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NE1 shift by oil pressure?

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  • NE1 shift by oil pressure?

    I have a really good 350 that I use on the strip sometimes. The engine is in a 76 3/4 ton truck with the usual high-performance bolt-on mods - Edelbrock StreetMaster intake 850 DP carb, stock exhaust manifolds with duals and Raptor mufflers and a re-ground Densmore cam (came with the truck). I've been saving up for a tach (the sun supertach looks cool), but am wondering if it is worth the money. The engine already has a really good oil pressure gage that I took off an irrigation pump, an plumbed in with a new copper line. I get 8 psi at idle, an it goes up to as much as 45 psi when it hits valve float. If I launch at 14 psi, I get the best bite and 60-ft time, and typically like to shift at 43 psi. Does that sound about right to you guys? I want to eventually wind this beast up to upwards of 50 psi, but I think I will need to hit the junkyard first for some of those beehive springs off a V-6. I think this would be money better spent than the tach, because the oil pressure gauge seems to be quite a good one already. What do you guys think? ???
    -dulcich

  • #2
    Re: NE1 shift by oil pressure?

    I love it honestly. The only problem I can see is as the bypass spring ages it might soften up and your oil pressure will climb slightly that and when you hit the bypass you have no idea what the engine rpm is at that point. There is also oil pressure loss as the motor loosens up but at this point it sounds well broken in so that would be a very slow process and it means you'll always have your eye on it to see if something goes wrong.

    Springs, are you talking L36 and L67 Buick 3800 Series II beehives?
    Central TEXAS Sleeper
    USAF Physicist

    ROA# 9790

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    • #3
      Re: NE1 shift by oil pressure?

      Not sure about those spring numbers, but I have a buddy who says these are the best. I don't know much about the bypass, but my cousin told me when I got the truck that if I wind it all the way to 55 psi it will throw a rod. Since I use this truck to haul scrap, blowing the engine will put me out of work. But man, I'd love the sweet sound of that small block winding to 55psi.
      -dulcich

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      • #4
        Re: NE1 shift by oil pressure?

        The bypass spring is the one in the oil pressure regulator that controls the maximum oil pressure by bypassing the pump outlet oil back into the inlet stream or back into the pan in the case of some high end pumps. Since it is a spring it will work as a linear device so it is decently predictable but it still is eating into your oil pressure increasingly as the pump pressure goes up it pushes the piston and spring back more till the bypass if fully open and stabilized your oil pressure at its maximum.
        Central TEXAS Sleeper
        USAF Physicist

        ROA# 9790

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        • #5
          Re: NE1 shift by oil pressure?

          When I get up to maximum oil pressure, this truck is flat hauling ass. So, are you saying it can be even faster by changing the spring in the oil pump so I can wind this bitch to 50+psi? ???
          -dulcich

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          • #6
            Re: NE1 shift by oil pressure?

            I've learned you can vary your shiftpoint by experimenting with different oil-weights.

            Thicker oil = more Torque = higher oilpressue/low rpm = earlier shiftpoints
            Thinner oil = more HP = lower pressure/higher rpm = later shiftpoints

            In your case I would head over to your local garage who only service small, lightweight cars and fill up 2 cans straight out of their waste oil-bin.
            As an added bonus the ATF-content in the oil helps clean out any dirt in your engine aswell.

            My Dutch 2 cents... ;)
            that's about the same as a US-nickle these days, fyi
            www.BigBlockMopar.com

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            • #7
              Re: NE1 shift by oil pressure?

              The Sarcasm here is thick.
              Escaped on a technicality.

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              • #8
                Re: NE1 shift by oil pressure?

                The real trick would be to get a shift light to work off the oil pressure gauge.
                Tampa, FL

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                • #9
                  Re: NE1 shift by oil pressure?

                  Yeah, and when the oil pressure light beams, slam that bitch to the next gear. ;D

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                  • #10
                    Re: NE1 shift by oil pressure?

                    Originally posted by Beagle
                    Wow! This is a really great thread, except it aint worth sh*t witout pictures. I really like dyno tests. Wallpapered my throne with 'em.

                    I hear them Chevy's dyno best in 28 inches of water. My neighbor is going on power tour, we can use their hose to refill my pool. My uncle is a Chevy guy, when he gets out he can help us. He talked to me one time about valve float - we could test that in the pool too.

                    Hey, I know it's off topic, but I was at my dentist, and he wasn't looking, so we got us one of those NOS kits, and man is it fun. My buddy thinks he knows a lot more than me, he says it's for the car. I said "Duuuuuude... you've been reading too many magazines." Is it true? He owe's me a bottle refill if he loses.
                    Forget the nitrous for a second.......beck to the pool! anyone hook up a motor to work as a pool heater /pump .........what rpm do the run irrigation pumps at????

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                    • #11
                      Re: NE1 shift by oil pressure?

                      Thanks for all the advice, guys - lots of good info here.

                      Big Block Mopar, wow! I never knew it was so complicated. I think I get what you are saying, but maybe Dave and Chad can do a movie on this. I mostly use the re-used oil already though. I put in a couple of hours a week at the wrecker doing the fluid drains, and you'd be amazed at the good oil you find!

                      I don't think I'll go with the shift light, I really like to see the sweep of the gage so that I can anticipate the shift point exactly right. I tried one once that I made out of a toilet paper tube wrapped with black electrical tape with a red Christmas tree light in the back. I found a pressure switch off an A/C system and wired it in, but like to go right off the gage instead

                      Sorry Beagle, no pics - dont have a camera yet, but am getting a good load of scrap on Sunday and hope I can afford a tank of gas for the beast, and maybe keep saving for a camera instead of that tach since it looks like most of you guys agree that the oil pressure gage is better.
                      -dulcich

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                      • #12
                        Re: NE1 shift by oil pressure?

                        all you have to do is listen to when the motor is about to blow......then shift ;D ;D

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                        • #13
                          Re: NE1 shift by oil pressure?

                          Originally posted by Joes66chevy
                          all you have to do is listen to when the motor is about to blow......then shift ;D ;D
                          or keep it planted... :D
                          The official Bangshift garage door guru. Just about anything can be built using garage door parts, trust me.

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