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#1 4.2 knocking noise

Posted: Sun Sep 29, 2019 3:16 pm
by JD-JAG66
Starting doing some test runs.
The 4.2 engine runs and accelerates very smoothly (originally from a 84 XJ6)with a Mangoletsi injection system. Unfortunately I have this knocking noise coming from the front of the engine, which is rather annoying.
Oil pressure is +/- 20 psi at hot idle.
I have made a short video, but can't find the youtube insert function.
I hope that the ignition light switching on and off several times during the short runs, does have nothing to do with this? Battery charge is hovering at 12V during idle.
Any idea's or suggestions would be most welcome.

Thx
Jan

#2 Re: 4.2 knocking noise

Posted: Sun Sep 29, 2019 7:29 pm
by politeperson
Slack timing chain?

Very easy to fix in a few minutes.

#3 Re: 4.2 knocking noise

Posted: Mon Sep 30, 2019 10:10 am
by sk99
Take the fan belt of and check so its not the water pump or alternator.
If upper chain is ok, maybe the lower chains hydraulic tensioner is the reason?
Is the oil pressure ok at normal running?

#4 Re: 4.2 knocking noise

Posted: Mon Sep 30, 2019 10:35 pm
by JD-JAG66
Cheers, Will check that out this weekend!