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Technical SBC new rebuild & 75 psi oil pressure with a drill

Discussion in 'The Hokey Ass Message Board' started by 31Vicky with a hemi, May 28, 2020.

  1. I’m putting this thing together and primed the oil system last night. With a crappy drill spinning the oil pump we had 75 psi. I’m thinking that’s way too high and at some serious RPM (set to see 6500) it’s going to be much higher.
    IDK shit about the new oil pump, it was handed to me, I opened it up, cleaned it, coated it with some redline assembly lube, locktite the bolts, installed the pickup.

    Mad thrash for Saturday and I’m not sure what to do about it.
    kidcampbell71 likes this.
  2. olscrounger
    Joined: Feb 23, 2008
    Posts: 3,900


    Seems high. 327 in wife's 55 runs 75 cold and about 50 at road speed when warmed up-30-35 at idle warm. Double checked it. Has been this way for 20 years.
  3. Did you buy the pump? Any idea if it has high pressure spring or relief piston is sticking? Never mind I decoded "IDK". I once ignored an oil pump while on the stand. Bit me in the ass later. Look into now.
  4. anthony myrick
    Joined: Sep 4, 2009
    Posts: 5,930

    anthony myrick

    probably high due to all the assembly lube
    slowmotion and Johnny Gee like this.
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  5. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 5,084


    Maybe the bypass opens at 75PSI, and that's the maximum you'll see. Get an un-crappy drill and spin the pump faster that your crappy drill will and see it the pressure goes higher. If it doesn't then you're good to go. When you opened it up and cleaned it did you disassemble the bypass to see if the plunger was free to move?
    olscrounger likes this.
  6. squirrel
    Joined: Sep 23, 2004
    Posts: 46,446


    Might want to let the engine warm up before you rev it to 6500.
  7. DDDenny
    Joined: Feb 6, 2015
    Posts: 13,674

    from oregon

    Been down that dusty road!
    When I was just a broke kid I bought a (new appearing) Melling pump at the swap meet for a 355 I was building, got it in the car, fired it up and blew two new filters off the engine due to a stuck bypass (rusty).
    I've been religeous ever since when it comes to oil system components!
    For those that don't know; if you use a big heavy drill motor for priming don't put undue downward pressure on it as it could score the oil pump cover.
    Made this primer years ago with a stop collar and nylon washer to carry the load of downward pressure.
    Sorry about the fat fingers!

    20200528_102847.jpg 20200528_102807.jpg

    Gman0046, Hnstray, pitman and 5 others like this.
  8. saltflats
    Joined: Aug 14, 2007
    Posts: 10,198

    from Missouri

    Remember the distributor will only turn half of crankshaft speed.
    blowby and ted kovacs like this.
  9. That 1/2” drill isn’t going anywhere near 3250
    Hnstray and Desoto291Hemi like this.
  10. 2OLD2FAST
    Joined: Feb 3, 2010
    Posts: 2,528

    from illinois

    Being that everything is cold , the fact that you have pressure is more important than the pressure #, I've seen engines carry 80-85 psi , cold idle struggle to carry 35 warmed up going down the road ........It would certainly be helpful to know what pump & what relief spring , save a lot of guessing !
  11. blowby
    Joined: Dec 27, 2012
    Posts: 6,741

    from Nicasio Ca

    There's probably an answer to this somewhere, but I wonder if a spinning engine 'helps' the oil circulate. Centrifugal force to the rod journals, clearances and oil holes opening and closing, lifters moving..

    Anyhoo, best I can remember most pumps I have spun with a drill took just about took both hands to hold it.
    Hnstray and Desoto291Hemi like this.
  12. gary terhaar
    Joined: Jul 23, 2007
    Posts: 655

    gary terhaar
    from oakdale ny

    What oil,and is it a hi volume pump.
    I normally see 65 psi during a prime with a std volume pump. 10-40 or 15-50 break in oil.goes to 40 psi hot at idle,65 is the blow off pressure.
    Rarely do I use a hi volume,wide main clearances and hi rpm I do,mostly no. Parasteic losses and cam gear ware are the main reasons I use a std volume pump.
    Standard pump hi pressure Mel-55 is my go to .Have one in a 355,solid lifter 7500 red line,500 Dyno hp. More than ample on refreshes.
    A hi volume with thick oil may see 75 psi.
    The oil press is mostly dictated by main bearing oil clearance,not rod or rod side clearance as some may say.
    Desoto291Hemi likes this.
  13. harpo1313
    Joined: Jan 4, 2008
    Posts: 1,893

    from wareham,ma

    turn the engine over a few times by hand , then try again.
  14. MAD MIKE
    Joined: Aug 1, 2009
    Posts: 540

    from 94577

    It's cold.
    It's tight.
    It's full of assembly lube.
    It's not rotating.

