knock??

[Daisy]

OK....

for those who dont know.. i am hearing impaired.. so please... any questions in relation to sound.. i may not be able to answer correctly...

I rebuilt my 4.2 diesel engine approx 8000kms ago.

After coming home from round 1 of WERock it was left at the haultech backyard for 4 weeks waiting on parts (new tyres etc)

Checked oil, etc and then started it.. it had a slight rough idle.. so i gave it a lil bit of a rev to 2500 , then proceeded to drive it up (20 metres) to the front yard where RUFF was working...

He commented to me that he can hear a knock comign from the bottom end.. .. it shook me a bit... coz i dont like things that i cant hear...

Little tom - my gfs brother told me that he heard it as well... and we investigated it a bit futher...

Ive worked out so far....

It only does it when cold...

knock onlys tarts after 2500 rpm when cold.. i leave it running for a few minutes before moving off to allow the engine to get warm first... - still a knock edible after 2500 rpm,, once temp has reached to just under 1/4 - it goes away..

I am prepared to rip the sump off and replace the bearings if i have to which i may do this week before goin to 4x4 expo.

What im lookin at is peoples opinions.. it uses Castrol oil... and im plannin to change that oil to a different type as i feel it may be contributing to the problems..

What do you think fellas???

when its warm.. its no problem at all.. no roughness.. revs right up to 4000 rpm no worries...

It has a GU turbo fitted to it..

And im plannin on an intercooler over the next few weeks in it and dont want to to proceed with it until i know the engines 100 percent problem free.

THanks in advance...

TOM

[adam.s]

As it's temp related, changing to a different oil might well help.

I'd try doing that first before ripping it apart.

[DieselBoy]

Could just be an injector, as you said its rough when cold and thats when it does it. If the oil pressure is as it should be when cold, checked with a proper gauge, at 2500 rpm, then chances are your bearings are all good.
Injector knock is present worst when cold. All these sounds transfer through the sump as the loudest point.
You could try loosening injectors aswell.
Just my thoughts,
Pete.

[Daisy]

Thanks fellas

isolated the problem..

5 injectors were loose...

retightened them and its running awesome

TOM