Why 50 weight oil?
05-05-2017, 04:18 PM
#41
Registered
Iron cam gear = melonized distributor gear.
Steel cam gear = bronze distributor gear.
Most Crane hyd rollers have pressed on iron gears, but others will have to verify that part number.
Merc 25/50 marine oil is NOT 25W50 (a 25 weight base stock with viscosity improvers added), but is instead a mix of straight 25 weight and straight 50 weight with full string olefin strands.
The problem running conventional multi viscosity automotive oils in a marine performance engine is that the constant heavy duty cycle of the marine engine causes premature breakdown of the viscosity improvers, leaving the oil very quickly at its base rating (a 15W40 will quickly break down into a 15 weight oil).
Mixing 20 and 50 weight stocks remains pretty much a mix of 25 and 50 weight stocks long into the useful life of the oil.
SYNTHETIC "multi vis" oils perform differently than conventional muulti vis oils.
A Synthetic 40 weight stock will generally yield the same cold performance and lubricity as a 10 weight conventional oil, so the straight full-synthetic 40 weight is labelled 10W40 but it contains nothing but full 40 weight (hot) synthetic stock.
A 5w40 synthetic is pretty much straight 30 weight synthetic with some viscosity improvers added. If it breaks down, it will still only break down to a 30 weight lube.
0W30 is more like 25W synthetic with some viscosity improvers.
At least that's the best Layman's explanation I can give,
m
Steel cam gear = bronze distributor gear.
Most Crane hyd rollers have pressed on iron gears, but others will have to verify that part number.
Merc 25/50 marine oil is NOT 25W50 (a 25 weight base stock with viscosity improvers added), but is instead a mix of straight 25 weight and straight 50 weight with full string olefin strands.
The problem running conventional multi viscosity automotive oils in a marine performance engine is that the constant heavy duty cycle of the marine engine causes premature breakdown of the viscosity improvers, leaving the oil very quickly at its base rating (a 15W40 will quickly break down into a 15 weight oil).
Mixing 20 and 50 weight stocks remains pretty much a mix of 25 and 50 weight stocks long into the useful life of the oil.
SYNTHETIC "multi vis" oils perform differently than conventional muulti vis oils.
A Synthetic 40 weight stock will generally yield the same cold performance and lubricity as a 10 weight conventional oil, so the straight full-synthetic 40 weight is labelled 10W40 but it contains nothing but full 40 weight (hot) synthetic stock.
A 5w40 synthetic is pretty much straight 30 weight synthetic with some viscosity improvers added. If it breaks down, it will still only break down to a 30 weight lube.
0W30 is more like 25W synthetic with some viscosity improvers.
At least that's the best Layman's explanation I can give,
m
05-05-2017, 06:16 PM
#42
Registered
05-05-2017, 06:59 PM
#43
Registered
iTrader: (1)
My main reason to change is there is a guy here on OSO which has been helping me and this is what he recommends. Never heard of Brad Penn before, and he's been great. Just installed new oil lines, and have a new cooler coming in. With the oil temp sender installed, we should get so good info this season
05-05-2017, 08:14 PM
#44
Registered
iTrader: (3)
My main reason to change is there is a guy here on OSO which has been helping me and this is what he recommends. Never heard of Brad Penn before, and he's been great. Just installed new oil lines, and have a new cooler coming in. With the oil temp sender installed, we should get so good info this season
05-06-2017, 07:38 AM
#46
Registered
Platinum Member
Picked up this boat with 150 hours on the 540. I ran castrol 20w50 for the next 450+ hours changing the oil once each winter - basically every 60-80 hours because that's how long my drives lasted. No time for oil changes mid season. First two years, oil temps would hit 300 if I stayed in it too long, so I re-rigged the entire oil cooling setup. On tear down after 600 some hours bearings and crank looked beautiful, and the 1999 Crower crank and Carillo rods were reused, untouched, for the next 4 seasons and were finally given a break this winter - blew an oil line last summer at 4-4,500 rpm cruise in rough water and didn't notice until the power dropped off - kinda dried those parts out a bit, lol. Crank can probably be turned for a drag racer, but not me, and 3 rods got cooked. I never ran a oil pressure switch because I thought I was pretty good at watching the gauges and had never needed one in 30 years of running boats hard. At that many hours the engine was eating and or leaking at quart every time it went out. Heads, cam, valve train were changed out during that time, so it was only the short block that went over 600 hours.
Left the rubber o-rings on the MSD dizzy before - had pretty fast wear on the melonized gear alright - now i run none, not the top or the bottom one since my Mallorys and Merc dizzy's have never used them. I used the bronze gear in a pinch once, when the local shops didn't have a melonized on hand, after loosing the MSD mag pickup, and had to stab in an old Mallory cause I wanted to go boating... ran it the entire summer, and the gear was hurtin when I finally pulled it - would only recommend that for emergency use. I've run cams from both crane and comp and the melonized gear always did fine.
Left the rubber o-rings on the MSD dizzy before - had pretty fast wear on the melonized gear alright - now i run none, not the top or the bottom one since my Mallorys and Merc dizzy's have never used them. I used the bronze gear in a pinch once, when the local shops didn't have a melonized on hand, after loosing the MSD mag pickup, and had to stab in an old Mallory cause I wanted to go boating... ran it the entire summer, and the gear was hurtin when I finally pulled it - would only recommend that for emergency use. I've run cams from both crane and comp and the melonized gear always did fine.
Last edited by Hang Time 27; 05-06-2017 at 08:23 AM.
05-07-2017, 05:39 PM
#48
Registered
iTrader: (1)
Your pressure is much higher then mine, at idle it's in the 30 psi cold and 20 or less when warmed up. I get up around 50 when running above 3000. So after changed lines, fittings, filter head (AN-10) and new cooler coming, we're hoping to fix the issue. Also attaching a mechanical gauge to double check the electrical one
05-20-2017, 06:05 PM
#49
Registered
iTrader: (1)
Got some updates just as info for what I'm finding
Replaced lines to AN-10, changed cooler to one for 525/500 and installed a mechanical gauge.
Found electrical gauge was showing 15 psi lower then actual reading from mechanical gauge. Replaced sender with 80 psi sender (appears it was a 100 psi sender) and now I'm at 60 psi cold and around 40 psi after a run. Cruise around 70 psi and a bit above that at WOT. Temps getting to 240 degrees at 3800 rpm cruise, and starting to climb above it a bit when running harder. Sounds like I might need a larger cooler
Replaced lines to AN-10, changed cooler to one for 525/500 and installed a mechanical gauge.
Found electrical gauge was showing 15 psi lower then actual reading from mechanical gauge. Replaced sender with 80 psi sender (appears it was a 100 psi sender) and now I'm at 60 psi cold and around 40 psi after a run. Cruise around 70 psi and a bit above that at WOT. Temps getting to 240 degrees at 3800 rpm cruise, and starting to climb above it a bit when running harder. Sounds like I might need a larger cooler
05-22-2017, 06:52 AM
#50
Registered
A lot of marine engines have very low oil pressure after running for a long period of time and then coming off plane, its not so much the weight at start but what its like after being run, so that is why merc now recommending 20w50, will be the 20w @ start up cold, and maintain higher weight when hot. As far as dist wear is concerned, most wear comes from dissalike metals or dist depth, need to run what cam manufacture says for dist gear, mis matching here can be real bad.
