[email protected]
Hotrod List  7 Jan 93
- Y'know, Crower claims a small Chevy can have as 80psi at one end of the
  crank and as little as 10 at the other, but I never thought about moving
  the regulator.
- Hmm... in a Windsor Ford or small Chevy, a logical place would be the
  main oil gallery, about 2/3 of the way to the far end of the block.  You
  could drill and tap into the gallery up inside the lifter valley, then
  mount the popoff valve in there where there's plenty of room.  The Ford
  also has the option of tapping the back of the gallery at the back of
  the block and putting in an angle fitting, running to an external popoff
  valve.  (the Chevy's oil pump is at the other end, so that trick
  wouldn't work)
- There are a couple of possible gotchas, though a careful eye on an oil
  pressure guage directly after the pump would prevent trouble:
        1)  the oil filter might see a lot more pressure than the maker
            bargained for, with predicatable results
        2)  if the pump's back pressure gets very high, the load on the
            distributor drive gears and timing chain goes up

[email protected] (Dave Williams)
gnttype  17 Mar 1994
- -> If it is rod-knock, how could the oil pressure be so strong?
- The rods are at the absolute end of the oil path; if you took #6 rod
  out entirely and let the crank bleed, it wouldn't affect oil pressure
  that much.  What you're measuring is back pressure at the pump.  It's
  not a direct relationship to the pressure at any other place in the system.
- This may be somewhat counter-intuitive if you're used to looking at
  hydraulic diagrams, where the pressure is the same anywhere.  The oiling
  system, however, is open-ended, not closed like the brakes.  The oil's
  viscosity provides a majority of the resistance to flow.
- The common way to diagnose a rod knock is to rev the engine up and let
  off.  If the noise damps down or goes away under load, then "clatters"
  when you let off, it's probably a rod.
- Other possible culprits could be carbon buildup on the piston domes, a
  cracked piston skirt, or even a loose torque convertor bolt.

[email protected] (Dave Williams)
fordnatics  07 Aug 1996
- -> That is a relief.  I'm running 10w40 dino oil, and not racing sludge.
  -> I know the "high volume" pump is physically larger, and typically a
  -> truck application pump, but if most of the "high volume" recalculates
  -> around the bypass in the pump, what is the benefit?
- No benefit if the engine is in good health.  For old-timey "racing" 
  clearances you just about had to have an HV pump to get any pressure at 
  idle.  There's also some advantage if you're running 5w or 0w oil and need 
  to get the pressure up at idle. 
- Unfortunately, idle is the worst case for the oil pump.  By 1250 RPM or so 
  it's on bypass - the engine's oil volume requirement doesn't change much 
  with respect to RPM.  I'd love to have some sort of variable speed oil pump 
  drive to keep the damned thing from sucking power and aerating the bitch out 
  of the oil. 
- For a track-only car it'd almost be practical to run a very small pump sized 
  to track RPMs and an electric booster pump for idling around the paddock.  
  Then again, it could be an extreme case of turd polishing. 
- -> I always thought it was better to flow high volume at the same pressure, 
  -> rather than the same volume at a higher pressure, or high volume at high 
  -> pressure. 
- True, since the volume is what helps cool the bearings.  I have a number of 
  references citing bearing temps >300F under high speed load; interestingly, 
  that's about where some of the lower melting point alloys start bubbling out 
  of the bearing shells.  Pump more oil through, the bearings stay cooler, at 
  least until the bulk oil temp in the pan exceeds your desired maximum 
  bearing temp. 
- The main bearings the 5.0 chucko spun a rod bearing in were down to the 
  copper backing.  I'd hate to see what skod's look like, since he was running 
  >300F oil temps for *years*. 
- -> higher pressure, or high volume at high pressure.  I knew the high
  -> pressure really ate horsepower, but the high volume eats a lot too.
  -> Did I waste $15 extra I had to pay for a high volume pump over the
  -> stocker?
- That's one of those hard-to-tell things.  For extended high RPM use the HV 
  pumps aren't always a great idea.  For a street vehicle, particularly 
  something pulling a trailer, trucks, or RVs, the HV pump will help keep oil 
  pressure up once the oil temps have gone into the "tilt" zone. You pays your 
  money and you takes your chances, as they say.  I vacillate back and forth 
  since I don't have any real data either way. 
- One tried and true rule of thumb has been "10 psi for every 1000 RPM". That 
  was originally Smokey Yunick wrt the SBC, but most builders apply it to 
  everything.  More pressure can't hurt anything, assuming you don't flood the 
  valve covers, but I've begun to wonder if it's applicable to the SBF.  In a 
  Chevy - even in most expensive aftermarket cranks - the oil holes in the 
  crank are drilled "backwards", ie, the oil must make an acute angle to get 
  into the drilling on the main.  On a Ford the hole basically scoops the oil 
  right out of the bearing, maybe 60 degrees vs. 270 or so.  I also have 
  several references which cite centrifugal force as being more than enough to 
  keep pressure in the rod bearings at high RPM; several builders claim they 
  can suck enough oil out of the mains to cause main bearing failure.  I find 
  all this stuff very interesting, but until I can verify stuff like this 
  myself I take the Missouri attitude to most of it. 

