delta_88_germany

Hey
I have a problem, when engine Is hot after 15 min driving i got a Loud knock knock Sound from the engine... Seem that something ob the valvetrain is wrong.

I checked the Rocker Arms and measured compression - everything fine!

Does anybody have an idea!??


Here is a video

Alex

oldcutlass

Not very good sound of the knock coming on my laptop.

delta_88_germany

Here is a 2nd video i Made

oldcutlass

Is the noise coming from under the valve cover?

delta_88_germany

Not clear but seems to comming from unnder passenger side valve cover...
I checked under the cover no rocker Arm has Play,,,

442craig

Is it hitting the valve cover? Any dents or scrapes on the inside?

don71

Yea, it sounds like a rocker arm is hitting a baffle.

I would be looking for any "witness marks" on the inside of that cover.

delta_88_germany

hey
the arms and cover are fine. i also checked the valve adjustment all nurs are tourqued right down....

maybe can be a lifter has an issue `

oldcutlass

You need to try and isolate the noise before trying to replace or repair things. Did you run it with the valve cover off to see if it made noise?

classicmuscle442

Sounds like a lifter.

delta_88_germany

i tried... its not comming from under the valve cover....

how can i identify a lifter?

also when driving abound with 49 mph its makes a fast not very loud tick tick tick sound ...

i also tied disconnecting each zylinder but does not affect ehe sound in idle ...

Oldsmaniac

It sounds external to me, hard to say....

delta_88_germany

i am sure that this is from the engine not from the accessory
i checked under the cover and every rocker arms looks moving correct...

if you are refering to the sound it seems that the knock is komming every 8 th turn... so its comming 1,5 times a second...

which pinthe to be a lifter

my other thought is that it could be a bearing issue like this guy in the video has... but his knock is way mor often then mine ...

so may i should replace all lifters ....
if the sound still appear is must be a crankshaft - rod bearing issue...

delta_88_germany

so the weekend is over and the engin is running smooth :-)

i replacend the lifters and rocker am studts to go to a adjustable vlave train..

the engine makes no chattering or ticking sounds, more quiet then ever :-)

used this instruction to set valve lash
http://www.boyleworks.com/ta400/psp/rockers.html

thanks