Hi folks,

Looks like I might have what seems to be a light and intermittent lifter noise. I hadn't noticed until I took my car to the tire shop and one tech noticed. He's done LS builds before and apparently has a good ear. It's hard to notice because it's a light tap, but it does sound intermittent which leads me to believe that it actually might be a lifter. I timed the intermittent tap and when it does sound, it taps at somewhere between 6-8 taps per second at idle, which matches the camshaft/valve/lifter rhythm. It's a huge bummer because these are new LS7 OEM/GM lifters that went in when I did my cam build, along with new BTR hardened 7.400 pushrods. Anyhow, I don't see any performance issues and I'm not too worried, but it's still a moderate concern. Knowing that these lifters are brand new, and knowing I did the correct procedure and correct torque value when I torqued the rocker arm bolts, what could have caused me to have this intermittent lifter noise? Might I be able to remedy it with some sort of oil modifier? or maybe by loosening all rocker arm bolts and doing the correct retorque procedure all over again? Or maybe I should shim the rocker arms next time? Basically looking for any possibility to try except taking the friggin heads off and replacing brand new LS7 lifters all over again.

FYI: I'm basically dailying my Vette, and I've beat on this engine HARD with no mercy since I did finished my cam build and car performs flawless everyday, at every load and every RPM.

 

Is it loudest around 2,000 RPM? If so, my rebuilt engine (also new LS7 lifters in new LS2 trays with aftermarket hardened pushrods) has been making the same noise for almost 10k miles now. During that time it's been through two HPDEs and has run 10psi of boost for the last 2k miles or so. Oil pressure is great, performance is great. I have messed with pushrod length and measured preload with a dial indicator and I'm sure it's dead on, makes no difference. I send the oil to Blackstone every change, so hopefully I'll know in advance if it's coming apart.

I have read about the same issue many times on LS1Tech with no conclusion. It used to bug the hell out of me but I've finally made peace with it and just enjoy the car. Good luck!

 

Do you still have that "cold start" issue ??...I believe you posted a few days ago with this issue ??

 

Good idea tapping the counts per second, I've done the same thing by taking a video and slowing it down. Did you use a pushrod measuring tool? Mine needed shorter pushrods with cam swap. Wouldn't hurt to pull the valve covers off and check what you can.

I had a light tapping noise that was 1/2 engine speed when I cracked #7 piston. I swore it was a top end issue but still towed the car home to be safe. Another guy who owns a shop that does lots of work on vettes thought the same thing. I highly doubt that's it, but it could be something else. Sounds are hard to track down sometimes. Do you have a stethoscope tool by chance?

 

 

 

 

A "tire shop tech" told you about an engine noise?

 

If you're going to pull the valve covers I recommend measuring required pushrod length while you're there. Whatever I read on the forums that my length "should be" ended up not being the case for me. Tool is cheap and pretty easy to do. You can probably measure the 4 corners of the engine to confirm or deny.

 

 

 

 

 

 

Mine ticks pretty much all the time to varying degrees, but I hear it more prominent now I guess because I'm paying attention to it now. I'd like to know if I can check for a collapsed lifter without taking the heads off. I was thinking of taking valve covers off and checking for any lash in between rocker arm seat and valve top BUT I don't know if these hydraulic lifters are supposed to keep enough internal pressure to maintain zero lash when engine is off and when lifter is seated on the base circle. If I can find that indeed I have a collapsed lifter, then I'll bite the bullet and plan for removing the heads again and changing the faulty lifter. I'm already 900 miles in after the top end rebuild and cam swap. I'd still like to try running a quart of Rislone oil treatment first before I try anything major.

PS: I can live with noise if it's a normal valvetrain noise, but if it's a potential of lessened engine longevity and wear, I'm not going to risk it.

 

Oil treatment isn't going to do anything considering that engine is basically new.

I almost hate to say it, but your combustion sounds a little off in the "Test Drive 3" video. I've come to expect a lot of valve clatter from these cars, but what I hear aside from that is a partial miss in your exhaust tempo which certainly could indicate a collapsed lifter.

 

 

A partial miss?? Well, that's a new one I haven't heard before, I didn't pick up any partial miss. Anyway, I think we can guess and dispute all day long and it will still boil down to me taking at least the valve covers off and checking for a collapsed lifter, one rocker arm at a time. Being that this is relatively easy and quick, I'll probably do this first before anything else. Nothing more than I hate than having to go over the same job twice, especially when I know I did everything by the book and with new lifters. If I have to take the damn heads off.......who knows, I might just go all out and get refurbed 243/799 heads and ditch the 853's

 

 

I could be wrong, but your exhaust note sounds a little off in the way I've come to associate with a cylinder not quite firing the way it should. And I've found that you do actually have to run pretty far out of whack before the ECM will throw codes for a misfire. Listen carefully around 0:55 to 0:57