boot

I am talking about "factory" bought . Not one of a kind jobs .
Wondering about engines from such places as mercruiser , Zuhl, Phaff, Eichert etc .

boot

Just gaining info. Some say 10 lbs for every 1000 rpm's is right .
I get nervous if it idles less then 40-50 lbs . My street rods have always been 70-75 lbs .

KAAMA

iTrader: (1)

boot,

Hope you don't mind me jumping in here, but I think the reason why street rods at times see better oil pressures than a boat are because they don't run the sustained RPM's that a boat does or with the same drag co-efficient.

I use a System One anti-cavitating oil pump. It comes pre-set from the factory at 80lbs warm. You can adjust it up to 125lbs, but the lowest setting is 80lbs. When coming off plane to an idle condition the System One is designed not to go below 60lbs of pressure. Actually, on the box it comes in it says something like:

"Factory pre-set 80lbs. warm"

I keep mine at the factory setting of 80lbs right out of the box and I have found that they work extremely well. In fact, last year I hurt the main bearings in one of my engines and I firmly believe that the System One oil pump may have saved my engine from further damage because when we took it apart the bearings were pretty much SHOT, but the System One pump was still able to maintain 40lbs of oil pressure at best and 20lbs at idle on my hurt engine. They pump about 19 gallons per minute vs about 12-14 GPM of the Mellings pump from what I was told.

Hope this has helped

WETTE VETTE

I have my own opinion on oil pressure. I believe less is better, to a point. Excessive pressure is hard on parts like the timing chain and the distributor gear and it also robs HP. Remember what pressure is. Pressure is resistance to flow. That is why when a bearing fails the pressure goes way down. Basically the flow is very high and the failing bearing opens the flood gate. With high oil pressures the pump is trying to push more oil but can't because of the small flow path created by the bearing clearances. This creates aeration in the oil and that isn't good for bearing life. Going back to basics Chevrolet recommends 50 - 60 psi max. They claim more pressure will not aid in bearing life, and the aeration in the oil along with the extra load with higher pressures is actually more damaging than running even less pressure, like 45 psi!!! Think of it this way, less pressure equals more flow which will dissapate more heat from the bearings, and will help to keep any contamination moving so that it can be filtered. I run 10W40 Amsoil at 60 PSI at 6300 RPM and have never had any signs of bearing wear, and we have inspected them numerous times over the past few seasons. This is my opinion as mentioned earlier!! Use the HP to turn the prop, not the oil pump!!!!

KAAMA

iTrader: (1)

I'm no expert, but I do believe there is merrit to what Vette has stated. With all the oil lines I have in the engine pit of my boat, I have to compensate for all of these lines i.e. remote -12 oil cooling lines, remote -12 oil filter lines and I'm running the BIG HP6 oil filters and HUMONGOUS oil coolers! I am probably running somewhere right around at least 20 to 24 feet of -12 oil lines alone! So I need a little more pressure and volume. I forgot to add that I use straight 40wt Valvoline mineral base oil and my oil pressures usually run at about 60-70PSI even though my pumps are set for 80 pounds---and that was LAST YEAR! This year the oil lines are longer because I had to relocate/remount the oil filters. The System One oil pumps are ANTI-CAVITATING---they run about $150 each. I'm quite sure you'd be fine without them though. I just thought I would give them a go.

H2Xmark

come on guys the engines that Boot is talking about run Dry sumps with anywere from one to three scavenge pumps, real trick seperators, so you don;t have a lot of the problems that you would have on a wet sump oil system, most of those high Hp engine's also restrict some of the oil pressure to the upper end, you dont need it with a full roller cam. Engine's like that, hot oil pressure at idle 35 to 40 and about 60 to 70 at high rpm should be more than enough

WETTE VETTE

I am clueless about dry sump oiling. I have heard you need to be very careful when running oil restrictors on marine engines because the valve springs need all the help they can get to keep them cool. Pulling oil from them can mean a very short life especially with a solid roller valvetrain with .650 plus net lift. Is the 800 SC a dry sump oiling system? Cool!!

KAAMA

iTrader: (1)

I certainly don't see many 900SC's so I was unaware that they are running a dry sump system and I certainly know less about them than I do about wet sumps---my bad.

However, in ref to oil restrictors for marine engines, I have to agree with Vette. You might get away with those for a drag motor application 6-12 seconds down the track, but in a marine engine where endurance/longevity is the name of the game, and you restrict the oil from the top end you're just asking for problems. Restricting the oil on the top half of the block is bad on lifters and bad on the valve train in a marine engine application/environment!

Mrgoodwrench

6psi per 1000 rpm is ok.

H2Xmark

it depends on the valve train parts also with restrictors,{most only cut 10 to 20%} Nascar has been doing this for some time now, and if you run a water crossover and no thermostat with custom oil coolers the water temp stay's on the low side anyway, that is also a reason merc and others recommend around every 50 hours a rebuild, gets expensive quick, {on the 900sc}