Knock in New Engine?

Ed Blown Vert · 09-27-2009, 08:33 PM

Still tuning the car. So idle is still rough. But have been hearing a knock from the engine. I first thought it was my exhaust hitting. But can't find anything wrong. I hope its not the engine.

When I bring the idle up, I can't hear it. So not sure it is the engine. but it sounds nasty.

Going to talk to the builder tomorrow.

Knock

KCS · 09-29-2009, 12:42 PM

Drain the oil, see if there is anything in there that's not supposed to be (ie metallic flakes).

99'CajunFirehawk157 · 09-29-2009, 01:03 PM

Couldnt hear anything out of your video except the s/c...damn, you have luck like I do, that car just came out of the shop...I feel your pain bro.

Ed Blown Vert · 09-29-2009, 04:31 PM

I didn't notice anything in the oil or on the plug.

Now that it is tuned better, the engine doesn't shake as much at idle.

I don't hear it anymore. So maybe it was something hitting. :dunno:

chet3310 · 09-29-2009, 04:35 PM

Sounds like procharged power to me!

Ed Blown Vert · 10-02-2009, 10:23 PM

Spoke to soon. Still hear it.

Car still runs great. Above idle I cannot not hear it.

DKITCHEN · 10-03-2009, 12:19 PM

My cam only LS1 was doing the same thing. Wasn't pulling any timing and still ran strong so I ignored it for too long. Ended up being the cam bolts had backed out and the cam was walking. Tore up the cam and lifters and hopefully nothing else, still under the knife. If it's like mine it will get progressively worse.

Ed Blown Vert · 10-04-2009, 11:30 AM

Did the sound change when you rev'd the engine?

Ed Blown Vert · 10-10-2009, 04:06 PM

Jacked the car up. The sound seems to be coming from the rear of the engine near the converter.

racer7088 · 10-11-2009, 02:13 PM

Check your converter bolts to the flexplate.

Ed Blown Vert · 10-11-2009, 02:48 PM

They all seem to be tight.

Once I get the idle dialed in, I won't even hear it.

muayyadf1 · 10-12-2009, 09:44 AM

looks like it's coming from front or the engine. Something is hitting the timing cover may be

Ed Blown Vert · 10-12-2009, 08:59 PM

CJ came down and helped me try to pinpoint the sound.
He couldn't, so I don't fee so bad.

We started eliminating things. We think the rough idle from the tune is causing the flywheel to make noise. And it sounded alot louder after unbolting the TC from the flywheel.

The engine builder doesn't think its the motor and also thought it was the flywheel.

When the idle is smooth, I don't hear it. So I am not going to worry about it after I get it all tuned up.

Knock from under

Flywheel unbolted from TC

Ed Blown Vert · 10-25-2009, 11:26 AM

A little more research and some say that the ARP Flywheel bolts won't tighten down enough on the stock flexplate. And I would need to buy ARP flexplate bolts. Opps

DaddySS · 10-25-2009, 12:58 PM

That sounds like a good bet

1BADAIR · 10-25-2009, 01:24 PM

with loose Tc bolts the noise normally goes away when in gear and just above idle

daryn c · 10-25-2009, 02:41 PM

try the arp bolts. , whats your motor mounts look like?

G Engines · 10-25-2009, 02:42 PM

You may have a rod hitting the windage tray if its stroked it needs to be spaced to clear.

Ed Blown Vert · 10-25-2009, 03:42 PM

Motor mounts are poly are fairly brand new.

Builder verified the tray is spaced.

So I hope its the flexplate bolts. Last engine didn't have them. This new one does.

Slow50h · 10-25-2009, 03:48 PM

possibly piston slap at idle? My import has slap at idle and right around 3000rpm with no load, but under load she purrs like a kitten. Guess it's a harmonic thing... dunno about on a V8, but on the 4bangers, i dont worry much about slap that low since most of the big pulls are done from 6-10k rpm.