Are you interested in an adjustable IP fuel pressure relief valve?
 

I have been having lot's of fun in up-ing the fuel pressure by tweaking the IP fuel pressure relief valve in this thread and getting some positive results.

http://www.peachparts.com/shopforum/diesel-discussion/284352-fuel-pressure.html

I just made this adjustable pressure relief valve. On the right is the adjustment (a socket head cap screw), the blue nut is a nyloc lock nut, there's an o-ring to provide a positive seal. By turning the screw CW, fuel pressure is increased, CCW, pressure is decreased. I still have to test it to make sure it works well. I have confidence it will.

This poll is to see how many are interested in buying an adjustable fuel pressure relief valve and renting the test equipment to set the pressure. The test equipment will be a banjo bolt that has a quick disconnect fitting with a 6 ft nylon line to a pressure gauge so you can set the fuel pressure, like the setup in the thread I linked to above. There will be a core charge on your unmodified fuel pressure relief valve. I only have 3 of them currently and need your core so I can continue to make them. Price is TBD. I am just putting this poll out to see how much interest there is.

http://i31.photobucket.com/albums/c3...092310_002.jpg

Clearly there is a need for a Fuel Pump Pressure test Kit.

However, I think the 2 way shipping charge needed to rent one could better be used to buy one or what you need to make one.

I am sure there are some who would like an adjustable Pressure Relief Valve.

Maybe you cold factory preset them to the OEM pressure. People could then do their own extra adjustment. You should be able to give a starting point like say 3 turns out from the stop. There are probably some down sides to increasing the pressure by too much like diesel leakage into the oil.

D911, good point about offering a fuel pressure test kit instead of rental with the 2 way shipping.

I could most definitely preset the pressure to whatever is desired.

I might be in but due to my current situation pricing would be the deciding factor.

I know a free solution; stretch the spring to 27mm like the factory tells you to and be done with it for good.

Yes, except the spring will slowly give and the fuel pressure will slowly drop. Looks like there is not much interest. That is good actually because I don't have a lot of time for another project. ;)

For some odd reason people don't seem to be concerned about fuel pressure??!!:confused:

Well if you get around to making one up for yourself. Throw one more together for me and pm me when done.

Possibly will be a requirement for balancing vo cars power strokes at some point. I do not use vo but will find a use for it another way.

I think it's the extra fuel milage and power that puts them off? The smoother idle as well perhaps? Might be the 10.00 or so cost of the fluid filled gauge holding them back. Or the effort to install it.

Also the unproven potential cause of the number one rod failure should not be ignored. .Even if this is thought just an outside chance . I think it almost compulsory to check pressure on the four cylinder 616 engines because of that issue.

By now at their age a percentage of lift pumps are defficent as well in pressure output. The system has just gotten old and tired. Yet cheap to restore as well if it is low pressure wise. More likely it is a diesel and if it runs it must be fine.

Seriously though I too find it strange more people have not checked the fuel supply area out better. Although quite a few have already. Just not mainstream yet. Those that go to 19 pounds are more than happy from their feedback every time.

When I say check it out I mean setting diesel fuelled examples to 19 pounds. There are no issues curently or in the future I feel at that pressure.

If you send your injection pump out for a rebuild it will come back set at nineteen pounds by many shops. So even if overall calibration was close enough when it went in it will still seem better.

I would be in if I could get an idea of a "Ballpark " cost. Or send me some complete info and I will see if it is something I can make.

From reading the posts on these "effects" it seems like they are completely anecdotal at best! Has there been any verifiable direct comparison "pre" vs. "post" data generated and shared for peer review?

Everyone really being serious has always quoted a change. Much depends of course what your original fuel pressure was.It is always hard to get believable accurate fuel milage numbers. So far no two cars have posted simular original existing fuel pressures. So no two cars will have the same exact gains at 19 pounds.

Now for the hard part. Since you have more power you have to disipline yourself to drive the car as it was before the power increase to get valid mpg comparisons. Most will drive into their new power to a certain extent I believe. This decreases the actual gain in mpg somewhat. Fixed cruise speed on the highway is probably the best comparison method. Did I mention the engines sound happier at speed as well has been reported.

If you consider what is actually occuring from say properly raising the pressure from 8 pounds to 19 pounds the answer is there. The principal point is all the cylinders then get a more equal charge of fuel with better timing. So the engine is far better power balanced. At low pressure there seem to be a few if not many undesirable conditions.

Some people will have to convince themselves over time. No body is trying to sell them something remember. Or try to consider it standard maintenance is another approach a doubter could consider. The manufacturer wants to see a minimum fuel pressure available. Too many cars are below their minumin requirements I suspect. They have just gotten old.

You could be the first to post extrememly accurate complete information. It does take some effort to gather it.

I had a chance to pressure test the adjustable pressure relief valve and it works like a charm! I'll shoot a video of it tomorrow and post.

Still have to install it and make sure the o-ring seal works otherwise all bets are off.

I am interested in this - however I have to be honest and say that I haven't a clue about the fuel system on a OM617. I'm still trying to figure out exactly how the basic system works. I'm still quite new to this.

