Oil Pressure Problem 351w |
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Ryan351w
Groupie Joined: May-24-2009 Location: United States Status: Offline Points: 43 |
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just a little rule of thumb...10psi per 1,000 rpms.
The better the machining the less pressure needed. I talked to a head guy at Melling and he was telling me that the NASCAR engines run only 70-80psi. Granted these motors come apart every race, regardless of that the motor would take itself apart if there wasn't enough pressure. Remember these motors turn over 9,000! Another little trick, diesel oil. I run it in everything, 500hp mustang, aurora, boat, diesel truck. The diesel oil is awesome. My buddies dad runs it in his blown 340, in the motor and the blower. It has alot of additives in it that were takin out that protected metal-to-metal contact. It was mainly there for lifters to cam lobes. But when roller lifters and OHC's came on the scene they decided that it wasn't needed anymore. Luckily diesel motors still use flat tappet lifters so those additives are still needed. Another piece of info-pump placement in the motor packaging itself has no effect of where you will get higher or lower oil pressure. The oil galleys are drilled where they are drilled. They feed the mains and rods then depending on the motor it will pull from the main galleys to feed the lifters/cam/push rods. So running a "jumper" line from the front to back or vise versa is helping a bad spot (low oil pressure) in the motor. |
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21109 |
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Careful! Most diesel oils have removed the heavy metal additives to comply with the new emissions equipment. This change has come about within the last few years. Only a select few grades still have the required ppm of ZDDP that flat tappets need. Rotella straight weights and Valvoline Racing VR1 still have pretty high levels of the stuff- I run the VR1 in all of my flat tappet boats. |
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GottaSki
Grand Poobah Joined: April-21-2005 Location: NE CT Status: Offline Points: 3327 |
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Consider checking your sources. You may have the order backerds, the failing cayalysts and extended gov'ment mandates for emissions warrantees drove the reduced zinc oil blends that neccessatated the roller cams, not the other way around. Automakers didn't just convert their fleets roller to be kewl. While i agree the oil is better, the diesel oil has much reduced zinc over the last two years, so be wary as this progresses. This is due the same driving forces. I think you are mistaken about the flat tappet lifters. I can report GM diesels haven't used flat tappets since the 350 olds/diesel abortion almost 30 years ago. Even the old detroit two-strokes are roller. |
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"There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing."
River Rat to Mole |
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Ryan351w
Groupie Joined: May-24-2009 Location: United States Status: Offline Points: 43 |
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Gottaski-http://www.cumminsdieselspecs.com/67.html My source. And in non-diesel engines rollers just allowed them more aggressive lobe profiles which = more power. Less duration/more lift. Idles better too. Possible friction advantage could be part of it too.
There have been roller motors for a LONG time in the OEM field. I know in the mustang the roller was introduced in 85. Dodges' in 91. Oil changed in early 2000's TRB-That’s exactly the oil I’m referring to. Rotella-T is a diesel oil. And when I buy generic stuff, I make sure they have the same mount of additives. |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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Ryan, Glad you stated the Rotella but keep in mind that it's the straight weights that have the ZDDP. I'd hate for someone with a flat tappet engine to be misinformed. The ZDDP has been researched and discussed at length here. I like Tim run the VR1 in all my engines. BTW, I am hearing about cam failures on old engines. A couple from flat head Hercules owners who were using what they thought was "good" oil!!!! |
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Ryan351w
Groupie Joined: May-24-2009 Location: United States Status: Offline Points: 43 |
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On a quick search while cooking I found that the Rotella with "triple protection" has..."Multigrade Oil SAE 15W-40 with Triple Protection Technology, our API CJ-4/SM specification product, typically contains about 1200 ppm zinc and 1100 ppm phosphorous as manufactured."
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Greg_SA
Senior Member Joined: April-19-2007 Location: South Africa Status: Offline Points: 168 |
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Hi,
Thanks very much for the responses... So it sounds like my old pressure is okay, but I'll double check with the mechanical gauge, and keep an eye on it :) Regards, Greg |
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1989 Ski Nautique (SN2001)
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eric lavine
Grand Poobah Joined: August-13-2006 Location: United States Status: Offline Points: 13413 |
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many cam failures lately on the flats, 3 to count on rightie bbc's, not a good percentage since they were the only 3 i took apart this summer, there are zinc additives out there also and probably wouldnt hurt on top of the oil change, i was a skeptic, now im not
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"the things you own will start to own you"
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GottaSki
Grand Poobah Joined: April-21-2005 Location: NE CT Status: Offline Points: 3327 |
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Ryan since it appears you are a student of automotive trivia, you may find it interesting the GM/allison 6.2L diesel was roller for its introductory year of 1982, three years before the mustang 5.0 HO roller cam engine, and even the 350 olds abortion i spoke of went roller half in the latter half of its run in 1980. |
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"There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing."
River Rat to Mole |
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eric lavine
Grand Poobah Joined: August-13-2006 Location: United States Status: Offline Points: 13413 |
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i recently took a 4.3 vortec apart, roller cam, roller lifters, a balance shaft, real potential for some power there, i see alot of them in boats already and pretty lean on the fuel useage. not recomending them for a ski-boat but was pretty surprised to see the roller rockers
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"the things you own will start to own you"
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eric lavine
Grand Poobah Joined: August-13-2006 Location: United States Status: Offline Points: 13413 |
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i was thinking of bolting 2 of them together though, a nice v-12????lol
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"the things you own will start to own you"
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Preston01
Newbie Joined: September-23-2018 Location: Mississippi Status: Offline Points: 19 |
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Hey y’all,
I am experiencing the same issues on my 83FN. Would replacing the 160 degree thermostat with a 140 degree help with the viscosity? Any other suggestions? |
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