What oil for 351 Winsor that runs at 120*

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This is interesting.

It's unfortunate that he doesn't have an oil temperature guage, for the most part, depending upon how long a duration and how hard the engine is being worked, the oil temperature could be some 50 degrees C higher then the coolant temp. This has been mentioned while in discussion of PCMO's and HTHS I think in "this" section.

As far as running a 20 weight oil...I wouldn't do it unless you're willing to experiment and run some tests. Where's my security blanket!
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His pressures aren't out of whack ...and it probably isn't a matter of viscosity as much as it is of how often he changes it. His oil temp, although probably lower than we would like, probably doesn't track with his extreme cooling. That is, I wouldn't assume that a lighter oil is any type of remedy for a problem that doesn't exist from a lubrication standpoint. I'm surprised that he hasn't attempted to alter the cooling system in some manner. It should not take too much to detune that system that will result in a better operating temp.
 
not prob. a good idea to run a 5W20 weight in that engine...clearances are pretty big, and it's not a newer engine, I assume.
 
I change the oil and filter every 25 hours.

BTW: the shortblock was replaced on this engine about 10 years (500 hours or so) ago. I blew a headgasket early this year, and pulled both heads. Everything was in remarkably good shape, the bores were near perfect, the heads were in good shape. I had them rebuilt, and put it all back together. Runs like a champ, just cold!

Gary, since this is the original Holman Moody setup, I haven't changed anything. It runs so good like it is. Idle is perfect at 500rpm, runs 5200 rpm top.

I'll infrared the dipstick this coming weekend, as well as the block and see what temps I'm seeing. I wonder if shooting the oil filter canister would give me a meaningful reading on oil temp?

I shoot my exhaust manifolds regularly with my infrared, they are aluminum old-style Edelbrock logs with HM risers. The temps are near-perfect, 90 - 100 degrees. So I know my cooling system is working fine for my exhausts.

A Holman Moody bypass cooling system works like this: lake water is drawn into the outdrive by a high volume crank mounted vane pump, and pushed into the block via a y-pipe (mounted where a circulation water pump would go on a car). The water comes out at the thermostat outlet and feeds into the exhaust manifolds then out with the exhaust.

Jim
 
The oil filter should be a reasonably accurate point to measure temp from. Just wait until you're at least 20 minutes into operation. It probably won't give you peak temps ..but it will indicate what range you operate in (160-180
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).

I wouldn't expect your cold temps to hurt your engine in terms of wear per se`. I would expect you to have more combustion chamber deposits due to incomplete combustion. Your pistons will still expand ..etc...etc.. I would expect your oil to get beat sooner ..but you have a pretty short OCI hour-wise. Your shunting a great deal of energy out the discharge of the coolant.
 
Well, you can't argue with success. I wonder if you're reading true engine temp
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What's your thermostat housing read with the infared?? (if you think of it ..check that when you're doing the oil filter)
 
It's a no brainer if it were mine: I'd run M1 15w-50 in it and change it out every 20 hours. That temp is not abnormal for that engine in a raw water setup.

Is there any way to put a fresh water cooling system on it? Folks unfortunately don't think about them unless it's near salt water, and are put off by the added plumbing to upkeep. But that would really stabilize the temperature and aid performance in so many other ways.
 
I would have thought it to be a part of any "salt water" cooling system. I think that there's a bit of nomenclature that I'm not aware of being used here.
 
If I am following this thread correctly....., it is a Raw water cooliing system. This is cooled by the lake, seawater or whatever.?

The other is a closed cooling system with heat exchanger, antifreeze etc. I don't know if I like the term Fresh water cooling. But it is used a lot. Confusing term.

Yours seems on the cold side for sure
 
As I recall, those pump vanes were some sort of rubber, and would deteriorate and not pump enough, or evenly. All sorts of problems would ensue.
 
"Fresh water cooling" is what a closed loop system is called in the industry. The direct cooling section is filled with clean "fresh water" (with suitable antifreeze/coolant additives).

"Raw water cooling" is exactly that: cooling by continuing direct exchange with raw "sea" water.

These are common cooling system terms used in any marina by boaters everywhere.

You gentleman aren't boaters, are you?
 
M1 15-50 without a doubt. Evne though your coolant temp is low your oil temp is not. I ran a couple different small block chevies with raw water up here in the northeast. One was over a thousand hours when I sold it running perfectly and literally hundreds of those hours were WOT at 5100rpms. that boat had a 120 deg stat. Current BBC runs a stock 140 deg stat but oil temps approach 250 cruising at 4800 for extended periods. it is still holding good hot idle oil pressure @20psi after 100hrs when I change it.
 
quote:
What's your thermostat housing read with the infared??
Click to expand...
That's how I determined that the temp really was that low. I changed out senders twice, then shot the t-stat housing. Sure enough, 120-125 degrees.

I'm not interested in changing to a fresh-water system. I'd add weight, and not much performance. Like I've said, this old boat runs awesome. I recently changed the intake manifold to a Weiand Stealth, and it picked up around 4mph.

As far as 15-50 M1, on 25 hour OCI what would be the benefit over the Kendall 20w50 I'm currently running? Temps are not a problem, obviously... Not looking to do extended drain intervals.

Jim
 
At 5,000 rpm, the M1 will hold up much better under that constant full load. Motorheads (unless they drive straight uphill at WOT for hours on end) don't really understand the unique rigors of a marine engine. Anyone advocating thinner than a 50wt is either an idiot or doesn't understand marine operating conditions.

While the oil temps are probably decent, it's still a high moisture environment and you don't want any oil in there too long. There's too much milkshake on the water already. And the M1 will clean much better while it's in there.

Kendall GT-1 used to be great (green) stuff years ago. I don't know what the he** is in it anymore. But I know what's in the M1 and you can count on it. I run it in my twin sixes and it just feels better at WOT.

You'd be surprised at what the equalized cooling of FWC will do for combustion efficiency (i.e. power). Weight? You're talking about 25 pounds total. BUT (a big but), your gasketing better be up to snuff if you ever do drop in FWC, as the whole system will now be pressurized for the first time. I've seen fools do it with tired old riser gaskets (that should have been replaced) that then blew and took out the upper end with it.

Geez, we're talking about a marine engine here. Why are you cheapin out on the lube? You'll burn the tiny savings up in under 30 minutes anyway.
 
The only advantage that I could see using a synthetic 50 weight over a dino 50 weight over that short a duration of use (25 hours) would be the fractional hp gains due the superior VI of M1. It will be closer to a 50 weight at a cooler temp then the dino. Again, you would need to see what oil temp you're running at. The Kendall GT-1 has a lower TBN ..but I would think that it would last 25 hours without difficulty in any application. The emulsification of having too cool an oil temp (unable to suspend moisture) ..will not change with a synthetic. Only the potential for acid formation will be less ..and this would depend on the duration of use.

But any gains in fractional hp with a thinner (closer to spec) oil ..is NOTHING compared to the thermal hp that you're sending out the chitter through the head and cylinder walls. This would be a great application for combustion chamber and piston top coatings to retain this thermal energy.

If you've got the $$$ (and it surely appears that you do) then I would even goto the expense of getting the headers internally powder coated to help reduce the shrinking of the exhaust flow.

[ June 21, 2005, 12:36 PM: Message edited by: Gary Allan ]
 
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