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.

 

pull the dist. and look at the gear.

 

usually if something makes noise awhile it leaves telltale signs behind...WW

 

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”

 

I ran into a similar issue when I installed my 396. I pulled the distributor and measured the end play on the gear. Long story short, I installed a shim and the noise is gone. There was some wear evidence on the gear. The good news was that it was a very cheap fix.

 

I been looking for how much end play I can't find any Info for this also what did you use to shim the end play.

 

I just bought a DUI distributor that came with .035 end play. I read a lot on the subject and ended up calling Pete K for an answer. Pete told me for racing .010 can be used, but for the street .015 is better. You can buy shims from summit racing. You have to knock the pin out, then put the washers on until you get a feeler gauge reading of .015, then tap the pin back in..Below is the washer shim set I used...WW

http://www.summitracing.com/parts/MOR-26140/

It could be your distributor gear jumping thats causing the noise, but the gears are cut at an angle that causes them to pull down on the dizzy gear to keep it from jumping up and down.. Most of the time shimming the distributor gear is used to stop spark scatter at high RPMs..

 

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

WTF thats what I was thinking.

 

if you dont have a mechanics stethoscope, you can take a long ssrewdriver, put the pointy end on the noisy part and put your ear to the other end and get a pretty good idea exactly where the noise is located

 

I tryed the screwdriver trick it was working but I could not pin point the noise tryed the rubber hose gotme in the area closer then tryed the sterhscope the noise is loudest at the Fuel regalator.

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

 

excellent

 

Just Ordered a fuel pressure regulator pulse dampener.

I been chasing this noise for almost a year now.