Lifter problem, noise/knock !???

[Charger1968R/T]

I am new  in this forum, but I hope someone can help me with a headbanging problem.   
Engine spec :

440, 906 ported heads, TRW 12:1 pistons, hydraulic Comp cam nostalgia .509, stock rocker arms. HW oilpump, procomp 850DP. Ign. timing set to appx 38 before at appx 4500rpm.
Everything is new inside engine, the cam was a "complete" set from Comp Cams, timingchain lifters and pushrods.
Pushrod-length 9.315 diam 5/16".

Oil 20W/50W,

And a and short story :

- Cold start, or when the engine idles after cold start, I have idle appx 1100rpm, (the idle mixture 4 corner is not yet perfect, but it is running), it drops until appx 700 rpm when I put it in drive. Then I have no knock or noise.
- When engine hot, I have the same idle in park and 75psi oil pressure, when I put in drive, appx 700rpm, and oil press drops to appx 65psi, then I get a, what I assume, lifter knock. I think I can locate the noise from cyl 1, when I use stethoscope, the noise is clearest from the front left vallypan.
- When I switch to park, the knock disappears completely after about 0.5 sek.

No noise when I rew the engine. And I have not had the car on the road, just rewing in garage.

- Have also disassembled all the lifters, drained them for oil and put back in, checked the pushrods. But still the same when oilpressure drops.

Anyone have some ideas ?? Can it be the pushrods that is a bit to short ? I see comp cam has 9.315"(the ones I have) and also 9.400".

I appreciate all help I can get, Thanks !!

[Cooter]

That's ALOT of compression for iron heads.

[Charger1968R/T]

Ok ??
I have not meassured the compression, but that was stamped on the pistons (domed).

But again, the engine has quick response, so it is only that terrible noise when in park, or low RPM. I also see that the lifter spec. is : Comp Cams High Energy Hydraulic Lifters:Specs – .904" diameter; 109g weight; 1.88" seat height

this is delivered with the cam kit, so again with pushrods 9.315"

Can it then be a combination of short pushrod and low seat high on lifters, that result in nearly fully plunger extention ? That will cause lower pressure when oilpress i lower, or am I totally wrong ?

[Cooter]

I can only assume you checked your piston to valve clearance? Especially with dome pistons? That noise might be the same one I hear in a few of my own 440's. Can't buy good sh*t today. Everybody is outsourcing to China and slapping Made in "USA" labels on their junk. And we/I keep buying it??

[Charger1968R/T]

No contact with valves/pistons. Have not exact messured compression, but I assume it is about 11-11.5 since there is a thicker feelpro gasket mounted.
And the knock/noise only appears when idle drops to appx 700rpm (oilpress is then 60psi, warm engine)

[JB400]

How about describing the sound it makes.  Is it a knock- knock or more of a tick- tick? No, I'm not making knock knock jokes

[Charger1968R/T]

Same as this clip : http://www.youtube.com/watch?v=hWCvuxTPs_8

But goes away around 950rpm. And nothing at top rpm.

[Charger1968R/T]

Or this : http://www.youtube.com/watch?v=043rflfGhNQ

But no sticky lifters, no exhaust leak.

[Cooter]

I can't see a lifter bleeding down with 60 PSI of oil press; but I guess it COULD be...

[cdr]

if running a mechanical fuel pump,i have had a couple through the years do that ?

[Charger1968R/T]

Sorry, forgot to inform that I run electrical pump.

I also have to inform that the finishing fine tune of carb is not done, now it is running a bit rich, and ign timing is appx 35 deg. (with no vacuum), around 20 deg at idle (1100rpm). But my oppinion is that this has nothing to do with that tapping sound.

Also have no thought that it is something with piston(glap), piston pin, main and rod bearing, cam bearing. These foults will also go through the whole, or be at the upper rpm.

Anyone know what is "stock" hight for the lifters ? These I have got from CompCam is : 1.88" seat height
I have read a tread that the "Hylift JohnsonLifters" reduses valve lash, any comments.....?

Could it be that the rockers are worn out ? If I have new pushrods, and a worn rod/rockerpocket seat, then maybee I could have some type missallignment ?? Or am I way off

[cdr]

get some adjustable rockers !!!! good ones

[Charger1968R/T]

You have some recomendation for rockers ??  What about : http://www.summitracing.com/parts/pro-66868

[cdr]

t & d are the best , harland sharp are very good,very pricey ,i have heard good about prw & the comp cams
http://www.summitracing.com/parts/cca-1621-16/overview/make/dodge
http://www.prwonlinestore.com/pqmoparshaftrockersystemstainlesssteel383-440-3244012.aspx

[Charger1968R/T]

Thank you !

Dumb question, but 1.5 ratio, or 1.6 ratio ?? I know I will get higher lift with 1.6, but is there any catch ??

[cdr]

not knowing how the heads are set up ie retainer clearance ,,,,i would go 1.5!!

[Charger1968R/T]

Ok, going for 1.5.

Thanks for all help !!

[Charger1968R/T]

A little update if someone has same problem.
I solved the knock/tapping noise With change the lifters to comp cam antipump up lifters. Still a bit noisy valvetrain cause the anti pump up lifters, (about zero to 1/8 turn preload, almost sounds like mech/solid lifters), but way better than before !!

[Challenger340]

see here about this problem
http://www.dodgecharger.com/forum/index.php/topic,95605.msg1094731.html#msg1094731