Slow motion valvetrain videos

Well I had my valve lash set way too high for the lifters I got. I did get it quieter but man it ran weird. Set it back to Comp's spec, and while I was there I got some videos to share

Left:

Right:

The sound is interesting. I'd think it'd be more "even" sounding.

Why would you choose to use solid lifters? Hydraulics are sufficient for street use, and you never have to be concerned with adjusting them.

Hey Fred! No, they're hydraulic. The different valvetrain parts had different preload specs and I tried tightening it up since I keep getting comments that the valves sound "loose". I set it back to the lifter recommended preload which is the least of all the numbers. The noise level isn't much different from what I can tell.

Regular speed BTW:

The standard set for hydraulic lifters is no lash plus 1/2 turn.

That was my understanding as well but not according to Comp on these lifters (#850)

Code:

As stated before, the recommended setting is 1/2 turn
of the wrench on the rocker arm adjusting nut past zero

There's a reference on a thread on the Impala SS forum that talks about these 850 lifters and that they should be set as Comp states, which I didn't think made sense either.

What are the instructions?

I checked with Comp Cams website, and they say that they are replacement hydraulic lifters for a 350. If that is true, the snug plus 1/2 turn should be the correct adjustment.

Ironically I can't find anything on Comp's site, but here's what came with the lifters on Summit's:

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Part 5 section 1 is the instructions for your lifter adjustment. The FSM has the same instructions for stock lifters. If you position the crank with #1 at TDC on the compression stroke, you can adjust the valves listed in the FSM for that position, then rotate the crank 360 deg. and you can adjust the valves listed in the FSM for that position.

Yep, correct. Difference we have in this example is that FSM says 1 turn, Comp says 1/2 a turn.

You can use anywhere between 1/2 and 1 turn, just do it the same on all of them. I always use 1/2 turn. I have the 900 series lifters in my BBC, and I use 1/2 turn.

Here is another set of instructions that includes the instructions to use one full turn. [You must be registered and logged in to see this link.]

Yup Fred, I think you're going down the same rabbit hole I went down, just wish I had a while ago. Those instructions you found I also did find - but aren't for the #850 lifters.

I did not go down a rabbit hole, I just pulled that as a FYI.

Adjust them to a "no lash" plus half a turn and you will be fine.

It makes me start to wonder if they are somehow bleeding down a bit due to being anti pumpup or slightly over sized bores. Does the noise change appreciably with engine speed? How far you can preload is a bit of guessing game as the "maximum" is really only where they go solid and can start holding the valves open on the base circle. Varies a lot with cam grind and leak down rate. I went through the same questions when I did my engine as it was the first GM style for me with a collection of aftermarket cam, lifters, rockers, pushrods that were mostly by different manufacturers. I did use a bit over 1/4 turn on mine and get no noise even at startup.

Fred, yeah, like I said, I went down the rabbit hole with a lot of different recommendations from different parts of the valvetrain. Comp's hard to find docs too... yes, 1/2 turn for these.

booster I had tried 1/2, 1, 1 1/2 turns. At 1 1/2 turns there was definitely less noise but I started getting signs that valves were hanging open a little, which got worse with higher RPM. Noise-wise honestly there's not much difference with the composite valve covers on, but at the 1/2 turn setting there's quite a bit of clatter when cold that quiets down quite a bit when warm.

I'm not sure what makes the noise. I saw other people complaining about noise with these particular lifters, so maybe they are making most of it.

I have to admit it sounds pretty cool in slow motion. Reminds me of the engine of a container ship.