Pieces of beef caught in between my teeth!

Its been several years since my HCI and the valvetrain noise (sewing machine with subtle clatter) is driving me INSANE!! It makes the whole motor sound loose. Those of you with cams know exactly what I'm talking about. Its like a child poking you in the shoulder repeatedly while you're doing your best to concentrate on something.

Yes this is a rant thread, a tribute to quite possibly the most annoying sound that could ever be produced...well certainly not much further down in the list from dragging a piece of styrofoam insulation across aluminum siding, dragging your fingernails across a chalkboard, or a politician flapping his yap.

Does this noise bother you as much as me? I can't even turn up the radio to drown it out, because although I can't hear it, I know its there waiting for me when there's a break in the broadcast.

Holy crap I want to rip that cam out and shove it up the tail pipe!

So, the question is, how does your valvetrain noise make you feel?

Or, if you have a large cam and your valvetrain is quite....you're lying! But for real, what cam, lifters, pushrods, and rockers are you running?

 

For reference, what's your setup? That way I'll know what to avoid!

 

Like I said, if you're running a large cam and your valvetrain is quite...you are lying!

The only way to avoid it is to run the stock cam or a baby cam...but then you're avoiding power too. It's crazy!

 

When I ran a small 220/224 (XER lobes) in my LS1 even that was noisy. I currently run a 224/236 (XFI lobes) and that is noisy as well. It's just the way that it is with these engines.

 

Now wait a minute,,,,,,,, An aftermarket high lift cam wont be as quiet as a stocker. I have heard some horribly noise valve trains and some quiet ones.

When I installed my cam 240/114+4/610 lift cam, I was dreading the excess noise.

When the engine fired up and settled down, I was very pleased with the lack of excess noise. There is some but nowhere near what you are describing.

Can you do a video and post so we can hear what yours sounds like?

What lifters and size push rods are you using and what preload is on your lifters???

I used caddy race lifters and I have been very pleased with them. Some lifters don't do well under high lift conditions and make noise no matter what you do.



Bill

 

In reality the noise isn't that loud, what bothers me is the noise. It just sounds like the engine is "loose" if that makes sense. Sewing machjne with subtle clatter. Nobody riding in my car has ever noticed the noise, or ever thought to comment on it....oh but I can hear it, I know it's there. The supercharger sound is much more in your face and mostly drowns it out. But I can hear it, and to me it's aweful sound.

Cam: 232 .573 112
Lifters: comp cams oem style 850-16
Pushrods: 7.4 comp cams hi-tek
Preload: .075

Maybe I went with too much preload?

BTW: you wouldn't be able to hear it in the video. The headers, supercharger, injectors, etc. are too loud.

 

thanks for posting this. As a person new to the performance scene, it helps to know both sides of the coin. I personally had never considered this situation and it is good to have this information when considering engineering changes.

i also have a bug about engine noise, and mine is stock. It just sounds a little uneven, I think it might be the coils since they have been fingered as suspects from a few sources.

 

The stock GM secondary ignition (coils) are very good! You will NOT gain anything more than stock by replacing the stock coils, wires and plugs with fancy high dollar aftermarket.

The first thing I would do is:

Clean the MAF and Throttle Blade with MAF cleaner, replace the plugs with AC Delco Iridiums and replace the wires with some GM Performance Red Wires.

Next, look for deteriorated vacuum lines and fittings and any air leaks in the ducting between the MAF and the Throttle body.

Bill

 

At least yours is modified!! My motor is bone stock and it sounds like a galvanized steel tray full of silverware being carried by someone having a seizure.

I have new plugs and wires about to go in and I'll be popping the valve covers soon to take a look at the top end but I think I'll have to check all my vacuum lines and clean up my MAF per Bill here too!

Fingers crossed I find something to remedy because I agree, it shouldn't be so 'loose' sounding.

--
VPP

 

Be sure to check the trunion of each rocker. See if you can find any lost motion for each rocker.

Check the torque on the rocker bolts.

BC

 

Bill, what made you run the Caddy lifters over the LS7 lifters?

 

When I built my engine, LS7 was just rolling out. The caddy lifters were plentiful and working very well on other modded LS engines.

