89L98T56

iTrader: (8)

So after the drive to CA from NM, my engine has slowly developed this knock. When the motor was first started up, it had really loud valvetrain noise. Sounded like a sewing machine. But I read up on it and apparently that is common when running a big cam in an LS engine. So I thought nothing of it. Now when I arrived to CA, the car was running fantastic but the valvetrain noise seemed to be getting louder. And then the sound changed a bit from sewing machine to a steady knocking consistent with RPMs. I immediately thought "pushrods" because I am running a 7.325 length pushrod to accomodate for the LS7 lifters being taller, and my milled heads being shorter. So I grabbed a set of stock length rods off a guy on here for free, installed them and nothing changed. I have triple checked all the rocker arms for damage and torqued them down to 22 ftlbs. I don't *think* that this is a rod knock and I am starting to lean towards collapsed lifters. Since I had so much bad luck with the TSP LS7 lifters from the getgo that is my next thing to try but ffffuuuuuuuu I dont wanna pull the heads!!! Have a listen and tell me what you think..... Oh BTW everything in the motor has about 1000 miles on it.

http://www.youtube.com/watch?v=NQNW94OUFTc

89L98T56

iTrader: (8)

Anyone??

SOMbitch

iTrader: (8)

Use a mechanics stethescope and pinpoint where the noise is comming from. Listen to it from underneath the car also to rule out bottom end problems. Oil pressure good or I assume you would have posted this....?? Unless some trash got in your lifters I can't imagine them giving up with so few miles. Doesn't sound exhaust leak related at all but I would check all your plug wires to make sure they are snapped on correctly. See if any pending codes are present and that might give you a clue....

Keep us posted.. Has me stumped but it is very hard to diagnose this stuff from an internet video....

One last ??? You mention a large cam so what are the cam specs, heads milled and HG gasket thickness? Was the PTV clearance checked....

AutomagicLS1

iTrader: (18)

Sounds to me like its coming from the top end. But seriously for starters how about removing the valve covers and making an inspection. If you fear its a bearing unplug each plug wire one by one and start the car. If it's a bearing the knocking will go away on the cylinder you unplugged due to no pressure on the bearing

89L98T56

iTrader: (8)

Yes oil pressure is good and doesn't fluctuate. All plugs and plug wires are good, I checked them. The car runs perfect, idles perfect, no missing, nothing. Just has this knock. It is definitely not an exhaust leak because that sounds more like a tick then a knock. And I am pretty sure this is not a rod bearing because this is consistent with RPM's and a rod knock is only every other rotation. This knock is every rotation. The engine specs are as follows: Callies compstar 4" crank, Compstar 6.125" H beam rods, Mahle flat top forged pistons WITH valve reliefs. The heads are AFR Mongoose milled to 62cc's. The cam is a vengeance vindicator cam specs are .605 .596 240/244. Stock rocker arms, LS7 lifters, and now stock pushrods. I have yet to check the codes because I have no way to.

It sounds like that to me too but its so hard to pinpoint, I need to try the stethoscope thing next. And like I stated in the OP I have checked the rocker arms, pushrods, and valves numerous times. And also I dont think it is a rod knock because this is knocking on every rotation, not every other.

SOMbitch

iTrader: (8)

89L98T56.....Keep us updated on this as it sounds like you checked into the right things so far.... I am stumped at this poin and am very curious what it turns out to be

89L98T56

iTrader: (8)

BUMP Im still stumped

TransWS6Am

iTrader: (41)

hey man remember me, i saw u on base, i have hp tuners if u want me to scan your car. just pm me

1quickirocz

I hate to say it but sounds kinda like bottom end to me. If it were valvetrain related it would be half RPM speed. sounds like it is same as RPM speed at idle. Just my opinion. disconnect fuel injectors one by one and see which one changes it. I hope im wrong buddy really i do....

89L98T56

iTrader: (8)

Actually a rod knock is every other rpm. A lifter would also be every other rpm unless more than one is bad. Im pulling the heads this weekend though.

1quickirocz

• At what rate the noise occurs, and at what location in the engine

Remember, engine noises are generally synchronized to either engine speed (crankshaft, flywheel, connecting rods, balancer, or pistons and related components) or one-half engine speed (valve train noise such as rocker arms, valve lifters, and timing chain). Try to determine the rate at which the noise is occurring.


That is straight from GM Service Information for a 2000 Camaro LS1. Not trying to say your wrong or anything but just dont discount that it could be bottom end noise.....again i hope im wrong i would hate for that to happen.

RRhodes1

Atleast from what i can tell in the video, the intake manifold is amplifying the sound, which if it were me, id start looking around up top. one would think if it were a rod bearing spun, or the like there would be some indicator , like lower than usual oil pressure etc.

z28adiction

iTrader: (1)

dumb question did u check ur pov clearence? i had to fly cut my stock pistons quite a bit to accomadate my vindicator.

mightybird

my car sounded the same way 3000 miles after h/c im pulling the heads off as well to see what happened. i think its lifter for sure but i could be wrong.

White.Lightning

iTrader: (53)

Pull your valve covers and inspect each rocker arm. They should rotate FREELY on the bearings. There should be NO friction/tension.

I had 3 rocker arms fail on me and it made a similar noise

ShevrolayZ28

iTrader: (4)

Sounds like my car after it broke a small piece off the #7 ring land, but I see you have forged pistons.

It would be nice if you could take a look inside the bores without taking it apart. Good luck and let us know what you find.

89L98T56

iTrader: (8)

UPDATE
Posted new vid...

I pulled the motor out this weekend and I have yet to find anything besides this....

About half of the lifters I am able to compress by hand with a pushrod. The other 8 are hard as rocks and wont move. I also pulled the bottom end apart and all the bearings look perfect. I only pulled the #8 piston out to inspect and it looks fine besides a little scoring on the friction coating on the skirt. cylinders look great, can still see the cross hatch pattern. No foreign objects anywhere, nothing broken. But 2 of the lifters have hairline cracks on the bottom next to the rollers. These came out of the drivers side.

Another question....all of my rocker arms make a crunching sound when moving the fulcrum up and down. Is that normal?? Will post pics of everything soon. Still haven't really found the source though unless those lifters are shot.

White.Lightning

iTrader: (53)

Rocker arms should rotate freely on the trunion and not make any noise

89L98T56

iTrader: (8)

They do rotate freely but when I grab the roller part, and move it up and down inside the rocker arm, the make a crunching sound. They all do this....

06tx4.8

iTrader: (19)

did u replace the trays as well when u did the ls7 lifters?