LT5 Assembly Project

[LGAFF]

Well if you share the good, you have to share the bad, its part of the experience of building a motor. At Bloomington, Pete and Marc saw the car. I have a ticking noise, which I dismissed as a fuel injector as the prior motor had the same ticking.

Marc and Pete thought it might be 1)failing lifter 2)not enough pre-load. Keep in mind they only had sound to judge....they did not inspect the car.

My finding is that when the stethoscope is placed against the cam cover, no ticking, against the cam bolt it there is a quiet ticking but not to the degree of the sound you hear outside the car.

With the stethoscope on the header the ticking can be heard. It is more pronounced on 1 and three tube and can be heard when stuck in the area where the primaries meet the collector. The sound is only on the D/S.

*There are new Sealed Power made in the USA lifters
*The lifters actually supplied too much load prior to checking with regrinds
*I have watson headers w/emissions tubes
*All header bolts are tight, no signs of leaks
*Oil level is correct
*Cold startup pressure is 75 PSI
*Warmed up pressure is 30-35PSI at lopey idle
*O2 is tight.
*Removing serp belt did not fix the issue, so not an accessory

I have read other threads on LS motors and DOHC engines and they experience what is referred to as header tick.

Let me know your thoughts...

Next step plan is to remove the header and look for issues, holes, etc.

[XfireZ51]

Originally Posted by LGAFF

Well if you share the good, you have to share the bad, its part of the experience of building a motor. At Bloomington, Pete and Marc saw the car. I have a ticking noise, which I dismissed as a fuel injector as the prior motor had the same ticking.

Marc and Pete thought it might be 1)failing lifter 2)not enough pre-load. Keep in mind they only had sound to judge....they did not inspect the car.

My finding is that when the stethoscope is placed against the cam cover, no ticking, against the cam bolt it there is a quiet ticking but not to the degree of the sound you hear outside the car.

With the stethoscope on the header the ticking can be heard. It is more pronounced on 1 and three tube and can be heard when stuck in the area where the primaries meet the collector. The sound is only on the D/S.

*There are new Sealed Power made in the USA lifters
*The lifters actually supplied too much load prior to checking with regrinds
*I have watson headers w/emissions tubes
*All header bolts are tight, no signs of leaks
*Oil level is correct
*Cold startup pressure is 75 PSI
*Warmed up pressure is 30-35PSI at lopey idle
*O2 is tight.
*Removing serp belt did not fix the issue, so not an accessory

I have read other threads on LS motors and DOHC engines and they experience what is referred to as header tick.

Let me know your thoughts...

Next step plan is to remove the header and look for issues, holes, etc.

Lee,

I thought it sounded like an exhaust leak when I heard it. Motor was running well. Could explain the O2 differential.

[LGAFF]

I am hoping, I would think I would hear more through the cam cover if it were a lifter.

[mike100]

use a small diameter vacuum tube rather than the stethoscope to find exh. gas leaks. stick one end in your ear and run the other open end along the header flange and all pipe weld joints.

as an example of how easily you can hear the smallest airflow, blow across the tube to test it out. You will find a small leak this way.

[LGAFF]

This is the same sound I have

http://www.youtube.com/watch?v=GrNfAOiP85E

[mike100]

Originally Posted by LGAFF

This is the same sound I have

http://www.youtube.com/watch?v=GrNfAOiP85E

Well then... try lugging it up a hill in 3rd gear and tell us if it gets louder. If it makes the same noise coasting downhill as it does under load, it might be mechanical.

exhaust leaks will get louder after some time also eventually making it too easy to not find.

[LGAFF]

Pulled the header off, is this a big enough hole to cause a tick, its in the air tube

[XfireZ51]

Originally Posted by LGAFF

Pulled the header off, is this a big enough hole to cause a tick, its in the air tube

No not big enough. You need to make it bigger!

[-=Jeff=-]

yes it could make a tick, I had a hole like that on an older Camaro once.. it had a tick too

[LGAFF]

Thanks Jeff..off to the welders..