Technical SBC lifters stuck? Bent valves. Possible cause?

Hi,
I have SBC in frie nds '53 Chevy. Both a little bit OT, but a problem is quite intimidating.
I've rebuilt the engine (~'85 i think) with thumper cam and Comp Cams lifters. Now it had returned to me with 5 bent valves. All of them on RH bank. When i took the lifters i noticed (not sure on LH bank, they are still on the engine yet) that they stay put. I can pound on them with a hammer, they will not collapse. I dismantled them and then they work as they should, collapsing a little. Oil was clean inside, oil galleries were cleaned with a brush during rebuild. Faulty lifters? One of them during dismantling had check valve in pieces, which is almost impossible to do.
I am thinking about simply replacing lifters, just am not sure what is the cause and therefore can't sleep with that .
Please advise.

 

Hard to tell....Are there any signs of an impact on the piston tops? The valves acutally look good in the pictures, maybe remove one or two from the head and roll the stem on a flat surface, if you see the valve wiggle it is bent. The valves would need something to hit against to be bent, I think. And if that happens there might aswell be a cracked rocker arm or a bent pushrod...
Are the lifters sticking in the lifter bores?
Maybe the heads have been shaved or the block been decked enough for the valves to run out of space one they are warmed up and getting longer...
Just thinking out loud...

 

Old Stale gas can make valves stick in the guides.

 

Valves are bent definitely, just a little. You can see that that exhaust valve is not closed.
Pushrods are not sticking in bores, just that plunger inside is stuck. When dismantled, i'm freeing oil from inside, then it works. Until pumped with oil. Faulty check valves inside?
Definitely it is lifter related. Hydraulic pressure should allow them to collapse, they are pumped even after removing them from engine.

 

The 289 in my Fairlane had sat for 13 years prior to my owning. After an hour of running it looked the same, three bent intake valves, push rods and two lifters that had come apart. All of the intake valves had left witness marks on the pistons as the valves were sticking in the guide's.

 

Sounds to me like you discovered how hydraulic lifters work. But that's not the problem.

Did you check to piston to valve clearance, as you were assembling the engine?

Did you check valve stem to guide clearance?

 

It has to be the lifters ,I wonder if they're made in China for Comp Cams . I'd bet the tolerances are to tight inside lifter barrel causing bind ! Get in touch with Comp Cams for help .

 

Has the head been disassembled yet? I'm also leaning toward seized guides as the primary failure. If so betting 4 of the 5 valves were exhaust since they see more heat.

 

I go with the valve not closing and the lifter pumps up trying to close the valve lash. If lifters bled down quickly you would get a lot of valve noise every time you started the engine.

 

Get the valves out of the heads so you can determine what caused them to seize. I'm guessing there's a fuel problem here ...

 

Its something folks refuse to believe. They think because they add some bottle of snake oil to the gas it will not go bad with age . When in fact today s gas no matter what in a very short time goes stale and gums up carbs and will make valves stick in the guides.

 

Looks like tight guides to me. Lippy

 

Guys,
I am not sure i am presenting this right, since english is not my native language, so one by one:
- engine was built almost 3 years ago, stock with only thumper cam added per owner's wish
- it rode without a problem, it made very many succesful miles
- there is no mark on the piston, but the valve presented on picture is the worst
- valves are not stuck in guides, they move freely; valves removed from head has no seizing marks, their stem looks like new
- heads were dismantled, checked, valves (indeed, 4 exhaust, 1 intake) replaced
- i know how hydraulic lifters work, point is, they seem not to work. I noticed all of this when setting lifter preload - you have to set them to zero lash and go 3/4 - 1 1/4 turn. Then i noticed not the lifter compressing a little, as normal, but the valve opening. Right now, before lifters were removed, valves with lifter preload set that way, were open all the time.
- gas is not stale, that Chevy is driven a lot
- inside a lifter there is not a clue of binding. after opening and oil pressure released (but should lifter have oil pressure inside after removing from engine?) everything moves freely, until mounting in engine and getting oil pressure, then everything happens again.
- before i opened that engine i've measured cylinder pressure and noticed some cylinders with weak pressure. Valves were ticking, then i noticed them not closing in full. I've tried setting valves on a running engine, when set valves to zero lash it worked ok'ish (valves were already bent), when proceeded to tighten them another 3/4 turn they started to get noisy
- i know that it may sound wieird, but as i have built about 30 engines to date, i don't know SBC that much

 

One more thing - valved were replaced in machine shop, i don't have tools to check their guide clearance. I sorta trust that machine shop, but it is valid point. How to check that using in-house methods? I have calipers, micrometers and such, just not that size.

