Technical SBC Valve Lifter Question?

It’s a first generation 350 GM crate engine that I replaced the heads /cam/pistons in a couple years ago. Last weekend I replaced the cam and lifters. I wasn’t having any issues other than I didn’t care for the original cam I had chosen. Then this problem started after replacement

 

You mentioned changing the pistons... Did you bore it or just replace them in a stock bore? Forged? Hyper? What is the cylinder to piston clearance?

The reason I ask is mine are forged with .0038" - .004" clearance, and the noise seems to get better the hotter it runs. Driver50x might be on to something.

I had a .030" over once, that went south on me, so I honed it to .040" to clean it up, but some of them didn't clean up until .005" clearance. It clacked until it warmed up, but it was the best power of any of the strokers I did.

They were KB hyper pistons and I know that is way too much clearance. I also know with forged pistons they like to be warmed up before you hammer it.

 

I know , you're supposed to be able to put new lifters on a used can , we used to do it at the olds , then Chevy , then ford garage in the 60's & 70's regularly with no problem , hell , I even put lifters from one used engine in another we no I'll effects . But , that was then & this is now , I'd be a bit concerned about swapping those lifters . We all know that they shouldnt rattle , but , if its not hurting anything , is it worth risking the components that will be damaged should the procedure fail ? ...

 

There is a simple solution for this problem. Solid lifters never bleed off or pump up.

You are not locked into the Lunati lifters. I like Erson anti pump up lifters myself.

 

I agree that this is best. Its not catastropic if someone doesn't do it, but its common sense that parts that have seated with each other will continue to work best when reassembled.

 

Sounds like a job for "Marvel Mystery Oil"..........

 

I’m honestly not sure what the bore clearance is. The engine was a brand new GM (Mexico) 4 bolt main long block. More or less with 0 miles on it because the car was not drive able due to a serious pinion angle issue ( A HAMB thread from a couple years ago) but the engine was brand new. The previous owner had put the Comp 280 mag in it with the stock dished pistons and 76 Cc heads. I put Sealed Power Hyper flat tops in it and the double hump 462 heads that had just been completely overhauled by a reputable shop. I wanted to change the color of the engine and change the cam which I did and have had issues every since. The new cam was installed last Saturday and other than the initial run in. It’s been down the road less than 10 miles. Here are the lifters I purchased to replace the Lunati junk.
Brand:Chevrolet Performance

Manufacturer's Part Number:12371044

Part Type:Lifters

Product Line:Chevrolet Performance Hydraulic Flat Tappet Lifters

Summit Racing Part Number:NAL-12371044


Lifter Style:Hydraulic flat tappet

Lifter Link Bars Included:No

Lifter Outside Diameter (in):0.842 in.

Lifter Offset:None

Quantity:Sold as a set of 16.

 

Montana1 May be on to something. Are you sure it’s not piston skirt noise cold?


Sent from my iPhone using H.A.M.B.

 

If it didn’t rattle or tick before, then kinda rules out the bottom end I’d think.

 

My thoughts exactly,,,,,,,no piston slap before,,,,,changing a cam and lifters could not cause anything like that .
I might be wrong,,,,,but it sounds like crappy lifters to me !

Tommy

 

You know how something suddenly pops into your thoughts when you weren't even thinking about that subject........Well I don't know why I suddenly thought about this, and I haven't thought it through, but it something to consider.
We all know that we need to tighten the rocker arm down until the lifter quits ticking, and then tighten 1/4 -3/4 turns more. Some rockers are tightened in the approximate middle while others are tightened by a set screw at one end. How can they both have the same effect on pushing the lifter? Your thoughts please

 

I think the Witch Dr. may have gotten you...

 

Whenever I did a lifter change, I always put the lifters in a "very clean" empty coffee can... Poor your best oil in there and one by one start pumping up the lifters with a pushrod.... Setting the lifters in a can and letting it sit overnight don't do a damn thing to the lifters other than coat the outside of the lifter.... They'll still be empty when you pull those out of the can.....

 

50 years of putting dozens of SBCs together. I have never soaked lifters. They fill up when I prime the engine. Never a problem.

 

That works also...

 

Check these out.

 

I was taught this way as well, as I was told, if lifters were full of oil, it could bend pushrods. As I was taught was to put the lifters in and rely on the lifter to be open? Not sure if he wording. Leave the rocker arms loose. Then do g to w rotation thing, feel for zero lash, then 3/4 a turn. After done, prime engine while rotating.

now I’ve never run a .600 lift cam, so take it from there

 

Look normal for an engine at rest with no oil pressure..

 

What is all that trash in the valley?

 

Here's a question , will a so called anti pump up lifter bleed down more readily than a conventional lifter ?
Correct me if I'm wrong.....at any given time , at least 8 lifters are not completely closed ..

 

Pieces of intake gasket. Motor is out of car now.

 

I agree! I like to have a better feel of the initial closed valve adjustment before they are pumped up. So does Comp...

Remove your new COMP Cams® lifters from the packaging, and clean the lifters thoroughly in mineral spirits or an equivalent solvent. It is not necessary to “pre-pump” hydraulic lifters full of engine oil prior to installation and valve adjustment. It is actually undesirable to do so as the “pumped up” lifters will cause the valves to open during the adjustment process, rather than positioning the lifter plunger in its operating position as it is supposed to do.

“Pre-soaking” hydraulic lifters in a bath of engine oil is a good idea but not mandatory. Doing so ensures that the lifters are adequately lubricated on their outer surfaces prior to installation.
https://www.compcams.com/pub/media/productattach/c/o/comp4-141.pdf

 

BTW, what kind of valve to piston clearance do you have? Rocker ratio? Rocker arm geometry? Did you degree it in? This would be a good time to check things over, while the motor is out.

I find it hard to just throw another cam in an engine without checking things, no matter how big or small it is.

 

Update. I replaced the Lunati lifters with Chevrolet Performance Parts replacements. Adjusted 0 plus 1/2 turn. No further clacking on startup.

 

Thanks for the update ,hope you've permanently solved the issue .Would be interesting to disassemble one of the sloppy lifters to see if there is a visible issue ...

 

Good for you!!!!!.....

 

Honestly I’d like to have my money back for the Lunati lifters. Feeding me that “ Oh that’s normal crap “ still doesn’t sit well with me. I’m thinking about sending them back to them. Already money in the hole for new lifters. Oil. Gaskets Etc. What’s another $10.00 postage cost. Probably would not do anything. But never know.

 

Thanks! I'll remember to never buy a cam kit from those guys.....

 

I'd feel a lot better if you found the problem before you sent them back .....evidence , you know..

 

This week I just went through what Grey Beard said. After 15 years I just thought it as it was time to check the valves. I had no issues at the time. I have set a lot of valves and never had this issue. I am running a early 70's edelbrock aluminum valve covers with just a 480 lift cam.. After setting the valves @ 3/4 and installing the covers I started it up and had a knock on the right bank and could hear and feel it in the cover. I pulled the cover again (second time) and could not se anything. By now the cork gaskets were crushed and bottomed out as this is the third time off. I changed to a new thicker gasket and the problem went away. Not sure why but this fixed my noise. I know the cover was bottomed on the head very hard as I need too because I mount my wire brackets on it. With the metal wire cover it would not let me actually bottom it. so all is good.