135 bar injector in w123 ono turbo?? - PeachParts Mercedes-Benz Forum

fred98050 · #1 05-05-2010, 11:53 PM

I am doing a pre buy on a 300d non turbo and found out that 1 of the injector had 135 bar written on it while the others were all 115 bar...

The engine seems to be running pretty well so I was wondering what king of damage would a 135 bar injector would do to a non turbo engine?
Is it possible that the core of a 135 bar was used to rebuild a 115?

Thanks

tangofox007 · #2 05-06-2010, 12:40 AM

Quote:

Originally Posted by fred98050

Is it possible that the core of a 135 bar was used to rebuild a 115?

That is entirely possible.

fred98050 · #3 05-06-2010, 01:23 AM

Quote:

Originally Posted by tangofox007

That is entirely possible.

Hey tangofox007,

Thanks,

Just curious here, what would happen if a 135 bar injector was installed in a non turbo engine?
Running rough? Not at all? Too much pressure?

biopete · #4 05-06-2010, 01:48 AM

Not much. I installed 4 new turbo nozzles in a 240D with new nozzles. It had 115 bar injectors but when done, pop pressure was 150 bar. Runs good. It just makes the ip work a little harder to get higher pressure but they can take it ( i would assume). Gives you better atomization of fuel. You get a little more nailing but new nozzles do that at first anyway. Also it may retard timing slightly so you could check timing and advance a little if need be.

BTW, can you advance timing by sound on these engines when running it -- ie loosen IP and just push a little toward engine and tighten till it sounds and feels good?

Diesel911 · #5 05-06-2010, 11:53 AM

Who knows why the Turbo Injectors are set at a higher pressure?

My though is that when the Turbo is working it packs more Air Volume into the Cylinder. When this Air is compressed in the Cylinder it is much denser (thicker) than it would be in the non-turboed Engine. This means the Injector Spray has to penatrate through thicker/denser air. An Injector with a lower pop pressure will not penatrate as far as one with a highe pop pressure; so they raised the opening/pop pressure.

So I think in the case of using Turbo Injectors in a non-turbo Engine the Injector spray would penatrate further into the Prechamber than in would with the 115 bar pop pressure.

In the long term would this cause damage; like burning up your Ball Pin? I do not know.

JEBalles · #6 05-06-2010, 02:00 PM

Quote:

Originally Posted by biopete

BTW, can you advance timing by sound on these engines when running it -- ie loosen IP and just push a little toward engine and tighten till it sounds and feels good?

I'm pretty sure you can't. I looked into this and it's supposed to be much different than setting the ignition timing on a spark-ignition engine. On a diesel, you can't do it by ear and, if done wrong, can seriously damage the engine. Doesn't seem like an area to mess with.

http://www.peachparts.com/Wikka/OM615OM616InjPumpTiming

I stand corrected.

Diesel911 · #7 05-06-2010, 10:48 PM

Quote:

Originally Posted by biopete

Not much. I installed 4 new turbo nozzles in a 240D with new nozzles. It had 115 bar injectors but when done, pop pressure was 150 bar. Runs good. It just makes the ip work a little harder to get higher pressure but they can take it ( i would assume). Gives you better atomization of fuel. You get a little more nailing but new nozzles do that at first anyway. Also it may retard timing slightly so you could check timing and advance a little if need be.

BTW, can you advance timing by sound on these engines when running it -- ie loosen IP and just push a little toward engine and tighten till it sounds and feels good?

It is hard to rotate the Fuel Injection Pump with The Fuel Injection Lines still Attached to the IP and the Injectors.

The newer model IPs have a spcial bolt to turn that would make the sort of rotataion you are speaking of possible. Also they have very long Fuel Injection Lines and I bet it does not take as much force to bend them.