marc_w

So there are some springs out there that some claim to be noisy, and may possibly trip the knock sensors.

Is the noise audible to the naked human ear?

Unaffliated Racing

iTrader: (15)

The valve springs don't determine the "noise". It's the ramps of tha camshaft that determind how quick and hard the valve snaps shut. Harmonics in the springs could cause issues in severe cases.

Cstraub

iTrader: (1)

Brian,
I was privy to a tech letter about year ago, it did state in testing that some of the valve springs when designed to "coil bind" made a noise that triggered the knock sensors. If I can find it, I will pass it on to you.

Chris

Unaffliated Racing

iTrader: (15)

Chris,

I can see that happening but, everyone on the board complains of noisey springs...which isn't the case of most noise.

Brian

marc_w

Thanks guys...

I think Chris rung a bell for me when he mentioned running into coil bind. That would make a lot of sense... I was under some sort of impression "the noise" could be from simple harmonics while the valvetrain was otherwise running/operating normally or ideally setup.

I'm not anywhere near coil bind on my 918's with my .560" lift... but I have an odd 'train noise I'm trying to sort out. I think I'll put up another post for that.

Sport Side

iTrader: (6)

Hey Marc,

Don't those rockers walk back down to a 1.72 ratio @ peak valve lift?

marc_w

These ones here go back down to about 1.82 I believe.

I think the 1.79's go back down to about 1.72.

My ~.560" calculation was with a straight 1.8 ratio on the calculator...

Sport Side

iTrader: (6)

alright cool.

vettenuts

iTrader: (4)

Curious as to why you went with Crane rockers and cam, but 918's for springs? I was thinking of the same thing, but Crane touts their springs as "quieter than Beehive design".

mrr23

iTrader: (3)

marc_w originally had a comp cam in his truck before going to the vinci 047 cam.

Another_User

You never get that "sewing-machine" sound with the hotcam. All you hear is the injectors. They are a little obnoxious. Oh yeah..and sometimes you can hear the check valve in the AIR pump, LOL.

marc_w

Yup, mrr23 was right there.. I originally had a Comp ground cam. I've got the VHP/Crane duals in the plans, probably as one of my next few changes.

I'm not sure what the noise is that I have, but I'm leaning towards a lifter problem.

A-U, what do they injectors sound like? Are the the things that make all that "tapping" or "clatter" at idle, from what sounds like the center of the motor?

Another_User

I wanted to be sure it was my injectors so I bought a mechanics stethoscope. Very helpful tool, and cheap too.

marc_w

I've got a stethescope, but I'm not sure if its the correct one. Is it just the standard type with the rod that you probe around with?

I used it to diagnose a noisy pulley driven component on my sisters car, but basically forgot about it since then. I'll have to dig it out this weekend.

MNR-0

Wouldn't happen to be a screwdriver type - would it?

CrimeSScene

iTrader: (9)

You put a stethoscope up to those injectors and you realize how loud those little suckers are. I still have another noise in mine that I can't isolate even with the stethoscope. Another-User is right though, good tool to have in your box, especially when you can pick on up for about three dollars.