morning everyone!!! i want to try to time my pump on my 1980 300d non turbo,it seems to run fine but am getting alot of dieseling knock. i have adjusted the valves and it didnt help, so timing it is. my qustion is- the Haynes manual makes mention of disconnecting the vacuum line on the IP before using the drip method(lotsa luck). where is this line? my non turbo vac lines have almost all been removed....no door locks,and the climate control is manual controlled(european model).my vac lines consist of the trans line and the shut off lines to the key and back (and brake module). there is that little module looking thing on the side of the injector pump,it has a white little lid and there were vac lines on that at one time but are long gone,like i said the car runs well,no smoke and starts great,what is the purpose of vacuum on the ip? is this only for transmission shifting purposes? do i need this line to make the pump run correctly? the reason it was disconnected was that it was not holding vacuum and causing the rest of the system to leak. it is disconnected when you time the pump,so if it is leaking at that point, will it effect the drip method well timing? or is the drip way a bad way to time?

The drip method is an acceptable way to time the IP but IPs don't just slip out of time. Have you tired a dose of Lubromoly Diesel Purge? Have you checked chain stretch? Are the delivery valves leaking?

It might be possible to time your IP visually if it has a timing lug and access port. It won't be perfect but it'll get you close enough to get rid of noises caused by wrong IP timing.

Sixto
95 S420
87 300SDL

where would i look for this timing plug and access port? i did check my chain stretch last week, but i used the cam line method(i know,not the most accurate) it was showing around 7 degrees with the cam marks in line....how bad is that? previous owner had the pump timed,along with updated glow plugs and new injectors.all within the last year....this guy is a friend of mine and i know its all true. the chain has never been replaced. car has 230000 on it(miles).funny thing is,this car starts and drives great,no smoke,does not seem that loud at idle. but i cant seem to track down the pinging.worse when its cold, but also when under a good load when warm. could this be timing? if the pump was prof timed within the last year....how much could chain stretch be a factor? WHAT ELSE CAN I TRY?

If IP timing was set within the last year by someone who knows what he's doing then there's little reason to revisit IP timing.

Start a separate discussion on 7* of stretch. Seems at the high end to me but I'm not sure what the effects are.

For pinging I'd try 2 bottles of Lubromoly Diesel Purge directly into the IP, not into the tank. If the noise persists then new delivery valve seals and o-rings.

Can you isolate the noise? Loosen the injector lines one at a time until the fitting leaks then tighten and move to the next line. Does cutting fuel to one cylinder make the subject noise go away?

Sixto
95 S420
87 300SDL

Look at this item on eBay as a reference -



Along the bottom of the side of the IP opposide the engine block there is a plate held to the side of the IP by two bolts. In the center of the plate is a big bolt that plugs the access hole for the timing lug. If you have this plate then you must have a timing lug. If there's no plate then your pump can't be timed using the RIV method.

Sixto
95 S420
87 300SDL

The bad news is 7 deg is pretty bad.
The good news is it's easily fixed.
Mercedes benz makes a woodruff key for 61/2deg stretch. Part # 621 991 02 67

using the cam lobes is considered by some people to be an acceptable method to check stretch. I check that way and with a dial indicator and got 4deg both ways. I added a 4deg woodruff key and couldn't believe the difference it made.

Being that your IP Pump was timed allready I would correct the chain first then retime the pump to bring everything back to specs.

P.S. Mercedes makes keys for 4, 6/12, 8 and 10 degrees of stretch.

Also putting timing chain and woodruff key into the search field will give you TONS of info!

danny

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1984 300SD Turbo Diesel 150,000 miles

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sorry for my lack of knowledge here but i need somthing explained. if the pump is timed already, and the car runs fine, why would you need to change this woodruff key to bring the alignment in? is stretch and wear in the motor
and other things not the purpose for having an adjustable ip to begin with. if i change this key, then i will have to re time the pump, correct? why would i not just leave it all alone? or does it get to a point with that much stretch that the pump cant be timed? if thats the case,it would be out of time now, wouldnt it?

Your IP was most likely timed relative to the crankshaft and the drip and RIV methods can verify that the relationship is still okay. The offset woodruff key brings the camshaft (valves) into proper timing as well.

You should check IP timing after installing the offset woodruff key but it shouldn't change because there are still as many links between the IP and the crankshaft sprocket. In a sense the offset woodruff key moves the cam, not the chain.

Sixto
95 S420
87 300SDL