New Engine - Sudden Valve Train Noise

[Norm K]

During a brief drive this afternoon my new engine started clattering. I know a valve adjustment is typically required but I figured to do that at around a thousand miles (I'm at about 200). I also wouldn't have expected it to go from nice and (relatively) quiet to this so suddenly ...

[mark houghton]

Good video sound but still really hard to tell if that's a rocker tapping noise, or a rattling sound reminiscent of a loose timing chain (not to scare you, but again - it's hard to diagnose from afar). The "suddenly" thing vs. gradual...hmmm. Are you running with the oil pressure fed tensioner upgrade, or the older style mechanical/hydraulic?

Again, not to cast undue alarm. I am not a well-seasoned builder as many here are, having gone deep into a Porsche engine only twice in my life and that was many moons ago.

[Ronnie's.930]

Norm, that sounds like an exhaust leak to me (as heard blasting on my BOSE multi-media speakers) . . would be wise to look into that first.

[Norm K]

Not exhaust, Ronnie, although I did go double check. Here's an interesting item: when I re-started it just now there was no untoward noise - the engine just purred along, "normal" air-cooled sounds notwithstanding.

Since I wouldn't expect valve train noise to be intermittent, I'm concerned that Mark might be onto something with his tensioner theory. I rebuilt the stock 930 tensioners - they're the later style but not pressure fed. I felt pretty good about the rebuild, as it took in the neighborhood of 15 minutes of slow and steady pressure to compress them for installation. Upon release they immediately rebounded and tightened the chains nicely.

[IMR-Merlin]

Do these cars have solid or hydraulic lifters?

[Norm K]

No lifters. Rocker arms directly contact the cam.

[Ronnie's.930]

^^^ Interesting about the noise disappearing - that kind of **** can wear out the ole' nerves in hurry (I know from many similar experiences).

Do they have the safety collars on them? If so, I would run/test it some more before getting overly concerned. Hell, I would do more "testing" regardless, if it were mine, before taking anything apart - however, that's not without risk, obviously.

Regardless, it's difficult to give reasonable advice for something like this and I know it can be very discouraging to be faced with the prospect of getting into the chain boxes again . . .

[IMR-Merlin]

That sounds like a "dead lifter" I guess a cam chain would make that also

[IMR-Merlin]

It's only on the right bank?

[Norm K]

When hydraulic tensioners are first installed there's insufficient space to install safety collars. My understanding is that most folks wait until the first valve adjustment to install the collars, as there's then enough space to do so. I have a set in waiting. Perhaps it's already time.

[Norm K]

Originally Posted by IMR-Merlin

It's only on the right bank?

Uncertain. The left side is far less "accessible" to the ear, what with the intercooler, downpipe, recirculation valve and such all being on that side.

[Ronnie's.930]

Norm, sorry to harp on this subject, but I just listened to that vid a few more times, and it doesn't sound at all like a mechanical noise to me - sounds like either an intake, compression, or exhaust leak.

In fact, Im'ma bet Paul's well worn ass on it!

PS - cam chain noise is loud and scary - much more so than what's in that vid.

[Norm K]

^^^^ If you lose, you win. If you win, I lose. No thanks.

[Ronnie's.930]

^^^ Don't be so sure about the "lose" part, as I hear that Paul is so skilled with that thing he can tie knots with it!!!

[slyguy]

sounds exhaustish to me as well, if you removed the air injection might want to check to be sure the plugs are all in place. After that I'd be into the rockers to check valve lash for sure.

[krasuskyp]

a'ight Normster, my $0.00002

I definitely disagree w/ Ronnie regarding exhaust / air nose - that is more ffffft fffft fffffft (I know as my header flanges leaked a bit upon initial install)... yours is more indicative of valvetrain like you speculated... clack clack clack.

When I'd installed my headers years ago I also took that opportunity to do my first valve adjustment.

Upon my initial shakedown run, I got maybe a mile and had to pull IMMEDIATELY OVER and shut her the F down with the hole puckering spine cringing CLACK CLACK CLACK sound suddenly being emitted.

LIMPED it home, pulled a valve cover (upper right) - one of my adjuster lock nuts had backed right off.

PHEW

so

maybe - just MAYBE... you... are... as bigofadumbass as I??? (MUWHAhahahaaa, if so - whatta werld, whatta werld whattawerld whattawerrrrrrrld!)

Definitely sounds like upper right for you there too.

Start there, easy enough.

DON'T get discouraged. Yet 8-).

We're pullin for ya brutha (nooooooot quiiiiiiiiiite the same way Ronknees is - beware his Popeye arm, might yank ya clean off!).

[Ronnie's.930]

Originally Posted by krasuskyp

. . . I also took that opportunity to do my first valve adjustment.

- one of my adjuster lock nuts had backed right off.

Ya' see, Paul, that's what happens when you fantasize about borrowing my free-candy truck (again) when you should be focused on your (own) nuts!

[T77911S]

i could not play it but tensioner.

[infraredcalvin]

Hmmm, I listened carefully to the video, sounds an awful lot like when one of my air injection plugs backed out on me. I thought it was something mechanical when it happened. Hopefully nothing major. Good Luck!

[356911930]

It's typical for me to jump to the worst possible scenario when I hear a suspect noise from the engine, so don't let that derail a logical approach. If it is not air injector plug related I would do a compression check. My guess is that one of your valve adjuster locking nuts has backed off and a valve is out of adjustment.

Good luck, looking forward to your next discovery.

Rahl