326 Startup.... Bad Knock...

[Makdaddy]

A gap between the head and header could create the same noise and go away when everything warmed up and expanded.

Stock manifolds or headers? If headers did you use any gap be gone (orange high temp rtv) between the header and gasket?

You used rtv on the exhaust manifold gaskets? Did you clean/and how the mating surface for the exhaust manifold gaskets?

^^^^^^ This

It did sound like an exhaust leak

 

[obxdude018]

Hopefully for the OP it's an exhaust leak, when my passenger side sprouted a leak, it was quite loud and got even louder with rpm's and never diminished once the engine was warm. However though, I wouldn't of used RTV as a gasket, the oem metal gaskets are extremely good quality.

 

[BruceH]

I doubt it's an exhaust leak, when my passenger side sprouted a leak, it was quite loud and got even louder with rpm's and never diminished once the engine was warm. However though, I wouldn't of used RTV as a gasket, the oem metal gaskets are extremely good quality.

Some header manufacturers suggest using copper rtv along with the gaskets. The JBA headers I'm currently running suggest it and the Mac headers I'm about to install are going to need it because of manufacturing tolerances.

Stock manifolds are ground fairly precise so it wouldn't really be needed with them. As long as factory studs were used and torqued per spec there shouldn't be an exhaust leak. If header bolts were used then they could be loosening. If a torque wrench wasn't used then there could be insufficient sealing due to not enough or too much fastener torque. It's just something that's quick and easy to check and eliminate.

 

[obxdude018]

Some header manufacturers suggest using copper rtv along with the gaskets. The JBA headers I'm currently running suggest it and the Mac headers I'm about to install are going to need it because of manufacturing tolerances.

Stock manifolds are ground fairly precise so it wouldn't really be needed with them. As long as factory studs were used and torqued per spec there shouldn't be an exhaust leak. If header bolts were used then they could be loosening. If a torque wrench wasn't used then there could be insufficient sealing due to not enough or too much fastener torque. It's just something that's quick and easy to check and eliminate.

The gaskets that came along with my LT's were that woven fiber(can't recall the name of the material), whenever I finally got the passenger gasket out it fell out in about 9 pieces, then I just made a assumption that oem metal's would be a better fit.

 

[Dark_horse]

Copper rtv was used along with the oem mls gaskets along with factory studs... all torqued properly... if the boss block had a poor machined finished I sure as hell didnt notice it... i put the manifolds on while it was still on the stand....

 

[psfracer]

Yeah, I don't know. Exhaust leaks don't "go away". They will get louder on acceleration, and quieter during de-acceleration, but in all the years I have had exhaust leaks, I have never had one go completely away when the engine gets up to operating temp. It may quiet down some, but as soon as you accelerate, you can hear it easily.

 

[weather man]

Copper rtv was used along with the oem mls gaskets along with factory studs... all torqued properly... if the boss block had a poor machined finished I sure as hell didnt notice it... i put the manifolds on while it was still on the stand....

I would make sure all easily checked items are rechecked, but they may have assembled on the far side of acceptable tolerances.

 

[rzaenglein]

How about the oil pump? Looked like the stocker from the picture. It sounds like valvetrain noise to me. That would kinda explain why the noise goes away at rev, do to the increase in pressure also when it warms up because the oil thins out. Would also explain why the noise was not there with the new primed lash adjuster for the first 3 to 4 seconds of start up. Just a thought.

 

[Dark_horse]

Oil pump is a frpp pump with tss billet gears...oil pressure is around 70 on cold startup I would think that is plenty unless the manley springs are too stiff...

Soo who thinks letting it warm up and driving it would be a good idea? I hate starting it knowing my window to get the rings seated slowly disappears everytime...

Maybe get the rings seated and get my breakin in miles done.. then switch to a thicker oil??

Sorry if it sounds like im clueless im just running out ideas and what is the proper direction I should take??

 

[Makdaddy]

Oil pump is a frpp pump with tss billet gears...oil pressure is around 70 on cold startup I would think that is plenty unless the manley springs are too stiff...

