I been trying to find a tapping sound the motor has about 7000 miles on it CC Ultra Magnum pro Steel full roller arms.
The rocker arms do make some noise but this not where the noise is coming from.

I replaced the roller lifters with GM LS7 lifters, Put new push rods in it just in case checked push rod lengths there good and as long I had it apart.

Tried many times to readjusting the valves preload.
The distributor has a Composite gear on it for the Roller cam.

Used the screwdriver to ear trying to find where the noise is coming from just can’t find it you can hear well thought the rear of the plenum area.
At first I was thinking it was a intake valve slamming close but they say the LT4-hotcam should not make this noise because you can hear it in the rear plenum area.

I was thinking it could be a bad bearing in the Distributor it’s pretty loud during cold start up after warms up it is still there but not bad but it is still there.
Just makes me nervous knowing it is not right it has made this noise from day one when fired up this motor.

I don’t have a spare Distributor to find out this is it I want to buy a new distributor but if I have to fork out the money might as well buy a nice one MSD Malory DUI which one to buy the car rev to 5500 RPM’s it is a street car.

I would like the smaller distributor cap makes things easier to get to and work on would be a big plus.

I would just get another HEI distributor... They will run well past 6k, so that's not to worry.

What kind of noise is it? Ticking? Tapping? Grinding?

The distributor shouldn't have a bearing in it to go bad.

Matthew

A tapping type sound it is like you have a loose rocker arm and it slapping on the valve stem.

It only realy can hear it a cold strats after it warms up you can barly notice the sound But I do I know it's there but you have to listen for it.

You sure it's not a reciprocating knock?

I am using Lunati valve spring part #73943.
With LT4 Hotcam do you think this could be where my noise is comming from.
Here are the spec's
Lunati 73943 - Lunati Valve Springs Details
Valve Spring Sets
Description Single Spring
OD 1.266''
ID .883''
Installed Height 1.750''
Installed Pressure 108
Open Height 1.250''
Open Pressure 339
Coil Bind 1.060''
Max Lift 0.630''
Spring Rate 462


Now OEM Hotcam Spring Spec's
LT4 Valve Spring Specifications
Part Number 12551483
Material Chrome Silicon SuperClean
Outside Diameter 1.337”
Inside Diameter 0.906”
Installed Height 1.780”
Seat Load 101 lbs.
Average Spring Rate 331 lbs./inch
Solid Height 1.215”

Imho I would suggest that you pull the valve covers off and take a peek.

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The valve covers off they were off last weekend when I was trying again to find the noise.

Drain your oil and open your filter up.
Check for any filings.

I know it's a long shot (a bad shot at that ~sorry~).....
but I had the same noise (sortta lifter/sortta tin like tapping) on my LT1 last year. Was coming from the rear of my intake. Stethicoped everything (intake/VC/heads/block/pan) and the loudest was up top in my intake. I thought it must be a rocker so adjusted those. Noise persisted after, so then I thought perhaps the oil pump drive gear (like your dist. drive gear). Never opened it up though.

Anyways, few days later oil pressure dropped a little (normally 45.....dropped to 35 or so).....The tapping noise was getting a little bit louder, but still only from the intake area. So I pulled the intake but everything 'looked' fine. Draining the oil found some filings and knew I was in trouble. Indeed I spun two rod bearings.

I've worked on many engines with a bottom end going out.....but this is the very first time it's sounded like that.....like your does.

What oil are you running. I had a lifter problem in my S10, but it was actually a poor grade of oil (quick change place).

I dropped the pan last month and took a look the pan was clean No shavings.

Oil Pressure is great 20 to 30 at idel 50 at cruise speeds.

Like Isaid the motor has 7000 Miles on it now it has had this tapping noise during cold start up from day one.




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I have tryed diffrent Brand of oils no change.

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Do you have forged pistons? They can slap/knock a little when cold until they expand.

Hypereutectic

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Okay this very Weird one the Noise is comming from the fuel regalator.

WTF thats what I was thinking.

I pull the fuel regalator apart I made it adjusable long time ago I removed the adjustment screw and washer that I think was making the noise welded up the bolt hole for the adjuster put it back together much bettter theres some noise still but much better than before.

Just Odered a fuel pressure regulator pulse dampener.

I been chasing this noise for almost a year now.

That's a new one to me.

Me also this sound been driveing nuts for a year now trying to hunt it down.

This sound scared me not knowing whee or what was the cause of it I am on motor number 3 I didn't want to put motor number 4 in the car so soon again.