Mystery ticking noise

Discussion in 'Troubleshooting & Diagnosis' started by jnkman61m, Aug 13, 2008.

  1. jnkman61m

    jnkman61m Member

    65
    0
    Aug 12, 2008
    Okeechobee, Fl
    Greetings, I am new to the forum and I have an issue with a 350 I recently built, I will try not to ramble however there will be alot of information in this post so please bear with me.

    Block is a 1pc seal 4bolt hyd roller bored.040 with torque plates, pistons are Speed-Pro Hypereutectic flat top 4 valve relief .020 in the hole, .028 thickness GMPP head gaskets, World Products SPortsman II heads, 64cc, LT4 valve springs retainers and locks. RPM AirGap with 770 Street Avenger, MSD Pro Billet HEI with MSD wires. Runs STRONG, smooth, extremely responsive. Melling Select Oil Pump and shaft with bolt on 3/4 pickup, Oil Pressure 60-70 PSI. If I had it to do over again, I would probably use a stock oil pump, but when I built this engine, I wanted a bolted on pickup tube, so thats how I went. Crank is stock standard size and the rods are later powdered metal rods with ARP bolts.

    The noise is a ticking noise that sounds like excessive valve lash. The cam is a ZZ4 Hydraulic roller. The lifters/valves have been adjusted per Exhaust opening-Intake Closing method everyone seems to prefer, several times. Initially set 1/2 turn past zero lash, now adjusted to 3/4 turn past zero lash.

    This noise is NEVER present at idle, it will ONLY be apparent between 1650-1900 RPM. The noise is barely noticeable when engine is cold, it is very apparent when fully warmed up.

    The rockers are Scorpion 1.5 alum rollers. Comp cams screw in studs and guideplates. Valvetrain-roller contact was checked meticulously upon trail and final assembly, contact pattern is centered slightly favoring the inboard side of the valve tip, with minimal travel. Rocker arms do not contact the valve covers.

    The noise is most prevalent under load...imagin driving the car, in any gear, the tapping begins to come in at 1600 rpm under light throttle as in cruising or just maintaining road speed. Noise present till 1850 RPM or so, letting off the throttle noise goes away, tipping back into throttle noise returns. Applying more throttle, in fact just enough to change the tone of the exhaust, the noise will either greatly diminish of disappear altogether, and will ALWAYS disappear as soon as it hits 1900 RPM.

    Torque converter bolts are tight, flexplate is not cracked, flexplate to crankshaft bolts are not loose. Unbolted converter from engine, noise is still there although its not possible to effectively load the engine, so it isnt as apparent but it is still there.

    Mechanical fuel pump removed from engine thinking fuel pump pushrod could be the fault, nope, that aint it. Noise the same.

    Bolted converter back up, raised car on lift, ran engine in gear in noisy rpm range, backed timing way off to see if reducing combustion pressure made a difference to no avail. FWIW, initial timing 14* total is 36 all in by 3300, with vac advance disconnected during timing test. Vac advance connected under all other test conditions. Disconnecting vac adv and driving car makes no effect on noise.

    Using a stethoscope, it SEEMS like its is noisier in the bottom center of the engine, along the side of the block just behind the motor mount bolt holes, but nothing really jumps right out and says "Here's your *&%^ing noise!!"
    I just cant seem to pinpoint it.

    I have shorted spark to the cylinders at RPM and nothing changes.

    I am thinking broken ring land, cracked skirt type of damage, but this engine has not been overheated or overloaded since I built it, only has about 600 miles since all new stuff.

    Running higher octane fuel does not help. The noise is most definitely NOT a header leak.

    Anyone care to jump in here with a wild A** guess? And any input on why it would be noiser hot than cold when it cant be isolated to one cylinder by removing spark to individual cylinders?

    HELP!!! I am STUMPED!!

    Thanks for reading my rather long and protracted post.

    Like I said, it NEVER makes a noise at lower than 1600 or above 1900. It is ONLY in this RPM range
     
  2. zekefreak

    zekefreak Veteran Member Lifetime Gold Member

    1,532
    4
    Apr 16, 2006
    western PA
    Sounds like detonation. Use a higher octane gas.
     
