Valve spring snapping when hand cranking

[Sunaj]

Hey just wanted to get an opinion on this. pretty new to doing a V6 engine and just changed the intake and head gaskets on a GM 3.1. Is it typical to hear the valves snapping back to position while hand cranking? I double-checked pushrod location.all the pushrods are in their correct spots. Here’s a real brief video of me hand cranking the engine. Looking forward to getting this back on the road ASAP as this is my only vehicle

https://youtu.be/qq9EEdGbAfo

Topic

[Richard Kirshy]

A question:
Prior to reassembly.
Did you well lubricate everything….
Oil up the lifters, push rods, rocker arms, tops of the valves where the rockers ride?
Also, are you 100% sure all the rocker blocks are properly seated and correctly torqued?
There should not be any “snapping” sound(s) during a hand crank.
It may also be because you only have half the assembly completed.
Can’t really say what type of noises could be produced with only 1 of the heads assembled, never tried to hand crank half a motor before.
You may be flexing the cam by doing that.

[Sunaj]

Oh man. That’s one thing I did forget to do was lubricate everything. So I need to go back and put oil all that stuff. I shouldn’t have to take the heads off again should I? And yes the Rockers are properly torqued to specification and are properly sitting well

[Richard Kirshy]

[quote=”Sunaj” post=182791]Oh man. That’s one thing I did forget to do was lubricate everything. So I need to go back and put oil all that stuff. I shouldn’t have to take the heads off again should I? And yes the Rockers are properly torqued to specification and are properly sitting well[/quote]

No, you need not remove the heads, but you will need to remove and reinstall the rockers and push rods in their original order they were removed from.
Also, before attempting a hand crank again, have both heads completely assembled with push rods and rockers lubed and torqued to spec.
No idea what could be happening to the cam with only one of the two heads installed.

[Sunaj]

Do the Springs require lubrication as well or only the pushrods and rocker arms?

[Sunaj]

Yeah I’m not sure what’s going on here. I’ve removed everything and reassembled both heads and it’s still making the noise. The only thing that was changed when I took the heads off were the valve stem seals. Been wrestling with this for about 3 days now

Here’s another video showing the results

https://youtu.be/hanJF3tSiQY

[Richard Kirshy]

Do the Springs require lubrication as well or only the push rods and rocker arms?
If you removed them from their seats, A little wouldn’t hurt

Yeah I’m not sure what’s going on here. I’ve removed everything and reassembled both heads and it’s still making the noise. The only thing that was changed when I took the heads off were the valve stem seals. Been wrestling with this for about 3 days now

[color=#00bbff]Are you 100% sure all the seals, valve springs and retainers are correctly seated and secure?
I Just did the same job a couple of months ago on a 3.4 Monte Carlo, never had any issue(s) that your showing.
If the engine was running well prior, you have to assume the issue is due to the repair.
[/color]

[Sunaj]

I’m quite certain that everything is seated well. I triple checked before installing the cylinder heads back onto the engine . The keepers seem 2 be doing their job it of retaining the valve springs and the valve. And what do you mean about the last part? about this being an issue due to repair?

EDIT: NVM. i understand u

Don’t see where I could have messed up at? Take the heads off, take the valves out ,remove valve stem seals, Lube a little, reassemble

[Richard Kirshy]

[quote=”Sunaj” post=182797]I’m quite certain that everything is seated well. I triple checked before installing the cylinder heads back onto the engine . The keepers seem 2 be doing their job it of retaining the valve springs and the valve. And what do you mean about the last part? about this being an issue due to repair?[/quote]
The meaning…
If the engine exhibited no “snapping” or valve train noise(s) prior to the repair work, chances are the valve train noise is due to something involved with repair work done.
You stated you pulled the heads.
Could be something involved with that.
Perhaps incorrect gaskets, debris fallen into the open block, I assume you replaced all the head bolts with new torque to yield bolts.

[Sunaj]

Well something could have fallen into the block. Real possibility but it was covered most of the time. The correct head gaskets where used and yes the bolts are TTY. Didn’t really bother to hand crank the engine prior to all this but didn’t notice any noises when the engine was fully assembled anyway. I mean I guess I can open the block a little more to see if anything dropped no I would really not do that but it looks like I have to.

For what it’s worth I don’t hear the noise if the pushrods and rocker arms aren’t assembled so maybe I won’t have to go that far

[Richard Kirshy]

[quote=”Sunaj” post=182800]Well something could have fallen into the block. Real possibility but it was covered most of the time. The correct head gaskets where used and yes the bolts are TTY. Didn’t really bother to hand crank the engine prior to all this but didn’t notice any noises when the engine was fully assembled anyway. I mean I guess I can open the block a little more to see if anything dropped no I would really not do that but it looks like I have to.

For what it’s worth I don’t hear the noise if the push rods and rocker arms aren’t assembled so maybe I won’t have to go that far[/quote]
That being the case …
Things to look at:
Lifters well oiled
Rocker pivots oiled and seated correctly
Push rods fully seated into the rockers (with oil of course)
Oil the valve spring seat and triple check that the springs are sitting in their seats correctly.

I know ..
Sounds like a broken record…
But somewhere in that chain of events is your issue.
It is easy to assume something is correct when it could be off.
Lord knows I’ve had it happen to me.
Did a timing belt.
Check the marks 3 times, was 100% positive everything was correct.
Engine would not run right (at least to my ear)
Turned out that the crank was off by one tooth, even though it looked correct at the angle I was viewing it.
It took lowering a video camera and recording the crank gear straight on to see the mistake.

[Sunaj]

I see what you’re saying. I just checked over everything and I am fairly certain that I did not do anything wrong. Also upon further inspection the sound is not coming from the spring it’s coming directly from the valve train itself. The noise seems to happen near the end of the cam lobes travel right when it releases the lifter for that valve. Almost as if the lifter is tapping against the camshaft. Really dont know right now .

The only thing I can think of is at some point I may have gotten sum springs mixed up but I highly doubt it now that I think about it but it is a possibility. I looked in the service manual and found no mention for different spring sizes. But if the mix-up poses a problem which may contribute to the issue I still don’t see that being the problem because it’s happening on every single s valve and I know that I didn’t mix each and every one of them up. 7 hours later i think ill take a nap now

[Sunaj]

Back at it in the morning. Anyone else care to chime in? Just checked my torque specs which according to service manual says 11 foot pounds plus 30 degree angle. Pushrod and rocker arm replacement it states 22 foot pounds but I suppose this does not apply to me since the components are not being replaced.. otherwise I’ll just torque to Specs put it all back together and see what happens when I run it

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