2007 Corvette with 52000 miles. M6. Purchased last fall. It had a slight ticking off and on that I attributed to lifter tick since I bought it. Not loud, not very noticeable, didn't pay too much attention to it TBH. A month ago or so the harmonic balancer suddenly started slipping so I figured while I was replacing that I would put a cam in it. Since then the tick is worse. It does not do it at idle and is most pronounced at around 2000 RPMs. It also is quieter when the engine is cold / louder when hot. I can hear it at cruise from inside the car if the windows are up and radio is off. I can also hear it at cruise with the windows down if I drive by a guardrail/another car/wall/etc, something that the sound can reflect off. I've done a ton of reading since then and everything I can find says it is pretty normal for LS engines, especially after a cam swap. I'm just hoping someone can watch my video I took tonight while the car was hot and let me know what they think.

Car was stock when I bought it last fall. Since then I installed LG Motorsports longtube headers, x-pipe, and NPP mufflers over the winter. I do not recall noticing a difference in ticking after that.

After the harmonic balancer fail, I installed a TSP 228/232 .600" cam, TSP hardened pushrods (stock length), TSP dual valve springs, and an ATI Superdamper. I did not change lifters or rockers. I installed a new oil pump o-ring when I had it apart. If I was getting the oil aerated I've read that I would be able to tell by pulling the dipstick after running it and seeing bubbles, I haven't seen that at all. Oil pressure is 40psi cold at idle, 30 when hot. Rises as it should with RPMs. I have measured and remeasured pushrod length multiple times and keep coming up with 7.400 as the correct length. I've pulled the valve cover multiple times to check the rockers, springs, pushrods, etc.

Everything in the top end is getting oil (ran it quickly with the valve covers off). Changed the oil since the cam swap and found no metal in it. I also ran Seafoam and ATF in the oil to see if the lifters needed to be cleaned before the oil change. I put 5w40 oil it to see if it changed anything, did not. I've listened to the car with a stethoscope and can't pinpoint exactly where the ticking is coming from except that its not the timing chain and I can hear it most when sticking it on the valve covers. I did hear it slightly more at the back of the passenger side valve cover but barely different. It runs great, I'm doing the tuning and have not see anything in the logs to indicate an issue.

Any input would be helpful. I'm debating just buying some LS7 lifters and bronze trunnion upgrades.

 

Sounds like a noisy fuel injector.

Tom

 

Thanks for the reply @TCW . I did listen to the injectors with my stethoscope and they didn't seem very loud.

Regardless, I decided to just go ahead with upgrading the lifters and rockers. I was getting nervous that I could have a lifter (or more) going bad and didn't want to wipe out my new cam, and it would be a good reliability upgrade if there wasn't an issue.

I've already got the motor going back together. Been working on it this week after work. Luckily the cam is fine and the original lifters look ok (no wear on the wheels). Got the heads back on and torqued down last night and should be finished tonight. I still need to press in the bronze rocker trunnion bushings.

At least I'll have the knowledge that everything on the top end is ok and won't need to worry about it anymore. Plus the assurance that I know I don't have a failing lifter and the rocker bearings won't fail.

 

Engine is much quieter now. I drove it around a bunch today and, while it still has some tick (what I would consider normal for a cammed LS), it is a night and day different. The combo of new LS7 lifters and bronze trunnions helped a ton.

 

Good to hear!….the ticking of an LS motor drives me crazy but it’s the nature of the beast. If oil pressure is good, no metal shavings in the oil, correct pr length, and oiling is uniform then I wouldn’t worry about it. I heard the ticking noise in my bone stock ls3, got worse when I added headers and now my car is in the shop getting a cam so I expect it to be much worse when I get it back. They all do it to some degree. I’m glad the lifters and trunnions helped, hopefully those LS7 lifters hold up good for you, I’ve been hearing of multiple failures… me being one of them

 

Just curious, where did you buy your LS7 lifters at? I’ve heard there a lot of fakes floating around right now

 

I got them from Summit. They are actually Morel lifters, which from what I read are LS7 lifters with upgraded valving.

 

Morel lifters and LS7 lifters are two different things. The Morels are supposed to be a better lifter but don’t have as wide of range for preload as the GM LS7 lifters. Mine is in the shop now getting a cam and I believe I’m gonna use the Morel 7717 lifters instead of the LS7’s… for whatever reason they are actually cheaper also. I had brand new GM ls7 lifters put in last summer and had one fail recently.

 

Morel 7717 is what I put in.

https://www.summitracing.com/parts/SUM-HT217-16

Summit lists them as LS7 lifters, I assume they mean "LS7 style" when they say that. From what I remember reading is they are basically an LS7 lifter with better valving to prevent pump up at high RPM. I'm certainly no expert though, just going off what I found with a google search.

 

I used that exact cam on my 05 LS2 and ended up using 7.425 PRs. All quiet afterwards.

 

Arw they pretty quiet? Also what length pushrod did you end up using? These lifters require less preload so I’m guessing I’ll end up using a 7.375 pushrod on mine. Of course measuring will need to be done but I would think a 7.4 pr will be too much preload on those lifters, they call for like .050-.060 preload

 

Between the lifters and bronze trunnions that engine is much quieter. I did use my TSP 7.400 pushrods, I thought these lifters needed the same preload. Looking around I see anywhere from .030 to .060 required preload depending on which site I'm looking. I'm going to recheck my preload this weekend hopefully (just had surgery this morning so not sure what I'll be able to do in a couple days) and possibly order some 7.375s.

edit: I just found on Morel's site the recommended preload is .045-.050 for aluminum head and block.

 

Yep .045-.050, which is a pretty tight window, but a lot of ppl have said to run closer to .060 to be nice and quiet. When you check your preload let me know where your at with the 7.4’s. I’ve asked the shop that’s doing the work for me to measure and try to get me somewhere between .050 and .060 so I’ll have to see what they come up with but I’d say it will be a 7.375 unless I go custom pr’s