Diesel pump advance

bikeboyz · Post by **bikeboyz** » 30 Sep 2004, 02:43

I have been advised that I need to advance my diesel fuel pump on its adjustment bolts. Its the Roto/CAV type, the Haynes comic really doesn't give any help at all. Is it as simple as marking the current placement of the pump against the housing, slackening and turning, and trying? I need to advance it to eleminate lots of white smoke I get at the moment. There is a manual fuel advance which can be operated at under 2000 rpm, which clears all the smoke.

rotodiesel · Post by **rotodiesel** » 30 Sep 2004, 03:41

The mechanics of advancing the timing are as simple as you describe, but I would very strongly advise you to do the job properly which means using a DTI. Ad hoc bodges are not a good idea here - over advanced timing can be destructive.
rotodiesel.

bikeboyz · Post by **bikeboyz** » 30 Sep 2004, 14:10

Well the "old girl" is 26 years old, with no current mot and appears to have a lego set of parts to make up the engine. With Lucas quoting a rather astronomical amount of money for this, more than a good second hand XD2 engine I've not much to loose!

woody-som · Post by **woody-som** » 01 Oct 2004, 00:58

its simple, and AFAIK, most garages, including a diesel specialist I went to once do most of this by trial and error.
I saw them do it to an engine of mine, because it smoked after a re-time.
All you do is slacken the 3 bolts on the end of the pump that hold the sprocket on. Only a little mind, and rotate the centre of the pump(spinde) either forwards or backwards. Tighten the bolts then try it, and see if its any better. hopefully the bolts are in the centre of the slots at the moment.

Brilec · Post by **Brilec** » 02 Oct 2004, 15:18

On the older pumps, the adjustment is made on the pump flange. Slacken these three nuts, and check that there is not another at the other end of the pump, under the high pressure connectors.
Then, as you say, mark the flange and rotate pump body to advance the timing. Do it by ear, advance it until you hear a knock, then back it off a touch.
White smoke from a diesel is unburnt fuel, almost always caused by retarded injection timing.
If you end up moving the pump much, it might be an idea to slacken off and re-tighten the high pressure connectors when you have finished, (and stopped the engine), in order to relieve the strain on the pipes.

mote · Post by **mote** » 03 Oct 2004, 22:58

I have the lucas/cav/rotodiesiel pump on my 205.
When you talk of manual fuel advance operated under 2000 rpm are you talking about the thing behind the little round panel in the side of the pump facing the front of the car? Or the idle adjust setting? Or something else?

bikeboyz · Post by **bikeboyz** » 03 Oct 2004, 23:48

The manual fuel advance, is a knob on the dash board. When you pull it out, you rotate a control screw on the side of the pump. The design is basically the same as your 205 one, but this feature was done away with in later years.
Thanks all for the current info, bought the allen key socket to slacken the pump.
Now Brilec says until I hear a knock then back it off a touch, I take it you mean do this with the engine running?? or move start and listen, switch off and do it again?
thanks

Brilec · Post by **Brilec** » 04 Oct 2004, 04:48

Do it with the engine running - slowly.
Ideally it ought to be at working temp, but this may not be possible. However, it would be worth just listening to it when it has warmed up to make sure it is not too rattly.

bikeboyz · Post by **bikeboyz** » 07 Oct 2004, 00:55

Thanks for the advice. I have already adjusted the valve clearances (push rod, no shims here!) so I know that the noise is genuine! I will let it run them until the thermostatic fan kicks in and give it a go.

bikeboyz · Post by **bikeboyz** » 11 Oct 2004, 03:46

Tried this today, slacked off the pump, mine has 6mm hex screw, what a b******d they are to get at

couldn't figure out why I couldn't move the pump even when all three nuts were slack. The comic book then actually for once gave it away, a hidden bracket, and I should have taken more notice of the message above. Trying again in the morning when the Gin is out of my system!!

)

bikeboyz · Post by **bikeboyz** » 12 Oct 2004, 01:03

Bingo, now hardly any smoke, it took quite a bit of twisting and I have to disconnect the delivery pipes to the top of the injectors. Hence couldn't do this with the engine running. Next question ; any MOT testers here? The old girl is exempt from free load max revs smoke test, being visual only. What is acceptable "visual" smoke?