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" Getting ready to winterize m

" Getting ready to winterize my 1965 Chris Craft 431, including the annual oil and filter change.

The manual recommends straight 30-weight oil, but I was considering a multi-viscosity oil to deal with the cold temps during the early start, and late end to my boating season. Also, since the engine is well worn in, I favor a heavier oil - in the 40 weight range, so I am considering 10w-40. Any thoughts on using a multi-vis oil in this particular engine?

Also, I have heard conflicting stories about detergent v non-detergent. I used a detergent straight 40 all summer with no problem, but some swear that this will cause massive seal leakage. Help!?!? "
 
"There is a ton of good info a

"There is a ton of good info about this subject on the web, including some excellent articles by several refiners and petroleum engineers. Just Google on motor oil and start reading.

I'll throw in one more opinion for what it's worth. I've had a number of older V8 engines that call for straight "weight" oils. All have run for years on modern multi-grades without problems. There's nothing drastically wrong with running a straight oil as you describe, but it does contribute to wear, especially on cold starts.

The folks that tell horror stories about multi-grade oils being inadequate, causing leaks, or seizing an engine are probably thinking of the multi-grades of the same era as the engine - in your your case, the 1960's. Back then most couldn't stand up to the rigors of marine duty, so manufacturers stayed with a "staight" oil to be safe.

But you'll buy today's oil, so there's really no comparison - and no reason to worry unless your engine has very loose clearances, which is not likely in the Ford/Lincoln 431. The anti-wear, shear resistance, detergent additives and viscosity stabilizers in today's top quality oils are miles better than oils of just 20 years ago.

If your engine is healthy, 10W-40 in a synthetic blend (just my preference) should work just fine.

"
 
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