Need help from a desiel mechanic

[6.5 rangie]

I just fired up my chev desiel this morning after having some work done on it, and there is a knocking sound i can here, not a bottom end sound, more like an ignition problem. When standing at the exhaust it sounds like someone is hitting the exhaust with a hammer (say every time no 6 fires).
This sound happened 3 out of the 5 times i have started it. The injecters where rebuilt 12 months ago, but the motor has not been going since march. Prior to having the work done on my engine it ran fine, no noises. Had to get some work done because the oil pump shit itself (loosing oil pressure when warmed up) But everything measured up good and no damage was done.
Was just wondering if this could be an injecter problem as the where sitting around for so long and may have gotten dirt in them or something, or if this could be a timing problem????

Damien

[Newhouse]

One thing you can do to check your injectors is the next time its running go along and "crack" each injector. What I mean by this is slightly undue the inlet to each injector, one at a time. You should here a difference in engine noise. If there is no change at one cylinder then most likely that injector it pucked.

[6.5 rangie]

Was going to do exactly that, was just after some advice. In the rerpair manual it says the following things for knocks are',
Injecters (most likely)
incorrect fuel (its definately desiel but it 9 months old)
injecter pump (its recoed, done 4 hrs work)
Rings (new)
Bearings (new)
Timing advanced (timing set correct, statically timed but not not dynamically timed)

Damien

[6.5 rangie]

Okay, I checked the injecters and they are all fine. The noise seems to have become alot quieter now BUT now i seem to be back where i started, when the motor warms up i loose oil pressure, when cold its around 220-250kpa, after a few minutes it drops to almost in the red (may'be 80-100kpa), rev it up to about 1500-2000 and it reaches 250kpa which is a bit low for that rev range, and then i shut it off.
Just had all the tolerances looked at and replaced the oil pump just to be on the safe side and now its still doing it. Got me stuffed why its doing this, but would love to know
Could it be the oil i have used, its Shell Helix Desiel 15-40w API CF/SH. once it gets hot it maybe to thin?

[mkpatrol]

Whats the specs for oil pressure for that engine?

A lot of the older designed US engines will run very low oil pressure at idle when warm, some times as low as 3-5 psi.

[shakes]

incorrect fuel (its definately desiel but it 9 months old)

your fuel hasnt gone off?

[Zute]

Does the oil filter have a bye pass valve ? filter may be gummed up.

[6.5 rangie]

Oil problem fixed i think, changed the oil to 20 - 60w Penrite Desiel as recommended buy Brunswick Desiel.
When it warms up though there is still that knocking sound, BD think it is either piston slap or a cracked piston.
Thats what i get for not getting a specialist to build it.

Thanks for your help
Damien

[Ruggers]

there could be air in the lines lines or a dirty injector from sitting around try bleeding them again at all points if it is a cracked piston then it should go away on that cyclinder and piston slap normal only happens cold unless engine is pretty worn

[Shadow]

I would also try dumping your diesel and getting some fresh stuff.

I know when I get a bad batch of diesel my engine is alot noisier.