300Tdi sudden noise

**Michael2** · 19th July 2015, 06:45 PM

I replaced the Injector Pump on my 300Tdi with a Bosch Factory refurb unit.

I made the following adjustments because it's running a VNT :
I turned the star wheel 90 degrees clockwise to reduce preload on the diaphragm
I turned the plunger pin to give the most concave face to the fuelling pin

I noticed a very slight increase in noise and very slight decrease in power, but figured it needed some fine tuning for the VNT.

I drove some hilly country this morning and all was fine, EGTs (pre turbo) got to 450.C by the top of a hill climb, no black smoke, 17psi boost, and no overheating in the engine 63.C.

On the way home I decided to put my foot to the floor and it started making what sounded like a loud tappet sound. It was REV related, not related to load (up or down hill the noise remained unchanged) and it was reasonably quiet at idle.

EGTs remained at around 300.C, engine temp at 63.C (block temp) and I kept the revs to around 2,000 to reduce the clatter, still pulled okay in 5th at 2,000rpm. No smoke - so if anything I think it's under fuelled given the low EGT as well.

I got home in the dark, so to check it in the morning.

What might it be?

I'll look at tappets and recheck the timing to make sure it hasn't slipped a tooth. I've pulled the rocker cover off and nothing looks broken.

What else should I check for or be wary off? The motor's done 305,000. I've done the last 195,000.

**roverrescue** · 19th July 2015, 06:57 PM

injectors / fuel lift pump / vacuum pump / tappets

can all sound like "tappets"

start eliminating

Steve

**Michael2** · 19th July 2015, 07:14 PM

Originally Posted by roverrescue

injectors / fuel lift pump / vacuum pump / tappets

can all sound like "tappets"

start eliminating

Steve

Thanks Steve,
The Injectors are about 100,000km old, so pretty new in the scheme of things.

I'll put a stethoscope to each component once I've done the tappets and double check.

Is there anything likely to bring on a sudden onset of "tappet" noise?

Should I re-bleed the injectors? I thought they were self priming and just cranked the motor a few times with the injector line tops loose before tightening them when I re-installed the injector pump.

**rangieman** · 19th July 2015, 08:18 PM

Did you happen to knock one of the lash caps off while doing the tappets

**Michael2** · 20th July 2015, 11:43 AM

Originally Posted by rangieman

Did you happen to knock one of the lash caps off while doing the tappets

yep, two caps missing

**Michael2** · 20th July 2015, 01:35 PM

replaced all 8 caps, but the noise is still there

**Michael2** · 20th July 2015, 02:44 PM

Roverland thought it was tappets, definitely sounded top end.

I replaced all the lash caps (2 were missing), but still had the noise.

I removed the rocker assembly and push rods, there was no evident damage. Replaced and re-set the tappets, the noise is still there. It's quiet at idle but a noise that matches a tappet movement on higher revs.

Any ideas? Please.

**Ancient Mariner** · 20th July 2015, 03:16 PM

The missing lash caps? found or making a noise ?

**SSmith** · 20th July 2015, 04:10 PM

Originally Posted by roverrescue

injectors / fuel lift pump / vacuum pump / tappets

can all sound like "tappets"

start eliminating

Steve

Find those missing tappets and move on to the next item. Id be looking at the fuel system seeing as it was disturbed during the inj pump swap.

Sent from my GT-S7562L using AULRO mobile app

**jboot51** · 20th July 2015, 04:41 PM

There was a post on here somewhere, where a lash cap had fallen down beside the pushrod and caused a bit of trouble.

Found it.
300tdi pushrod damage - cause?

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