Oil Pump clearances and oil pressure

Discussion in 'Buick FAQ' started by LARRY70GS, Oct 24, 2017.

  1. Jim Weise

    Jim Weise EFI/DIS 482

    I will add some thoughts.. based on what I do in the shop at least a couple times a month.

    With the engine on the stand, here is how you fill the oil pump so it will prime right away.

    Put the damn vasoline away.. no kidding, a TA assembled pump that had unknown to me, sat 4 for years, full of that junk, cost me a motor last year.

    Assemble your pump dry.. and I will tell you, put the end play measuring tools away.. The only thing you want to measure is the new pump gears.. insure they are the same length, correct as required... as for measuring end play, your more likely to make a mistake in measuring that will lead to too much end play, than you are to accomplish anything good. Use the test assembly method. The correct gasket/shim setup for pump clearance is the one that allows the pump to spin freely when it's all tightened up. Simple, done.. don't over think it.

    Now, you have a nice, dry pump assembly that spins freely.. Bolt it up to the engine, and put the oil pan on. Because I block the hole in the DS deck on a 455 block, or both in a 400/430 if we are converting to pushrod oiling, I pre-lube just the shortblock. The only motor I prelube with the heads on, is a 400/430 that is maintaining thru the block rocker oiling.

    To insure it primes up right away, do this..

    Flip the block over on your stand, until this hole in the pump cover is vertical..


    That's the output from the pump chamber to the filter, we are going to squirt oil in this hole, while spinning your priming tools backward (counterclockwise) with your fingers. It takes just a few squirts of oil, until you will hear the gears go "glug glug glug" as they get coated with oil.

    Now..spin the filter on, turn it over, fill the oil pan, install the lifters, and then prime just until the drill slows down.. If you sit here and prime and prime, all your accomplishing is to wash the good prelube out that you should have used on the cam, rod and main bearings (Clevite bearing guard or similar).

    When installing the valvetrain components, you lubricate them well.. they will oil within seconds of the engine starting and coming up to cam break in, or warm up speed.

    I recommend Lucas engine assembly lube for all valvetrain components.. With used TA roller rockers, flip the shaft upside down and squirt break in oil into the holes in the pushrod cup.. this will prelube the rocker.. don't touch them with new rockers, just lube the pushrod cup and the valve tip.. they come pre-lubed.

    Don't forget you have to plug the hole in the deck surface to do this, without taking a bath in oil.. See the oil mods thread for that procedure.

    Again, I can't stress this enough..

    I don't care what anyone says... vasoline has no place in your engine, and IT WILL partially plug the filter, until the engine warms up enough to melt it. And on first startup, that is not when you want to be reducing oil flow. When given a pump assembly that is full of vasoline, I get the heat gun out and melt it out.. The one time I did not do that, cost me over 1k, and the customer several weeks more wait time. That motor lost the cam bearings, and number 5 main on startup. Number 5 main is the last to get oil, without a equalization line, and the cam bearings are absolutely critical to have oiling immediately once it starts.. a few seconds delay melting out vasoline is too long.

    If your installing a new pump on an engine already in the car, then simply oil the pump before installing it.. using the same method I outline above. Pre-lubing the engine is a requirement before start up.. PERIOD.. buy a pre-lube tool if you don't have one.. IT'S NOT OPTIONAL.. So the argument "We want to make sure it has oil pressure when it starts" is a silly one. Educate your customers..

    Rule of thumb on relief springs... always start with the stock, or "weakest looking" spring. A well assembled aftermarket, or properly ported stock pump assembly, rarely needs the white or orange spring.. (stock 455 or later universal cover respectively). Even with the .0025 to .0027 main clearances I often use. Rod clearance is not a factor on the ability to maintain oil pressure at low engine speeds to any great degree, that's a really all about lifter to lifter bore clearance, and main clearance, balanced against pump output at low rpm.

    For all street builds, and most race builds, desired oil pressure is between 75-80 at 6000 rpm, with the iron block. Use the thinnest oil you can, to achieve those pressures, and as Denny Manner said, "anything above zero" is fine for idle pressure. We like to see 10-20 lbs, which is fine, as long as it goes right up when you step on the gas.


    PS.. Let's dispel on old fable.. "Changing to a stiffer relief spring will not change idle oil pressure".

    With conventional thinking of how a pressure relief system works (relief stays closed until pressure is seen by the valve, then opens) one would deduce that would be the case. But, in reality, localized pressures in the pump assembly are much higher than you see on the gauge. This makes that relief valve oscillate, long before the "set point" is reached. Therefore, increasing the spring rate of the pressure relief spring, will in fact cause an increase in oil pressure, at all rpm's including idle.

    Try it for yourself.. add a 1/4 inch cap screw to the end of your relief spring, (Old KB trick)...or simply crank your Adjustable regulator all the way in.
    Last edited: May 3, 2022
    BUQUICK and john.schaefer77 like this.

