Advance Pump Timing Query ??

sooty · Post by **sooty** » 19 May 2005, 03:40

Is there any benefit of advancing the Injector pump timing by a degree or two to gain better response and torque, as you do with petrol engines. ????
I know it might be more clattery, but I think I've read somewhere there are benefits to be gained.
More from the black stuff ????????????
[:D]

JohnT · Post by **JohnT** » 19 May 2005, 03:50

No, but there could be savings in less combustion thereby creating a less dense hyperbole explosion, in the nether regions of the piston circumnavigational pressure module? I suggest you may achieve the effect by ripping off a couple of teeth off the cam belt? However I do suggest you take the 'precortion' ( in the interest of work and safety) that you keep your fingers clear in the process.

JohnT · Post by **JohnT** » 19 May 2005, 04:03

Furthermore it will be most interesting for those behind you when you hit the hard pedal? Excessive smoke ( what colour would it be if three teeth out?) will ensue. This could be a new craze within the M25 corridor? Not elswhere please.

fastandfurryous · Post by **fastandfurryous** » 19 May 2005, 06:32

Eh? what on earth are you on about JohnT?
Adjusting the pump timing a little bit to advance does indeed give very small gains in efficiency, at the expense of increased noise. The amount you have to move the pump by is tiny... barely visible in fact. You don't want more than about 1 or 2 degrees more of advance, and because the pump runs at half-cranshaft speed, this means no more than 1 degree of change. If you have a Dial test indicator, you can set the pump um very accurately, and set it right at the upper limit (maximum advance). I've done this with my 405, and it has helped a teeny tiny bit.

j_roc · Post by **j_roc** » 19 May 2005, 06:44

DO NOT CUT TEETH/TAMPER WITH CAMBELTS - YOU HAVE BEEN TOLD.

sooty · Post by **sooty** » 19 May 2005, 11:36

I have'nt a clue what JohnT is on about, ripping teeth off the belt etc.
I know the pump is adjustable by small amounts in order to ensure perfect timing using an DTI.
I thought the small amount of advance would improve performance as its what the cold start device does and you can notice the difference in the performance when cold.
So I might scribe a line on the pump casing and try turning the pump clockwise a degree, looking towards the pump from the gearbox.

jeremy · Post by **jeremy** » 19 May 2005, 12:41

If your pump is worn it will take slightly longer to achieve injection pressure which in effect retards the timing. This won't show up on a dial gauge test but might if you had one of the expensive strobe timing sentups.
This wear can be compensated for to some extent by advancing the pump.
Nice wind up John - well done!
jeremy

Post by **Peter.N.** » 19 May 2005, 14:02

I broke three crankshafts in Perkins 4/108 engines through having the pump timing to far advanced and the only symptoms were increased knock when cold. Altering the timing makes very little difference to the performance, retarding it will make the engine quieter but can also cause it to smoke and overheat, it also makes it more difficult to start, advancing it improves starting but makes it run rough and puts extra strain on the internals.

rossd · Post by **rossd** » 19 May 2005, 16:55

If you are tuning the engine (eg incresing the fuelling) advancing the timing can help, it allows you to turn the magic screw that much further without seeing too much smoke. Just for a comparison, the injection advance on a TD is about 11 degrees, whereas on the N/A its about 18 degrees. (At idle, 800 rpm) Granted there are other factors but to a certain extent this shows there is a small leeway of 'safe' adjustment.

mrbump · Post by **mrbump** » 22 May 2005, 07:16

Why not have a bash and see what happens? The adjustment is not as tiny as you think. There is a good 20mm of adjustment, you could play around with +-5mm and still be perfectly safe.
I have just adjusted my td timing to the specified 1.07mm for the na using the na cam. Havent tried it yet, but I expect teething problems!
Advancing the timing will move the power higher up and it will create more power at those higher levels. It will also create higher in cylinder temps and pressures. As with petrols, it may be advisable to use better fuel the further you go.
I think alot of this stuff when tuning these engines is either still theory, folklore or bad information, so why not find out for sure? If it doesnt give a noticeable benefit, wind it back a bit!

bikeboyz · Post by **bikeboyz** » 22 May 2005, 23:00

When I first bought the 504 it had been standing in a barn for about 10 years. It poured out white smoke when running, I adjusted the timing on the pump, but slackening off the 3 allen screws on the mounting plate (lucas pump), it was also necessary to slacken the pump to injector pipes to get some movement. With the engine running slowly turning the pump by hand, until the white smoke cleared and excessive knocking started, then turn slowly back until the knock and smoke is gone.
The Lucas pump on the 504 has a fuel adjustment lever, controlled from the dash board. It just advances the timing for cold weather starting, it just makes the engine knock unless its really minus temperatures outside. Soon as the engine heats up or the revs increase it automatically retracts.
Without the tools to set up the timing correctly, the human ear is the best bet - certainly worked for me!