What should my oil pressure be? |
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first boat
Newbie Joined: May-27-2011 Location: Lakewood, CA Status: Offline Points: 32 |
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Posted: June-08-2017 at 5:41pm |
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I have a 1993 SNOB PCM 5.8 Pro Boss and in preparation for the summer I just changed the oil and filter using Castrol Conventional 5 w 30. I put the boat in the water and the oil pressure gauge on the dash read 80 (max) virtually all of the time. After the engine is warmed up and goes to idle after 3000 rpm for a few minutes it goes down to indicate 70 or so but i thought it would be lower at idle after warming up.
I'm on the Colorado River so i run in 95-110 degree temperatures at all times. Should i pick a different oil? I ordered a test kit so I'll try that this weekend to see if the gauge is accurate but I'm wondering what the proper pressure should be? Thanks, Steve |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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10psi for every 1000 rpm is the rule of thumb. Make sure you get a pressure gauge T'd next to the sender. With that thin of oil, your readings are high. The pressure bypass may need attention. Also, check on the ZDDP content of the Castrol. Why the 5-30 weight? Common would be 15-40 or 20-50
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bb12
Senior Member Joined: March-24-2009 Location: Kansas, USA Status: Offline Points: 355 |
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Best to confirm with a mechanical gauge and go from there. A lot of guys, including myself, run 20w50.
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1989 Ski Nautique 2001
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fgroce
Senior Member Joined: July-05-2016 Location: Georgia Status: Offline Points: 350 |
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Question does the 93 Pro Boss have a roller camshaft or a flat tappet camshaft. If it is a roller camshaft then it will not matter how much ZDDP the oil has in it. I run the 15-40 Amsoil is our boats it is good for either flat tappet camshaft or roller tappet camshaft.
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FGroce
88 Ski Nautique For 28 years Now 2002 Ski Nautique |
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21108 |
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Only the vortec and later chevies are roller... all fords were flat tappet, all the way to the end of the run in 2002.
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MourningWood
Gold Member Joined: June-13-2014 Location: NorCal Status: Offline Points: 885 |
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70 is too high.
As advised, measure with a hard gauge plumbed into the oil pressure sender port. May have faulty sender. Also, unless the motor has been rebuilt with super-tight tolerances (like modern engines), then use 20w-50 non-synthetic oil. |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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Steve,
Yes, how did you come up with running the 5-30 in the engine and why the Castrol? |
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MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3590 |
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The 10psi per 1,000 RPM rule goes back many years, I believe Smokey Yanuck coined that term, and it does take care of an engines needs but newer engines are built better and even oil pumps in 1970 had enough volume by 400 RPM to already start opening the by pass.
I like to have an engine tight enough to hold steady 40psi at idle and max at 60 psi wide open. If the tolerances inside are good this works well. When I build one with .002 clearance on the Rods and Mains it generally holds the oil pressure right at the By-Pass rating cold and hot with a stock oil pump, not a High Volume pump. Marine engines are generally a little loose compared to automotive so the idle oil pressure will be slightly lower due to more spill. 10 psi at idle will work but it also tells me something is very loose in the engine. Cam, Main or Rod Bearings. It would help to know the history of this engine, did it always have high Oil Pressure or did someone rebuild it and install a high pressure oil pump. With that high Oil pressure I would not go to a thicker oil but as mentioned make sure your oil has the additives necessary to protect your camshaft. You can buy Diesel Oil at Walmart for $20 a gallon that has all the additives you need. They have added a 10-30 Diesel oil in Delo Brand (Chevron) which used to only be available in 15-40W, this is good oil and would work. I use it because it has what the engine needs and is way less than the $8. per quart for the fancy oils. If you switch to 20-50 you might have 100 PSI in this engine I would not do that. I have seen engines with high oil pressure twist the oil pump drive shaft into spaghetti on a cold start and I saw one blow the spin on oil filter housing right off the engine. Modern race engines are running thin oils, not the thick oils like were used in the 50's, 60's and 70's. I know racers using "0" weight in race engines. They have found as much as 30 horsepower advantage using light weight oil. These engines were clearanced for these light oils. You cant' just decide to start running the super light oils. My only point is the comments on needing 50 weight are old school and 20 years past current thoughts. You do need ZDDP in these flat tappet engines as advised but you don't need heavy oil. My 1978 Nautique 351W gave me 1,500 hours great service on 10-30 weight 30 years ago. It needed new heads at 1,100 hours but the lower end was still rocking when we sold it. Clean oil with ZDDP is important for survival. |
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first boat
Newbie Joined: May-27-2011 Location: Lakewood, CA Status: Offline Points: 32 |
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Thanks for the help guys.
I picked the 5 w 30 because i thought it would be better in the heat, do I have that backwards? Will thicker oil bring down the oil pressure or raise it up generally? I've ordered a mechanical gauge so I'll start there. I definitely have some dash gauge issues - my voltage gauge says 9 when running but the multimeter says 14.2 - so I'm hopeful it could be a readout issue. I will also check the ZDDP on the oil, I didn't pick the Castrol for any specific reason, it was one of the few conventional available with a name brand. i bought the boat from the original owner, 1400 hours, never rebuilt. |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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Steve,
Oil viscosity selection is really how the engine is built and how "tight" it is as mentioned above. Temperature doesn't come to play since marine engines these days have thermostats. (old marines did not!!) Also regarding temperature, keep in mind unlike a car, we have an unlimited supply of cooling available with the lakes we run. I do suggest getting some oil with some decent ZDDP levels to protect the flat tappet engine. I run 20-50 VR1 Valvolene in all my boat engines but there are other good oils as mentioned. |
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 10644 |
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Thicker oil will bring the pressure up.
