You most likely have the 490 lifter, the last one listed.

 

I think youre ok. I have a 232/234 .595/.598 114 lsa cam from Texas Speed. I used the 7.4 push rods and I use the stock rockers, but I did have the trunnions upgraded by Hinson Supercars. Its been 6 months and at times, Im not quite used to the valve trane noise. Like others have said, its a little louder than normal between 1600-2000 rpm.

Even before the cam swap I noticed the LS6 was noisier than other SBC Ive had in the past. I think the miss you have is just the cam overlap. Mine shakes pretty good. My idle is set at about 750.

 

"Perfectly normal, perfectly healthy behavior" ....
Its just the way the LSx sounds with a higher lift cam. I know I was always hearing things when I got my first cam(it went in with a fresh engine). Its always after you thrash on it and are wondering "did I hurt something!?" After a while you just get used to it and stop worrying

 

Year Travel Preload
1999 .125" .062"
2001 .125" .062"
2003 .166" .082"

 

Here is some info I found:

Perhaps the noise is from too much preload.

Comp Cams Documents
The High Energy Lifters™ can be used with adjustable and non-adjustable valve train setups. Through various testing we have discovered that lifter preload should be set between .030" to .040" or ½ to ¾ a turn of the wrench past zero for optimal performance.

http://www.z06vette.com/forums/f5/qu...install-79058/
What lifters are you running? Preload on you lifters could be your problem. If you are running stock lifters look for 1 1/2 to 2 full turns on the rocker arm bolt from 0 preload. If comp 850-16 O.E. lifters, which are stated as stock replacement, they only like 1/2 to 3/4 of a turn from 0 preload. If comp R lifters they are very touchy and only like 1/5.

stock .060 - .120 preload
850-16 .030 - .050 preload
comp r .004 -.010 preload

all are hot preloads and you will lose about .010 preload from cold adj. due to the expansion of our aluminum blocks and heads.

I recently ran into this problem with the 850s, and a TR 224 cam. I had 1 1/2 turns and at first it was quiet but after 50 miles it is loud. So I am going to 7.35 pushrods. Comp is horrible with their product tech. No instructions and like I said its an O.E. replacement lifter so I just put them at stock specs. WRONG!!! well my pushrods will be in thursday so I will let you know if it makes a difference. Or if I collapsed a brand new lifter!!!!! sucks

your are correct to a point. Too much preload is also going to make alot of noise. If you have more pressure on the top of the lifter, more preload, which will also limit the amount of oil for cushion (travel). So you push all of your oil out on the up stroke and have none when you come back down, or not enough to cushion anything. This will give you too little preload on the way down (plunger depressed due to no oil) and CLACK!!!!! I know this to be true with my car because it is only loud below 3000 rpm. Above that and it is the sewing machine noise. This is all dependent on oil pressure. At Idle it is not enough to counter act the springs and ramp rate with to little oil below the plunger, and once its bled down it will stay like that until you get more oil pressure. By going to 7.35 rods they will allow .050 more oil under the plunger while keeping a .030 preload. It will still bleed down but will still have plenty of oil left for cushion, plenty of preload to keep it quiet, and less of a refill the next time around. this is why preload is so important. Why do comp Rs only have .004 preload? Cause they are used with aggressive cams that have serious ramp rates and tough springs that are going to push down the lifter plunger. The lifter is the same length as stock. It is also built stiffer than stock. just my .02 Oh and I got all this info from LG

 

I am at about 3000 miles on my H/C and the sound seems to bother me more after I have run through the gears and I start to think the same thing. Plus I think I notice it more becuase my daily driver is so quiet and smooth.

 

After ECS built and installed my engine, the valve train noise wasn't real bad but was more than I wanted. A few thousand miles later I had John (shortly before he passed) check the preload on the pushrods which were stock 7.4's. We had discussed reducing the preload to .040. As a result of checking he removed the stock 7.4's and installed 7.35's. This change combined with swapping in some HS roller tip rockers did reduce the valve train noise to acceptable levels. Engine now has about 15K miles and valve train noise is still acceptable and the same. There were a lot of posts and discussion about LS7 lifters and that they were taller than stock lifters and caused an increase in preload using stock pushrods; I wanted my preload to be very close to factory settings to decrease noise.

 

No matter how many people talked about this, it had nothing to do with the stack height. The early lifters had a longer body, but the distance from push rod ball to the bottom of the roller was the same as current.

 

I can believe that but the discussion about the lifter height was the cause for me to have the preload checked and the result (for me) was a reduction to a .040 preload that did result in a quieter valve train.

 

But didn't you also change the rocker at the same time?

This would have made a bigger difference than preload. This may also have changed the geometry. It is normal to adjust for wipe pattern with roller tips.

 

Has anyone ever experimented with oil viscosity to change the lifter's hydraulic characteristics? Would a higher viscosity and corresponding high oil pressure affect valvetrain noise?

 

I've run:

0w40
5w30
10w30

I've never really noticed any difference in valvetrain noise.

 

I found this thread researching similar valvetrain noise on mine, '01 LS1 with a TR224 cam and 7.400" pushrods.

Mine has been normally fairly quiet w/ minor sewing machine noise, no clatter...but I normally run Mobil-1 10W-40 High Mileage oil.

I had switched to Pennzoil Ultra 10W-30 in early Fall, ran an autocross and put around 2K commuting miles on it. Noticeably louder sewing machine noise and with audible minor clatter at low revs.

I changed back to the M1 10W-40, noise was initially still there but after a ~50 mile commute it was gone, back to normal minor sewing. Probably took a while for the old oil to pump out of the lifters.

I have a set of rockers out to Hinson for Comp roller trunnion upgrades, and new Comp 7.425" pushrods on the bench...will report back next spring when they're installed and the car is out of hybernation.

 

When I did the Heads/Cam/Fast90 install on my 02 ZO6, I initially worried about excessive valve train noise. I installed EG's Whiplash Cam and he recommended 7.40 push-rods.

From first start, there really wasn't any excessive noise. I do have a very different faint CLOP, CLOP, CLOP noise. I really couldn't pin point it until I slowed the idle down and ZEROED in on it with a stethoscope. You can actually hear the valves shutting on the seats.

Now that I know what it is, it doesn't bother me and no one else really picks it out. The valve train is surprisingly quiet for a high 240 duration cam with .610 lift. I used the Caddy Racing lifters and a Melling high volume oil pump. I also run the stock Mobil 1 oil.

BC