[email protected] (Dave Williams)
gnttype  05 Dec 1996
- -> make folks infer that heavier weight oil will produce more wear on an
  -> otherwise good oiling system in the TR.
- You need an oil viscous enough to show whatever minimum pressure you want at 
  hot idle.  Past that and you're not doing anything useful.  The timing 
  chain, front cam bearing, and front main bearing will thank you kindly, as 
  will the oil pump drive gears. 
- Some people run heavier oil to quell piston slap caused by excessive 
  cylinder clearances.  Might be a reasonable justification, though the noise 
  doesn't hurt anything that I know of. 
- -> people see the extraordinarily low oil pressure on the typical TR motor
- The rotation of the crankshaft inside the bearing builds up a "hydrodynamic 
  wedge".  Basically, as long as you have an oil feed - even a drip feed - the 
  bearing generates its own pumping action due to the rotation of the crank.  
  Some people have the idea the oil pump somehow floats the crank on oil, and 
  the more pressure the better.  The pressure is in fact barely relevant; the 
  only reason you're using more than 1 or 2 PSI is to ensure *flow* through 
  the bearing.  Bearing temps can easily go over 300F even in low-horsepower 
  engines like stock 5.0 Fords when run hard.  This is the melting point of 
  some of the alloys used in the bearing shells, as I found out to my dismay 
  when experimenting with moly coatings.  The heat comes from the internal 
  friction of the oil in the bearing clearances. 
- For endurance racing engines the need for cooling the bearings and the need 
  to keep internal windage down are opposing problems.  You need to pump lots 
  of oil through to cool the bearing, but if you pump too much you'll 
  overpower the tray, scrapers, and oil rings.  This isn't really a problem 
  with drag motors. 
- -> "problem" that really isn't one.  More pressure than "stock" will not
  -> increase bearing life assuming there is sufficient volume  - indeed,
  -> too much pressure can just whip more air into the fine oiling system
  -> GM designed for the little 231 V6, and cause problems.
- Absolutely true.  Still, it takes a strong-willed builder not to slap a
  high volume/pressure pump in there "just in case."
- -> a problem, and the concern may be unwarranted, but remember that
  -> several SAE papers have suggested that 50-80% of all engine wear
  -> occurs in those first few seconds of cold startup.
- The origins of those papers are questionable.  (most of them originate from 
  Petrolon, the makers of Slick 50)  I've taken apart a bunch of motors and 
  I've never seen anything I could point to as "startup wear." Worn slam out, 
  rods hanging out the bottom of the oil pan, or fried because the owner 
  didn't worry about the oil pressure guage reading zero since no idiot light 
  came on, yes.  Startup wear, no. 

[email protected] (Dave Williams)
diy_efi  13 Dec 1996
- -> WRONG.  Why the heck would it be called a high volume pump if it
  -> didn't pump more volume per revolution?!?!?  If you carefully compare
  -> the stock pump with a high volume pump, you will note the body of the
  -> pump is longer, denoting longer gears in the pump, and thus more
  -> swept area of the rotors. More area x same RPM = higher volume.  This
  -> will equate to higher average oil pressure, all else being equal.
  -> The only circumstance the oil pump recirculates is if the filter is
  -> allowed to clog up, at which point there is a bypass valve in the
  -> block which still allows oil to circulate, albeit unfiltered.
- For ordinary Ford and Chevy applications there is an internal bypass in the 
  actual pump casting itself.  A spring loaded plunger in the bypass short-
  circuits the flow from the output to the input side of the pump when design 
  pressure is reached. 
- With the same spring, both the standard and high volume pumps will flow the 
  same amount of oil at the same running pressure.  None of the "high volume" 
  ever makes it out of the pump. 
- The only time you will ever see a difference between a standard and high 
  volume pump is when the standard pump can't meet its designed pressure.  
  This happens at idle and very low RPM.  Past 1500 RPM or so you're pumping 
  far more oil than the engine needs.  A constant-volume pump isn't the best 
  choice for high RPM use, but it is mandatory if you want to have oil 
  pressure at low RPM.  Some true racing engines like the old BRMs use 
  centrifugal oil pumps which took far less power than positive displacement 
  pumps.  However, these engines never had to idle for more than a few 
  moments. 
- The filter bypass valve you discussed has nothing to do with this.

