Hi all, my brother has a ‘13 427 with 55k miles and started hearing this noise coming from the motor at idle. When he throttles up the noise goes away completely. It’s only at idle do we hear it with the hood open.

I know the lifters/valves are a common issue with these cars as well as worn springs. Most people get the heads/valve train addressed so we wanted to see if anyone here had this happen and can shed some light on if his car has the issue. My gut feeling is that it’s a valve guide or spring but not totally sure. Thanks!

 

Well at least under throttle the noise goes away. I don’t have an LS7 but I’m sure you’re well aware of the valve issues, maybe it’s a bad valve guide. I would definitely pull the valve cover off at a minimum and take a close look and make sure the rocker bolts are tight. Usually a bad lifter gets louder under throttle but I guess not always. Good luck

 

If the heads were never redone now is the time . Look at threads about this. I don't think I would even run ot anymore until issue is adressed. It is catastrophic when they drop that valve.

Anthony

 

Thanks for the advice, that’s not an invasive job at all, we’ll definitely check them to make sure everything at least tight. My gut is a valve guide too since I’ve seen them where you can literally grab the guide and valve (with it out of the head) and feel the gap it created.

 

Thanks Anthony. The heads are original to the car, and your advice is the same I told my brother: don’t drive it too much until you know for sure what’s causing it, and if it’s the heads or a valve guide then get them done. I’ve seen some of the failures and it’s not pretty…good thing (sorta) we have salty roads so our cars are put up for the winter. Should give him plenty of time to have them addressed before next season.

 

My 2013 427 sounds exactly like that. Always had loud valve train since new. I took the car to the dealer when new and came back as normal. This was after reading all the dropped valve posts in 2013/14... I have 58,xxx miles on the car now.

My oil PSI is also around 15ish at hot idle. Again all normal. Also remember ALL 427 LS7 cars came with the ZR1 / Z07 oil cool/heater and ZR1 Exhaust. The engine oil is warmed and cooled with engine coolant. This brings the engine oil up to temp faster and keeps it cooler. I just had all the fluids changed, tires changed (3rd set), brakes done at the dealer. Same tech has looked at the car since new. He said keep driving it. Don't let it sit.

drive it.

 

Thanks for the info. I'll let him know but I think he's set on checking torques on the lifters and spring compression at a minimum just to be sure nothing is worn out, relatively non-invasive. The "quick" check is worth it to make sure his motor doesn't give up the ghost. What gets us is that he drove it about 3k miles this summer and just recently started hearing/noticing the tick which make us worried something is starting to go. I can see if it was like that since new like yours and has gotten clean bills of health, then it would be a non-issue. We'll see what we find out, but good to hear you use the car how it's meant to be!

 

Make sure to post results.

Thanks

 

While it has been mentioned to remove the valve covers and make sure your bolts are tight... I would intentionally take it a step further and remove/inspect every single one of your Rocker Arms.... it only takes a few seconds to remove each one and physically inspect them.

I had a similar tick on my engine... it was after I installed a Texas Speed stage 2 Cam with new dual valve Springs as well as a new trunnion kit. I do NOT blame TSP, their customer service has been second to none. I chock this up as being part of the hobby. But hind sight is 2020... I would suggest going to a bushing kit over bearings on any cam swap.

About four months of daily driving after installing camshaft, it developed a slight tick at idle. It still make 495hp 454tq on the DYNO with the slight ticking... I assumed it was a lifter tick as it went away as soon as our RPMs went up... I continue to drive without much worry until I parked the car and placed it in storage with my insurance company to save a few bucks... while it was parked I took the valve cover off and found one rocker noticeably damage. On one of the Rocker Arms one bearing was completely gone needles as well as both inner and outer races.... It was as if no bearing had been installed at all... I was amazed at how soft the tick was and would have expected much greater valvetrain noise considering one complete bearing was literally MIA, however it was fairly quiet. On the same rocker, the other bearing had more than half of the needles missing and half of the inner race was gone... I did a quick visual of all the other others from a distance and did not see any that looked out of place.... so I called TSP who quickly sent me a new rocker which one kit pre-installed.

While waiting for this rocker to arrive, I decided to purchase a large 3" "earth magnet" and 2 magnetic drain plugs... with the earth magnet I dragged it on the bottom of the pan towards the magnetic drain plug... each time I pulled the drain plug out. It had needle bearings attached to it... I did this until I could no longer pull any metal out...

I installed the new rocker and fired up the engine. Only to learn there was still a tick.... immediately pulled both valve covers and took a much closer look... without removing any rockers, I found two more rockers that showed evidence of damage that I had initially overlooked. I immediately contacted TSP who shipped me two more rockers... after the phone call, I decided that I should really remove each rocker and inspect each one closer... this is when I found 3 more rockers that had worn out the race and where about to fail. This makes a total of 5 rockers at different stages of failure. 3 of them really were difficult to see when installed.

