Anyone using Rotella T4 15-40 blend on older engine?

[El Capitan]

I'm reading more about flat tappet motors and I know my 1970 2.5 mercruiser has to be due to its age. Getting ready to do my seasonal oil(s) change and I normally buy mercruiser oil online but not sure about the whole high zinc zddp better for old engines question.

Anyone using this high zinc Rotella?

Thanks,

 

[HardHead]

I've been using Rotella straight 40 W
on 1996 7.4s for numerous years.
No problems.

 

[hottoddie]

If your engine has a flat tappet camshaft the zinc is used to protect the camshaft and lifters from the extreme pressures on the camshaft lobes. I use Valvoline VR1 racing oil. Available on Amazon.

 

[Snapon24]

I use Caterpillar non ULS 15W40 DEO in my 7.4L's. Higher zinc than the ULS diesel oil and Mercruiser oil. Whatever brand you use just make sure its only rated for CI-4, not CJ-4 or CK-4. Those 2 are ULS with less zinc.

 

[paulswagelock]

Rotella t4 is a good choice for your motor. High zinc and phosphorus, good shear stability.

 

[El Capitan]

Thanks guys!

 

[Getaway]

If your engine has a flat tappet camshaft the zinc is used to protect the camshaft and lifters from the extreme pressures on the camshaft lobes. I use Valvoline VR1 racing oil. Available on Amazon.

I second Valvoline high zinc VR1 Oil. NAPA carries it on their shelves.

Carquest carries Brad Penn high zinc racing oil which is another great choice.

 

[JohnGordon]

I also use Valvoline VR1 oil in both mains and the generator.

 

[Mikerosoft]

I use Rotella T4 15-40 in my 86 5.7. Aside from the zinc content, the diesel oil has an excellent detergent package that helps keep these cooler running marine engines clean.