delsold

iTrader: (7)

Well the other night i was driving home and my car decided it would like to make a terrible machine gun noise from under the drivers side valve cover.

Stock heads
Patriot Gold Duals
MS3
Comp 7.4 hardened pushrods
Rev Limiter at 6500 (was not revving it out when it started making a noise)

Well anyway the noise is a consistent loud tapping from under the valve cover. It sounds like someone is tapping under the valve cover with a very small hammer.

Since the car was kind of cold and i had just started driving i didn't really beat on it, but i downshifted from 3rd to 2nd to make a turn and the rpms rose as normally, and once i shifted back into 3rd it started the noise. Rpms maybe went up to 4000ish. I suspected I had broken a valve spring (they have 11,000 miles) but when i pulled off the valve cover I don't immediate see anything out of the ordinary.

Is it more likely for the exterior or interior spring to fail?
Would a collapsed lifter make this kind of a noise?
Could i have bent a hardened pushrod at that low of an rpm?

Any advice on what i should check now, or look into would be awesome.

Thanks guys!

stoverz28

iTrader: (8)

If it was a push rod it should have been obvious when you took off the cover.

camaroguy26

iTrader: (21)

a buddy of mine had those springs and I'm not sure what size the MS3 is but he had a 242/.616 lift cam or somewhere around there and he had 8 of the inner springs fail on him. I had comp 918 springs and a 228/224 .588/.588 cam and one of the springs shattered. It made a noise somewhat to what you describe but since my valve relies on one spring it fucked more **** up in there and my engine died immediately

00MaroonZ28

iTrader: (3)

I bet it's a collapsed lifter. Did the same thing to me on my truck and had the same sound. Try some of the real thick Lucas oil and see if it fixes the problem. Worked on mine.

Randy WS6

iTrader: (69)

I made the same noises when pulled a rocker bolt or (stripped) the threads but didn't pull the rocker bolt plum out , It just loosened up enough to make a loud pecking noise.

usaf_hess

iTrader: (8)

id try seeing if all the rocker studs are tight first then go from there.

eallanboggs

iTrader: (1)

Could be a spun bearing, but it wouldn't be a bad idea to pull the rockers first. That will allow you to check the pushrods, rockers, and rocker bolts and their threads in the heads(hope you didn't over torque them or cross thread them). I once removed a 918 that was broken. I didn't even know it it was in two pieces until I got it off and it didn't make any noise. Have you run low on oil or had oil pressure problems? Do you change your oil regularly?

Websy21

iTrader: (34)

Could be many things but hope that its valvetrain. There is only one way to find out, start with taking the rockers and rods out. Good Luck!

1320 killer

iTrader: (6)

check all the springs inner and outer. i would also check the rocker pedestal. I have broken a few.

delsold

iTrader: (7)

Thanks guys. I am almost certain it is not a spun bearing. Its definitely an upper end tap. The lowest in the engine that this noise would come from would be a lifter. It doesnt quite sound like a lifter tap though...but It might be. I regularly change my oil, and have great oil pressure with a ported ls6 pump. it has 10w30 mobil 1 in it now because i just changed the cam about a month ago (this is my second oil change since the cam swap one at about 150miles after, and now this is the second batch of oil) It smells fine, and had good viscosity. I am going to pull the rockers to see if any are loose, or a pedastal is broken.

Would I be able to tell if the inner spring is broken by just rotating the engine by hand? I can't see anything apparent but that was my first guess was a failed valve spring, especially since the engine was so cold.

PI HAT

I had a complete valvetrain upgrade (see sig) and noticed a similar noise. I pulled the valve cover to find a stock rocker had spun a couple of those small needle bearings. They were correctly torqed to 22. I started checking the rest of them and about half were beggining to go. I was lucky that none of the needle bearings fell down through the head. I told the wife it was a good reason to upgrade!!!

frankmarroquin

iTrader: (31)

Dude hope you fix ur problem... My car has almost the same thing but the noise is more of a scratch than tapping... I pulled the valve covers and pushrods and everything looks fine... Rockers, Push rods, and Springs all look good. So tomarrow I am gonna remove the heads Hopefully nothing to serious.

unknown pontiac

it sounds like a lifter to me from what you say.

delsold

iTrader: (7)

thats what I'm afraid of. I haven't had much time to tear into it much but since its the weekend I will find out whats wrong tomorrow..

delsold

iTrader: (7)

I'm starting to think its not a lifter because I've listened to about 10 different video clips of lifters that are collapsed and they seem to be more of a ticking noise. This sounds much more like the ticking that everyone calls "the sewing machine" of the ls1.
What should I check for with the rockers to see if I've lost, or have some needle bearings going? Does anyone have any pics?
And also with the valve springs would the spring usually be totally broken, or would it have a crack of some sort.

StevieZ

iTrader: (3)

Usually inner springs break first. Also check your rocker stud bolts

StevieZ

iTrader: (3)

Do you have a torque wrench? Pull the covers and remove the rockers to inspect everything carefully. Also by removing the rockers and then retorquing them, sometimes a collapsed lifter will pump up again.

84ls1_transam

iTrader: (11)

Was there any sludge in the engine? I am a mechanic,for GM, and I have dealt with lifter noise of gen 3s for years. Before you take any **** apart, I would try this trick. Add 1 quart of ATF to the engine, take it down the road for a hot supper. Bring it back, dump the oil and filter, while still hot, and watch the sludge poor out. Fill it again with 5 quarts of clean oil, and another quart of ATF and a clean oil filter. Drive it again. Change the oil again while hot. Add clean oil and filter. This should have taken care of your noise pretty well. It works probably 9 out of 10 times. ATF is a high detergent fluid, and should raise oil pressure by clearing any blocked oil passages. If that doesn't fix it, lifters.

delsold

iTrader: (7)

Well that sounds like a good trick but ATF also has a very high concentration of friction modifiers...something im not 100% keen on going through my engine. I'm pretty **** at doing 2500-3000 miles oil and filter changes. You could practically eat off my valve covers, and when i dropped the oil pan this summer it looks great up there too.

I will however take off the rockers on both sides and retorque them and maybe throw a little heavier weight oil in to see if i can get the lifter to pump up again, unless when i remove the rockers i find a inner spring that is broken.

StevieZ

iTrader: (3)

Loosen them and then re-torque them. And while you're loosening them, take them off and make a good inspection of everything.