internal injection pump pressure

[Quantum-man]

1)Are we saying that a good pump has a minimum internal pressure range?
2) That a car (my 1st QuantumTD) that does 52mpg US must have a 'good' pump?

...Approx 160000 on the engine nothing changed apart from bare head AFAIK... When I changed it I was a virgin diesel lad and naturally assumed that pressurised coolant was due to the giant cracks between the valves; and that I'd caused them by adding water to a hot engine .... (It was on the side of the road and I had just suffered a burst top rad hose and the family was nagging me ...)
Being the kind of chap who never throws any thing away I still have original 'made in Germany' head in the back of the shed... Maybe it is still good.

[tawney]

Another option for attaching a pressure gauge on the pump: take a spare OUT bolt, drill and tap the top of it for a fitting. In my case, an off-the-shelf mechanical oil pressure gauge, the fitting needed 1/8" pipe threads, a tap that was already in my SAE tap and die set. You can easily check a pump in the garage by turning it with a drill, or check it in the car by temporarily replacing the out bolt.

[libbybapa]

That is indeed a way to test the internal pressure, unfortunately, unless you leave the gauge and bolt on the engine, it is not a good way. The reason is, that the orifice in the out bolt is specifically sized to resist the flow of diesel and an integral part of the pump internal pressure system. The out bolt orifice could wear or be a slightly different diameter and so your reading would be meaningless. If however you decided to install the pressure gauge on your engine as a permanent fixture, it is a good way to go.

Andrew

[Fatmobile]

I think it would be hard to drill and tap it without ruining the screen inside the "OUT" bolt.
Without the screen, any junk wouldn't be caught before it clogged the small "OUT" bolt hole so I don't think it could be used for extended periods.
Yep, the "OUT" bolt is matched to the pump, checking the pressure, then changing the "OUT" bolt wouldn't leave you with valid info about pump pressure.

[hagar]

Now that the barrel is getting down right nasty ---this posting is more important than ever.

SO ? , bite the bullet and use a gauge.-----it is sooo simple and soooo important for good SMILEAGE.

yes Fraulein Bunny Bondo is better than ever , in Nov 2007.

Beauty is skin deep ? , with Bondo it is the other way.

hagar uses optimum numbers all around , like if a tad higher or lower pressures work best ? --- that is what I use.

hagar.

PS my Email address has been changed , if important send me a PM .

[tawney]

I took the five out bolts that I have, installed each in succession on the same pump with the same fuel, and turned the pump with the same drill using the same pressure gauge, and there was no observable difference in pressure: about 60 psi at about 800rpm. The pumps they came from were a mix of 107, 108, and 109. None was a TD pump; I did not measure outflow rate.

Page 11 of the Bosch manual on the VE pumps agrees with both Andrew and Fatmobile stating that the pressure-control valve and the out bolt, (overflow restriction,) are 'precisely matched to each other' but I couldn't confirm that there is any difference between outbolts with the ones that I have. It could be there was some slight difference in pressure that was too small to show up on my pressure gauge, and, of course, five out bolts can not be said to be representative of all of them, only a random sample of a few. It could also be that at higher rpm the difference would be more pronounced, but for what it's worth, these are my results. Somebody with better equipment should run a similar test and let us know. And maybe he could also let us know where to get those pedestals from the na diesels that are 'readily available'?

Just for fun, while I was doing this I dumped a quart of 40 weight motor oil in the galon of ULSD I was using and only saw a 6 pound increase in pump pressure. More tests somebody?

One result I'm fairly certain of, however, in all this playing around with pump pressure: my Caddy was getting 43 mpg (highway) before I attached the pressure gauge to it. With the gauge I was able to adjust the pressure up somewhere close to the 76psi @1000 pump rpm that Hagar recommends, and on a 320 mile trip today I got 52 mpg.

So, I think you guys have got me hooked on this pump pressure issue. Sometime soon I'm going to get a tachometer that runs off a transducer attached to the injection line, and a bigger/better pressure gauge so I can look at the pressure along a broader rpm range even on the pumps that are sitting in my garage.

Steve

[hagar]

Bravo tawny ----more testing ? -- IMHO ---we just started.

Andrew in Flagstaff AZ is close to getting the highest award from BOSCH ----EH ? Iron cross with Kanola leaves.(Blue Agave ?)
I just want to say that I agree with a lot said on this posting.

107A -----XXXXX--numbers and up -----are similar inside.

Pressure regulator valve and Outlet bolt orifice was precisely calibrated to work together ---yes Valves and Bolts with same number will work in ANY other pump of the type..
Bosch calibrated to # 2 diesel (no longer to be had here).

SO ? we are making progress. --knowing the flow we can calculate internal pressure --likewise if we know pressure --- we can calculate Size of orifice.--Kabish ?.

A barrel is hitting 98 US Dollars -----SO ? hagar does NOT worry -----but some of you may --EH ?

hagar.

PS : if you do not have FUN now ? you will NEVER have FUN with a Rabbit IMHO.

[libbybapa]

And maybe he could also let us know where to get those pedestals from the na diesels that are 'readily available'?

All I know is that I've got 2 of them, so I'm all set.

Andrew

[libbybapa]

--knowing the flow we can calculate internal pressure --likewise if we know pressure --- we can calculate Size of orifice.--Kabish ?.

Yes, but, you would need to calculate the flow without a restrictive orifice and then calculate it with the restrictive orifice in order to take into account the wear in the vane pump. The test might still not be accurate as it wouldn't be taking into account the reaction of the vane pump to resistance (higher internal pressure). And so, although a flow rate test is very useful information, IMO using it for calculating internal pressure would be more difficult and less accurate than simply attaching a gauge.

Andrew

[surfcam]

With the gauge I was able to adjust the pressure up somewhere close to the 76psi @1000 pump rpm

I was wondering how you where adjusted internal pump pressure.

[libbybapa]

From page one of this thread:

Right here:


It is a simple plunger spring assembly. Under pressure the plunger moves up and opens the passages on the side and routes fuel from after the vane pump back to the pump inlet. The indented center of the top of the regulator is a metal plug that can be tapped down slightly to increase internal pressure. To lower the pressure, the regulator can be removes, placed inverted in a vice and tapping on the bottom of the plunger should push the plug the other way.

Andrew

[Vincent Waldon]

I was looking at this thread again and thinking... there's lots of room on the lid itself, and the oil pressure gauge fitting is tiny (10x1 hole)... any reason not to pull the lid, drill and tap a permanent hole, and have a permanent way to measure internal pressure ?? Now you can swap OUT fittings and pressure regulators at will and always have a gold standard way of measuring.

In fact, you could run a short piece of nylon oil pressure hose to another electric pressure transducer mounted somewhere in the engine compartment, and use a switch on the dash to toggle between oil pressure and fuel pressure ??

Gauges gauges gauges... love 'em.



Vince

[tawney]

Vince, you mean like this?



Just make sure the fitting doesn't protrude into the pump enough to interfere with the governor.

[libbybapa]

Yes, that would work as well, and is a good solution for a permanent attachment of a gauge, but, moreso than the banjo bolt, is limited to the single pump.

Andrew

[3Bunnys]

The blond notes with interest that something as expensive, precisely machinely, finely tuned, intricate, finely engineered, that is calibrated by specialist with umpteen dollar machines and sensitive to contamination as a Bosch IP is,
is adjusted with a HAMMER.....

And now she wants me to explain it to her.... Help guys... its hard enough to explain simple things like on/off switches
Richard

ps... I will be drilling a spare "OUT" bolt tonite,,,,,/// the blond was definitely impressed with "tawney's" work ... I will have her deliver some beer as award!!!!