Soo who thinks letting it warm up and driving it would be a good idea? I hate starting it knowing my window to get the rings seated slowly disappears everytime...

Maybe get the rings seated and get my breakin in miles done.. then switch to a thicker oil??

Sorry if it sounds like im clueless im just running out ideas and what is the proper direction I should take??

For what its worth we just put new heads with new 105lb springs with a new SC and a set of headers.
On my sons 3800
On start up the lifters sound real bad, we freaked and shut it down, the started it again it still ticked like crazy.
We pulled the valve covers double checked all the torque settings on the new roller rockers
Had oil up top everything looked good
So I told him let's push it out of the garage start it and let it run for 10 minutes

After 10 minutes maybe more like 5 the lifters pumped backup, engine was quiet and runs strong.
We figured new stronger and tighter springs caused the lifter issue
So you may be on to something

 

[BruceH]

How close are you to just accepting it? I don't think this has been covered but it's one more straw to grasp. Are the phasers locked out?

 

[Dark_horse]

I may start it without the valve covers on and just double check that the heads are getting oil flow as they should

 

[Dark_horse]

How close are you to just accepting it? I don't think this has been covered but it's one more straw to grasp. Are the phasers locked out?

Phasers are locked out

 

[UltraKla$$ic]

Run it!

 

[Wes06]

Run it!

Coming from you this is just comical

 

[Dark_horse]

Run it!

Lol...not sure if serious

 

[weather man]

Lol...not sure if serious

Sounds like you are at the point of tear it apart and measure everything twice or....run it.

I would say use another shop to check specs, it you go that route.

 

[psfracer]

Do you have the engine specs from the builder? Piston to cylinder wall clearance is?

So you replaced the lifters and followers
You replaced the starter
You verified oil pressure
You verified its not an exhaust leak--as in the gaskets are intact, and no evidence of a leak anywhere? (Integrity of the gaskets/silicone, any discoloration anywhere? all header bolts torqued?)
Phasers locked

Have you shown your video to the engine builder? Is the builder local? I still say if this is a result of some mechanical failure then the noise would not go away after a few minutes.

Since the phasers are locked, you could try a thicker oil also--just talk to your engine builder first.

 

[crownaviation]

Do you have the engine specs from the builder? Piston to cylinder wall clearance is?

So you replaced the lifters and followers
You replaced the starter
You verified oil pressure
You verified its not an exhaust leak--as in the gaskets are intact, and no evidence of a leak anywhere? (Integrity of the gaskets/silicone, any discoloration anywhere? all header bolts torqued?)
Phasers locked

Have you shown your video to the engine builder? Is the builder local? I still say if this is a result of some mechanical failure then the noise would not go away after a few minutes.

Since the phasers are locked, you could try a thicker oil also--just talk to your engine builder first.

Pretty much nailed all the things that "normally" are the problem.. OP did not state the ptw clearance.

High rod angles (stroker), 2618 and a huge ptw would possibly do it.. Just not many other ways to explain why it goes away warm.

I would definately be knocking on the builders door for some specs.. or tearing it down myself to check. See if you can come up with a scope and check the cylinder walls before you take anything apart tho. Think that was mentioned here already

You are right about those rings tho.. I would still be leery of putting a big load on it, especially the way I prefer to break them in.

 

[Dark_horse]

Do you have the engine specs from the builder? Piston to cylinder wall clearance is?

So you replaced the lifters and followers
You replaced the starter
You verified oil pressure
You verified its not an exhaust leak--as in the gaskets are intact, and no evidence of a leak anywhere? (Integrity of the gaskets/silicone, any discoloration anywhere? all header bolts torqued?)
Phasers locked

Have you shown your video to the engine builder? Is the builder local? I still say if this is a result of some mechanical failure then the noise would not go away after a few minutes.

Since the phasers are locked, you could try a thicker oil also--just talk to your engine builder first.

Yes to all the above mentioned... my engine builder is todd maschmeir who is currently defending his drag week title... im going to have him stop by when he gets back and has time... when I called him and told him whats going on..he watched the video and said welcome to racecar motor 2618 pistons...