This weekend my engine started making a odd ticking/knocking sound. It only happens above about 2000 rpms and does it in all gears including park and neutral. It gets worse when you are going down the road and let off the throttle slightly. I know it is not a lifter or rocker tapping. I would appreciate any help.

The engine has less than 5000 miles, 350 bored .30, crane cam 216 dur. @ .50 and .454 in. lift, Cloyes true double roller, speed pro pistons H345NP, clevite 77 bearings, Edelbrock Performer RPM intake, Edelbrock Performer 600cfm carb, and a stock crank and rods.

 

Since you say its not a lifter or rocker nock, what about an exhaust leak? Are you running headers and have you checked the tightness on your header bolts lately?

 

Is the ticking RPM related? Does it go up and down with engine rev's? Or is it consisitent? Does it get louder or quieter at any time?

 

I do have a exhaust leak do to a cracked stock manifold but I know what it sounds like and this is a metalic sound between similar to marbles ticking and a lifter ticking. If that makes any sense. It goes away if you hold a steady rpm but when you let off and drop 200 rpms or so it get louder and some times again when you shift going down the highway.

 

If it's an auto, check for a cracked flexplate.


I have heard one knock that gets louder when you let off the throttle.... spun rod bearing.

 

Flex plate will make that sound....I had one do it. Are you running a mechanical fuel pump? Not only have I seen the pump make that noise the pump rod to cam will wear out making a lifter/rod noise also.

 

It is an automatic and i do have a mechanical fuel pump. This weekend I plan on breaking out the stethescope and trying to chase down the location of the sound. A good friend (builds engines for people at the local drag strip and dirt track) of mine said he thought it could be a piston pin by what i told him. He wants to drive it tommorow to see what he comes up with.

 

I had a car that was making a similar sound once... and it was actually the dist'. Turns out that some of the screws came undone...

These things can be a pain to track down.. good luck.

 

If you go all over the engine and cannot locate it, it could very well be the flex plate. My truck engine had a bad knock and I could not find it. I went all over the top bottom and sides of the engine yet could not locate the knock. I had checked the flex plate but could not find any cracks. Drove the thing all winter and the knock got worse ad worse. Over the winter I rebuilt a 350 for it and said if the engine does blow so what it's only a 305,, in the Spring the flex plate had cracked enough and I could see cracking. When I pulled the tourque converter off I could pull the flex plate right off the engine as it broken all the way around.

 

its kinda odd but check that ir spark plugs are tight and secure , i had one back out on me and it caused this weird ticking sound

 

If it sounds at all like a pinging noise then I would check the timing.

 

I finally pulled the oil pan to find out i had bearing shavings in the oil. I removed the rod caps to find two spun bearings.

 

Hmm... I've heard spun bearings and they never sounded like ticking...
more like thuds....
Good luck fixing it though.