters and cam lobes on flat-tappet camshafts common to classic and high performance vehicles slide rapidly against one another, producing high friction and heat. The friction between the two components can eventually wear down the cam and affect valve operation, ultimately resulting in lost engine power and reduced efficiency. In addition, these areas are splash-lubricated rather than pressure lubricated like other areas of the engine, which adds extra strain on anti-wear additives like the zinc and phosphorus in zinc dialkyldithiophosphate (ZDDP).

AMSOIL Z-ROD Synthetic Motor Oil is formulated with high levels of ZDDP to protect flat-tappet cams, lifters, rockers and other areas susceptible to wear. Its high-zinc, high-phosphorus formulation provides the extra wear protection these critical splash-lubricated components require.

Provides Long-Term Protection from Rust & Corrosion
AMSOIL Z-ROD Synthetic Motor Oil is formulated with a unique blend of rust and corrosion inhibitors to ensure maximum protection during long-term storage. To prove its effectiveness, AMSOIL submitted Z-ROD Synthetic Motor Oil to the Standard Test Method for Rust Protection in the Humidity Cabinet (ASTM D-1748). This test evaluates the rust-preventative properties of oil under high-humidity conditions, similar to those faced by a covered hot rod in a damp garage. The metal coupon treated with AMSOIL Z-ROD Synthetic Motor Oil showed no signs of oxidation after 192 hours, while the coupon treated with a leading competitor’s product failed the test after 24 hours.

APPLICATIONS
AMSOIL Z-ROD Synthetic Motor Oil is recommended for older or modified engines requiring either 10W-30 or 20W-50 motor oil. Z-ROD Synthetic Motor Oil meets API SL and earlier specifications, allowing for increased levels of anti-wear additives. ZDDP levels in Z-ROD Synthetic Motor Oil exceed the limits of API SM and newer specifications.

COMPATIBILITY
AMSOIL Z-ROD Synthetic Motor Oils are compatible with conventional and other synthetic motor oils. Mixing AMSOIL Z-ROD Synthetic Motor Oils with other oils, however, will shorten the oil’s life expectancy and reduce the performance benefits. Aftermarket oil additives are not recommended for use with AMSOIL Z-ROD Synthetic Motor Oils.

SERVICE LIFE
Because engines in classic cars, hot rods and other performance vehicles are generally modified, a universal oil drain interval recommendation for these applications cannot be given. Responsibility for determining the drain interval duration rests with the owner. As a general service guideline, the maximum drain interval for Z-ROD Synthetic Motor Oil should not exceed 5,000 miles or one year, whichever comes first. In heavily modified engines (e.g. forced induction, nitrous) the maximum drain interval should not exceed 3,000 miles or one year, whichever comes first.