lifter clatter

[jaws]

I have a 360 that I put together 4 yrs ago. I have been fighting a lift tic ever since. Its got a comp cams hydrolic with the specs from a 68 340 4spd cam, nothing wild. When I start it cold it clatters like a bit@$ for a couple seconds then smooth a silk. However, when I drive it and it warms up, I get lifter clatter not bad but there just the same. Called Comp and they told me they got a bad batch of lifters and to replace them. They sent a new set, broke them in and same thing. So now I am getting ready for the summer so I pull the covers off. With the lifters on the bottom of the the lobe, I can roll the push rods with 2 fingers easy. This seems like a little to much, like not enough pre load. Is it possible that I need longer push rods, or do I have another bad set of lifters. This is the first small block that I bilt,sooo now what?

 

[dgoplen]

do they all spin the same?hughes told me that when they spin lightly thats 0 preload about 1 turn of the adjuster adds .020 preload and thats minimum..040 is goal.oh by the way mopar doesnt have adjusters do they.lol.. i have found that comp cams has a noisey valve train with their fast ramp cams too. i changed to fel pro 8553 head gaskets and found today they are about .051 compressed not the .039 they say .it cost me amonth of grief and about $100 in pushrods as i had to get the 7.550 longer pushrods hope to have it fired up soon to make sure, so id check your preload on all your lifters first.

 

[fishy68]

In 2007 I got 2 of those bad batches of lifters in a row. Got tired of messing with them and switched to Lunati and haven't had a problem since. In your case it could be either defective lifters or like you think it may not be enough preload. The only way to know if it's a preload issue is to measure it. As for the pushrods being easy to spin meaning it's zero preload, that happens even when everything is correct cause all hyd. lifters bleed off a little when the engine isn't running. The only way to know if the preload is correct is to measure it.

 

[fishy68]

hughes told me that when they spin lightly thats 0 preload about 1 turn of the adjuster adds .020 preload and thats minimum..

Hughes said 1 turn of the adjuster = .020" preload??? Those must be some super fine thread adjusters cause standard 3/8-24 thread adjusters load it approx. .041"

 

[moper]

Personally, i can't tell by twisting the pushrod if there's 0, .020, or .040. I have to actually look at them. Any rebuilt engine that was not blueprinted can have this issue with anyone's lifters. I agree it sounds like a pushrod with a little more length will fix it permanently.

 

[80fbody]

If you are using stamped (non-adjustable) rockers & the thick headgasket then you probably do not have enough preload. A set of 273 style adjustable rockers should solve that. Much better purchase than custom pushrods, imo.

Of course, I have both in my 360 because my heads are shaved down to around 62cc.

 

[66dartman]

Sounds like you need longer pushrods or adjustable rockers. I prefer an adjustable rocker even with hydraulic cams.

 

[jaws]

I was thinking that I didn't have enough preload, as I can move them around quite a bit now that it's cold. I will have to see if I can find some ajustable rockers and push rods. Like I said, first small block, have all that stuff for a big block.