On Oct 18, 2012, at 7:50 PM, "Curt Raymond" <curtlud...@yahoo.com> wrote:
> I wish Marshall were still around, he'd know more about it. You asked.... Here is a couple write ups from AM Booth on the subject... Delivery valve seals will NOT fix a problem with idle speed adjustment!!!! Replacing delivery valve seals is RARELY needed, but IF required, nothing else will solve the problem. Maybe 1-2% of Mercedes injection pumps require them during their lifetime. There is really NO reliable test of delivery valve seals except with the pump on a test stand. It is probably wise to replace the pump seals IF you're going to replace the "O" rings on the delivery valve pipe fittings as the seals are inexpensive, but it's rarely actually necessary. The only reason to replace the seals is if there is uneven delivery from the IP to the injectors. My very crude test of delivery seals is to remove all the injection lines and crank the engine while watching what comes out of the pipe fittings - each should deliver about the same amount of fuel. A really proper test (the way it would be done on a test stand) would measure the output and pressure of each port during some number of revolutions of the pump - each should deliver about the same amount of fuel. When playing with the injection pump a little finesse and care is required. The pump body is quite easy to distort if anything is overtightened (usually "repaired" by loosening and retightening using the proper torque/release technique as outlined in the Tech Data Manual), or a little too much force on a wrench CAN crack the housing and if that happens a new pump is the only solution. I do NOT recommend people trying to "tune up" their injection pump as injection pumps rarely fail, do NOT routinely drift out of adjustment and about 90-95% of all injection pump problems occur right AFTER the pump has been "adjusted." Only if all of the injectors have been TESTED and shown to be working PERFECTLY but fuel delivery still seems uneven is there sufficient justification to even consider playing with the delivery valve seals (in MY opinion). Get half a dozen new seals AND "O" rings (and several spare "O" rings as it's easy to damage one or more when installing the delivery valve fittings). Oil the "O" ring when installing it. You'll need the splined socket and a torque wrench accurate in the 30-40 lb-ft range. The fittings CAN be removed with the intake manifold in place (but it's a little tight). Worth checking the engine manual. http://mb.braingears.com/124_DISC1/Program/Engine/602_603/07.1-8627.pdf Marshall -- Marshall Booth (who doesn't respond to unsigned questions) He meant NEWTON METERS Dave M. wrote: > One tiny adjustment... the torque range neeed is, I believe, 30-40Nm, > not lb-ft... make sure you use the proper setting on your wrench. > Over-torquing can damage the pump. The torque procedure is listed in > the TDM (Tech Data Manual), not the normal service manual (don't ask > me why). SORRY - final torque IS 35 Nm NOT 35 ft-lb. Proper sequence is: torque to 30 Nm and release, torque to 30 Nm and release, torque to 30 Nm and then an additional 5 Nm for the final step. Then, IF the pump makes a racket determine which cylinder is noisy and redo the torque sequence on that one! Needs to repaired promptly as it can damage or destroy the IP. I'm told that even experienced techs will produce a noisy condition maybe one out of ten times. Happens a little more often for a novice. Thanks for catching that Dave!! Very careless of me. Marshall Harry Watkins wrote: > I recently replaced the delivery valves o-rings, copper seals and springs on > an 86 300 SDL and followed this torque procedure; go to 25 ft lbs and loosen > twice, the third and final torque was 30 ft lbs. IIRC that was Marshall's > instruction from long ago. I was not sure if they should be done one at a > time or not, but that's what I did. Its been over a month and all is well > so far. > > Please keep the area clean, clean, clean. Woe! The Mercedes specs are in Nm, not lb-ft. Multiply Nm by 0.74 to convert from Nm to lb-ft. The delivery valves (or any part attached to the pump) must NOT be overtorqued or unevenly torqued. If they are stressed, the pump may distort or even crack (that can ruin your day). Tighten to 30Nm (22.2 lb-ft) and release. Repeat. Tighten to 30 Nm and then an additional 5 Nm (3.7 lb-ft). That gives a final value of 25.9. Even when properly torqued, the pump housing can occasionally still distort. That will usually cause the pump to make a clattering sound and the engine will idle roughly. To cure this, loosen the fuel lines one at a time until you discover which one is causing the roughness and re-torque that one. Marshall Rick Sent from my iPhone _______________________________________ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