[email protected] (Dave Williams)
fordnatics  02 Feb 1997
- -> ANY engine should hold 35 to 50 lbs. of oil pressure unless it's worn
  -> out. My 429 has over 100,000 on a rebuild, and holds over 30 lbs. at
  -> idle, and over 60 lbs. when revved. I would consider less than 20
- Modern (1990s) engines typically run much less oil pressure than they used 
  to.  15 pounds or less at idle with an honest guage, 30 to 35 at road speed.  
  All in the name of the holy C.A.F.E., you know. 
- Mazda, being heavily weird, runs over 100psi oil pressure in some of their 
  rotaries.  The rotaries have three (3) bearings, all very wide, which is 
  good, of fairly ordinary diameter.  The loads are low, and by most design 
  standards you could *almost* get away with a wick and an oil cup.  Nooo, 
  they go nuts with oil pressure.  Who knows? 

[email protected] (Dave Williams)
fordnatics  01 Apr 1998
- -> OK...somebody explain to me how you can have an oil pump that produces 
  -> higher pressure without producing higher volume...or vica versa. 
- A "high volume" pump has longer rotors.  It would, given a chance, make more 
  pressure as well, but the internal bypass spring (oil pressure regulator) is 
  the same as stock, so it simply dumps all the oil overboard. 
- Unless the engine is a horrible bleeder you'll be bypassing oil by 1500 RPM 
  or so; the high volume pump merely foams up the oil in the crankcase to no 
  advantage.  The only reason to run a high volume pump is if the engine won't 
  maintain sufficient hot idle oil pressure, either from being worn slam out 
  or because it was built with old-timey "racing" bearing clearances. 
- -> btw...about how much pressure does a stock pump make  (example 351W)
- Dunno about a 351W, but the '74 302 in TRX, 175,000 miles, makes strange 
  sounds when cold, on 10w30 mineral oil, runs 55psi hot oil pressure at idle, 
  55psi on the highway.  At a track event it will drop down to 25psi at idle, 
  probably because the crankcase temp is much higher. 
- GM reduced their idle oil pressure across the board; most of their later V8s 
  idle at 20-25 pounds.  I don't know about Fords, but the later models fake 
  the oil pressure reading on the guage.  The service manual for the family 
  '65 Chevy truck says anything over 15psi at idle was good for anything 
  Chevrolet made in 1965.  And as the crowning touch, most oil pressure idiot 
  lights don't turn the light on until the pressure drops down to 5-7psi, 
  Ford, Chevy, or Chrysler.  This tells me that Detroit isn't worried about 
  "low" idle pressure, even in a warranty environment.  Remember the pump is 
  still moving the same *volume* of oil through the bearing anywhere below the 
  bypass point; the bearings are being lubed just fine.  The practical lower 
  limit is when the hydraulic lifters no longer have enough pressure to 
  operate properly, which seems to be around the 5-7 psi the factory sets the 
  warning switch to. 

[email protected] (Dave Williams)
fordnatics  02 Apr 1998
- -> I do not agree that the crankbearings only need to be lubed. If you
  -> don't have enough oil pressure, the crank will sort of lean on the
  -> bearing and deteriorate it.
- It doesn't work that way.  Any machine design reference should have a 
  section on plain bearing dynamics. 
- -> deteriorate it. In an ideal case, the crank never touches the bearing
  -> since there is an oil film inside the bearing, over which it is
  -> floating, hence the need for more pressure the higher the crank RPM.
- Nope, the crank makes its own pressure by its rotation.  A good engineering 
  reference should have a polar plot showing typical pressure distribution. 
- -> Remember that friction grows by the square of speed i.e. 2 times more
  -> rpm = 4 times more friction, 3 times more rpm = 9 times more friction.
- Not for a plain bearing, it doesn't.  "Friction" in a plain bearing is 
  determined by the characteristics of the lubricant; for oil based lubricants 
  the oil is in shear and develops heat, but the friction/RPM curve doesn't 
  even approach linear, much less square.  For water or air bearings it's 
  practically steady state. 

