Valvetrain Noise at Part Throttle above 1800RPM

[93BlkOnGreenPro]

Just as the title states, I'm having a "rattling"(for lack of better words) noise from my head once the engine is around 1800rpm and above, but ONLY when it is part , or light application of the throttle.

Its a brand new (reman'd) head and a new short block. However, when I out the head on, I did (newb mistake) put the HG on backwards and it blocked the oil supply to the head (Chevy HG's only go on ONE way). I drove it like that, not knowing what the issue was, for approx. 250 miles. But fresh oil was getting to the head.

The car runs perfect, but that sound gets to me, as I know its not suppose to make that sound (or is it?). It kinda sounds like the lifters need to be tightened on a sb chevy, but these are adjusting, if I read correctly.

Any ideas? It'll be awhile before I can do anything, but it'll be good to start planning now on what I need to fix, since I need to replace the oil pan gasket, fix the ac, do the rear power windows, paint the tan plastics black, fix the gap from the manual seatblets, etc and I should be able to knock all this out in one day.

So what are your thoughts? I can get a soundclip is yall would like.

[jay]

If you're very lucky it's just a bad hydraulic lifter. It may reinflate after a while, but it should only take a few minutes at most. If you're not lucky, that reman head is about to break a camshaft.

[93BlkOnGreenPro]

Its been doing it for 20xxx miles. Its nothing new. I took the camshalf out of the old head bc I figured that the lobes on the other cam may have wore down due to lack oil to the head. And it doesnt sound like a lifter ticking noise, but more of a rattle type of sound.

And why do you say its gonna break a camshalf?

[gofanu]

"Its a brand new (reman'd) head and a new short block."
"Its been doing it for 20xxx miles. "
?????????????

"it blocked the oil supply to the head"
"But fresh oil was getting to the head."
??????????????????AGAIN!

What planet are you on?
Things don't seem to work that way here.

All that aside, I cannot think of any valve train related noise that is associated with throttle opening. Such noises generally have to do with cylinder pressures, stuff like rod bearings, busted piston rings or pistons, etc.
Or, it could be detonation aka "spark knock" due to too much advance at light throttle.
Is your timing set to stock or have you advanced it as many do?
Any codes set?
Any other strangeness in running?
There are a lot of things the ECU might consider in setting part throttle advance, and bad info from a number of sensors might influence it. Light throttle is where it would be most advanced by the ECU.
I see you said "camshaft". Is it a B8 SOHC?

FRM

[jay]

One cause of a top end rattling noise is due to cam towers not set to correct torque. With varying altitudes of cam tower support, the flex in every rotation can break a camshaft. This noise is easier to hear at part throttle. But it may be that the cams are fine and the rattling noise has far more to do with having been driven for 250 miles with a HG blocking the oil feed.

[93BlkOnGreenPro]

All that aside, I cannot think of any valve train related noise that is associated with throttle opening. Such noises generally have to do with cylinder pressures, stuff like rod bearings, busted piston rings or pistons, etc.

I have a very strong knowledge of cars and what not, and i think I would know if a bearing was bad, or if I had a busted piston, or if I had bad rings bc i would see a definite lack in power. I didn't say that part throttle was the direct cause of the noise, just that is was associated with it.

Or, it could be detonation aka "spark knock" due to too much advance at light throttle.

I know what spark knock sounds like. and This isnt it.

Is your timing set to stock or have you advanced it as many do?

Stock.

Any codes set?

Nope.

Any other strangeness in running?

Nope. I said in my first post that the cars runs fine.

There are a lot of things the ECU might consider in setting part throttle advance, and bad info from a number of sensors might influence it. Light throttle is where it would be most advanced by the ECU.

Irrelevant.

I see you said "camshaft". Is it a B8 SOHC?

Yes.

FRM

One cause of a top end rattling noise is due to cam towers not set to correct torque. With varying altitudes of cam tower support, the flex in every rotation can break a camshaft. This noise is easier to hear at part throttle. '

The cam towers were torqued to the fsm specs, as was the whole engine.

But it may be that the cams are fine and the rattling noise has far more to do with having been driven for 250 miles with a HG blocking the oil feed.

Thats what i was thinking, but what? Would bad or worn valve springs cause a noise like this?

Also, this noise is not all that noticeable. Radio off, windows up, you can hear it. Its not like it a diesel sound (although it did sound like that when I put the hg on wrong). I didn't hear this noise with the old engine, or the 5th gear "whine", but this car has alot of little things that need to be addressed. Non of which are time sensitive.

[jay]

No. If valve springs get weak, you get high rpm float, not part throttle low rpm ratttle. I'd have to guess that the cam bearings didn't like having that hg in backwards. Since they're getting oil now, it might not get any worse, and since there ain't a damn thing you can do about it besides replacing the head, turn up the stereo at part throttle...

[93BlkOnGreenPro]

Cool. Thats good to know. I know I spent that money on my little sound system for a reason.

I appreciate the straight forward, helpful feedback. Now on to turn the radio up!

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