I'd figure out if you have an indication problem first before deciding on oil but if you're thinking about a diesel oil, read this old thread and go to the PQIA website that's linked in that thread to figure out zinc content. You can probably find your Castrol 5w-30 in the pasenger car motor oil section and figure out that the zinc levels are reduced for newer engines You'll get plenty of oil opinions here on CCF. |
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MourningWood
Gold Member Joined: June-13-2014 Location: NorCal Status: Offline Points: 885 |
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I wouldn't get too fizzed up about high-zinc oil. Yes, it's better for older motors with flat tappets, but yours has hydraulic flat tappets, not solid, mechanical ones.
The hydraulic lifters to provide a cushioning effect to minimize lifter-to-cam abuse. |
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63 Skier
Grand Poobah Joined: October-06-2006 Location: Concord, NH Status: Offline Points: 4232 |
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Sorry, there's just a ton of evidence at this point that the Ford flat tappet engines in our boats need zddp. I suppose it can be argued as it has in many threads on this site, but since there's no negative to using zinc why would anyone take the chance?
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'63 American Skier - '98 Sport Nautique
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Riley
Grand Poobah Joined: January-19-2004 Location: Portland, ME Status: Offline Points: 7946 |
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Is 20-50 really necessary or better in a pretty stock flat tappet engine? VR1 is made in 10-30 as well and would seem like a good choice in places where the temps rarely exceed 90.
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bb12
Senior Member Joined: March-24-2009 Location: Kansas, USA Status: Offline Points: 355 |
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I'd venture to guess you have a ground issue at the dash if you're only showing 9 volts and the oil pressure pegs. Run a jumper ground from your gauge to the negative terminal on the battery and see what happens. |
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1989 Ski Nautique 2001
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63 Skier
Grand Poobah Joined: October-06-2006 Location: Concord, NH Status: Offline Points: 4232 |
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I don't know if it's necessary, but I've run VR1 20W50 in my '63 V6 Buick, '98 GT-40, and '86 454 and none of them shows excessive oil pressure. In the '63 it helped keep pressure up at low power levels. I run them in pretty cold water/air at times and still no issues with excessive pressure. I really expect Steve to find out his gauge is off.
Steve, what oil filter did you use? |
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'63 American Skier - '98 Sport Nautique
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first boat
Newbie Joined: May-27-2011 Location: Lakewood, CA Status: Offline Points: 32 |
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I'll get that ground jumper going and see what i get as a reading.
Maybe i can return that oil pressure gauge... thanks for all the tips on oil, I definitely wasn't looking for ZDDP. For the filter I used Fram Ph8A. |
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fgroce
Senior Member Joined: July-05-2016 Location: Georgia Status: Offline Points: 350 |
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Hate to say it but the Fram filters are some of the worst on the market. I would try a wix or a purolator pure on oil filter.
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FGroce
88 Ski Nautique For 28 years Now 2002 Ski Nautique |
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MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3590 |
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Flat Tappet lifters, mechanical or hydraulic both need the same zddp additive to survive.
Roller lifers are immune to this and since new cars mostly run roller lifters the zddp has been removed from modern oil standards. The 351W marine engine ran flat tappet hydraulic lifters but absolutely needs protection or you can cause a cam lobe to go flat. |
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first boat
Newbie Joined: May-27-2011 Location: Lakewood, CA Status: Offline Points: 32 |
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I finally got to check this stuff out.
The minute I pulled my dash out to get to the gauges the voltage gauge went to 12 so I'm thinking the ground was a little jacked up. The oil pressure remained at 80 indicated and when I jumped the ground it did drop to about 70 indicated. I used the external gauge to test it and it indicated 40-60 between idle and about 3500 rpm - so I'm thinking I'm fine on oil pressure? perhaps it's the indicator or the gauge? Now back to the oil debate, it seems that ZDDP is needed - what weight would you recommend now in the high ambient temperatures where I'm running? and oil filter now that 1 says Fram stinks? |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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fgroce
Senior Member Joined: July-05-2016 Location: Georgia Status: Offline Points: 350 |
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I know a lot of people here do not like synthetics. But I like Amsoil they make a real good 15-40 Marine oil . One added plus with this oil it is a mil spec rust preventative for when you have the boat just laid up. It is also a diesel oil. They also make a real good oil filter the one you would need is a EAO-15. I have been running these oils for years with awesome results. Hope this helps. Some people think that it is a waste of money, but I have many motors with high hours that run strong as new.
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FGroce
88 Ski Nautique For 28 years Now 2002 Ski Nautique |
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SNobsessed
Grand Poobah Joined: October-21-2007 Location: IA Status: Offline Points: 7102 |
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I'm not following adding a ground to the dash gauge. I thought the ground was at the engine sensor.
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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Correct. The ground source is the engine block. The only reason there's a ground on the gauge is for illumination. |
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