bwill03z

Ok guys I've decided it's better to be safe than sorry so my mechanic and I are going to swap my lifters because I got a nasty tapping sound on every cold start. Just want to get opinions and make sure I am getting everything I need. Going to get GM ls7 lifters, new trays, factory GM multi layer steel head gaskets, valve cover gaskets, manifold gaskets, and ARP head bolts. Anything else I need?

Bill Curlee

Well,,,,,,,,,,,,,,,,,,,,,,,,, Here is my take. Been down this road several times and...................

I would get the ARP HEAD STUDS. You will have less of a chance stripping out the head bolt threads inside the block. The head studs are absolutely amazing.. Once you use them, you will be HOOKED!


NOTE!!!!!!!! WARNING!!!!!!!!!

Regardless of what head fastener that you use,, Make absolutely positive that each head bold hole (in the block) is ABSOLUTY DRY & CLEAN. If you leave ANY water/liquid or debris inside the hole, you can and will RUPTURE the block. They are BLIND HOLES! Check, Check and double check!!!!!!!!!!!!!!!

New lifter Trays!

There is an ALUMINUM PERCH for each head that each ROCKER sits on. Examine the small saddles on the perch for each rocker and make sure that it isn't worn. If it is, replace the perch. They are NOT expensive. I've seen worn ones that cause the rocker to sit on the valve crooked!

PUSHRODS. Purchase an adjustable push rod check tool. Measure the zero clearance length of each lifter/rocker and add in the manufactures recommended lifter piston PRE-LOAD to get the proper length pushrods. CHECK TWICE and order the correct length pushrods that provide you the proper lifter piston preload.

When was the last time you changed the valve seals and how many miles do you have on the ones installed??

BC

bwill03z

Thanks for all the info. I believe the valve seals were changed when I had new valve springs put in after buying the car, which would have neen just under 10k miles ago. I will consider the new pushrods but why do you suggest I get new ones?

feeder82

I think Bills advice on the pushrods is for guys that did a aftermarket cam swap

Bill Curlee

IF, they are the INCORRECT LENGTH, why would you use them? That alone could cause the noise.

Im NOT saying purchase new ones because its just a nice thought. You have to have the correct length push rods to put the correct PRE-LOAD on the small piston inside the lifter.

If you measure and the push rods are the correct length, YES, re-use them.

bwill03z

I got ya. I will be sure to check them and if they aren't all correct length I will most def order new.

k24556

Factory exh manifolds or headers? Everyone that put headers on hear more valve train noises than before.

All I'm sayin' is make sure you have diagnosed the problem correctly. I would guess you would be unhappy after pulling the heads, getting them reworked ( a really good idea once you are that far) replacing the lifters, only to find you still have the noise.

Are you sure it is a lifter, sometimes a bit of carbon can accumulate at the top of the piston and will click until the engine warms up and everything grows thermally a bit. I had a Chevy 2500/6.0 that did that, and I could never get the dealer to fix it, and it went another100k hard pulling miles with that friggin' click when it was cold. IIRC in 2001 some engines had a ring issue that caused a click.

Before you pull your heads, why not first measure what pushrod length you need. That is the purpose of the tool Bill mentioned earlier. If the heads have never been re-worked (valve job) then there never should be a reason to replace the pushrods unless one is bent. If the heads are orig or were reworked PROPERLY, then you should only need to measure one valve with the tool. Then you can measure the length of the pushrod you take out. You can measure the others, but they should all be the same length.

Finally, if you do indeed decide you have a bad lifter, then there may be damage to that cam lobe, so I would probably pull the cam and have it checked. Now you are getting pretty deep into the engine and maybe looking at mistakes a previous builder made. Then, fur sure I'd replace the lifter trunnions with the ones with C clip retainers. The existing trunnion/bearing is pressed into the rocker arm and have been known to puke bearings.

bwill03z

I have long tube headers and no, I'm not positive it is a lifter. That is what I have been trying to figure out for months now. The car was bone stock when I bought it so it isn't a mistake from a previous builder. I have posted several videos on the forum and the majority think it is a lifter. I have listened prob 20 diff times with a stethoscope and cannot pinpoint the noise, but it is definately coming from down in the motor. It is very loud underneath the car. I have ruled out an exhaust leak, belts, and anything on the top end. The only other thing I know to do without removing the heads is pull the pushrods and measure. Its not going to be cheap to replace the lifters but if it fixes the problem it will def be worth it. I am really at the point where I dont know what else to do. Here is a short clip I made yesterday if you would like to take a listen for yourself.
https://youtu.be/4VLl_xAKSHU

Bill Curlee

I have helped troubleshoot several LS engine valve train noise issues. Here is one thing I found to plague several engines after a cam swap or change to heavier springs:

Remove the valve covers. Engine HOT. Attempt to depress the pushrod into the lifter. If the lifter is working properly, it should be full of oil and resist the pushrod from easily being pushed into the lifter. If you can easily push the pushrod into the lifter, the piston inside the lifter or the small check valve inside the lifter is leaking (bleeding down) and the lifter is failing. That in its self can cause the noises that you are dealing with.
Restart the engine for a short time to pump the lifters back up and then let the engine sit and do the same check cold. Compare ALL the lifters to one another and if you have one or several that are exceptionally easy to collapse, I would look there for a possible noise issue.

