Justins00ss

iTrader: (18)

All right guys I am stumped on this one. Need some really experience people to chime in on this one! Little background on the car. 06 LS2 M6, BTR Stg 3 cam package, 7.4 pushrods, c5r timing chain, new oil pump, BTR dual spring kit and new valve seals, Kooks long tube headers, Kooks catted mids, magnaflow catback.

So here is whats going on. I know most ls motors make some sewing machine noises, especially with headers and a cam. My issue is I am getting a tapping noise in the top of my intake at about 2k rpm. If I put my hand on the intake I can feel it right at the front of it. At idle the motor is fine. My first thought was a bad lifter. So I just got done swapping in a brand new set of lifters and the noise is still there. The heads seemed fine, no valve marks on the pistons, no bent valves from what I can tell. No metal in the oil pan and the oil pump o-ring is not pinched. I didn't really notice the sound before the cam swap, mainly afterwards. The car has been on the dyno and driven quite a bit and the noise has not gotten any worse. The noise does seem to go right along with the valvetrain movement. I have had a spun bearing before and this definitely does not sound like a spun bearing. My only other guess is a bad intake gasket or header gasket. At the this point I am about to just drive it and say screw it all! Any professional input would be great.

redtan

iTrader: (5)

What intake do you have? I remember when I ported the stock intake I noticed an increase in noise. It got even worse when I put on a FAST. You just hear more of the lifter noise that's all, doesn't mean something is wrong.

It's the reason you now see intake manifolds with sound deadening material from the factory. Look at the LS3 piece, it has foam both under the intake (by the valley cover) and on top of the plenum.

lil john

Rocker arm? there only so many parts that tend to tap on the top end.

Justins00ss

iTrader: (18)

This was my other thought. I have paper work from when I bought the car stating the LS2 intake was ported. After having it off the car I really couldn't tell. But I have heard that the ported ls2 manifolds/FAST intakes can be loud. My non ported ls6 intake on my cammed ls1 wasn't this loud.

Def not a rocker arm. I checked to see if one puked it's needle bearings and all seem good.

lil john

If it makes more noise with 1 intake than the other FOAM it or use some type of insulator.

CAMSTER

iTrader: (10)

Can be possible valley cover bolts are keeping intake from seating down low enough to seal some intake runner in case of a Fast intake, I had to cut off half the valley cover bolts heads.
May want to remove washers from bolts if any from ls1 intake.

A sure bet with double roller timing set use with out the chain damper will cause the chain to make noise in 100% of the cases in front of the engine area.

I once send out two lifters to have checked cause I was sure they were noisy it turn out to be noisy fuel injectors, this is easy verified with a stethoscope.

Possible rocker arm heating spring retainer may require rocker clearance.

Pls let us know the outcome good luck.

Justins00ss

iTrader: (18)

Well unfortunately I only have one ls2 intake and that's the one on the car. I am not running a double roller. Just a C5R timing chain on the stock gear set. The noisy injectors sounds like a possibility.

I also just remember that most of the brass inserts for the intake bolts were missing when I pull the intake bolts out of the manifold. Any chance that could be it?

MuhThugga

Broken inner valvespring?

CAMSTER

iTrader: (10)

It may have split area around a bolt without the insert cause a possible leak, just a possibility wont hurt to replace the missing inserts, some one on here may have them.

Check the rockers clearance at point when valve is full open, split a straw open it and if it fits between rocker and spring retainer you are good, if real close check all of them.

A straw is about 0.004 thick but that's all you need.

Justins00ss

iTrader: (18)

Thank you for the advice. Was also told a 7.425 pushrod would be better than my 7.4s with unmilled 243's

SStheBest

iTrader: (2)

I thought the stock length was 7.4?? Id be double checking that. Also you said you changed the lifters? Did you inspect the rollers for pitting or any unual scarring? If by chance you had a lifter go bad...it usually takes a lobe with it. Just my $.02

Justins00ss

iTrader: (18)

Stock length is 7.4. But most aftermarket cams are .050 smaller base circle. I inspected all the lifters and the all were fine as far as roller damage. Had a rolled and lobe go out before on another car and it was noisy at idle. This sounds fine at idle. Really thinking its a pushrod length issue.

SStheBest

iTrader: (2)

Ah makes since.

turboost

iTrader: (1)

Just a thought, I have a noise coming from mine that you would swear is coming from the intake area but when you get under the car is sounds like its coming from there. We have honed in on it coming from the transmission but sounds like the intake from the top. Have you used a stethoscope to help pin point?

Justins00ss

iTrader: (18)

No not yet. Have a friend that is going to come by some point to help diag it. Thanks for the tip...

Realcanuk

You didn't mention what rockers you are using. If they are not the stock ones, they may be hitting the valve covers. This happens with many after market rockers.

Harley-Davidson88

iTrader: (71)

I had a loud tapping noise that I couldn't figure out in my 408 when I put it together. It was hard to pin point with a stethescope even. It turns out I was actually running too much preload for the Morel lifters. I got some shorter pushrods and the noise quieted down to typical LS valvetrain noise. I would double check how much lifter preload you are running and see if it is within the recommended range for the lifters you have.

Justins00ss

iTrader: (18)

Sorry, using stock rockers

That's exactly what I am going to do. Talked to my guy today and asked him if a 7.425 is common. He told me he uses anywhere from 7.350 to a 7.450. Told me to shoot for 1 to 1-1/4 turns from zero lash while the lifter is on the base circle.

Justins00ss

iTrader: (18)

So just a little update. I have tried a set of 7.450 and those were too long. Installed a set of 7.425 and no real change.

Also used a stethoscope and pinpointed it to right on top of the front of my ls2 manifold near the MAP sensor area. Thinking its just airflow I am hearing. At a loss here!!!! Car runs fine too.