    Don't worry about the oil pressure(actual) until you get it running and up to temp.
    Remember, the rotating assembly is a controlled oil leak to sling oil on to the cylinder walls, if it is coated in lube and not rotating the oil is just going to go out and in of the passages that it can find.
    pitman likes this.
  15. flamedabone
    Joined: Aug 3, 2001
    Posts: 4,770


    Run the engine, see what it does and if it is too high, go to a bit thinner oil.

    I like to worry about stuff too, but I think you are going to be OK.

  16. Budget36
    Joined: Nov 29, 2014
    Posts: 3,613


    Since you took the oil pump apart/etc, it must have been in that engine before?

    If so, I'd go back to the source for a baseline and see what the pressure was...if it's a new pump, then should be able to fugure out what it is set up for.

    If you did the engine assembley, you know all the clearances, so shouldn't be an issue there. But if you didn't do the assembley then you are pissing in the wind guessing.
  17. Not my first rodeo here.
    I Usually see 30 psi or about 1/2 that with the drill. Another weird thing is I’ve not seen one pump up and oil the top end that quick.

    But it’s kinda weird deal. I’m assembling, but someone else is doing secret prep to the parts I’m being handed.
  18. RMONTY
    Joined: Jan 7, 2016
    Posts: 1,884


    Let the secret parts guy decide how to proceed. At this point you are just the wrench and seem to be confident of your abilities.
    loudbang, tb33anda3rd and Nostrebor like this.
  19. my engine was over 50 with a slow old hole hog. DSCF4071.JPG
  20. big duece
    Joined: Jul 28, 2008
    Posts: 5,949

    big duece
    from kansas

    Possibility its a high pressure, high volume pump? I have always used standard pressure, standard volume. mellings M55
    31Vicky with a hemi likes this.
  21. Ted Chandler
    Joined: May 25, 2020
    Posts: 24

    Ted Chandler

    Is the pickup tube welded to the oilpump? I have seen the relief plunger tack weld itself it place a time or two.
    Budget36 and big duece like this.
  22. 6sally6
    Joined: Feb 16, 2014
    Posts: 1,177


    Slightly off topic (or maybe not!) but........why do SB Fords usually run about 30# or less on a fresh engine but a Shivel-lay needs 50# or more sometimes when running?
    Ford more efficient?!.......Chevy has an inferior oiling system? Seems like......both engines would be just fine running the 30# OR even less pressure. Less parasitic drag = better performance.
    Wonder where Shivel-lay 'missed it'?
  23. doesn't "need", just does.
    Johnny Gee likes this.
  24. Allen wrench pump shaft maybe? :D
  25. Budget36
    Joined: Nov 29, 2014
    Posts: 3,613


    May be because Ford was trying to catch up with GM for many years?

    Truckdoctor Andy likes this.
  26. 2OLD2FAST
    Joined: Feb 3, 2010
    Posts: 2,528

    from illinois

    Sling oil on the cylinder walls and the camshaft !
  27. deathrowdave
    Joined: May 27, 2014
    Posts: 2,172

    from NKy

    My 32 is Ford powered , it has scary scary high oil pressure as in 70 psi plus cruising , 45 at idle in traffic . Is this to much YES , has it hurt anything to date no . Will it break tomorrow , don’t know , don’t care .
  28. Wanderlust
    Joined: Oct 27, 2019
    Posts: 139


    My 292 y block also has high oil pressure 75 at idle, pre startup of the rebuild I also used a 1/2 in drill to pre lube ( on a stand). I did not have a gauge on the engine at that point but while pre lubing the seal blew out of the filter adapter, at that point not knowing how much press. I had I assumed it was the adapter plate which was used and had been over tourqued previously, so I straightened it out and reinstalled, put the engine in the truck and started it. Promptly blew out the seal again, on startup I had a 100 psi, but also an engine with assembly lube and grease, searched around for another adapter plate, found a better one and installed that, happened again, this time I found an old stiff rubber gasket and basically glued it in with aviation gasket maker ( awesome stuff) and let it sit for a couple days to cure, along the way I also pulled and investigated the pump, new high volume and bypass working properly, compared it with a used one I had (pretty much the same) also had a used stock Ford pump but it was too badly worn to consider using. So now I’ve started this motor 5 times and still haven’t run it in! I’m fairly pissing my pants as you can imagine, finally success! no leaks at the filter, other leaks but that’s another story, and ran it in. My pressure is 75-95 and I’ve learned to live with it.
  29. karl share
    Joined: Nov 5, 2015
    Posts: 103

    karl share

    I put a 340 oil pump conversion from hot heads in my 331, with 20/50 oil it runs at 85-90 psi cold,
    once it heats up it drops down to 55 at 3000 rpm.

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