Ls3 idle and possible exhaust leak

[Sean1985]

I just finished up a ls3 525hp and a tremec swap in my 67. I probably put about 100 miles on it with no issues. Changed the oil once and it looked great.
A couple days ago I started to hear a light tick and really thought nothing of it. I got on it a little to about 4500rpm in 2nd gear and it got worse. I immediately thought it was a exhaust leak so I swapped the headers gaskets and tightened down the collectors. Still the same.

I found the Evap line was rubbing the idler pulley and it wore a hole in it. So i capped that off and the same thing. The rpm is a little spiratic. Sometimes is stays at 2000 rpm when I start up or if I rev it a little.

At this point I'm a little stumped. No check engine light and I don't have a tool to plug into. Not sure if I need the Evap. The harness does not have a plug for it. Any help would be great. Thanks.

[GMC-YA68]

Not saying this is your case, but in a previous swap I had an oil pump o-ring go bad and was causing ticking. Got worse as the oil warmed up.

Was this engine a pull out? Using the factory LS3 exhaust manifolds? It's possible they could have been cracked in the wreck.

[BR3W CITY]

Put a screwdriver on the valvecover and tell me if you can feel the tick through it. (older guys should understand what I mean by this).

If its valvetrain noise or lifter tick, you can usually feel the mechanical *tick*in the vibrations of the motor.

If your using a tube header (anything buy a cast manifold) which has a thin material thickness, you will hear much more noise than you would with a cast manifold. Its not actually valvetrain noise, its hearing the valve operation from the header side.

I'm not second guessing you, but are you SURE this is a new noise? 100miles isn't a ton of time to get familiar with all the noises/strains/whistles the engine and truck will make at various speeds and rpm. A hot motor will sound different than a cold one, and if there was any fresh build work, the breakin period will change the sound as well.

[Sean1985]

Just a little update. Took it to gm since the motor is brand new and so far they found a loose rocker arm and broken valve spring. They're still digging into it. Pretty crazy. I followed th break in procedure perfectly. So far the dealer has been super honest.

[zach_carver]

Wow wouldnt of expected that.. Atleast they are figuring it out!

[66ChevyMax]

Glad you took it in and progress is being made

[solidaxel]

Were you using the GM warranty that came with the LS from GM?

[Sean1985]

Yes it's under warranty from gm. Also just got word they replaced valve spring and rocker arm. Same thing. Replacing lifters which is what I thought was the problem. I've heard some lifter issues with the ls3.

[solidaxel]

Originally Posted by Sean1985

Yes it's under warranty from gm. Also just got word they replaced valve spring and rocker arm. Same thing. Replacing lifters which is what I thought was the problem. I've heard some lifter issues with the ls3.

I guess I better fill out my warranty card and send it in!

Just paid for a LS-3 (19301326) but do not have it installed.

How long did you have the engine before you started it?

Is there a time period on these new crate engines, and does it start with delivery date?

[Sean1985]

Originally Posted by solidaxel

I guess I better fill out my warranty card and send it in!

Just paid for a LS-3 (19301326) but do not have it installed.

How long did you have the engine before you started it?

Is there a time period on these new crate engines, and does it start with delivery date?

I had for about a 6 weeks before I started it. I didn't get a warranty card. Just took my receipt with me. I ordered it from jegs. As soon as I got the motor I did a Holley oil pan and then primed the motor while it was on a stand. Then I primed it again before start up.

[solidaxel]

That it !
Your Chevy dealer sounds like a great outfit!!

[Sean1985]

Bad lifter and this was my push rod. Took 2 weeks but everyone was super cool and did a great job

[72MARIO]

How do you prime a ls engine ? Glad the dealer took care of the problem nice to see a warranty actually mean somthing

[Sean1985]

Originally Posted by 72MARIO

How do you prime a ls engine ? Glad the dealer took care of the problem nice to see a warranty actually mean somthing

I primed it with a oil primer tank. You put the oil in the tank and fill it with compressed air. I took out the oil pressure sensor and bought a fitting for it. Then I took my Holley oil pan and drilled and tapped the block off port to accept a 1/8" pipe tap. Then put a gauge in it. I did a mechanical guage when it was in the garage then I hooked up my Dakota digital guage when it was in the truck.

[66ChevyMax]

You can also turn the motor over without the ECU being hooked up. I did this with my gauges hooked up, took about 5 hits with the starter before I had oil pressure.

Originally Posted by 72MARIO

How do you prime a ls engine ? Glad the dealer took care of the problem nice to see a warranty actually mean somthing

[66ChevyMax]

That is one sad looking push rod, glad you got her fixed up.