Oil for 1998 Ski Nautique

[Rogerscasey31]

Thanks for all the great advice. I hope to get started soon. In the meantime, I have another question about oil. The po ran a synthetic Amsoil 10W40, which is a high zinc oil comparable to VR1. Any thoughts on switching to the VR1 or is Amsoil a quality oil?

[SilentSeven]

Oh no....oil questions! The next holy grail along with boat polishing!

Indulge yourself here - https://bobistheoilguy.com/

High zinc oil is typically used for stressed engines to mitigate wear...ie / racing engines. Unless you're doing something unique with your engine I don't think you need it but it can't hurt (except in the pocketbook). Amsoil is generally considered a quality oil so no issues if you want to continue with that. Personally, I don't see normal GT-40 use stressing oils that much - RPMs rarely get over 3500 RPM, temps are contained, the environment is free of dirt, and you benefit from a modern ignition and fueling system. IMO, most important is the correct viscosity for your location and temps so you benefit good lubrication at startup. And...like everyone says....change it at 50 hours or so. I doubt most people follow the 60 day recommendation...i know I don't.

This is a snip from the factory manual on oil selection.

[Stevemo14]

I use Amsoil in all my stuff. In the boat i use Amsoil 15w40 Marine and Diesel oil.

[H2O]

If it's a Ford motor (GT 40) then an oil high in zinc should be used to protect the camshaft from wear because it is a flat tappet system.

[Stevemo14]

I have a firend who has an old ZR-1 Vette, and he uses Amsoil Z-Rod Oil, says it works great

https://www.amsoil.com/p/z-rod-10w-4...RoCGZwQAvD_BwE

Its easy to be come a preferred customer. I think its like $25.00 per year or something. I share the cost with a few buddies and we all use the same account.

[Jonny Quest]

Valvoline VR1. SAE 40 or 15W-50. You can also add a little Lucas TB Zinc Plus to oils that need a bit higher ZDDP content. But, yes, a flat tappet cam does need at least 1,200 ppm ZDDP for lobe protection. I’ve seen cams with lobes completely flattened due to the wrong oil. That’s why the gear-heads like roller cams....however, the reason ZDDP levels have dropped in the automotive world is that ZDDP plays havoc in catalytic converters.

JQ