New Engine is Knocking

Discussion in ''Da Nailhead' started by KDML, Jun 12, 2014.

  1. KDML

    KDML Well-Known Member

    Finally, got my new engine running, after chasing down numerous electrical issues with the old wiring

    Unfortunately, the engine is knocking so it needs to come back out. I am planning on pulling it on Sunday to tear it down as I am guessing it's an internal issue as I believe I have eliminated the easy fixes. Here is what I have done to identify the problem thus far:
    1. Oil pressure is good. Starts out at 40psi when cold and drops to maybe 20 once warm
    2. Engine doesn't run hot. Gauge reads about 190
    3. 145-150 psi in compression on all cylinders with engine warm
    4. Leak down test shows 9-10% leak down on all cylinders with engine cold
    5. Drained break in oil and found no particles (strained oil through cheesecloth and found nothing significant)
    6. Cut open oil filter and found nothing significant
    7. Unbolted torque converter from flexplate and noise did not go away
    8. Swapped in new fuel pump and noise did not go away
    9. Removed all belts and ran engine and noise did not go away
    10. Hunted around with stethescope, but can't pinpoint anywhere that the noise is louder. I can hear it everywhere
    11. Pulled plug wires one at a time and noise did no change
    12. I did notice the engine puffs some blue smoke from the tailpipes when you first start it and periodically at idle. No smoke when you raise the rpm. I am thinking oil is sneaking down the valve stems. There is quite a bit of oil on top of the heads. I have TA roller rockers, but am oiling from the rockers only.
    13. Dropped pan and checked for loose rods - found none.
    14. Can't find any exhaust leaks where the manifolds attach to the heads or where the exhaust pipe attaches to the manifold. There are leaks back by the mufflers as the exhaust was just rigged for the break in
    15. Turned over engine with valve covers off and noted all rockers appear to be moving as expected
    16. Re-adjusted lifter preload

    I am sure I am forgetting other things I checked. Does anyone know of any other things I should check before I pull the engine? My current thoughts are possible main or cam bearing issue.

    Here is a short video of it running (hopefully the link works) Uploads/IMG_1045_zps315292bb.mp4.html

  2. 69GS400s

    69GS400s own amusement ride!

    look inside the pan and valve covers for wear marks in case anything is hitting them.

    Take the spark plugs out so there is no compression and spin it and note if there is any spot where there is a difference in resistance while spinning it

    ... sux, good luck
  3. RVA65GS

    RVA65GS Active Member

    I have heard of the idler gear shaft on the oil pump hitting the crank counter weight. I do not have first-hand experience but have heard it from those who do.

    Harmonic balancer making contact with something?

    Those TA rockers are taller than stock, correct? Could a rocker be hitting the valve cover?

  4. Brad Conley

    Brad Conley Super Moderator Staff Member

    Almost sounds like a rod it hitting the oil pan which will sound just like a rod knock from a spun bearing. Even a shallow dent will take away all you clearance.
  5. KDML

    KDML Well-Known Member

    Thanks for the ideas

    I did find the rockers were hitting the valve covers during my initial startup, as they are larger than stock. I loosened the covers and slid them over, but it did not stop the current noise, only eliminated the initial noise. I suppose they could still be hitting. I will run the engine without the covers to see what happens.

    I did not check to see if something was hitting the pan when I had it off :Dou:- its back on now. I will check it this weekend

    I will check out the balancer as well. Figured I would have noticed this as I have been spinning the engine by hand so much lately

    I did check the crank/oil pump clearance as it looked tight, but did not appear to hit and did not see any wear marks. I even tried to slide the crank back to see if it got any closer

    Keep the ideas coming

  6. gsgtx

    gsgtx Silver Level contributor

    if the rockers are still hitting you need to grind out the bolt holes in the valve covers so you can pull the valve covers over more. hope you don't have to pull the engine.
  7. 69GS400s

    69GS400s own amusement ride!

    I've double-stacked cork gaskets to gain some clearance for the valve covers in a pinch - they do sell extra thick cork ones

    .. before pulling the pan again, run it and put your hand on it - you'll feel if its hitting
  8. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    Check and make sure the flex plate bolts are tight,those will make all kinds of racket if they're loose.GL

  9. telriv

    telriv Well-Known Member

    Stacking gaskets does no good as the rocker adjusting screws will hit the valve covers. Almost sounds like a lifter hasn't pumped up or the crank is hitting the oil pump. Sounds more lifter related. Pull the covers & run the engine & put a finger on each rocker. If it is a lifter you will feel the difference.
  10. Babeola

    Babeola Well-Known Member

    It sounds more valve train related from the video. Rods have a deeper sounding knock (thunk?) and mains would show more loss in oil pressure. Here's to thinking positive!

    Cheryl :)
  11. 66BulldogGS

    66BulldogGS Platinum Level Contributor

    I agree with Tom and Cheryl. Definitely sounds valve train from the video. Do as Tom suggested and run it with the valve covers off and check each rocker. If its too hard to tell that way, you might also consider pulling the intake and valley cover and reaching your hand in there to each push rod to check for excess slack or lack there of for each lifter.
  12. gsgtx

    gsgtx Silver Level contributor

    it is very hard to get all the pushrods into the rocker arms, one was not in right, then after start up it got back in. so it would be loose now. could still be hitting the side of the valve cover. the guys are right its valve train and that's good news
  13. wkillgs

    wkillgs Gold Level Contributor

    I have no idea what kind of sound it would make, but did you check valve spring retainer-to-guide clearance? , or valve-to piston clearance?
    You could try swapping the roller rockers out and re-installing the stock rockers and see if that makes a difference. The rollers add extra lift, reducing retainer-guide clearance, but hardly affecting v-p clearance.
    Check for bent pushrods or scuff marks on them while the rockers are out.