 

I'd send the lifters back to comp and see what they say. Never seen a lifter stronger than a valve spring lol. JMO but I never go past 3/4 of a turn of preload. How much lifter plunger travel is there in one of those lifters? Lippy

 

When empty, i can collapse that lifters by hand, and set lifter preload even a little bit past 1 1/4 turn without opening a valve.
I have two another SBC's waiting for their turn to be built and removed lifters from them and tested - they can be pushed with no problem. That's why i am convinced that this is a problem with lifters, but i checked most things mentioned above and i'm pretty sure nothing is wrong there...

 

To check the valve guide to stem clearance, properly, requires a small dial bore gauge, and a micrometer.

https://www.shars.com/0-24-0-4-dial-bore-gauge-0-0001

for example

 

Preload setting depends on the comp cam lifter you have, I remember my instructions from them setting the 268 Extreme Energy lifters is 1/2 past zero lash.

So looked up the other comp lifter preload instructions and found.

High energy & High Tech lifter gets 1 turn past 0 lash

Pro Magnum zero to 1/8 turn past zero lash

 

Could your friend have over-reved the engine in to float? That could over extend the lifters, leading to valve to piston contact and bent parts.

Once pumped up, the lifter should stay solid. Maybe not forever, but for quite a while.



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I adjust valves with the engine running. With Hyd lifters I back off till they clatter. Then tighten till they just get quiet. adjust then all then turn of engine and turn 1/4 turn. Been doing it that way for more than 5 decades.

 

A hydraulic lifter will be hard to collapse after use and the piston at the bottom has oil behind it especially when fully extended from slack in the valve train. When setting initial lash cold with new lifters it's pretty much just the spring you're compressing, running and pumped up you need to go in small increments as the lifter will self adjust slowly. If you back out a lifter running till it ticks, go back till it doesn't and add 1/4 turn at a time it should stop misfiring about 5 seconds or so after. If it never recovers the lifter may be bad (assuming that cylinder ran good to begin with). Kind of chasing your tail too since you never actually inspected the head yourself. Also pretty much impossible to have a bent valve and no evidence on it or the piston.

 

Thank You guys!
In fact, for break-in, we installed only external valve springs. After a few months (busy period) internal springs were installed. Then, after 1-2 months, friend started complaining about valve ticking noise. It may have been overrevved, i don't know. I can't see anything on the piston, but there is a little bit of carbon buildup and i may be not seeing everything. Also then i noticed valve not closing properly. I know it was bent then, bu found that the lifter is holding the valve continously open.
Then the head was removed. I trust my machine shop, they've done numerous heads for me, so i think that is not the problem. I think that lifters are sticking in fully extended position. Could that be possible?
I can hear you saying about other possible causes, i will see some things once again.
I have workshop manual saying to set lifter preload 3/4 - 1 1/4 turn. You say that 3/4 is enough and not to go beyond? Problem is that with these lifters even 1/8 turn opens the valve. I can't collapse lifters even after removing from engine. Lifters removed from other SBC i have laying around collapse without a problem. I just don't know if that seems as a possible cause to this problem?

 

Did the lifters work when the engine was first assembled? If they did, then I don't see how they could have stopped working. Unless perhaps the oil is much too thick?

It could be that the valves were bent when the inner springs were not yet installed. You are supposed to install them after camshaft break in (after the first half hour of running the engine). With them missing for a few months, it's likely the lifters "pumped up" and bent the valves while driving.

 

Not to start an argument, but my GM service manuals say 1 turn past zero lash.

 

Thanks.
I know that additional springs should be installed right away, and am quite certain that my friend revved engine until valves bent a little. But as i am putting that engine together, half of the lifters (but not all of them on one side of engine) allow for preload setting and are collapsing, half of them - not, instead valves are opening. On a base circle of a cam. That is not quite right .
I am certainly replacing lifters, just am not sure what caused this. Bent valves are propably another problem, but putting all needed valve springs should get rid of that problem.

 

There’s a lot of thing that where clearly done out of the norm and easy to point fingers at. Some things in the timeline are confusing though.

What I find worthy of investigation is this apparent lifter problem is just on one side. That’s where I’d start.

When you do get new lifters, take them apart inspect and clean them before installation.

 

I had a Rhoads lifter go solid on me once after many miles of driving luckily I was going slow . The valve hit my forged piston and snap the head off . Made a mess of the head.

 

Too much oil pressure one side ?

 

The lifter preload is actually so many thousandths of an inch, just like lash is expressed in 0.018.
Based on TPI count of the rocker stud and rocker ratios that distance is extrapolated into “turns” past zero lash.
This Zero lash is done by “feel” and can be subjective. It could be set on lifters that are sticky or that were assembled incorrectly or dirty by an 8 yr old child working hard so they don’t harvest his organs.

That exhaust valve looks to be quite proud off the casting. I’d check the clearance before sending it out again

 

No
“Going solid” is exactly what they’re supposed to do at 3500 rpm. Tossed retainer locks, broken springs, seized valve guide
Otherwise the first Time you went to 3500 Rpms the calamity would have started