What to adjust, how and why? (Monark Nozzles) - PeachParts Mercedes-Benz Forum

cirrusman · #1 04-24-2011, 04:55 PM

I got a set of 5 new Monark Injector nozzles which I'm getting ready to install. I checked out the pictorial at diesel giant and it doesn't look too bad. Only that I've read on this forum about the necessity of adjusting the nozzles somehow for correct pressure, and seen a video or 2 about how to make a bench tester and detailed instructions how to test the injectors. However, nowhere could I find instructions on adjusting the injectors to the right pressure or why wouldn't they be at the correct pressure once the injector has been rebuilt.
Knowledgeable responses will be greatly appreciated

compress ignite · #2 04-24-2011, 05:32 PM

"Shims" of differing thicknesses are used depending on the "Pop Off" pressure
observed during Testing/Adjustment.
There is a Formula used to figure out which thickness.
Dealers can order shims (YOU WILL NOT LIKE THE PRICING)
Bosch Diesel Service Stations can also order the thickness you need at a much
better price.

Unless your New Avocation [Hobby] is Testing/Adjusting Diesel Injectors (?)

It would be much easier and less costly to have a pro do it.

Member C Sean Watts imports and "Sets Up" (Tests/Adjusts) Monark Nozzles.
'Contact him about Installing and Adjusting Your New Nozzles in your Injector
Bodies!

LuckyEddie · #3 04-24-2011, 09:54 PM

I bought mine from C Sean Watts in Raleigh, NC and set them up myself. I do have a Bosch pressure tester but they were fine and did not need anything after assembly. If you have them do one at a time and you should be ok but that is just my .02. Keep things clean or they will leak.

Good Luck
Robert

Diesel911 · #4 04-24-2011, 11:19 PM

You need to set the Pop/Opening Pressure on the Injectors because none of the Springs will have the same tension on them and the dimensions of several of the parts inside of the Injector that compress the Spring are not all the same size.
I also do not think a Monark Nozzle verses a Bosch Nozzle will have exactly the same dimensions either as far as compressing the Spring goes.

when you get your new Nozzles remember that the 2 parts of each Nozzle are mated together. Keep all of the parts of one Nozzle together.
Also, keeping all of the Parts that come out of one Injector together makes it easier to set the opening pressure because it will be closer than if you mixed the parts.

There is also 2 different types of Injector Bodies. While the 2 different types of assembled Injector Bodies can be mixed on the Engine the parts of the 2 different types are not interchangeable and cannot be mixed together.

How to Rebuild Injectors
http://vincewaldon.com/index.php?option=com_content&task=view&id=20&Itemid=28

Diesel911 · #5 04-24-2011, 11:22 PM

The Pop/Opening Pressure has an effect on Fuel atomization and the timing (high pressures have a later timing than lower pressures).

cirrusman · #6 04-24-2011, 11:42 PM

Thanks for your input gentlemen. Sounds like C Sean Watts knows what he's doing. I live in Utah, however, so we're a bit far apart and shipping back and forth would probably be costly (not to mention risky if the parts get stolen...)
Thanks Diesel911 for your input too, good website! I think I'll end up having a pro do the pressure adjustment this time, but that's really good info, if not for anything else, at least to look to the mechanic like an educated fella who knows what he's talking about and would be harder to fool...

Thank you much guys for your posts. I'll post here whether my MPG improves once I'm done with it.