Thread: [1968] Mystery Noise 63, Rob 0
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Old 01/25/2014, 12:17 PM   #1
robert campbell
My Car Details

Location: Bremerton Washington
Joined: Apr 07
Posts: 3,912

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Mystery Noise 63, Rob 0

To all you DIY's and "want a be" mechanics! I have just been brought to my knee's by a customer car. I thought I was an ok mechanic, but wow, what an experience. The mystery noise has been found, but I will lay out the start and the diagnostics. After that you get to guess for a day or two and then I will let you in on the cause.....

The start:
1968 J Code Fastback, 4 speed. Pictured in Photo your winter Fun. No fun was had....
1. Remove engine farm out short block and heads to respected machine shop.
2. .020 over bore, computer balance of rotating assembly, Sona Ray for core shift and received back in short block form with original cam and roller timing set installed.
3. Specify facing of exhaust manifolds and all 3 head surfaces. Look great.
4. Original cam is a Crane grind. Lifters seemed very good so reused as it ran great and had no noise.
5. I Rebuilt 4 speed for owner and restore stock linkage. Fresh turn on flywheel, new clutch, pressure plate, and throw out of course.
6. New water pump, new Comp Cam roller tip rockers. Reinstall old Offenhauser intake and 600 Holley. Reused stock distributor with Pertronix. Reused fresh looking fuel pump. Installed rebuilt Power Steering pump.
7. New heater core and new U joints blah blah blah.

After assembly and installation started after usual Rob anal procedure. Warm oil. Static set on the hydraulic valves with around .040 end play. Around 20 minutes with the drill motor (65 pounds with the drill motor on my fluid filled gauge installed next to oil filter) until all rockers and valves have oil from the push rods. Second set on the valves bringing them down to zero lash and 1/4 turn more. Fill engine with hottest tap water I can get. Pure water only.

No need to break in cam. Engine fails to start, fuel pump died on the bench. Drain water install new fuel pump, restart, all is good. Hot idle at 40 pounds with the straight 30 weight oil. Great vacuum and runs like a top.

The Noise:
Immediately a high pitch, very light, tapping noise. Tried to video it, but camera would not pick it up. Easy to hear with naked ear, even 20 feet away with hood closed . Noise seems in front of the engine. It is kinda random but does increase in frequency when RPM is increased. Seems similar to a rocker arm tip to valve tip.

Get out the auto stethoscope and start in. Noise all over the front of engine, but with the stethoscope a consistent tapping is easily heard on the fuel pump where it bolts to the timing case. Rockers sound fine.
1. Get new fuel pump (stock NAPA). Same noise. New fuel pump over pressurizes carb. Fuel out the top. Floods engine fortunately! Start up my GNS with Holley mechanical. Nice swooshing quite noise. Get a known stock fuel pump and install. Same noise. finally take pump off GNS install and it is very noisy now.
2. Remove power steering pump belt. No change
3. Remove alternator/water pump belt. No change.
4. Remove fuel pump and install card board block off plate. Run it with a full float bowl of gas. No change.
5. Rummage around in attic to find valve cover with top cut out. Have not used in years. Hot setting is a thing of the past in my mind. Loosen rockers on both sides. At 1/4 turn, nice loud tacking noise. Deeper than other noise and more consistent. Stumped...
6. Decide there is problem with fuel pump eccentric of timing set. Try to look at eccentric with mirror through fuel pump hole. Not easy to do. So I take front off motor. Of course requires you to drop pan if you are doing correctly. Drain all fluids first.
7. All looks normal. This was the hand off point from engine builder. I had check the torque on timing gear/eccentric bolt before, but starting to doubt myself. Bolt was fine. No marks anywhere front of block or engine. Timing set looks normal, but hard to discern if a link is bad. Consider installing a stock set from Napa. Bought one and took tons of measurements. All seem fine.
8. Put all back together hoping something would happen or onto somewhere else. Start engine, no change. Getting tired of noise.
9. Call engine builder. He feels it might be a roller tip on a rocker arm. Reinstall old rocker arms and push rods. Nope, same noise.
9. Sample engine oil and it is perfect. No evidence of shavings of fine particulate. Take it for a short drive in hopes it would heal itself. This never happens, but wanted to set rings. Did not heal itself.....

Round Two:
Get old friend that is a machinist and old Ford lover with lots of motors in his past. Spend two hours going over motor. Stop the belts and yes, install remote gravity feed fuel tank to feed carb at idle. Hang from bottom of hood. Run engine with all accessories and fuel pump off again. Noise still there of course..... Old friend thinks it is mid motor and he feels it is a lifter noise. Not a rocker to valve tip, but the lifter itself. We close up shop again.

So, off with the front and new Comp Cams hydraulic cam and lifters. Upon removal I did find one lifter that after very thorough inspection was "ok" and I feel would have lasted, but heck maybe it is it. Tiny bit of knife edging on lobe and the tiniest almost indiscernible cupping in center. Needed magnifying glass. Cam lobe was just fine to my experience.

So new cam and same start up, valve lash adjustment, and oiling procedures. Start engine, not joy. As it comes up to 2,500 RPM I think I still hear it. 30 minutes later, bring it down to idle. Noise still there..... Looking for a gun to shoot engine.... Or self!

Have Val take a ride on the lift. Stop all belts and take her up with engine running. Spend 10 minutes all over bottom end with stethoscope. Had done some of this before on bottom of front, but with lift complete access to pan rails. No noise similar in rhythm. Down bottom of each exhaust manifold, not leaks. Nothing unusual. Down scope. Go all over the engine on top side once again. down exhaust manifolds to the donut. shut down garage. Drink heavily.... Drinking does not help....

Take one last short drive (30 miles) hoping for self healing. No luck. Starting to hate my garage. Val names the car TFM (that "freaking" Mustang) TFM definition is in pg. version of what she really said. More heavy drinking. Three "3 day" weekends and some late week nights have been consumed.... Starting to babbled incoherent words...

Call up engine builder. Only thing left in my mind is harmonic balancer. By the way, pulley on balancer is nice and snug. And again noise is there with no belts. Make appointment and take car to Tacoma, 40 miles one way. Get to shop. Car again did not heal itself. thank God, nice sunny day.

Found noise. You get to torture yourself to ease my pain. Give me some guesses!! I will share all soon.

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