I then used a scope to stick down into all the cylinders and through all the push rod holes to search for more missing metal... the camera has a magnet on it, and I was able to find some small pieces.

im still missing large portions of the inner and outer races of 2 of the bearings. They are MIA.

inspecting the rocker shafts shows excessive wear on the bottom... also the mounting plate that sits under your rockers shows signs of wear as if the shafts are twisting side to side. Those are being replaced with new billet mounting plates to better secure the rockers.

moral of the story, if you hear valvetrain noise, it literally takes some common hand tools and about 10 minutes to remove your valve covers and about 10 minutes to remove, inspect and reinstall your rockers... possibly 10 more minutes to button it all back up.

still waiting on a CHE bushing trunnion kit... so while waiting I decided to remove the oil pan to see if there was any more metal in the pan... found nothing... it appears my magnet 🧲 fishing worked well.

since the pan is off I ordered an oil baffle and some earth magnets to stick to the baffle... this should help keep the pickup submerged and catch any potential valve train components in the future...

cause? I'm not totally sure, it could be the increased spring pressure and cam profile causing early rocker bearing failure. Perhaps the factory bolt torque is to low allowing the shaft to walk at higher rpm's which cause the plate to wear slowing for greater shaft movement leading to bearing failure?

I also plan on purchasing ARP rocker studs to add a few more lbs of clamping torque...

sorry for the long post... I guess I'm just trying to say, remove your valve cover and rocker then inspect each one one by one...

SPEED SAFE NICK

 

Sorry for the long post... I guess I'm just trying to say, remove your valve cover and rocker then inspect each one one by one...

SPEED SAFE

This is all fantastic info to have, thanks! I'll forward this to my brother. You're right, it doesn't take too much time to just pull the rockers off and inspect them. I've read the needle bearings are a weak point and if they fins their way into the cylinders I can only imagine the damage they'll do. It's also good insight to my personal plans with my C7Z. I plan to have a TSP cam package installed with DOD/AFM deletes, stiffer springs, hardened pushrods, and an upgraded trunion kit to eliminate the needle bearings. I'm surprised the bearings on your rockers failed...kinda has me a bit on edge about their kit but I'll talk to my tuner since he's doing the install and ask what he's seen with them.

Over the winter we will tear off the valve covers and take a close look at the rockers and see if there's any chips or needle bearings missing like the pictures you sent. My guess was either a lifter or valve guide which seems to be the consensus here.

 

Man, we hear a valve tick and it’s like, she’s going to blow! I get it. GM should, or should have already, recalled all LS7 and fix this problem.
I test drove a 427 conv today and I didn’t love the car but the fear of the LS7 breaking one day was in my head. Resale value down the road because of this issue was a concern. The owner of the car lot (who specializes in Corvette), said he was unaware of any valve issues on 427, never heard of it. I was like, ok, we’re done here. He was acting desperate to sell it. Sorry.

 

Sounds completely normal to me.

But considering this is an LS7, I wouldn't even bother checking the valves or guides. I would pull the heads and purchase the American Heritage Performance LS7 head package with the Ferrea SS valves, hardened guides. Do the core exchange so they send you a set of heads then you send them your old heads to there is minimal down time. Can choose different options for the new heads depending on what you want (I'd likely stay mostly stock but have them do a CNC porting).

The LS7 head problem is catastrophic and engine destroying.

 

I think it sounds fine also

 

yeah when they get real bad you dont even have to take the springs off to know they are bad. You can literally grab the whole thing with the rocker on and all and wiggle it around (scarrrrrry).


https://americanheritageperformance....cylinder-heads

 

I had no idea about the LS7 's until after my brother made me aware of his car. I would say resale value isn't a concern as long as the heads were addressed, in my mind I think it would actually increase it just because of the peace of mind. If you're looking the a 427 I would just have that question ready for any car you go and see.

 

That's what we're going to do after we pull the valve covers off. Since I would say most people just have the heads done, the couple grand it would take to get them is WAY cheaper than having something fail and grenade the motor. Thanks for the AHP insight, I'll forward them to my brother.

 

No way, I had no idea they could be THAT bad! That has to be at the razor's edge of failure. I'll give your info to my brother, he's currently shopping around for them so this will give him another place to look.

 

Yes sir scary stuff indeed when they get that bad.
Yes have him get in touch with us and we would be glad to answer any questions he has
310-326-2399 or HP@americanheritageperformance.com
Text message or email works best to get in touch with me

https://americanheritageperformance.com/