If I was building a caddy engine today

Discussion in 'Big Block Cadillacs' started by dave brode, Oct 16, 2017.

  1. 8ad-f85

    8ad-f85 Well-Known Member

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    Thanks for sharing that.
    It's a fine line between throwing off too much oil with an already starved pump and things distorting and rubbing together ending life quickly.
    I've always seen that the same general things apply to every engine, if indeed the same things are really happening.
     
  2. dave brode

    dave brode Well-Known Member

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    There's a thread with discussion on the subject of an external line from pan to pump like on bb mopars. A spacer between the block and pump could allow it, but clearance at the pump/filter often exists as is.

    ProstockTom's friend Juan runs a bad ass race boat that he really thrashes. Belt drive external and no durability issues.
     
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  3. Darius

    Darius Well-Known Member

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    If I were to build a new Cadillac engine major consideration would be given to things like belt driven external pumps or at the least an external pickup going through the side of the oil pan. From the existing data, our current pickups are a major contributor to the oiling limitations. So, why not take a good look at other possibilities?? So often the answer to "why not" comes down to fear. Some here on the forum don't trust electric fuel pumps and prefer to spend their dollars on mechanical pumps, cheap one or expensive ones. So be it. For me, the ONLY fuel pumps that have left me stranded were mechanical units. My experience if different from that of others and my decisions then are different. All that to say that I would not be fearful of trying something different. It might work, or it might not; but trying a different approach might solve a long standing problem, if fear didn't stop me.

    Just sayin.

    Best,

    d
     
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  4. pila78

    pila78 Well-Known Member

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    After reading all the stuff about bearings in the oil filter,:( I'm not very confident of these engines. I haven't changed the oil yet, with only 2000 miles on it. Maybe I'm just more nervous than I should be ! It runs good though & easy to start etc. Sure seems like a re-designed oil pump with taller gears wold help the oiling. So if the folks who make pumps, to clear the frame, suspension etc, would add a bit taller gears and the housing to match, it seems to me that the increased volume could help the oiling situation.
    I may be full of crap on this, but it's 6:20 AM here and I can't sleep :)
     
  5. MadMax

    MadMax Member

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    I have been running a SBC belt drive oil pump (1.25 width gears) on my mini modified tractor puller for years - with a AN16 inlet - at half engine speed, but set to 80 PSI.. No problems with rod or cam bearings (CadCo grooved). Turned it 7600 RPM on two pulls. This is with a balanced,stock 4.06" 472 crank.
    Just my experience.
     
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  6. 8ad-f85

    8ad-f85 Well-Known Member

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    The pump seems to have plenty of volume.
    The issue is that with the long thin pickup it will pull a vacuum and starve anyways, negating longer gears or more pump volume.
     
  7. Darius

    Darius Well-Known Member

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    Madmax,

    Thank for sharing that personal experience with your oiling system. That's the kind of information that says way more than our just speculating. True, yours is a small block Chevy but the question that comes up is often about the reliability of belt driven oil pumps.

    I wonder if anybody here has knowledge of such a setup being run on the street??

    Best,

    bro. d
     
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  8. pila78

    pila78 Well-Known Member

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    So, it must be time to re-design the the whole pickup tube !!;) If that is part of cure, no one seems to supply a better part ?
     
  9. Darius

    Darius Well-Known Member

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    In your experiences what pickup tubes have you seen, with commendable designs, which might be a starting place?

    d
     
  10. 8ad-f85

    8ad-f85 Well-Known Member

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    A few brands have improved pickups available for std pumps.
    I haven't found any problems, but have read of manufacturing concerns here and there.
    I've used slightly larger tubing in Cadillacs, but more out of not having the same size as stock :D
     
  11. pila78

    pila78 Well-Known Member

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    So, there must be a limit on how large, in diameter, a pickup tube can be ?? I'm no physics guy, but too large a tube may have trouble priming the pump ?? Maybe a pair of tubes together ? Maybe not...just wonderin' .. If I have to pull my engine for some reason, it seems a good thing to improve the oiling system a bit, while it's out, including outside oil lines that have been discussed at length here, along with a better oil pan that I have planned.....
     
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  12. 8ad-f85

    8ad-f85 Well-Known Member

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    I think you'd bust through the block before you could make the tube too big, that's one reason why they end up outside the engine to the oil pan.
    It doesn't take much of an ID increase to substantially increase the flow.
    .625" to .750" is a 44% increase in area.
     
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  13. El Diablo

    El Diablo Active Member

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    Brother D, the biggest problem with a belt drive pump other than the initial cost or packaging concerns is the belief that this is race only hardware. The way I see it is that if it can stand up to the rigors of Top Fuel drag racing, F-1, the Trophy Trucks & truggies in off road racing, and cars like the legendary GT-40, it can work on a street car or truck that sees some track or strip time. Just keep an eye on the drive belt like you would your fan belts.
     
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  14. 8ad-f85

    8ad-f85 Well-Known Member

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    Timing belts hold up to considerable demands in their life, such as imperfect dust covers and import enthusiasts removing them to some degree.
    Oil pump belts tolerate circle track racing...their radiators don't, for very long (in dirt).

    I don't know too many outside of myself that have put hundreds of thousands of miles on performance builds.
    I can't picture many driving 150K on a 750hp NA Cadillac, although I'd encourage more of it :) .
    The maintenance schedule changes anyways...valve springs, flex-plates, spark plugs, etc., have shorter life compared to weekends and occasional 1/4 mile trips.
    I would bet the typical oil pump belt life to be much longer than a dirt track or asphalt CT racer, measured in time @ full throttle or severity of duty.
    I can't imagine it terribly complicated to make a belt cover.
     
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  15. 48Austin

    48Austin Member

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    What vehicle(s) do you drive?:
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    Why not an electric pre-oiler? Pressurize the system first before start. After initial startup everything should be ok.
     
  16. 8ad-f85

    8ad-f85 Well-Known Member

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    That always helps, but even just a film of oil will glide the crankshaft for quite some time until the system pressurizes.

    The issue with any of these engine types requiring modification is that at higher rpm there's more oil being slung out of the rotating assembly than the pump pickup can supply to the oil pump.
    The demands increase due to looser clearances and the need to wash more volume through to cool the bearings.
     

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