I went to extreme measures to keep my LS6 from sounding like a Singer Sewing Machine after my Can swap. I was successful.
That being said, I have to fully agree with "k24556" about being able to hear the valve shutting on the seats when you have headers. At a slow Idle I can hear the valves shut. CLOP CLOP CLOP CLOP........

bwill03z

I have pulled the valve covers two different times, on both sides, and checked to see if i could push the pushrod into the lifter. I could not. I haven't tried it on a hot engine only cold. Bill did you happen to watch the video I posted on my previous thread? That sound completely disappears once motor is hot. Everything in the motor is stock btw. I will try again to collapse the lifters on a hot motor but like I said it disappears once warm.

don37

Definitely dont put the heads on with bolts. I just hope the tapping isnt a sign of a larger issue. Does the engine miss at idle?

bwill03z

No missing at idle or under throttle. What kind of larger issue could it be?

don37

a collapsed valve seat or a cooked No.7 piston. Some notes i made. No. 7 piston cracked - https://www.corvetteforum.com/forums/c5-tech/3927117-another-cylinder-7-failure-victim.html#post1593816561

Push rods. Check tool. Part # comp cams 7905-1. Stock length - 7.4"(incl pre load). Next size 7.425"

bwill03z

I wish one of you guys lived close by and could help me take a look at it. I really don't have the time or knowledge to tear the motor down and check everything. I really hope its only a lifter bleeding down and nothing more.. and hopefully my cam is ok. I guess Im just going to have my mechanic take it apart and check everything. I have let this bother me for too long now and cant enjoy the car.

don37

change the cam dude.

bwill03z

Gahh I have a feeling this is going to get very expensive. Does anyone know how much I can pick up a stock ls6 cam for?

k24556

Hold on a sec. I listened to your vid. I have the same noise in the engine of my track car, and it has been pounded on the road courses for a bunch of years now. Headers bring out a lot of valve train noise. It is also the same noise I had on my 2500/6.0 chev truck, which now is owned by a landscaper friend, and after I put 140k on the engine, he has proceeded to add another 100k. The only duty that truck saw was either hauling my trailer, or his. It still ticks all the time. He almost did not buy it from me because of it, but pretty much ignores it now.

So about a few suggestions to try before spending $5k chasing this.

1. change the oil. Change the drain plug to one with a magnet. At the next oil change check for particles. If a cam is being worn, the wear detritus will be magnetic.. Depending on the cam material (cast iron or a steel forging) the detritus will either be a fine black goo (cast iron) or shiny flakes (forged steel). At the risk of starting an argument, either cam material is suitable. No detritus is good news.
2. run your video on the other side of the car, if you hear similar noises, they MAY be normal for your setup.
3. If you are tracking the car, consider running Mobil 1 15W-50. The oil is not necessarily thicker at a give temperature, but the M1 15W-50 has additional sulfur and zinc that will offer better high temp lubrication. The downside is this is harder on your cat converters; the Mobil oil guys don't recommend this for street/daily driving.
4. put your stock exh system back on and see if you still have your concerning noise.
5. If you are concerned that your valve seals were not done right, then get them changed. Adding oil from the top end of the engine will crud up the combustion chamber unnecessarily. These LS engines like to be clean there and usually are unless you are burning oil.

If it were a rod-knock noise, then I would really worry, but what I hear is not. I think it is a piece of carbon on a valve.

bwill03z

I put in a magnetic drain plug awhile back and on one oil change I had a significant amount of metal shavings. The problem is that I dont know if the oil change where I had the shavings was the first change since installing the plug or the second, I cant remember. If it was the first then those shavings might have been there for a long time. Last time I changed the oil I didnt not have any shavings. The noise is hard to pinpoint, I used to think it was louder on the pass side but it sounds present on both side. Sounds like its in the middle of the motor and is very loud from underneath the car. The car doesnt see any track time. The only work that has ever been done to the motor was valve springs, seals ans retainers. I dont recall ever hearing this noise prior to having long tubes put on. It may have been there but def wasnt as loud. I had shorty headers on prior to the long tubes so I assume sounds would be amplified with those like the long tubes. I do not still have the stock exhaust to put back on.

~Josh

I had that issue and it turned out to be the crappy Mobil 1 oil. It turns thin and that has an effect on the oiling hence lifter tap.

Changed to the same 5/30 Castrol Syntec and it was cured. Might try that first.

bwill03z

Did yours sound like mine? I did try Penn Platinum 5w30 with no change