340 Lifter Preload Issues

Discussion in 'Small Block Tech' started by GSDrew, Jul 11, 2020.

  1. GSDrew

    GSDrew Well-Known Member

    Guys I need some advice here on my 340 with only 10K miles on it. I finally had my worn rocker-arm assemblies re-worked and now I'm having issues with setting the lifter preload, with adjustable Smiths push-rods, and the intake installed. So, i can't see how deep I'm pre-loading the lifters. The original head oiling system is still intacked, so I'm not oiling via the push-rods. Prior to making any adjustments I spun the engine up (with the push-rods adjusted to a min, with lots of end-play) to insure proper oil circulation and lubrication before making any adjustments. The problem I'm seeing now is... As I adjust from obviously lots of end-play to a minimal amount, and then turn another 3/4 a turn... the push-rod locks up, on most of the lifters, to the point I can barely rotate them with my fingers. They do not spin freely. Should they? As I recall they did spin more freely during assembly on the engine stand with no oil prior pressure. Is the lifter not relaxing?
    BTW... I'm running a TA cam with factory type generic lifters. A friend said that I should not have pumped them up (the lifters) with no load. So I used an Olds 455 3/8 ball tip, hollow, push-rod to try to push in and relieve any pressure in the lifter, but I still cant fell the preload of the lifter spring, The lifters do not seem to be
    collapsing. What am I doing wrong?
     
  2. Mark Demko

    Mark Demko Well-Known Member

    Not quite sure what you mean by that, you cranked the engine over with the starter?
    Anyhow, it sounds like you pumped the lifters full and the pushrod cup is at the top of its travel, which is fine, it actually makes finding zero lash easier, the adjustable end of the pushrod positively stops at zero lash, and another 1/2 turn your good.
    Doing it this way the valve WILL more than likely start to open, don't worry about it, its actually good to feel the lifter plunger is NOT collapsing.
    Once you start the engine the lifter plunger will "self adjust" to wherever you set the preload, in other words, it wont stay pumped up hard.
    I've experienced this many times and its no issue.
     
  3. wkillgs

    wkillgs Gold Level Contributor

    With excess clearance, the pushrod will spin easily using your fingertips and it will rattle around if you move it side-side. As you SLOWLY increase pushrod length and get to zero clearance, the side-side movement goes away you will feel how it will no longer spin easily. That's zero clearance. Go slow and you will get a feel for that point. The additional 3/4 turn sounds like a lot. 1/2 turn should do it.
    Assuming the cam lobe is on the base circle when you are adjusting each valve!.....
     
  4. GSDrew

    GSDrew Well-Known Member

    Thanks Guys, for your input.
    Mark, yes I spun the engine up with the starter motor to get oil pressure to insure the everything was oiled nicely, as I had to rotate it by hand while adjusting the pushrods. I didn't think about filling the lifters.
    It was Tim at TA Performance who said to adjust 3/4 of a turn past zero lash.
    What surprises me most is that when I inserted a real long and hollow 3/ ball pushrod down into the lifter, applied some pressure... the lifter didn't seem to bleed down and relax. As I expected it to do.
    Walt, Yes, I was on the heel when making the adjustment. I was using a method that Ol' Dave Ray (the distributor guy) taught me. As the exhaust starts to open, adjust the intake, and as the intake starts to close, adjust the exhaust. I could have that backwards, either way I have the correct way written down.
    So what you both are telling me is... It's ok if the pushrod won't turn easily or not at all?
    I haven't touched anything since Friday, but will get back to it this week some time.
    Stay tuned.
     
  5. telriv

    telriv Founders Club Member

    When I adjust valves even on HP applications I use the overlap method. The firing order is 1-8-4-3-6-5-7-2
    So that means when #4 is at TDC on the overlap stroke, The exhaust valve will be almost fully closed & the intake will start to open. When they are about even, same height, time to adjust #1 & the timing mark on the balancer should be at or close to ZERO. Next in line is #8 & #5 will be on overlap on down the line. When it has reached #1 on overlap #8 is ready to be adjusted.
    I find this so much EASIER than the many other methods being used. Once you get used to it it's so simple & a time saver.
    I know some use the cam base circle for this & when they are done adjusting the valves they almost always have 1 or 2 that will tick because the adjustment is not right to begin with. This way assures, by using the overlap method the valves/lifters are in the correct relationship with the cam & TDC.
    Just my thoughts.

    Tom T.
     
