KenWH

Hi guys,
Sorry in advance for the long post.

Car has 11k miles total...9k of those miles are with the cam, ported oe heads and melrose headers. I bought the car with the mods already on it.

I recently had Chuck COW tune my car when he was in Bowling Green...it was driven fairly aggressive during the data logging hops. After the car sat awhile we went to drive to dinner and I noticed the car now had a slight tick at 1300-2300rpm. Chuck thought maybe it was normal header noise or a slight exhaust leak...at the time the tick wasn't very loud and so he wasn't that concerned. One of the other guys there getting a tune heard my car pull in after the tune and made the comment that it sounded like I had an exhaust leak.

On the way home(200mile drive) the tick got worse. It's most noticeable with the windows up but at low speeds you can easily hear it with the windows down when passing close to buildings or cars. It goes up and down in speed and loudness with the engine rpms.

When I got home I took it to a muffler shop and had the exhaust checked and they didn't find any leaks. I took it to my dealer and they thought it was a lifter. I took it to a LSx specialty shop in Memphis and they agreed it sounded like a lifter.

The LSx shop pulled the heads and found two of the oe pushrods had scratches where they pass through the head. They also found one cracked lock in one of the Comp 918 valve springs but it hadn't failed yet. They didn't see any further damage. Signs pretty much pointed to a couple bad lifters.

They installed new Caddy lifters, hardened Comp push rods, and a Patriot Gold spring kit(.650).

Got it all back together and it's still ticking. They noticed a tick from the front of the motor so they pulled the cam cover. They found that the shop that did the cam install originally used some jerry rigged parts(hand drilled the bolt holes in the oe sprocket and used crappy shims) to get the cam installed. The sprocket had a wobble from the shims and was hitting the sensor. So they replaced the cam sprocket and sensor with proper parts.

Got that back together and the car still ticks. The shop says what I'm hearing now is normal for the LSx with a cam but I disagree...it would have been ticking like this from day one...not just after the tune.

So 1.5 weeks in the shop and about $2k in parts and labor later I got everything fixed but the original ticking problem.

Again...the car was not ticking at all before the tune.

Talked to Chuck several times since and he's been helpful but there's only so much he can do over the phone.

Any ideas what it could be?

Thanks,
Ken

FloydSummerOf68

Return it to stock tune and see if it goes away.

If it does then it's the tune.

If it doesn't then you know to keep looking.

Craigster05

Oh, man...sorry to hear about your troubles....it's got to be very frustrating. I am thoroughly amazed at what some shops do and get away with....the cam nonsense is unbelievable.

Take a good look at the sides of the heads where the headers attach...look to see if you see any faint carbon lines. We saw a small leaking header gasket on Welcome2try's car that he described as a "ticking on low speed cruise". It did sound like a ticking, but was actually a leaking header gasket.

If you can post a video or sound clip, it might help us as well.

FloydSummerOf68

If an exhaust shop looked at it to confirm it not being an exhaust leak and then it turns out to be an exhaust leak.....well that will just be insane

Craigster05

If they looked underneath the car, and not in the engine bay, they could well of missed it....a "muffler" shop is not necessarily employing techs that know what they are looking for even if they did look in the bay of a Corvette.

FloydSummerOf68

I would be blown away if all three shops couldnt tell it was a simple header leak.

KenWH

Thanks for the reply guys...another long post...sorry
Here it goes...

One detail on the tick I find interesting is that under light/normal acceleration right when the trans is about to shift and the motor kinda unloads for a second(if that makes sense)...the tick gets noticeably louder and faster.

Yes...it's been very frustrating.

The hand made cam shims that first shop used were crazy...I guess the bright side is that the money and time I've spent thus far hasn't been totally wasted. Small hidden problems are getting fixed before they become BIG problems. Now I just need to fix the pink elephant.

Chuck had me look around the header flanges as it was his first thought also. I looked all around the flanges but didn't see anything signaling a leak.

If I did miss something surely the shop in Memphis would have seen signs of leakage when they pulled the heads to change the lifters and install the springs.

On an earlier suggestion from Chuck I'm dropping it off at the dealer tomorrow for a compression check...just trying to rule stuff out at this point. In hindsight I should have had that test done first but all the signs were pointing to a lifter issue so we jumped right into that.