I guess this could be a reason why everyone has not been hammering down your door funola.

Can you direct me (and perhaps others) to some good diesel injection systems for newbies / dummies threads?

Curious
 

Would this work on cars such as mine with the non adjustable spring?

Don't understand why adjustability is required for anything other than spring fatigue over time.

Don't see the need to overpressure the fuel in the IP, either there is enough pressure to deliver the volume to the delivery valves, or not. So long as there is enough pressure, the valves are full and you get a full charge down the line.

Once the critical pressure is met, what does the extra pressure buy you? Nothing. It can't possibly increase the flow to the injectors. It can't possibly change your MPG or power.

To get the critical pressure, just replace the original spring, or stretch it a bit, as per FSM.

None of the poll options have what I'd vote for, so I didn't vote.

Army, you're no newbie with all the work you've done. I don't have any links to good threads on the inline pump but a search should turn up a lot.

4the sporty, it is a direct replacement of the non adjustable. As a matter of fact, it is a modified non adjustable and I would need your's as core, if I was actually going to make them.on a continuing basis.

I also do not understand how this would provide any benefit over a correctly adjusted IP.

It's raining here and this was taken under an overpass, noise you hear is vehicle traffic. I am pumping the tire pump and you can see as I turn the adjustment screw c.w. the pressure increases. The gauge goes from 0 to 30 psi.


CLICK TO PLAY!
http://i31.photobucket.com/albums/c3...093010_001.jpg

With the adjustable relief valve at 30 psi, I am turning the adjustment scew CCW and the pressure decreases accordingly. Still have to install it into the IP and make sure there are no leaks through the o-ring.

CLICK TO PLAY!
http://i31.photobucket.com/albums/c3...093010_002.jpg

Answer
 

Sending you a PM with links.


.

Thank you very much. For those who may want to know more Wikipedia gives a great overview

http://en.wikipedia.org/wiki/Diesel_engine#Early_fuel_injection_systems

The links that were kindly sent by whunter were:-

Fuel Delivery:
http://www.peachparts.com/shopforum/diy-links-parts-category/142399-diesel-fuel-delivery.html

Diesel Injection:
http://www.peachparts.com/shopforum/diy-links-parts-category/142405-diesel-injection.html

Run away diesel, why does it happen?
http://www.peachparts.com/shopforum/diesel-discussion/101404-run-away-diesel-why-does-happen.html

Engine blow-by test, Blow a bag of blow-by
http://www.peachparts.com/shopforum/diesel-discussion/193602-engine-blow-test-blow-bag-blow.html

Blow-By curioisty questions
http://www.peachparts.com/shopforum/diesel-discussion/188320-blow-curioisty-questions-2.html#post1798266

Diesel TURBO issue Links thread
http://www.peachparts.com/shopforum/diy-links-parts-category/229542-diesel-turbo-issue-links-thread.html#post1929856

Engine oil cooler and hose/line issue, link thread
http://www.peachparts.com/shopforum/diesel-discussion/211352-engine-oil-cooler-hose-line-issue-link-thread.html

Valve adjustment OM615, 616, 617 FYI.
http://www.peachparts.com/shopforum/diesel-discussion/107729-valve-adjustment-om615-616-617-fyi.html


Sorry to go off on a tangent funola - I'll say no more!

It looks good - when are you planning to fit it on your car?

Higher than 19 pounds fuel pressure may be better with vo use. The viscosity is just heavier than diesel. You are attempting to get an element fill equivelent to the 19 pounds with diesel fuel use.

Checking the milli volts properly at different pressures should enable you if possible to balance the engine better. Equal fuel injection at all the injectors is where you want to be. Overpressure does produce yet better power. This area has suspected unknowns on diesel fueled cars.

If the current gentleman has a meter to measure the milli volts at various pressures it may show one of the effects I am talking about.

Some doubter should ask him if he is going back to the twelve pound pressure he originally had. I believe he will tell you there is no way that is in the cards. He has seen and experienced the differance..

To have a correcly adjusted IP, amonst the many "adjustments", one of them is to either replace the tired pressure relief valve with a new one, or use my adjustable pressure relief valve. Last I heard new ones are NLA.

Hopefully tomorrow.

Correction
 

0000747284 Diesel fuel return valve/banjo bolt
http://www.peachparts.com/shopforum/mercedes-parts-reference-library/246848-0000747284-diesel-fuel-return-valve-banjo-bolt.html





Have a great day.

Installed the adjustable pressure relief valve today. It works! I can vary the fuel pressure up or down by turning the socket head cap screw and lock it down with the nut. The socket head cap screw I used is too long and does not lend well to using a hex bit since the temp sender in the head is in the way and the block too close not giving much room to work with. I will use a shorter bolt with a hex head on the next one and that should make it much easier to adjust. I want to put more miles on to make sure it is leak free. I have a white tissue wrapped around it right now and will inspect it in a few days- hopefully dry.

Update request
 

What is the verdict?

That's a nice work Funola. I like it.

I made some design changes to it and MTUpower has it now in his 300TD wagon. No problems so far. I have to make him a banjo pressure gauge adapter so he can change and see fuel pressure.

