Should I replace camshaft or just lifters?

[Angelo M.]

I have a 1970 350 small block which has loud tappet noise between cylinder 1 and 3. My chioces right now are, option 1, to replace the lifters and attempt to break in the new lifters with the old cam. The engine has approxmately 300 miles on the rebuild but has been sitting for some time. I was told by a mechanic that you should replace both cam and lifter as a unit because they both need to be broken in together. Is it really necessary to replace both cam and lifter together? When pull the old lifters out what should I be looking for? What are my changes that a new lifter replacement will do the trick?

[Clem Z.]

Re: Should I replace camshaft or just lifters?

I have a 1970 350 small block which has loud tappet noise between cylinder 1 and 3. My chioces right now are, option 1, to replace the lifters and attempt to break in the new lifters with the old cam. The engine has approxmately 300 miles on the rebuild but has been sitting for some time. I was told by a mechanic that you should replace both cam and lifter as a unit because they both need to be broken in together. Is it really necessary to replace both cam and lifter together? When pull the old lifters out what should I be looking for? What are my changes that a new lifter replacement will do the trick?

if the lifters look good on the bottom, they should be convex,check with a straight edge then i assume they are hydraulic i would take them apart and clean them. if the bottoms are convex the cam lobe is most likely gone and you will have no choice but to change cam and lifters. keep track of which lobe each lifter came off of so they can be put back on the same lobe

[Scott S.]

Re: Should I replace camshaft or just lifters?

if the lifters look good on the bottom, they should be convex,check with a straight edge then i assume they are hydraulic i would take them apart and clean them. if the bottoms are convex the cam lobe is most likely gone and you will have no choice but to change cam and lifters. keep track of which lobe each lifter came off of so they can be put back on the same lobe

I think you meant to say "...if the bottoms are concave the cam lobe is likely gone...."

[Bill M.]

Re: Should I replace camshaft or just lifters?

When pull the old lifters out what should I be looking for? What are my changes that a new lifter replacement will do the trick?

This happened on a mechanical cam 396. It was noisy.

[Clem Z.]

Re: Should I replace camshaft or just lifters?

I think you meant to say "...if the bottoms are concave the cam lobe is likely gone...."

that is what happens when you start typing before the first morning cup of coffee.

[Mike M.]

Re: Should I replace camshaft or just lifters?

Need a little more info.
How old/how many miles on the cam and lifters.
If they are not fairly fresh, mechanics say always replace both.
How do you know it's the lifter?
From above info, you could luck out with a lifter change. Don't get your hopes up.
Cam could be the culpret (Flat), or the rocker or the pushrod.
I had agreed to a price on my first Corvette. When the car was being delivered it developed a miss, then a click, then a clatter, then it snap, crackled and popped. Barely made it to the dealer.
Thinking the engine was about to blow, the seller quickly knocked off $200. from the price.
I got it home, pulled the valve cover to find a chewed pushrod, presto, chango....good as new.
This is only a small part of the story, but, my fingers hurt.
HaND and Good Luck!

[Dick W.]

Re: Should I replace camshaft or just lifters?

If you replace only the lifter, take 1000 grit sandpaper and use mineral spirits as a lubricant. Slightly scuff the bottom of the lifter before you install. Use a generous amount of cam break in lube on the base of the lifter when it is installed

[Angelo M.]

Re: Should I replace camshaft or just lifters?

I just pulled all the lifters and I took them to this mechanic. He said they all have normal wear and look to be in good condition. He recomended that I look at the rockers themselves for any wear. I looked and they all seem find. He recommmended that I soak lifters in marvel mystery oil for a day or 2 and push the plunger in on the lifters every now and then. The rockers studs are studed in the cylinder head and they are threaded in so I don't suspect any movement from there. These are hyd. lifers.

[Joel F.]

Re: Should I replace camshaft or just lifters?

If you replace only the lifter, take 1000 grit sandpaper and use mineral spirits as a lubricant. Slightly scuff the bottom of the lifter before you install. Use a generous amount of cam break in lube on the base of the lifter when it is installed

Dick,

Same recommendation for a new cam/lifter combo? Or is this simply to aid in marrying the new lifter to the slightly worn cam?

THanks in advance.
Joel

[Clem Z.]

Re: Should I replace camshaft or just lifters?

Dick,

Same recommendation for a new cam/lifter combo? Or is this simply to aid in marrying the new lifter to the slightly worn cam?

THanks in advance.
Joel

stock GM solid lifters had a "aggressive" finish in the bottom that i always polished on fine emery paper. i have use the same set of lifter on a lot of different cams during dyno tests of cams with out any problem.