My 74 454 has "sporatic" clacking of the lifters. It seems to always happen on the second start of the day. The first run is quiet. After some time I get back in the car and in a while the lifters start clacking. After about a mile they quiet back down again. Any suggestions as to what could cause this?

We need to know some variables first:

Stock or Aftermarket cam/lifters.
Stock rocker arms or roller rockers.
Mileage on engine.
Type of motor oil.
What is the oil pressure at when cold/hot?
Were the valves adjusted recently?
Is the noise coming from one particular side of the engine?
Was the car driven normal or hard/raced that you know of?

We may be able to help you out with some answers to the above questions.
Sarge

The engine is all stock. 56K original miles. I use straight 30 weight oil. Oil pressure does not vary much to either side of 40psi and maintains that pressure when the clacking comes. Have not adjusted anything yet. Clacking mainly from the right side of the engine. The car has not been raced and was pretty much babied by the one previous owner.

It sound like one of a few things.

1. The lifter is just worn out. But I would not expect this one from your description

2. The lifter is clogged with deposits, making it stick internally part of the time.

For this one you may want to try some crankcase cleaners such as 5 minute motor flush, then change the oil. An old trick that works very well is a quart of transmission fluid in the motor oil. Drive gently for several miles, or just idle for a while. Let it sit a few hours or a day, and drive it some more. It won't hurt the engine, but you don't want heavy loads.

Then change the oil. The trans fluid is a great cleaner.

3. The lifter is coming out of adjustment, and needs readjusted.

I would try a cleaner first, then check the adjustments. If both fail, you will probably need a new lifer. If the adjustment was off, be sure to check the rocker stud and see if it is fully seated in the head. Also check for wear at the rocker and push rod. Also check the adjustment nut to be sure it has enough tension to hold it's adjustment

if you have a automotive stethoscope you can find the offending lifter..

if its not adjustment (which i suspect it isnt since it only rattles part of the time..) then the oil flush or trans fluid ken mentioned is great..

the only thing I can add is.. if you replace one lifter.. replace them all.. no point in replacing this one and having another start skicking 6 months from now.

since it only has 56K miles on it in 30 years.. did the car sit for any extended periods ??

My theory.. you might have a lifter or two that have weak springs in them.. when it warms up the spring expands and behaves properly..

this can occur from extended periods of inactivity

here is a cut away diagram of a roller hydraulic lifter.. your wont be roller.. but same principle



|UPDATED|12/7/2004 9:06:33 PM (AZT)|/UPDATED|

Thanks guys. I'll try the cleaner first. I am always leary of putting "mystery" stuff in the oil. There's a ton of them on the market. I'll try the transmission fluid.

i use dextron it has detergent in it follow kens advice and you cant go wrong

My '70 454 valve train is just plain noisy. I don't have anything to compare to. Is it just me, are others noisy, or is it because of the lack of acoustical value in the chrome valve covers?

These are the original heads.

Bill Folse

does it have solid lifters?

if hydraulic they could be worn out..

they could be improperly adjusted..

Thanks and noted on the comments re: noisy engine.

I have never had a hydraulic chevy block apart. Will report when I get down there for more info.