As to changing back to the previous tune...Chuck assured me nothing he did to the ecu/tcu would cause it to tick...that said I may end up sending him my ecu to reload my previous tune. Again...just to rule it out.

I also keep thinking it could be the o-ring in the oil pickup which several people have had problems with when doing a cam. But why would that wait so long to cause a tick. I mean the car ran tick free with the cam for around 9k miles. Plus my oil pressure is steady at 46psi on fresh 5w30 M1 while cruising at 75mph (around 1500rpm)...all the while I can still hear faint ticking even at those speeds.

Could I have just got a bad batch of Caddy lifters...with my luck that's not too far fetched.

The oe rockers were reused...would a bad rocker cause a tick?

Thanks again guys and keep the ideas/suggestions coming.

-Ken

Xlr8yourC5

Just a FYI that as I mentioned in another thread here a month or two ago - my (totally stock cam/heads/manifolds) C6 had a bad ticking sound (most noticeable at appx 1800-2K rpms) - I checked the torque on the (stock) exh. manifolds - some were about 1/2 turn off the torque spec. There was no visible evidence of a leak (no soot, stains, etc.)
Retorqued them all - problem solved. (Car only had 8K miles on it btw.)

With your setup that may not be it but something you can check/do yourself (I used a swivel socket adapter on some IIRC) - just in case the shops didn't check that (may have but just a FYI)

BTW - Someone else here mentioned a loose plug was a source of his ticking IIRC. (Again with your mods neither of these may be the cause though, but worth checking...)

KenWH

This afternoon I was detailing the car before it's trip back into the shop tommorow for the compression test and I got an idea. I recall someone using a candle to check for exhaust leaks.

With the motor idling I took a stick lighter and moved it around the header flanges and sure enough...6 of the 8 cyl sucked the flame toward the flange/joint and extinguished the flame.

Still no black residue around the flange however. I know the shop in Mem. just reused the gaskets that were on it but I'm not sure if these are oe mls gaskets or something else.

I think I'm going to postpone the comp. test tommorow and just install new header gaskets then go from there.

What do you guys think?

edit:
Bolts are tight btw.

XLR8yourC5...your description of the tick sounds very similar to what mines doing. Can't hear it at idle but once the rpms get into the low teens it comes on strong. Everyone was saying that I'd be seeing black residue if the header flange was leaking...your proof that thats not always the case.

I just called the shop in Memphis a minute ago and told them about the flame test. They said they've never seen the oe style gaskets leak that bad and that if there was a leak in that many cyl. I'd have black residue. He did say he'd install new gaskets for free if I wanted since I'm still having problems.

TLewis4095

There is no way Chuck's tune could cause anything like your hearing & and with your description I still agree it is an exhaust leak at the headers/head joint. Get some good thick copper gaskets & put them on in place of the OEM ones & I bet the problem goes away IMHO.

Good Luck!!

KenWH

Got any suggestions on which brand gaskets to use?

Braciole

Get new header gaskets its cheap insurance, and in my opinion thats the problem. When chuck tuned your car the extensive beating on the car (bad choice of words) loosened things up not a big deal, sounds to me like you needed to spend the money you did to keep those problems small
Good luck
Mike

C6~Missle

I would bet it's a header leak.. The tune isn't going to make the engine tick louder.. If I had to guess, I would say your new tune is making or was making the car run leaner which caused the EGT's to go up. This in turn has probably un-seated the header or gasket by a slight warp.
Exhaust leaks sound very mechanical.. like a metallic knock.

At least you got some other issues resolved that could have been a major issue...

0Chuck CoW

Hey there.....

Here are some suggestions...

First..... What headers do you use? I only use the LG PRO LONG TUBES in our shop..NEVER any problems....

Second.... We ALWAYS use/reuse the factory MLS header gaskets and both sides of the gaskets get a faint coating of "SENSOR SAFE PERMATEX ULTRA COPPER HIGH TEMP SILICONE"... We NEVER have leaks.

Third..... Remove BOTH headers, cats, and X-pipe and inspect for cracks MOST ESPECIALLY around each flange/port at the head and again at the collector. MANY times we've found bad welds on headers or cracks at flanges.... Some headers don't fit perfectly and can tap on the chassis or bellhousing....On some brands of headers we routinely find the front O2's rattling against the bellhousing....Especially on the driver side. Watch for the headers touching the frame. or the flanges of the collectors on other parts of the car.

