goatkeeper

Hello,
Long story short...bought an 02 Z06 that had a dash fire, unable to hear car run, owner was a 22 yr old that knew nothing about cars, he had owned less than a year... So when I get things cleaned up, replaced the few wires and components and crank engine...it brings back childhood memories of Mom's sewing machine! It was the first thing that came to my mind. Rev it up sewing machine goes faster...
It's not the throw-out bearing, 40 lbs of oil pressure at idle, definately a top end noise...not bearings. Pulled a rocker cover and no obvious issues. The springs have been changed to duals, so I suspect a cam change...sounds like it as well. Could the kid or prior owner have installed a cam and not known that pushrods would need to be changed??? Would this create the sewing machine sound??? Any other ideas???
BTW, there are no codes!
Thanks in advance for the help!!!

enoniam

LS engines have been known to sound like sewing machines after a cam change.

Bill Curlee

What modifications does the engine have?????

The only way to figure out if the pushrod length is an issue is to obtain a push rod checker, use it to see what should actually be installed and to measure and compare it to what you have install now.

I have a pretty big cam in my 02 ZO6 and have headers installed. With headers, you normally get a little more valve noise because the thin wall of the headers (you can hear the exhaust pluses enter the header and a little more of the valve noise.

If your valve noise is excessive, take a look at the spring, retainers and rockers and see if there is any issues. See if any of the rocker trunions are LOOSE when the valve is closed/shut. If there LOOSE, there a problem somewhere.

Bill

XotiK ZO6

As was stated earlier, if the rockers are loose, there is an issue.

Would full roller rockers make the valve train less noisy if everything else checks out?

goatkeeper

Thanks gentlemen! I spent a little time searching LSx sewing machine noises...I was surprised. No idea the issues cam changes seem to make. I guess I will spend some time trying to check what I have and see if I can tell what has been done. The noise seems excessive, especially since it still has stock exhaust manifolds. Might consider going back with stock cam...if it would get rid of noise.

goatkeeper

Interesting question XotiK ZO6...would folks that are running roller rockers chime in...do they help????? I have a set that I planned to use on my truck, if they would help...I'll try them.

RonSSNova

Rollers are noisier. More moving parts.
Remember too, that what is really noisy to one guy, is pretty quiet to another.
LS with stiff springs and a cam will make noise.
How does it run?

XotiK ZO6

That doesn't make sense. Roller tips would not make noise and neither do the fulcrum of the stock rollers. If they do your needle bearings are bad.

Bill Curlee

I don't care what type of rocker or springs that you run,,,, If the lifter pre-load isn't correct, you will have valve noise. If the lifter that you are running cant handle the extra seat pressure, you will have valve noise.

Mine has little if any noise. I have .610, Patriot Gold springs, lift running stock rockers.

Another problematic point is,, if the person who assembled the engine MOD, used the OEM rockers with an aftermarket CAM and higher spring rate, that could contribute to more noise than normal.

I used Caddy Racing Lifters and they seem to work excellent. I shift at 6850 and it doesn't miss a beat or make noise.

Its tough to figure all this out because you don't know if any short cuts were made when they installed the valve train.

Bill

goatkeeper

True Bill, until I can get time to check pre-load and other issues...there is no way of knowing what was done right or wrong. It was just very startling to hear the excessive noise from the rocker cover area upon cranking...had no idea that many LSx owners are experiencing similar noises. Being a diehard Pontiac purist...it was nothing I was use to hearing...

Bill Curlee

After the engine shuts down, remove the valve covers and see if you can compress the push rod into the lifter.

If the lifter is good, it should not compress very easy if at all. If you are able to collaps the piston inside the lifter, that would be a very possible problem that needs to be considered.

Bill

leadfoot4

Another thing, it appears that the OE lifters don't work well with higher than stock lift cams, because the rockers' trunnions aren't set up to rotate completely, like an aftermarket rocker does.

By installing the CompCams trunnion upgrade kit, you can eliminate this possibility.

RonSSNova

There are no needle bearings in the roller tip.

Paul 75 L82

How does the car run. Good power?

goatkeeper

Hope everyone has a Blessed Thanksgiving! Lots in our everyday world to be thankful for, especially if you are blessed with good health...you don't have to look far to find less fortunate folks!

The little I have cranked and run the engine, it seems strong. I do not want to run it much, because the factory crank pulley is separating! Noticed it when initially checking to see if the noise was coming from an idler. I have ordered an ASP pulley and don't want to run it much until I can get it installed. It does has factory rockers, so that is an area to check...may just install the Comp rollers I have for my C10...to see if it helps.