4BD1 engine rattle

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Originally Posted by Lost Landy

Well I am certianaly having dramas finding a place to get new parts from tryed FWD motors, Queensland Diesel Spares, and a few other places with no luck :mad: does any one here happen to know from past experance where i can get the parts i need from? looking at all options from replacing the offending piston/sleve + bearings to the full over haul kit!!

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As above - Isuzu are often the cheapest (in AU).
Otherwise Don Kyatt.

Or ebay: ISUZU NPR 3.9 4BD1 4BD1T 1985-1991 ENGINE REBUILD KIT | eBay

Well thought ill give you all an update to whats been happening. After I removed the cylinder head i cound see damage to the upper surface area of pistion No2 so i pulled out the piston and could see where a chunk on piston was missing about the size of your thumb nail as well as half the upper commpression ring missing.
I was going to go with just 1 new liner & piston and do a quick fix but decided not to instead a full engine over haul was done.
I had 4 new pistons/rings & liners fitted.
New Big end bearings & mains.
Crank was linished was there were a few small burrs found.
Replaced all seals.
Also to be on the safe side I got all 4 injectors over hauled and while at it got the injectior pump over hauled.
So now i have the peice of mind that the old truck will be reliable for a few more years.

having once owned a Series 3 with a 4BD1 that had never had the head off it, with only had 950,000 km on the clock, I though that all Isuzus rattled :D:D:D



Wasn't it suposed to rattle??? I thought that rattle was normal!!!

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Originally Posted by JohnF

having once owned a Series 3 with a 4BD1 that had never had the head off it, with only had 950,000 km on the clock, I though that all Isuzus rattled :D:D:D



Wasn't it suposed to rattle??? I thought that rattle was normal!!!

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The engine version used in stage 1's seem to be the worst culprits. The version used in Isuzu trucks is much better, with accoustic measures in several locations, and was further improved late in 1988 with other changes for improved combustion.

Knock from direct injection diesels mainly results from the rapid cylinder pressure rise due to high fuel flow rate during the ignition delay period at low engine rpm.

The high fuel flow rate helps produce the high cylinder pressure at top dead centre required for high torque, it also creates high NOx pollutants.

Modern diesels use the engine managment computer to control the injection rate during the ignition delay period, then ramp it up for torque.