Im stumped. 350 Chevy,sounded like a lifter click,and at idle a little like vacum leak . Cant find any vacum leaks . Have run lifters several times with motor running. No change ,plugs wires etc all good ,timing good. Visualy watched rockers all seem to be moving the same . Compression check shows all at 130 to 135. No exhaust leak,not fuel pump rod.Dont see any sparkly's in oil carrries 30+ at idle and 40+ running 50 at start up. Its in a 29 coupe with no accessory's , Just off idle by maybe a couple hundred rpm's seems to stop clicking and motor smooths out. Other than at idle it hauls the mail. Im coming up with nuthing and have ran out of ideas any help or things to check would be great. Thanks ..
What trans are you running? Could be a cracked flexplate, automatic, or something in the clutch on a manual transmission. Does it have factory manifolds with that heat stove thingy to run the choke? Sometimes those things corrode away and can rattle around. Maybe just some piston slap????
I had a tick in a small block chevy once. Sounded like exhaust leak or possibly a lifter. A stethiscope narruowed it down to the dist. Everyting there was new. I never did find out what it was before I sold it.
Running a 350 turbo,all checked out fine ,dip stick fine,dizzy fine. Ive done the listen with a screw driver ,piece of hose ,and mechanics stethascope (spelling) and cant pin it down,seems to be on pass side up high,at first just thought lifters ,then maybe a cam lobe going ,but with all the rockers moving the same dont think so pluss as I said when you get on it runs way good.
Rocker arm wear, check the ball and the valve contact area. Or even the pushrod cups, or the pushrods themselves. A noise that will go unnoticed in a family sedan will drive ya nuts in an open engined rod.
Weak spring on a mechanical fuel pump will make the same ticking sound too and the pump will still work.
I had strange tick at idle on a 350 in a camero years ago. Couldn't find it for weeks turned out to be a rock lodged in the pully on the crank. only made noise at idle because if you increased engine speed the fan made to much noise to hear it. And who would ever look down there for something wrong?
I also had the same noise in a 69 Nova SS with a 350. It turned out to be a broke spring in the mechanical fuel pump. Unfortunately I did not discover this until after I reworked the heads for a 2nd time !! I discovered it by inadvertantly putting my hand on top of the pump as I leaned down close to the motor to listen for an exhaust leak. I could feel a slight knocking in the pump as the motor idled. Replaced the GM pump with a 10.00 Autozone unit and problem fixed. It ran fine for several years until I sold it.
Lifter nosie should disappear with adjust.Broke ring makes a tic but I think you would know by now.. Use a rubber hose or broom handle to isolate tic.I think exaust . What exaust on it,headers or stock, heat riser?
I had a mechanical fuel pump pushrod wear down until it got short enough to make a clicking sound, drove me nuts because I could figure out what it was. Then one day the truck just stopped in the middle of the street, no fuel in carb, so I thought I ran out of gas, but it turned out the push rod got so short that it quit actuating the pump, pot in a new push rod and all was good, no clicking. Never heard this happen to any body else, but you never know until you check.
If it sounds like it's up high, the first thing I'd do would be to pull off each rocker, one at a time. Check for the following: (1) Using a plate of glass, make sure that the pushrod isn't even sightly bent. (2) Inspect the rockers carefully for wear or cracks. It's easy to crack a stamped Chevy rocker if the cam you're using has more lift than the rocker is designed for. (3) If the studs are press-in, check the heights to make sure that one isn't slightly taller than the rest. (4) Check the 'inner' valve springs to make sure that one isn't 'loose' or cracked. Hope this helps... Dave B.
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