I have to make a few more. Been busy with other things.

What
 

Is life getting in the way. :D

I understand how easy it is to get buried in projects.. :eek:

I pretty much agree with your comments.

But, what I am thinking is that the Performance guys would be interested in upping the pressure because they are trying to max out the Injected Fuel quaintly.

So with more Fuel injected there is less Fuel left inside of the Element after Injection and that means more fuel has to pass through the fixed size feed hole in the Element; but, there is no extra time to do that.

A higher pressure will move a higher Fuel Volume through the feed hole given the same amount of time to do so.

If you are gonna play with your fuel pressure relief valve, you really should have a way to measure fuel pressure.

I bought 100 ft of nylon tubing and 10 sets of fittings to make the pressure measuring kit (pic below). The banjo bolt is tapped with a 1/8 tube quick disconnect fitting. It replaces the banjo bolt at the IP going to the fuel filter. Comes with 7 ft of nylon tubing, plenty long to run into passenger cabin and a 1/8 female NPT fitting to the gauge (not included). You supply the gauge of your choice. The gauge must be 1/8 male NPT to mate up to the fitting. It should be glycerine filled 30 psi unless you want to go higher.
I have 4 kits at the moment and need more banjo bolts to make more.

Please PM me if you want one.

http://i31.photobucket.com/albums/c3...a/DSC00193.jpg

Yes! Yes yes yes yes yes!
 

Funola,


Count me in. I very, very much would love to have this in hand.

Bottom line, it's assistance like this that will keep our old Mercedes on the road. One of the things that make owning a 1966 Checker Cab easier, is a network of other enthusiasts who stock up on all the Unobtanium, or decide to make new parts to replace those that have fallen out of production.

For example, when WHunter posted that he had bought up the last remaining handful of springs, I sent PeachParts an email asking if the spring for the 617 IP was still available - I got a reply that, nope, they're all gone. What this means is that for now, I'm stuck having to stretch an already worn spring (*IF* my IP has the non-factory sealed part).

So - adjustability? I can dial in the appropriate pressure myself? Or better yet, have it pre-set for me so it's a quick replacement without tuning?

Can I fork over my dough fast enough?

Diesels may be rugged, but their one bugaboo is fuel delivery. Any kinks in volume or pressure, and all sorts of fun weirdness start. Knowing that this is a weak point with the Bosch system means all the more that I'd like to have a fix, and a permanent one at that. Everything with fuel should be to Mercedes Spec. If it's not, you're opening a pandora's box of weird.

James Smith
1982 300SD / 371,000
mohawkjames@gmail.com

I like your ideas and I've been toying with something similar myself for adding an electric fuel pump.

I will say however, DO NOT run fuel lines into the cabin! You MUST use an isolator.

No! Bad! :whip:

So, when the hose is disconnected the QD shuts off flow?

I am just curious as I would not always want to have the gauge hooked up.

Yeah I agree with you. This is temporary instrumentation and is not meant to be a permanent install. That said I have mine in the cabin for about 3 months now without a problem. At some point I will remove it once I have the fuel pressure dialed in. I even tested it in by removing the gauge thus creating a leak while at idle. Only a little bit of fuel squirts out due to the small i.d. of the 1/8 line, not bad at all. Probably a lot less than if the oil pressure gauge line sprung a leak.

No it does not! Once you have your fuel pressure dialed in, you remove it and put the old banjo bolt back.

Yeah, you have it rigged nicely and it's not much of a concern. It's just one of those unsafe practices that really shouldn't be left connected forever. :)

On second thought, I will include a plug so that the tapped banjo bolt does not have to be removed. To disconnect the gauge, you remove the quick disconnect fitting and install a plug in its place. If you want to take a fuel presure reading again, you remove the plug and install the QD fitting. Is that better?

In addition to being able to see the pressure one has..
I think you need to make this device to where it can be adjusted from IN the car While driving..

That seems like a way the differences.. IF ANY.. would show up...

That should not take much time to invent ... you have plenty of spare time..
LOL

That would be cool but it would raise the price considerably and no one would want it. ;)

Funola, nice work

Let me just make sure I have the right idea of whats going on here. Too use your device I would hook up your adjustable banjo fitting with the hose and gauge in place of the old banjo containing the ball and spring, right?? Then after running the car for a while and making the adjustments for 19 psi I could remove the gauge and just check the pressure when needed?

So I would need your adjustable banjo for all my cars but just one gauge and hose?

Hopfully this could be applied to the "M" pump as well.

Thanks Stevo.

No, the adjustable fuel pressure relief valve (inside a banjo bolt) and the fuel pressure measuring (banjo bolt) are different items and go into different ports of the IP. After making the adjustment of the fuel pressure, you can remove the gauge and it's banjo bolt and put the original banjo bolt back so you can use it on a different car.

It should work on the M pump if the thread pitches are the same.

The relief valve doesn't need to be adjusted. Stretch the spring to 27mm as suggested by the service manual and you're done.

Thanks, I see, I will go back and read the entire thread, obviously I missed something:o