  6. GSDrew

    GSDrew Well-Known Member

    This week I finally found so time to spend on my car, and successful got all the pushrods adjusted, though I hadn’t started it yet. Stay tuned.
    My problem was… I started off trying set the length as I did when the lifters were new and empty of any oil. At that time, 10 years ago, it was easy to feel the lifter spring pressure, besides the engine was on a stand. I started out trying to repeat that process, but when I felt no spring pressure, I thought something was off and then basically confused myself. Mark you were totally right… After I realized what was happening, it was very easy and fast to zero the end-play and then add another half turn.
     
  7. Jim Blackwood

    Jim Blackwood Well-Known Member

    Bear in mind hydraulic lifters generally have well over 3/16" of internal travel. You can go a little heavy on preload and not hurt a thing, and this will often solve a lifter tap problem. I generally set them in the range of .060-.080" even though you see recommendations in the .020-.040" range. In my opinion trying to hit that .020" number is just asking for trouble.

    Jim
     
  8. LARRY70GS

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

    It would also depend on the exact lifter used. There are some short travel lifters out there that use less pre-load. When I replaced my Morel hydraulic roller lifters with the Johnson rollers, JW told me that they were short travel lifters with a higher refresh rate, and that I should use no more than 1/2 turn on my roller rocker adjustment. That's about .025". My motor has never been quieter.
     
  9. Jim Nichols

    Jim Nichols Well-Known Member

    With stock lifters I always go .050 which corresponds to one full thread on the adjustable pushrod.
     
  10. Mart

    Mart Gold level member

    I run my rollers at 2/3 rds of a turn. That's 0.0333333334 :D:D
     
  11. GSDrew

    GSDrew Well-Known Member

    Not Good news to report, and I still haven't tried starting it yet.
    Now that all the pushrods are adjusted, I decided to do a compression check to see how well balanced the cylinders are after 10K miles, was also thinking this would indicate a misadjust pushrod. I was surprised to see #1 & #2 @120 while the rest were at 150, +/- 5 (note that the TA cam I have is pretty lumpy [TA 284-88] so lower cranking compression is normal, or so I'm told). I adjusted the pushrods again on the low cylinders and got the same results. I tried to measure the rocker movement, but all I have a caliper. It seemed to be approx the same as the others. I know that this method does not have the resolution to check for cam wear.
    So, what's next? Adjust the pushrods from a half to a full turn of lifter preload? Could these generic OEM replacement lifters be failing at 10K miles... Or do they require more preload? If this compression issue is not lifter, I guess I could do a leak-down test.
    Incidentally, last weekend I changed my oil pump pressure spring back to the standard pressure because I noticed it was taking too long to build cranking oil pressure. The first attempt of the day to prime the system would take about 30 seconds to get oil pressure (45 PSI w/the high pressure oil pump spring), then each of the following attempts takes about 10 seconds. I swapped in the standard oil pump spring, and repacked the pump gears, because I thought the pressure would come up faster but it didn't help, though the cranking pressure is now 30-ish. Isn't 10 seconds a little long to build oil pressure when cranking? Could my oil pump be loosing its prime while it sits overnight?
    BTW... On my 340, I'm using the 455 oil sump pickup from TA, I had the pickup oil galley drilled out to match the 455 pickup, I'm using the TA steal Booster Plate and I did some porting on the oil pump. I would think that I oil flow and pressure would be the least of my issues.
    Not sure what to do next other than adding more preload, but will give it a try... nothing to lose.
    Is it also possible that when I changed pump springs, I got air in the system (#1&#2 lifters) and it just hasn't purged out yet, even though they felt firm after priming and the second preload adjustment?
     
  12. ap1672

    ap1672 Silver Level contributor

    Start it up. Do the lifters tick. All the pushrod should be rotating while the engine is running.Engine oil pressure drops to zero when shut off. Takes along time to lose prime, not a day or two. What is the oil pressure hot and idling?
     
  13. LARRY70GS

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

    Too much preload is way worse than too little. Too much can prevent the valves from sealing. Try less preload, not more. I would not judge priming time to build oil pressure, it will build way faster with the engine running the pump.
     
  14. Jim Blackwood

    Jim Blackwood Well-Known Member

    Ideally you would set the preload with the engine running, get some miles on it, and then set it again. The lifters will automatically adjust so that the valves close but they can take awhile to do it. So setting them cold and then doing a compression test is an almost surefire way to get bad test results.

    Jim
     
  15. GSDrew

    GSDrew Well-Known Member

    I was getting a little lifter noise noise on startup. It started making a lot of valve train noise under load only, the noise was too fast to be low-end. Oil pressure hot on idle was 30 PSI.
     
  16. GSDrew

    GSDrew Well-Known Member

    Ok... Sounds like I need to get it back together and start it.
     
  17. Mark Demko

    Mark Demko Well-Known Member

    Get the oil completely warmed up by driving it and see where its at.
     

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