I just did h/c/i on my 404. Car ran perfect before. Put on l92 heads, big cam, and fast 102/102. Now for some reason i am getting a lot of squeaking noises and it runs terrible part throttle and idle. Runs amazingly WOT.

I am wondering what it could be, we tried wd-40 on my pulley tensioners and they seem fine.

I was worried it was a cam bearing, but i installed the cam perfectly and i have great oil pressure.

That leaves it to exhaust leak or maybe even tune.

Is there anything to be worried about?

 

Just for some clarification... you put a L92 setup on a stock bore 346?

 

It specifically says 404 which would indicate bore and stroke. It's an ls2, btw.

 

Ptv?

 

Whoops... don't know how I missed that!

You say the car was quiet and ran well before. What did you have before? What is the PCM currently calibrated for?

 

Wouldnt ptv problems just destroy the engine pretty much immediately? I've taken her up to 7grand a few times with no issues.

PCM is calibrated for my old top end setup with the 404. Was a ls6 intake, ls1 heads, torquer 3 cam.

 

How's your valve geometry?

 

Going from that to a 102mm intake with a "big cam" on the old tune would probably explain the idle and part throttle problems, but not the squeaking.

When is the squeak present?

 

Squeak is present at idle and low rpms, seems to go away with rpm.

Not sure why, but it seems that playing with timing will change the pitch of the squeak.

 

http://www.youtube.com/watch?v=46_zopQ2FpA
http://www.youtube.com/watch?v=6eeytAFlteI

Here are some videos

Valve geometry looks fine, ran the same setup on another engine and it was tested, we briefly verified that it is correct on this one again.
I didn't check ptv clearance, but i assumed it would be ok, did some test turn overs without issue.

Its a 242/252 .620/.620 113+4 cam, l92 heads milled a slight bit with stock gaskets, and -2cc pistons.

 

It's really hard to hear any pronounced squeaking in those videos. The audio quality isn't great, and the FAST manifold's vacuum sound is too prominent.

But from what I could hear, your idle is WAY too low. It should be up around 900-950. That sounds like 700-800.

What engine mounts do you have? Hopefully not stock!

 

Raised the idle since the video, stock motor mounts.

The squeak is the very high pitch noise that goes along with the lope.

I checked double checked installed height and made sure im not getting coil bind.

I found a crack on my y -pipe near my header. Do you guys think this would make that sort of noise?

 

I'm betting it's the engine mounts.

 

After my swap i had a squeak caused by the cam lope, stock mounts can't handle a large cam they practically fall apart. I went with a set of poly mounts from Spohn and haven't had a problem since

http://www.spohn.net/shop/1998-2002-...ounts-LS1.html