Fourth.... C6 ALTERNATORS can have a problem when accelerated aggressively..... Remove the accessory belt and (not for too long) run the car to see if the ticking continues. (I've seen this happen twice on 07 Vettes.)

Fifth......No disrespect to the shop who recently went in the motor, but What EXACTLY was done with the camshaft endplay and shims or what????

Sixth....... MANY people install the oil pumps incorrectly and while it may not tick at higher revs.....@ lower revs a ticking can be heard from the valve train....THIS IS POPULAR. The o-ring does not seat or gets cut and oil suction is compromised.

Seventh...... Was the chain and cam sprocket replaced??? What style of cam bolt/s was used? Also, inspect the oil pump.

Eighth..... When the heads were off.....Was there any evidence of piston to valve contact????

Ninth....... Did you check the rockers/ inspect them/ or maybe try another set from a known good motor....This one is easy....

Tenth...... OK, what is the lifter pre load??? and who set it up??? Who selected the push rods? Did you use the same head gaskets for the repair and were the heads milled?? You might get in trouble here.....BE VERY CAREFUL.... If this is not done right or checked....You will have a tick FOREVER and never find it. Caddy lifters are great, but will make slightly more lift than the other ones and could change your situation for the worse even though they are superior parts to the originals.

These are just SOME of the things that come to mind.....The tune you have in your car is EXACTLY the same tune everyone else gets with respect to the rev limiter and the trans shift points and the like.... It hasn't caused a problem for anyone yet and works like a dream even in totally stock motors..... However, with the suspect/sketchy cam shims and stuff...I'd have to question the original install in it's entirety and would like to have a look at it. If something wasn't right with the setup, it is VERY possible that (indirectly) the new tune could have brought this on....

One thought to consider..... If you possibly had an piston contact with valves, the piston skirts could have "tweaked" and you would have an ongoing knock/tap/tick. Some LSx engines have loose pistons and you could be hearing a piston knock....

My advice, if you don't find any resolution with my suggestions...is to bring it here. It sounds like a long ride, but 2 weeks ago, Jim Johnson of Kentucky made the ride in his A6 and I think he had a good ride here and an even better ride home!

If you can make the time to come up, I'll do what I can to help you out.....I'm pretty sure we'll find it pretty quick.

Chuck CoW

pwoolford

My 05 has ticked since i bought it with ~7k miles on it. The car was pretty much bone stock when I bought it. I added LG Pro headers and it still ticked. The whole top end was recently upgraded to LS3 and it still ticks. Mine almost sounds like a solid roller setup. I figure if it gets worse and comes apart one day I'll find out what it was.

Brett Hunter

Wouldn't an exhaust leak show up during tuning? If it is leaking I would think you should have seen an imbalance in the 02 readings.

LSCHLEM

Remember the guy with the ZO6 , He had vids of his care
ticking on the passenger side. We all gave input to possible
problems from collapsed lifters to exh manifold gasket. It went
on and we never heard from him. He came back on CF a month
later and we asked him what the problem was and he said
" I dont know it just went away " Hope this guy has as much luck.

Craigster05

Too bad Spin isnt still in Memphis....

VET4LES

Good response Chuck. It sounds like exhaust to me but as you pointed out it could be a lot of things.

KenWH

Thanks for the help everybody!!!
And to Chuck for the great info and offer to look at the car.

It's leaking at the header gaskets for sure.

I took the car to the dealer this morning. I talked directly to the tech that diagnosed the lifter tick originally and he asked why I was back. I said most of the valve train had just been replaced and the car is still ticking. He says "hmm,...did the shop fix the header leak also?"...I said header leak...nobody told me they were leaking!!! He said they were leaking at the flanges when he first saw the car 3 weeks ago and he told the service advisor that I had a lifter tick AND leaking headers.

The service advisor never said a word about the headers leaking.

Just to be sure the tech came out to the car and listened again felt around the headers. He said they're definitely still leaking. He said both sides are leaking but the drivers side is worse. I did the flame test again with him looking on and the flame obviously reacts when it's above the header flanges...no doubt about now.

Lesson learned....always talk to the techs!!!

They had to order the oe mls gaskets...they should be in tommorow.

I'll let you know how the new gaskets work out.

Thanks again guys!!!

-Ken