If I built the engine today, I would use the LS7 lifters.

 

Have you popped off the valve covers to see if you have any nice surprises?
My valvetrain sounds like $h1t and has since the day I installed my cam.

 

This couldn't be further from the truth sir.

I have custom lobes that run .610-.630 total valve lift that are nearly dead silent.

Abusive lobe designs sold by certain cam vendors are a major culprit. Couple that with the fact that the camshafts are sold with a stock length pushrod and/or everyone assumes the 7.4" length is "fine", and you've now amplified the problem. Now you've got a lobe slamming the valve on the seat creating noise and wacked out lifter preload causing lifter noise. You are absolutely going to have a noisy valvetrain with the more popular Comp lobes and an improperly set up valvetrain.


Another issue that can cause excessive amounts of valvetrain noise (IE: getting louder over time) is a wiped out lifter, cam lobe, or both. We see quite a few cars a year that come in with valvetrain concerns to find a failed Comp camshaft along with some torn up lifters.

OP, if you're valvetrain has gotten louder over time you need to pull the intake manifold & valley pan to inspect the camshaft. You could have some wiped out lobes. If it's been loud the entire time and a set of 7.4" pushrods were blindly dropped into the engine without any measurements done, the pushrod length is more than likely wrong which can also cause excessive noise.

An aftermarket camshaft will be shrunk on the base anywhere from ~.025-.060 depending on the size of the cam. This travel lost on the base circle has to be made back up with a longer pushrod length. The more popular XE-R lobe camshafts are always .040-.050 smaller on the base requiring a ~.050 longer pushrod to achieve proper lifter preload. Problem is, nobody measures. They assume. I've actually got the XE-R stuff to run pretty quiet in the past just by setting it up correctly.

Then there's issues of jerk, control, valve spring harmonics, and so many other things that come into play which can create or destroy a stable valvetrain.


An improperly set up top end and abusive cam lobe is going to make noise, period. This does not mean every cammed LS1 is going to make noise. A smooth lobe design, correct pushrod length, a matched valve spring choice, etc all play a role in having a nice & quiet valvetrain. High lift also does not mean loud either. Total valve lift is only a portion of the equation when designing a lobe. This is why those considering a camshaft installation should consult with someone who's knowledgeable in this area so they can get something dialed in for their goals without all the BS that comes along with blindly picking an off-shelf high production cam because it's on sale.

 

Josh

Well stated!! My valvetrain is pretty quiet but,,,,, I thought I was lying..

Bill

 

Im soo sorry but that statement just had me rolling

 

I noticed mine got at least twice as loud when I added BTR dual springs over my soft pac 1218s when the larger lift cam went in.

It is extremely annoying, yes. And there is something about the vette where the VT noise comes right in the cabin and that is all you hear with the windows up.

If I go boost, I may throw in a factory cam or something really on the low lift side, so I can run softer springs.

 

Thanks, I did all of that, some inadvertently while on another task. I was trying to address stock performance only. Thought one of the coils might be a little unmatched or weak. It's about the only suspect left.

 

Thanks for posting this info.

I'm running Dart Pro 1 heads w/ beehive springs. My cam is a comp cams 228/232 .571/.578 112, my lifters are also comp cams OEM style lifters, and I'm using 7.4" comp cams hi-tek pushrods. I used the comp cams pushrod length checker and determined for .080 preload I would need 7.4" pushrods (stock are, of course NOT 7.4", but rather 3.85") I probably checked every valve to come up with this number. The valve train noise has always been annoying, not sure if it's getting louder or if I'm getting more sensitive. Maybe this winter I'll install LS7 lifters and recheck the length. If anything, I'm probably running too much preload.
I've heard many cammed LS1s and they all pretty much sound the same. So, I say again, if you have a cammed ls1 and claim it's quiet I'm here to tell you the emperor is naked. .
If the LS7 lifters don't quite it up, a near stock sized cam is going back in. A 700hp sewing machine sounds like $h1t and id be more than willing to lose 100hp just to have a motor that doesn't sound like it's falling apart.

 

rofl