IP timing curve - PeachParts Mercedes-Benz Forum

Graminal95 · #1 04-13-2009, 01:18 PM

Does anyone have the advance curve for the IP? I have a vibration at X rpm and wonder if it is related to the IP timing.

#2 04-14-2009, 03:42 AM

The advance is up to 8* until 1979 and 7.5* 1980+. There is no specific RPM.

Bajaman · #3 04-14-2009, 03:54 PM

I was thinking along the same lines and suspected that the timer was malfunctioning. Since it's just a centrifugal device the only thing that can go wrong are the springs. I replaced the springs and the center pins in my timer with new ones and it made absolutely no difference. both springs and pins showed significant wear, so I was hopeful, but no such luck. I have the part numbers at home if you want/need them.

#4 04-14-2009, 03:59 PM

Yes, part numbers would be handy. I need to inspect mine as well.

Graminal95 · #5 04-14-2009, 05:13 PM

Do you have to remove the timer to replace the springs? Also is there a difference between the turbo and non-turbo engines?

I wonder if I can put a 300dt IP back with a rack damper bolt in to help with the 240D's shakes.

tomnik · #6 04-15-2009, 12:28 AM

Quote:

Originally Posted by Graminal95

Do you have to remove the timer to replace the springs? Also is there a difference between the turbo and non-turbo engines?

I wonder if I can put a 300dt IP back with a rack damper bolt in to help with the 240D's shakes.

Hi,

shaking is a result of unbalanced cylinder forces. Compression, valve adjustment, injectors,.. from engine side. Or/and from IP side: unbalanced timing of the individual elements or different amounts of fuel. The tolerances of BOSCH i.e. for the timing is +- 1 deg among the elements. In a MB internal advice they say put it to +- 0.5 deg in case of customer's claims of shaking. Similar with quantity. The damper is not in use on a well running engine.
Clear the origin.

Tom

Bajaman · #7 04-15-2009, 07:35 AM

I agree with Tom's advice. My main purpose in checking this out was a lot of black smoke above 3500 rpm. I thought that the springs could have been weak or broken, which would not bring the timing back to 0. Anyway, like I said it didn't change much. The smoke went away with the VNT.
Part Numbers: engine: 617952
Pin: 617 075 03 74
Spring: 617 993 07 01 up to 85
Spring: 617 993 27 01 from 85

I'm trying to remember exactly how I did this. I know I didn't remove the whole timer. I think that I just removed the vacuum pump, camplate and very carefully removed the segment plate leaving the drive mechanism in the block. Replaced the springs and pins then put it all back together. It wasn't too bad, just don't drop anything!!

Graminal95 · #8 04-15-2009, 12:10 PM

The vibration is always present and it fells like a hesitation at X rpm. I'm not sure what the RPM is as I don't have a tach. After X rpm the engine runs much smoother and revs up much faster. If I can dig up a camera with sound I'll try and post a short video of it. The vibration seems to be enhanced with the 5 speed box. So If I can sort out that vibration I might be able to use the 5 speed for daily use.

Tomnik I'm not sure about compression, but I have rebuilt injectors with 261 nozzles and set to 131bar +- 0.7bar, and just did a valve adjustment. It could be a difference in compression but I'm not convinced. I wonder how much it would cost to have a IP setup or atleast checked out.

JonL · #9 04-15-2009, 01:51 PM

Have you changed anything in the crankshaft balance assembly? Harmonic balancer, flywheel, crankshaft, conrods, etc? How about engine mounts and transmission mounts? Does the vibration happen with the transmission in neutral, or is it only when driving at a particular speed/rpm?

Graminal95 · #10 04-15-2009, 02:39 PM

Nothing on the engine has been changed internally, just the turbo and IP output.

The vibration is at a particular RPM and is independent of the transmission or speed. If I take the transmission off, the vibration is there. If the MB transmission is hooked up, its there. If the clutch is engaged or not, its there. If the BMW 5 speed is hooked up the vibration is magnified greatly.

Its like the engine is not happy (running rough) then smoothes out as the RPM's climb then it start to vibrate again and then its all smooth.

I have never had a very smooth 240D, but my father's 300DT is supper smooth. I would love to get close to the 300's smoothness, but I don't know if that is possible.

tomnik · #11 04-16-2009, 12:14 AM

That is possible! The vibrations result in unbalanced quantity on the single elements. On the bench you could see it. Well adjusted in low range rpm it could happen that you have increasing quantities in higher rpm. I had this with bad elements. The only thing is to adjust a compromise or better to throw them out. Unbalanced individual timing would cause vibrations in the whole range.
I am quite sure it's quantity.

Tom