Timing for Fuel Injector Pump - Remounting

[Skitzerow]

I am on the last leg of my engine rebuild journey.  I have the camshaft notch lined up.  The crank shaft and #1 piston at top dead center like the book says.  Now where should the alignment be for mounting the fuel injector pump?

I know the notches on the injector pump have to be aligned in the spline.  But where does the injector pump sprocket have to be relative to top dead center on the piston and crankshaft.  Where would the factory have set the injector pump position the first time they were assembling every thing.

Should the keyway on the sprocket be verticle, straight up?  Makes sense from an engineers standpoint if they were first designing the engine.  But don't know the engineer.

Should the top of the injector pump be taken off to set the position of the piston for cylinder # 1.  This would be a nice exact approach if you knew the exact dimension measurement.

I could set out to get all the sprocket ratios and calculate position in fractions of a second when the injector piston should be squeezing the juice in.

But someone here has to know what the simple factory procedure was when they built the pumps for mounting in production.

Any help is greatly appreciated.

SDK

[merrill]

sdk
do a search on this topic there was a good thread on this procedure

for my 66 230
basically on the inj pump line up the 3 marks,  set the motor at 20 deg ATDC and you are done.

find the link and there is more info.

unlike the diesel inj pump you do not have to turn the motor / inj pump till you get a drip of fuel on the no 1 rail.

matt

Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230

[ja17]

Hello Scott,

Make sure your engine is at TDC #1. The no. one engine piston should be at the top and the camshaft  lobes over #1 should be upward (10 o'clock and 2 0'clock roughly). Make sure the rotor on your distributor is pointing to the slash mark on the distributor rim also. Now turn the engine to 20 degrees after top dead center. I prefere to slide the splined sleve onto the shaft in the engine no reference needed here. Next align the slot of the injection pump spline (or slash on injection pump shaft) to the slash mark on the pump housing. Alignment by "eyeball"  is definately good enough  with type injection.

Make sure the splined coupling is installed in the block and the plastic insulator and its gaskets are also in place before sliding the injection pump into place.



Joe Alexander
Blacklick, Ohio

[bpossel]

Hi Scott,

I would also ensure that you right away replace the injection pump paper gaskets (x2) and flange (x1).

The order of install is: engine housing, then paper gasket; then flange; then paper gasket; then injection pump.  I also used a bit of #2 Permatex.

I replaced my IP Pump a couple of years ago.  The paper gasket and flange looked good at the time, so I only replaced the 1 paper gasket between the flange and the pump. Not good!  It started leaking this summer, so I recently had to pull the pump and redo the right way!

Good Luck!
Bob

bpossel  (Memphis, TN.)
'71 280SL  /  '97 E320

[enochbell]

Skitzerow,

Careful here.  Joe has given you the correct steps for alignment, in the correct order.  BUT, depending on which pump you have, the crankshaft position is spec'd at 20 BTDC, 0, or 20 ATDC (with the timing mark aligned on the pump collar).  I am sure you can find the correct setting for your pump on this board, first step: which pump do you have?

Best,
g

'64 230sl, fully sorted out...ooops, spoke too soon

[ja17]

Hello enochbell,

I am only aware of one timing spec for these engines and that is 20 degrees after top dead center.? Are you sure you are not thinking of a different model Mercedes engine?

Joe Alexander
Blacklick, Ohio

[enochbell]

Joe,

You may be correct, I am going on my memory of the instructions I got from Pacific about 7 years ago when that delightful fellow (Gus?) gave me an instruction sheet for setting the timing on my '64.  I thought the instructions included a warning about different settings for the early style (mine) as well as for at least two other models of later pumps, but they could have been referencing other engines besides these M127, 8, and 9.  In any case I have searched and can't find either the instruction sheet or any other reference to different timing anywhere on the net.  If you say 20 for all, then it is 20!

BTW, did you ever have that fantastic photo of the high-tech pump testing apparatus you assembled printed for framing.  I would sure like to get hold of that pic, it is priceless.

Best,
g

'64 230sl, fully sorted out...ooops, spoke too soon

[ja17]

Hello Greg,

I have a 383kb size photo of the "Blacklick Injection Pump Test Stand" if you'd like me to email it to you. ja17@worldnet.att.net

Download Attachment: 62kb.JPG
64.69 KB

Joe Alexander
Blacklick, Ohio

[Skitzerow]

I know this may be a stupid question.  But I don't have a battery and starter hooked up yet.  But want to rotate the crankshaft in the right direction as I am setting the timing for mounting the injection pump.

Which is the right direction, for me and future reference.  Clockwise or Counter-clockwise as you are standing in front of the engine.

On the 280SL, which 20 degree mark is the one for setting the injection pump.  The mark left of the TDC, or to the right of the TDC.  I think it is to the left of TDC (0).

I just want to be 300% sure, as I have already mounted the injection pump but think I did it on the wrong 20 degree mark.

I about 99% sure, but someone could just confirm the other 1%.

Thanks
You All

SDK

[glennard]

Skitzerow, Engine goes clockwise as you look at it from the front. 30mm(?) socket on a 2" extension and a 15" breaker bar should do it.  Line up the marks on the pump, turn the crank to 20 degrees ATDC, and slide the pump in.

An aside-- Any one ever analyzed the dynamics on fuel/air flow at 6000rpm.  The IP cams/helix/etc. send fuel down unequal lengths of pipe to the injector nozzles which spray on the open intake valve.  What is the sync of the IP cams to the cam shaft cams- the inertia of the stop/go in the fuel lines and the air intake pipes-  the nozzle spring/spray???   At 6000rpm does it make any difference?   Bosch CIS(continuous injection system) finesses the whole problem?  Inquiring minds want to know.