Timing Advance On A Diesel? (Specifically Xud(7))

[shorty_15-92 1]

I have been told by advancing the fuel pump on a diesel, you can gain a couple of bhp and mpg.

 

Basically, what are the advantages and disadvantages of advancing/retarding the fuel pump/injectors?

 

I know how it works i a petrol engine. Am i right in thinking, with a diesel (as there is no spark) it is when the fuel is injected?

 

If i were to advance the pump, would it be simply turning it back a tooth on the timing belt, or is it a bit more complicated?

[Tom Fenton 1,542]

I am fairly sure the mounting holes that fix the pump to its bracket are slotted and so allow for some adjustment. Advancing the pump is a fine line as too much and it will diesel knock very loudly e.g. sound like the crank is trying to get out, also increasing the advance will make it harder to start.

 

1 tooth on the belt is too much, it will just about run but sound awful. You can do it by ear really but to be honest don't expect to gain much.

[Paul_13 212 1 Cars]

The mounting holes are slotted on the pump bracket, one of them is an arse to get to .

 

But to be honest I wouldn't bother, if you're after more power fit a 1.9 dturbo engine from a 306, 405,406 etc

 

Ryanstdt advanced the timing on his engine and it threw a rod through the block

Edited January 14, 2013 by Paul_13

[Strictly_Derv 34]

Unless your running 200bhp I don't see the point in touching the advance on XUD's. I'm guessing your on a standard '7 lump so if that's the case just give it a stage 1 tune. You can easily achieve 120bhp on the engine as it is with just a few tweaks to the fuel pump and wastegate. but watch out for heat soak.

[Uberderv 6]

I have only heard of advancing the timing when veg oil is used as it aids starting.

Its done by moving the pump on the bracket as mentioned. Doing the stage 1 tune will net a good few extra HP. Also grinding the LDA pin is a good free mod.

[jamie_1992 66 1 Cars]

I used to do this on my 306

Undo the 3 bolts around the pump and one on the bottom the rear ones is an arse use a long extension and a uj then when there all loss ( don't take them right off ) get someone to start the car while you hold the pump

You advance it by pushing the top of the pump towards the engine do this till you hear a knock the back it off slightly. Then turn the engine off and get your mate to tighten the bolts in place while you still hold the pump .

You may need to crack the lines off if you move it a lot

If you are after more bhp I would also turn the fuel and boost up first

Is it a Lucas pump or Bosch ?