    BQUICK Gold Level Contributor

    I can see that it would affect cold start idle pressure but hot idle too? I put a Stage 1 spring in a stock 70 455 that was warmed up and no difference from the stock 40lb one. 25-30 lbs with both.
  3. Mart

    Mart Gold level member

    I added a capscrew that I cut the head down in half. Increased cold idle pressure from 70 to 80 and hot pressure from 62 to 70lbs @ 7k. Hot idle remained at 18lbs @ 650 rpm.
    No noticeable hot idle increase that I can detect, but gave me my desired 10lbs per grand at rpm.
  4. derek244

    derek244 Gold Level Contributor

    Jim, the engine is still in my car. After reading this post I bought a priming tool to use after my timing cover and pump. I was reading through the factory repair manual (because I usually read the directions after I nest things up) and was surprised to see that they recommend petroleum jelly to be packed in the pump. I am sure that this will continue to be done until folks read threads like this one.
    Dadrider likes this.
  5. Jim Weise

    Jim Weise EFI/DIS 482

    Yup, it's in the factory manual.. which was written 50 years ago plus..

    There are plenty of outdated procedures there. I read the engine rebuild section and chuckle..

  6. allan m johnson

    allan m johnson Well-Known Member

    oil doesnt disolve vasaline,alot of the junk 455,s i used to get out of the bone yards had vaslilene in the oil pump,just a side note was many years ago but i used to get complere big blocks for $30,if you find out what eng the rebuilders dont want anymore you can buy em for cheap b4 the yard scraps em!
  7. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Vaseline is petroleum jelly, and will easily dissolve in oil, especially in hot oil. It isn't going to hurt anything. I have done it in the past with absolutely no ill effects. I have heard of individuals using chassis grease, now that is more problematic.
    The factory wanted no chance of an oil pump not priming, so they may have done that on the engine assembly line, not sure but it would make sense. I bought a complete timing cover with assembled oil pump from TA Performance years ago. The pump was packed with vaseline. It primed instantly, and I had no problem with the engine oil after that.

    Having said that, there are way better ways to prime the pump today. All it takes is some oil to wet the gears, and then a priming tool attached to a drill. The important thing is that anytime the oil pump or timing cover seal is disturbed, you take the time to spin the pump and confirm prime/oil pressure BEFORE starting the engine again. Vaseline is no big deal. It won't hurt anything. There are better ways to do things today.
  8. allan m johnson

    allan m johnson Well-Known Member

    i dissagree

    BQUICK Gold Level Contributor

    I don't like Vaseline blocking oil flow until it melts....sure it might all melt in a couple minutes but that is critical breakin time. Dealers used it alot but they were usually on broken in motors that were getting a timing chain job.
    And the dealers didn't really care about the cam bearings, etc.
    I too would do it on a stock used motor but not on anything performance oriented.
  10. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    That's OK.
  11. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Vaseline will not block oil flow. If it did, the factory would have had major problems from it. I know you have a thing about this Bruce.:). I used vaseline to pack a pump way back when I didn't know there were better ways. I never had a problem. You are way over thinking this.
  12. BQUICK

    BQUICK Gold Level Contributor

    The pump has to push it thru the system until it melts. Good luck with push rods esp on driver side. WILL make lifter noise until the Vaseline melts.
    I talked to a friend at Buick dealership about it and he said they didn't even own a priming tool. So Vaseline was only way to assure a prime.

    Also the dealers really didn't care....they just wanted them out the door and if they wore out faster ....good...might be back for a new one sooner than later.
  13. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    You are entitled to your opinion. I have done it in the past when I didn't know there was a better way, but it never hurt anything. Once it dissolves and mixes in engine oil, you never see it again. This has been discussed here and on many car forums. I have seen plenty of guys who have used it in the past with no problems at all, and other opinions about it being harmful. I just consider that theory based hysteria. It's the kind of thing that spreads, and people just repeat it because they read it somewhere. IMO, it is much ado about nothing.
    Last edited: Jun 12, 2022
  14. allan m johnson

    allan m johnson Well-Known Member

  15. BQUICK

    BQUICK Gold Level Contributor

    I really don't care what people want to do with Vaseline....but put some Vaseline in a pan on the stove and turn up the heat slightly....yes it melts but a COLD engine takes time to make any heat in the oil system....until then it is petroleum SLUDGE.
  16. allan m johnson

    allan m johnson Well-Known Member

    as Hilary said"at this point what does it matter! just use jw recomendation!
  17. derek244

    derek244 Gold Level Contributor

    I have never been as intimate with my Buicks timing cover and oil pump as I am now. I am surprised at how many passages the gaskets and cover block oil flow. It is confusing and keeps making my question the gasket set I have. I wonder why so many ports are blocked. Strange.
  18. Tom Righter

    Tom Righter Well-Known Member

    I always spin the oil pump over before putting lifters in. The oil and Vaseline will take the path of least resistance and come out The first lifter hole on the passenger side. It also gives you a chance to monitor how well the oil is flowing from the pump. And then install passenger side lifters first adjust them and turn the pump over once again without the driver side lifters this pushes oil out through the passages to get oil to the driver side. Again you get the monitor oil making it over to the Driver side and anything that may have been missed during blowing and cleaning out passages gets washed out.
    DaWildcat likes this.
  19. BQUICK

    BQUICK Gold Level Contributor

    Good idea....I had a few lifters pumped up on breakin years ago I bet it was the Vaseline. Luckily the cam survived.

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