Lifter tap on 1973 454

[Mark E.]

Re: Lifter tap on 1973 454

My '73 LS4 cracks valve spring nuts. Has done it three times in the last ten years. A retired Chevy parts manager told me that I should carry half a dozen of these nuts in the car with me. They are just $1 each. He said these big blocks break these nuts all the time back in the day.

That was the fix when the engine started tapping.

Do you mean rocker arm nut?

[Peter G.]

Re: Lifter tap on 1973 454

Yes. Holds the rocker arm down.

Thanks.

[Mark E.]

Re: Lifter tap on 1973 454

The only failure I've encountered with the nut are worn threads. Since they are friction threads, they can lose their tension if adjusted a lot.

[Bruce C.]

Re: Lifter tap on 1973 454

If the problem turns out to be a noisey lifter,most lifters can be replaced on a big block without intake removal.Remove the valve cover,and you will see numerous access holes(large),remove push rod,using a strong magnet,pull the trouble lifter out of the bore.If the lifter is varnished up, wash with 2 plus 2.Sometimes they can be a fighter to get out of the bore,but rotating and pulling and you will be able to extract it.Also make sure the fuel pump lever is not loose.