[email protected] (Dave Williams)
fordnatics  28 Dec 1998
- -> 1)  A high volume pump takes more power to pump more oil.
  -> ( more likely to twist the drive shaft (in FE at least))
- Right.
- -> 2)  A high volume pump produces the same pressure.
- Right.
- -> 3)  Flow in the engine at a given pressure is somewhat
  -> constant (passage sizes are the governing factor)
- Right... but with some qualifiers.  Flow is a function of the viscosity
  of the lubricant, which is also a function of temperature.
- -> A question,  What IS the ideal oil pressure if there is such a thing?
- You really need very little, enough to overcome edge losses from the 
  bearings.  With careful design, you don't even need that.  There were 
  automobile engines with splash oiling built after WWII.  As long as some oil 
  is *there*, it will roll up its own hydrodynamic wedge and float the crank. 
- The trick is, the oil is attached to the bearing and the journal; layers in 
  between shear.  The shear generates heat.  As long as the load is low enough 
  for the oil or bearing material not to be damaged, you're okay.  Past that, 
  you need to cool the bearings.  The simplest way to cool the bearings is to 
  pump oil through them. 
- That's where a high pressure pump can be useful.  I prefer a lower pressure 
  pump with a less-viscous lubricant myself, but either method works. 
- For most production motors the pump volume is fixed, or has only one or two 
  larger volumes to select from, so you don't have a lot of room to maneuver.  
  The pump is sized for the worst case the engine will likely see in operation 
  - hot idle.  Not drive-to-work hot idle, we're talking fourth-track-session 
  or pulling-the-speedboat-through-the-mountains hot idle, where you're 
  pumping lots of entrained air as well as oil.  If you can get 15psi at that 
  point you will be pumping plenty at running speed. 
- Plain old centrifugal force is something to be reckoned with; it's the 
  reason some very high RPM motors run 80-120 PSI oil pressure.  In this case, 
  the pumping action from the oil drillings to the rod throws generates plenty 
  of pressure at the rod bearings, which at low and intermediate RPM are 
  usually the tail-end, low-pressure point in the system.  Centrifugal force 
  works so well at 8000+ that it can cause problems with the main bearings.  
  It doesn't actually suck them dry, but it causes large pressure variations 
  that beat up the bearing shells. Depending on how the oil drillings are 
  timed, it can also allow the wedge to break down and the crank will sit 
  directly on metal from time to time. 

[email protected] (Dave Williams)
diy_efi  03 Apr 1999
- ->> will never gain the full lift and duration of the leak down lifter.
- -> Huh?? Aeration.   If there is any air in the oil, the lifter won't
  -> fully pump up. Remember these little suckers use a lot more oil than
  -> stock lifters to work.
- That's why you sometimes hear cars come into the pits at a track event going 
  "tickety-tickety-tickety" at idle.  They've aerated the crankcase oil until 
  the lifters aren't able to stay completely pumped up at idle, and they're 
  soft enough to miss the cam's opening and closing ramps. 

[email protected] (Dave Williams)
Fangle  09 May 1999
- In regard to the recent comments on splash oiling:

     O /
  (---X----[snip]------------------------------------------------)
     O \

  Car Collector Feb 80
  - Hudson article
  - "A controversial feature of Hudson engines was splash lubrication.
     Baits (chief engineer at Hudson) and his engineering department
     believed almost religiously in splash lubrication, and Hudson
     developed the splash system to its highest sophistication.  Advantages
     of the splash system were pointed out in 1929 by Baits to Harold F.
     Blanchard of MoToR Magazine.  Interviewing Baits, Blanchard had
     started off by asking, "Would you, if you were to design a new engine
     from the ground up, use splash lubrication?"
-    Baits replied emphatically, "Yes, because I believe a fully developed
     splash system has notable advantages...
     a) oil goes to all bearings the moment the engine starts.  With
        pressure lubrication some bearings remain dry until oil is pumped
        up to them.
     b) grit isn't forced into bearings, as with the pressure system
     c) splash oiling makes engines run 30-40 degrees cooler, because it
        mists the oil in the crankcase, which releases heat
     d) any fuel in the oil is evaporated in the same misting action
     e) one loose bearing in a pressure system unloads presure to all the
        other bearings, while with splash one loose bearing does not affect
        the others at all.
-  Baits emphasized that these claims applied only to a "fully developed"
   splash system, in which crank-case wall baffles and troughs kept the
   oil in controlled circulation; in which dippers were designed to feed
   the right amounts of oil to vital engine parts without emptying the
   troughs at high RPM; in which misting lubricated the cylinder walls,
   wristpins, camshaft, and all other such parts. Such a splash works as
   well as a pressure-lubed engine and better than some.  (Years later,
   when Reid Railton, the British sports car engineer and Land Speed
   Record car designer, talked to Baits about Hudson engines in Railtons,
   Baits assured him that these engines would hold 5,000 RPM continuously
   without trouble.  They did, too!)