  3. 68400BIRD

    68400BIRD Veteran Member

    2,947
    7
    Feb 7, 2006
    GO PACK GO
    What are the chances that the oil pump is making the noise? Do you have a windage tray? What kind of oil are you running? Matched gear on the bottom of distributor to cam gear? I know it sounds like it's coming from the bottom but I have had a slight tick from my cap and rotor before. Just throwing some wierd ideas out at you.
     
  4. Eaglefixer

    Eaglefixer Veteran Member Lifetime Gold Member

    1,574
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    Feb 25, 2002
    Warner Robins, Ga
    Double check that the emergency brake cable is not touching the top of the exhaust pipe as it crosses over from drivers side to passenger side. Had the same type noise and found out that was my problem. Had to tight the cable up a tad to keep it off the pipe.
     
  5. jnkman61m

    jnkman61m Member

    65
    0
    Aug 12, 2008
    Okeechobee, Fl
    I currently am running 93 Octane, and have backed alot of timing out, in fact enough that it was actually firing ATDC at idle, and disconnected the vac advance under several conditions to no avail. I did think of this, however it is not a classic spark knock type of noise. It sounds EXACTLY like a lifter. Not slamming your idea, I appreciate the reply.

    I will try octane boost and see what happens.
     
  6. jnkman61m

    jnkman61m Member

    65
    0
    Aug 12, 2008
    Okeechobee, Fl
    I have thought of the oil pump, just not sure how to actually diagnose it. It is a Melling Select 10552 10% increased volume pump with the bolt on pickup 12558. I am using the stell retainer type oil pump shaft supplied with the pump.

    I have the small oil "baffle" that is used on many L31 Truck engines, it isnt much of a windage tray really , but it's better than nothing. I removed the oil dipstick and ran the engine at RPM thinking the windage may be pushing the bottom of the dipstick around into something, and that did nothing.

    The dist according to MSD has a gear compatible with my ZZ4 cam.
    I have NOT pulled the distributot and actually inspected the drive gear,that will be done shortly.

    Ive had a ticking from a dist cap as well in other engines from cap misalignment, this one is on correctly.....good idea though.
     
  7. jnkman61m

    jnkman61m Member

    65
    0
    Aug 12, 2008
    Okeechobee, Fl
    Thanks I'll check that out, I do seriously believe its internal engine noise though.

    I really appreciate the replies, all ideas are good ones...and I really like this forum.
     
  8. John Wright

    John Wright Veteran Member Lifetime Gold Member

    13,932
    42
    Aug 9, 2002
    Rustburg, Va
    Sounds like a good goose hunt...Hmmm. My first thought was windage tray or crank scraper...but that was already discussed. Crank isn't touching the pan anywhere? Timing cover? cam isn't walking...I think you have a keeper on that block.
     
  9. John Wright

    John Wright Veteran Member Lifetime Gold Member

    13,932
    42
    Aug 9, 2002
    Rustburg, Va
    .....maybe a piston rocking in the bore?...well, that usually gets quieter when warm, not louder.
     
  10. jnkman61m

    jnkman61m Member

    65
    0
    Aug 12, 2008
    Okeechobee, Fl
    We are apparently in double secret agreement. Cam end play was in spec when I installed it and used BLUE loctite on cam retainer plate bolts and the cam gear retainer bolts. Made sure the Timing gear did not rub the oil gallery boss since I was installing a double roller chain setup and have had to do some minor grinding for clearance in other builds.

    I made sure the pan wasnt getting rubbed by anything when I mocked it up by installing the pan without a gasket in place and rotating the crank with rods and pistons installed. No issues there, and its a stock 3.48 stroke cast crank and rods anyway.

    My next move is to pull the dist, check for gear wear issues, perhaps the pump is chattering, transmitting vibration to a worn gear area creating a tick.......

    I did cut the break in oil filter open looking for foereign material, but nothing was found......I'll update if or when I find something worth posting

    thanks again to everyone.
     

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