What oil to use in Westerbeke 4-230?

[donradcliffe]

Originally Posted by a64pilot

The myth of syn oil causing leaks is mostly just that, a myth.
I say mostly as there is some truth to it, if your old engine is sludged up and this sludge is helping old leaky gaskets seal, a good syn oil has very good detergent properties and can clean out some of the sludge over time, and this can lead to leaks.

If any of you are old enough to remember engines that ran non detergent oil, what happened if you ran detergent oil on one, pretty similar to switching to syn oil on an engine that has run Quaker State forever and missed more than a few oil changes.
However my 30 yr old Yanmar doesn't even have any seeps, much less leaks, even running T6 Rotella Syn oil.
On my common rail Duramax, I do run the T6.

I'm pretty sure the Westerbeke is based on a British Leyland block. I tried 15-40 once in my Perkins 4108, and over twice as much oil went into the bilge between changes as with 30W. Switched to straight 40 weight and I could live with it.

[uncle stinkybob]

Originally Posted by donradcliffe

I'm pretty sure the Westerbeke is based on a British Leyland block. I tried 15-40 once in my Perkins 4108, and over twice as much oil went into the bilge between changes as with 30W. Switched to straight 40 weight and I could live with it.

and that's a point that should be made here. If the engine manufacturer require's a straight weight oil, that means the whole engine is built with tolerances for that oil, including the oil pump. To maintain proper oil pressure and lube critical areas like lower end bearing it really should be the oil weights recommended by manufacturer. Many here may disagree, thats fine do as you please, but I have been inside to many engines and seen the damage done by improper oil being used.

[sailingunity]

Hey everyone, thanks for the replies. Sorry I've been out a couple of days, been getting ready to leave the dock.

In point of fact, the owners manual for the engine says I can use anything from 10 to 40 weight depending on the temperature. I was saying 20 weight initially because that's what the temps here dictate. Given the range, safe to say the engine wasn't designed for a single weight?

[sailingunity]

Excerpt from the owners manual.

I also see where someone wrote in the owners manual:

Same part numbers:
British Leyland 1500
British Leyland 4-98
MC-110
Leyland 1.5+
BMC 9/16
Nunfield 425
Perkins 4-91

Edit: Apparently my attachments are being blocked, but basically it says below 0F is 5W/20, below 10F is 10W, below 90F is 20W and above 90F is 30 weight.

[Jim Cate]

Originally Posted by uncle stinkybob

and that's a point that should be made here. If the engine manufacturer require's a straight weight oil, that means the whole engine is built with tolerances for that oil, including the oil pump. To maintain proper oil pressure and lube critical areas like lower end bearing it really should be the oil weights recommended by manufacturer. Many here may disagree, thats fine do as you please, but I have been inside to many engines and seen the damage done by improper oil being used.

So, how did you determine that the damage you saw was indeed caused by use of the wrong oil, and how "wrong" was it? Just the wrong weight, multi vs single weight, syn vs mineral, olive oil instead of engine oil... just what?

It seems pretty hard to determine just what caused unusual wear ( I suppose that is w hat you are referring to) long after the fact. So, could you elaborate a bit, please?

Jim