      O /
   (---X----[snip]------------------------------------------------)
      O \

- Some of Baits' justifications were spurious, but for a 125hp engine of 175 
  CID, splash was apparently sufficient. 
- The article also talked about why Hudson had moved from a flathead to an F 
  head.  The fuel entering the cylinder from the intake valve in the head 
  impinged on the exhaust valve on the block, where it was vaporized before 
  proceeding into the cylinder proper.  This allegedly allowed them to run a 
  highest CR than their competition without running into detonation.  The 
  Hudson combustion chamber also had over 50% of the piston top under the 
  quench area to provide extreme turbulence in the combustion chamber. 

[email protected] (Dave Williams)
Fangle  23 Jul 1999
- -> Hmm.  Seeing how oil pumps take a bit of horsepower to run, would it
  -> be possible to design/fangle an RPM-sensitive valve/regulator so that
  -> only the amount of pressure needed for a particular RPM is delivered
  -> by the pump? Seems you'd get some horsepower out of it.  Would it be
  -> enough to make it worth the hassle?
- The engine's oil volume requirements are nearly constant with regard to RPM.  
  The serious racer types adjust the flow to control the temperature inside 
  the bearing shells.  Ideally you'd want the volume proportional to bearing 
  temp, not RPM or load. 
- All we need is a cheap variable displacement pump...   One of those 
  swashplate hydraulic pumps would be a-verra-nahss. 

[email protected] (Dave Williams)
fangle  04 Nov 2000
- -> a non galling, heat tolerant.  Also, min oil demand, so that could
  -> run with next to 0 oil pressure, 
- Actually, the bearings *can* run with next to zero oil pressure.  Even a 
  wick feed would do.  The problem is, the oil has internal friction 
  (viscosity) which generates heat.  In general, the more load and RPM, the 
  more heat.  Almost all the oil flow in the engine is for cooling; to flush 
  the old hot oil out and put cooler oil in.  The bearings don't care much 
  about feed pressure; they generate their own by their rotation.  If you look 
  at a polar graph there is a high spot where the pressure is very high; 
  that'd the 'wedge' the bearing makes and floats on.  On very old engines you 
  can sometimes see worn spots in the bearings where flak runs through the 
  wedges.  Lots of people think it's "startup wear", but it's just the wedge. 
- On a V8 engine you'll often see two worn spots on #2 and #4 mains; under 
  racing conditions the crank flexes enough for the wedge to move from top to 
  bottom. 
- Anyway, the primary purpose for pumping all that oil is for cooling. That's 
  one reason I'm a firm proponent of running the thinnest oil that will keep 
  the lifters from collapsing at hot idle; the thinner oils generate less heat 
  to start with, and you can pump more of it through the bearings. 
- I'd still love to see a variable-displacement swashplate pump down there, so 
  I could control the oil flow by watching temperature... 

[email protected] (Dave Williams)
fordnatics  30 Dec 2000
- -> - few/no buzzy brackets.  Crank-snout-mounted gerotor oil pump - no
  -> helical gears, no provision for a distributor drive.
- Bah.  OEMs brag about those things, but they make them because they're
  cheap and quick to assemble.
- Long suction tubes bite, including the ones on Fox Mustangs.  A proper pump 
  runs at a positive head, which means you stick the damned thing down below 
  the oil level where it's not sucking air on a cold start. 
- They get away with two foot pickup tubes, but it's bad engineering just the 
  same. 

[email protected] (Dave Williams)
fordnatics  31 Dec 2000
- -> a) No helical drive gears means less power lost in driving the pump
- Many of Ford's factory racing engines (Indy 255, T/A BOSS 302s, etc.) 
  mounted the pump down by the front main cap and drove it via a small chain.  
  No parts in the lifter valley, no helical gears, and the pump was properly 
  down in the sump where it belonged.  Several foreign OEMs also do this on 
  their street engines. 
- -> b) Getting the pump out of the crankcase means more flexibility in
  -> sump design
- Not a factor unless you're going to yank the pan up until it just misses the 
  crank, such as for lowering the powertrain (fat chance with an OEM-style 
  clutch or torque convertor) or major crossmember interference.  Ford's 
  double-hump pan in the Fox body cars was just another example of their 
  chassis guys being clueless.  Whoever designed the Fox K-member and steering 
  setup (why not just slide the whole damned thing a few inches forward and 
  avoid all that wierd stuff, anyway?!) should be staked out over an anthill.