What causes my valvetrain clatter at high RPM's?

[Ozz]

Greetings,
My MM is approaching 60k miles and I've noticed that the valvetrain is clattering quite a bit at higher rpm's (4k+) recently. I never really noticed it before the last few thousand miles.
Any idea what's going on and how to fix it? Is this clattering normal or something to be worried about?\
I have perceived a loss of high end performance but that could just be me lifting when I hear the clatter... :confused:

Thanks.

[RF Overlord]

Are you sure it's valvetrain-related? Detonation will cause similar sounds at high RPMs and also cause a loss of performance...

[magindat]

Yeah, what Bob said. :rolleyes:

I had a tuner (some friends talked me into) tell me it was valve chatter. Funny, though how it blew black smoke on the dyno (sign of detonation) right about the same RPM's it 'chattered'. :mad2:

:shake: Back to a real tuner for a real tune and 'valve chatter' go buh-bye... :bows:

If it really is valve chatter and it could be junk building up on them if it's getting worse with age, then Seafoam it a few times 'till it don't blow white smoke no more. The directions say 1/3 can and let it sit like 5 min. I say (and have done) a whole can and let it sit like 15 or 20.

if the 'valves' don't quiet down, make sure you're REALLY getting the octane fuel you're paying for. If that don't do it, retune. ;)

[fastblackmerc]

Also might be that the cams need to be re torqued.

[Dennis Reinhart]

Greetings,
My MM is approaching 60k miles and I've noticed that the valvetrain is clattering quite a bit at higher rpm's (4k+) recently. I never really noticed it before the last few thousand miles.
Any idea what's going on and how to fix it? Is this clattering normal or something to be worried about?\
I have perceived a loss of high end performance but that could just be me lifting when I hear the clatter... :confused:

Thanks.


This to me sounds like spark knock stay, out of WOT, what gas are you running does, the car have a tune in it??

[crouse]

This sounds like what I was noticing. I don't think it's knock because mine is too consistant.

http://www.mercurymarauder.net/forums/showthread.php?t=42964

[Ozz]

I always run 92 or 93 octane from one of the bigger gas chains (BP, Amoco, Mobil, Shell). I have just the basic Superchips 1725 tune on it (set for 91 octane). I have iridium plugs in it (gapped at about stock - can't remember exactly). Stock thermostat, gears, etc... Daily driver.

The clatter only happens when I am really on it.
Does the 4v 4.6 block have a detonation sensor? Would it function at WOT (open loop ECU mode)?
I supose it really could be that. I will keep track of what gas I put in it and when I hear it and see if I can make a coorelation. I can remove the tune for awhile too and see if it goes away.

With gas prices what they are - who knows what's coming from the pump I guess...?

[RF Overlord]

Yes, this motor has a knock sensor, and yes it functions at WOT, but it only has limited range. It may already be pulling as much timing as it can, which could explain your perceived performance loss, but you may have other issues.

Then again, it COULD be valvetrain-related after all...your idea of reverting to stock programming is a good start.