pressure relief valve` - PeachParts Mercedes-Benz Forum

TurboSDL · #1 06-22-2009, 08:38 PM

where is the pressure relief valve located on my 617 turbo? i was reading a thread where the spring can compress to a smaller size than it was stock, (27mm if im not mistaken). i wanted to take it out and measure it to see where mine was at. thanks

nhdoc · #2 06-22-2009, 08:41 PM

Back of the IP, it is the banjo bolt which the return line comes out of and goes to the filter housing. There are two types, one you can take apart and one is sealed. If yours has a hex head cap at the end of it you can open it up and measure the spring and stretch it if it has shrunk.

snookwhaler · #3 06-22-2009, 08:56 PM

I looked into this a few months ago. I'm not sure if it has to do with years or what. Mine is an 85 and it has the one you cannot take apart. Still, it is nice to know where these things are.

Diesel911 · #4 06-22-2009, 09:01 PM

I might be nice to know what pressure you have before you take it apart.

Also Fastlane has brand new Pressure Relief/Over Flow Valves as per Hunters post about 2 months ago.

barry123400 · #5 06-22-2009, 09:15 PM

Why not just read the fuel pressure it is currently allowing? If substantially low pinch off the return line to establish that the lift pump can produce the higher than needed pressure first.

If it passes and say the pressure relief valves release was very substandard. Take an adjustable type relief valve off a wreck and install it. If it requires adjustment as well so be it. The sealed type valves are expensive if required but available. Both/either the lift pump or relief valve can deteriorate with age and use. Nothing lasts forever.

TurboSDL · #6 06-23-2009, 05:34 AM

i noticed on my car there is a banjo on the side of the ip (facing the head) and there is where the return line goes to the fuel filter. is this where it is? how much would it cost to buy a new one if its one i cant take apart? or are you saying i can swap it out with one that i can take apart?

TurboSDL · #7 06-23-2009, 03:22 PM

Quote:

Originally Posted by TurboSDL

i noticed on my car there is a banjo on the side of the ip (facing the head) and there is where the return line goes to the fuel filter. is this where it is? how much would it cost to buy a new one if its one i cant take apart? or are you saying i can swap it out with one that i can take apart?

is that where it is? i dont want to take it off if its not...

barry123400 · #8 06-23-2009, 06:13 PM

Yes the relief valve feeds the return line. The two types of relief valves are interchangeable.

A guy should get a pressure gauge on the system before anything sensible can be determined. Other than that you just do not really know what pressures are really present.

This is a nice inexpensive area to check and at least upgrade to factory specs if needed. The lift pump kit is only about ten dollars and the adjustable relief valve can be harvested from a salvage yard.

winmutt · #9 06-23-2009, 06:21 PM

On the 85 the pressure reliefe valve is non serviceable.

TurboSDL · #10 06-26-2009, 07:37 PM

so where do i hook up the pressure gauge? can i put a permanant type on there? and if the pressures are not within spec then should i replace the relief valve since its not serviceable or should i swap it with one thats serviceable? what would be the move to make?

whunter · #11 06-26-2009, 09:32 PM

Quote:

Originally Posted by TurboSDL

where is the pressure relief valve located on my 617 turbo? i was reading a thread where the spring can compress to a smaller size than it was stock, (27mm if im not mistaken). i wanted to take it out and measure it to see where mine was at. thanks

Fuel injection pump starvation with good a good lift pump
http://www.peachparts.com/shopforum/showthread.php?p=2133911

fuel pressure
http://www.peachparts.com/shopforum/showthread.php?p=2156755

Have a great day.

TurboSDL · #12 06-28-2009, 11:54 AM

OK WHAT IS THIS ELECTRONIC TIMING DEVICE PEOPLE ARE USING TO CHECK TIMING, I WANT MY CAR TO RUN RIGHT AND YET WITH MORE POWER. I DONT UNDERSTAND WHAT A WOODRUF KEY IS AND WHAT IT DOES, AND WHAT DOES THE LIFT PUMP DO? IF I REPLACE THE PRESSURE RELIEF VALVE WITH ONE FROM FASTLANE WILL I GET ONE WITH THE SPRING IN IT OR A YEAR SPECIFIC ONE THAT IN MY CASE IS NON ADJUSTABLE? IF ITS ONLY 26 BUCKS I MAY AS WELL JUST GET ONE.

barry123400 · #13 06-28-2009, 12:35 PM

Archives reading is where you should go. For all practical purposes the lift pump is the fuel pump.

Buying parts not really required is not particularily helpful. This area should be examined with a cheap fluid dampened gauge from a place like harbour freight. That way indications of things needing attention will be present. Or perhaps all is well. At present again you just do not know. Cost of pressure gauge is around 10.00. Plus fittings.