Tapping sound?

[mike561]

I noticed for a while now the engine makes kind of a tapping or rattling sound when at idle and mostly in park, it sounds like its comming from under the pass. side valve cover. The engine runs fine and smooth but i just cant figure out what this noise is, ill try to get a audio clip up in the next few days too. kinda sucks too cause i got this nice flowmaster setup but the tapping takes away from the nice rumble sound you know?

[silicon212]

Sounds like a loose rocker or collapsed lifter. It might also just need an adjustment and if this is the case, it could indicate a cam lobe failure in progress.

[mike561]

Now that you mention it, i think someone else was having a simmilar issue too, i dont think it does it when i accelerate, just at idle. would those things be a big expensive fix? or could a beginner like me dive into it?

[silicon212]

Originally Posted by mike561

Now that you mention it, i think someone else was having a simmilar issue too, i dont think it does it when i accelerate, just at idle. would those things be a big expensive fix? or could a beginner like me dive into it?

Do some research on how to adjust valves with the engine running (warning: this is MESSY!), before you do it. However, it is simple but DOES require starting the engine with the appropriate valve cover off to adjust the valves.

[mike561]

ok ill look into it

[j cAT]

Originally Posted by mike561

ok ill look into it

try some engine oil additive to clean the lifters... I found #8 cyl. to start to make noises first.. how does the oil look ...is it black ? or very dark ?

[mike561]

the oil looks like a light black, i have some of that marvel mystery oil too

[j cAT]

Originally Posted by mike561

the oil looks like a light black, i have some of that marvel mystery oil too

this sounds like you have a rich mixture... did you adjust the carb mixtures.....or if not that then ,,,the plugs/wires/coil are not supplying the correct spark ...


oil will get dark brown.. but if its black this is carbon ,, and will cause lifters to make noise ,,, as well as wear out the internal engine componets...


dirty air filter ? is the exhaust pipe at exit black / sooty?

[mike561]

The air filter is clean, the car used to shoot out black soot when i first got it but hasnt in a while now

[GreyGoose006]

if your oil pressure is low, or you dont have enough oil in the car, the lifters wont work.

[mike561]

I gotta change the oil again soon, i checked the dipstick and ther is oil, its at the add mark, so ill put some in and see what happenes

[Sunbound85]

Originally Posted by mike561

The air filter is clean, the car used to shoot out black soot when i first got it but hasnt in a while now

Hello, this reminds me exactly what my Caprice was doing when I purchased it... that rhythmic ticking noise from the left valve cover (only at idle)... I ripped off the carb, intake manifold and replaced all the hydraulic lifters, it cost about maybe $150 in total (new lifters, intake gasket and a fresh oil change)... What I had not counted on was the amount of dried up crusty black matter that was EVERYWHERE in the lifter valley - I spent about a week swearing w. a can of WD-40 in hand. I had to use miracle oil and a magnetic extension slowly 'lubing' the old clogged lifters out of their cruddy encasement.

To top it off I put a jar of Lucas oil additive to help break in the new lifters and prevent any damage from loose debris in the oil. After 2 additional oil changes (within a 2 month period), I can safely say that ticking is gone : )
However, if you can get someone to do this nasty job for you, I wouldn't hesitate to let 'em dive into the tarpit (unless your engine has been well maintained of course)

[silicon212]

Originally Posted by Sunbound85

Hello, this reminds me exactly what my Caprice was doing when I purchased it... that rhythmic ticking noise from the left valve cover (only at idle)... I ripped off the carb, intake manifold and replaced all the hydraulic lifters, it cost about maybe $150 in total (new lifters, intake gasket and a fresh oil change)... What I had not counted on was the amount of dried up crusty black matter that was EVERYWHERE in the lifter valley - I spent about a week swearing w. a can of WD-40 in hand. I had to use miracle oil and a magnetic extension slowly 'lubing' the old clogged lifters out of their cruddy encasement.

To top it off I put a jar of Lucas oil additive to help break in the new lifters and prevent any damage from loose debris in the oil. After 2 additional oil changes (within a 2 month period), I can safely say that ticking is gone : )
However, if you can get someone to do this nasty job for you, I wouldn't hesitate to let 'em dive into the tarpit (unless your engine has been well maintained of course)

DO NOT REPLACE THE LIFTERS WITHOUT REPLACING THE CAM!

[Sunbound85]

Originally Posted by silicon212

DO NOT REPLACE THE LIFTERS WITHOUT REPLACING THE CAM!

Silicon212, I didn't think to replace the cam, is the stock cam inherently bad in the 305 engine? My lifters were in a pretty bad state - they had very noticable depressions on the bottom where the cam lobes meet the lifter. Should I seriously consider replacing my cam now as well?

[silicon212]

Originally Posted by Sunbound85

Silicon212, I didn't think to replace the cam, is the stock cam inherently bad in the 305 engine? My lifters were in a pretty bad state - they had very noticable depressions on the bottom where the cam lobes meet the lifter. Should I seriously consider replacing my cam now as well?

Yes, and the lifters again! If you see the (old) lifter is concave, think of what that cam lobe looks like. Your new lifters are already toast. The cam lobe and lifter wear into each other. If you look at the bottom of a new lifter real close, you will notice that it is not perfectly flat, but slightly convex (like a lens). Likewise, the cam lobe is not perfectly flat either, but slopes from the back down to the front at a slight angle. The whole reason for this is that when the parts are new, the lobe moving under the lifter will impart a 'spin' or slight rotation to the lifter. This rotation is CRITICAL to equalize wear. If there is no rotation, the cam lobe will eat into the lifter and the lobe/lifter will wear at an accelerated pace.

The slope on the lobes of the cam also act to thrust the cam backward in the block, so the thrust surface on the cam sprocket is pulled against the block and the cam remains properly located in the engine. This is why roller cams must either have a bolted plate on the sprocket, or a 'button' with a spring on the front of the sprocket (they don't have the angle on the lobe, don't need it).

When you replace one, you MUST replace BOTH!

If your old lifters showed any concave, that cam lobe is wiped. Running an engine with new lifters on an old cam that doesn't have the proper profile will result in immediate damage to the lifter.