    Did you look inside the distributor for anything hitting in there?
    Broken valve spring? or coil bind?
    Are the flexplate-to-crank bolts too long? could be hitting the block.
    It's tough thinking of new possibilities... you guys have got nearly everything covered!
  14. KDML

    KDML Well-Known Member

    Finally had a chance this morning to look into the engine noise.

    Nothing appears to be hitting the oil pan. Felt it with my hand and used stethoscope. Harmonic balancer is not hitting anything. Ran engine with valve covers off and noise remained, so it does not appear that rockers are hitting covers.

    Definately sounds like a valve train noise. Put a finger on each rocker and all appeared to be working the same. I have uploaded some more videos to my photo bucket account which seem to show everything working as it should (links below). Put stethoscope on the side of each rocker and noise did not appear to be louder on any one rocker. Few things I noticed so far:

    • Oil flow from the rockers appears to be greater towards the front of the motor. Lots of oil coming from the rockers in front. For some rockers you can see oil dripping off where the pushrod meets the rocker, others there is nothing dripping off. Also, saw that the there is oil coming up from the rocker shaft stud for the second rocker shaft stand on each side. Re-tightened stud and nut, but saw no difference. I believe the nailhead rocker shafts oil from front to back, so it's possible the pressure is greater up front, which is why I am seeing more oil flow. You can see most of this in the videos.
    • Noticed the pushrods move up and down in the holes as the rocker moves. The clearance between the pushrod and the inside of the hole is very tight for some pushrods, when they reach their highest point in the hole (I believe this is when the valve is fully closed). I did not have a wire feeler gauge to test clearance, so I used a piece of binding wire, which is about .045". In some cases, I could not insert the wire between the the top of the pushrod and the hole. With engine running I was able to insert as pushrod moved. I am running T/A 5/16" diameter pushrods. I am wondering if they are too large in diameter and the noise I am hearing is the pushrod hitting the head. I don't see any wear marks on the pushrods.

    I am going to keeping examining the valve train. Let me know if you have any other thoughts after watching the videos Uploads/IMG_1059_zpsa1bd0178.mp4.html Uploads/IMG_1057_zps3de4ef00.mp4.html Uploads/IMG_1056_zps916667cf.mp4.html Uploads/IMG_1055_zpse2c65f87.mp4.html Uploads/IMG_1054_zps36d5131a.mp4.html

  15. gsgtx

    gsgtx Silver Level contributor

    what did u set the preload at. also how many turns are the adjustment screws down. what kind of end on the pushrod. after u turn engine off can u push down on the pushrod and rockerarm
  16. telriv

    telriv Well-Known Member

    Would almost be willing to bet it is definitely valve train related. Noticed on one of the videos on left side of engine running looks like #8 cyl. intake is not always opening consistently the same while running. Could be angle of camera or??? I would re-adjust the valves using the overlap method. Unless you have some lifters collapsing, as seen in the video mentioned, I believe this will solve your problem.

    Tom T.
  17. John Codman

    John Codman Platinum Level Contributor

    If the 20 lbs of oil pressure hot is at idle, it's fine. If it's at a operating RPM it is definitely not.
  18. KDML

    KDML Well-Known Member

    Preload was set by turning the adjuster screw 1 turn. Per T/A instructions screw should be adjusted 1 to 1.5 turns (1 turn is .050"). When I assembled the engine I set the preload at one turn. After I first starting hearing this noise, I pulled the intake and valley cover and reset the preload again, making sure the cam was on the base circle when I adjusted. I could go another 0.5 turn to see whether the noise goes away. Pushrods have ball ends. I ordered them from T/A after explaining my setup. When I measured for length, I came out with 8.25". When I spoke with T/A they recommended an 8.3" pushrod. I cannot push the rocker and pushrod down when I turn off the engine

    Tom, not seeing what you are seeing in the video, but I will pull the car out again tomorrow and watch more closely. I agree this sounds like a valve train problem. Too bad I can't run the engine with the valley cover off to see what is happening with the cam and lifters

    John, 20lbs is hot at idle. It rises when rpm goes up

    Also, just so we all have the same information, as Joe, just PM'd me about this. When I ordered the cam, comp cams sent me lifters with a part # of 852-16. Anywhere I tried to find comp lifters from a Buick 401, the part # 869-16 came up. I contacted comp after receiving the lifters and called them two more times to verify whether I had the right lifters. In both phone calls the verified these lifters were correct. The difference between the two part numbers was the location of the oil band. I am thinking of pulling the intake and ordering the #869 lifters. It would eliminate one more possibility. Would this be OK since the cam is already broken in with the existing lifters?
  19. gsgtx

    gsgtx Silver Level contributor

    did you set it one turn after all the play was out of the pushrod and how many turns did it take to get the play out of the pushrod to start with. also what happens if the lifter oil band is out of the lifter bore. ?
  20. KDML

    KDML Well-Known Member

    Yes, one turn after play was out of pushrod. Both times I set preload the intake was off, so I was able to see that all play was out of the pushrod, before I turned one time to set preload. Can't remember how much I had to turn to remove play, but I don't believe it was much. When I was running the engine today, I even tried to slide a .010" feeler gauge between the rocker and valve step tip to see if there was any gap - there was none.

    I am guessing, if the lifter oil band comes out of the lifter bore the lifter will bleed down, but I would have expected to see this when watching the valve train in motion. Just another reason I want to pull the intake to see where the band is when the lifter is at max lift.

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