Crazy P7100 question...

HRDROKN

HRDROKN

Prestige Worldwide
Joined
Apr 16, 2008
Messages
621
I just need to throw this out there and hopefully get some good feedback as to why not to do this.... other than "you'll screw it up"

If I have a stock pump that's balanced within Bosch specs and I wanted to get more flow by rotating the barrels.... could I accomplish this by putting a dial indicator on each barrel and rotate each the same? It would seem that I could do this without losing the balance between barrels?

What looks good on paper, doesn't always work out so well in application....

:doh:
 
theroretically it would work, but the cut of the helix on each plunger and the orientation of each barrel would only need to be slightly off to "screw it up".... I wouldn't recommend doing his, though I have thought of it as well at one point of my life.. It just isn't accurate enough..
 
would be interesting experiment but its only 300 bucks for my local injection shop to max barrels, balance and flow. maybe someone else could answer with some technical evidence
 
GOLDDUSTERS5703 said:
would be interesting experiment but its only 300 bucks for my local injection shop to max barrels, balance and flow. maybe someone else could answer with some technical evidence
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That would be interesting... I dropped my 3rd pump off today to have the barrels maxed and balanced, but it still seems to be a good question.

I wonder how closely the barrels are balanced +/- xCC's ?


:Cheer:
 
CTDYoungGun said:
Depends on what shop you have do it...

wear on the b&p can throw some error in too...:Cheer:
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So that goes back to the original thought.... how much more error can you possibly introduce by rotating each barrel .010" (for example) on a fresh pump?

:what:
 
Mark the barrels, move them all the same and see if it runs right, if not, rotate the barrels back to the starting point marks.

Are you looking to build a maximum effort perfectly balanced machine or just play around with the pump and experiment. I'm more of the experiment type, don't have the funds to build 1,000 HP professionally balanced and blueprinted motor.
 
Big Blue24 said:
Mark the barrels, move them all the same and see if it runs right, if not, rotate the barrels back to the starting point marks.

Are you looking to build a maximum effort perfectly balanced machine or just play around with the pump and experiment. I'm more of the experiment type, don't have the funds to build 1,000 HP professionally balanced and blueprinted motor.
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Ya... more of the experiment type myself; just don't want to lose the work that I already paid for by screwing around too much. Even if I mark the barrels and need to go back.... it could still be off by a thousandth either way, so is that enough to make a difference? I would think not, but then again I have not seen the effects of small moves on the bench... maybe a couple thou is a lot?

Anyone have an idea how close each barrel needs to flow to be considered balanced? When they measure the flow is it recorded in cc's for a given time or cycle??? How is that done?

:Cheer:
 
You are assuming the barrells are balanced now! You may be suprised, not to mention Cummins spec. and what a good shop can/will get them balanced to are very different!
 
HRDROKN said:
Ya... more of the experiment type myself; just don't want to lose the work that I already paid for by screwing around too much. Even if I mark the barrels and need to go back.... it could still be off by a thousandth either way, so is that enough to make a difference? I would think not, but then again I have not seen the effects of small moves on the bench... maybe a couple thou is a lot?

Anyone have an idea how close each barrel needs to flow to be considered balanced? When they measure the flow is it recorded in cc's for a given time or cycle??? How is that done?

:Cheer:
Click to expand...


I work on these pumps every day...there is no way they will be equal even if you measure and turn them all the same...and if you tried to set them back where they were you could get close, but they would never be as accurate as if they had been set on a test stand.

To be considered "balanced" the pump should be set within 2 to 4 cc's max variance between cylinders at idle (as idle is below 30cc's on pretty much all application stock or sport) and that should net a max variance of 8 or 10 cc's at max fuel...

If you really want more fuel that bad, there are plenty of shops more than capable of racking the barrels to max fuel, then balancing them...it's not rocket science...some do better jobs and spend a little extra time getting them exact, so look for shops with good reps already...$.02
 
HRDROKN said:
When they measure the flow is it recorded in cc's for a given time or cycle??? How is that done?
Click to expand...

Fuel "flow" is universally stated in cc's flowed per 1000 strokes. So if someone says they have a pump set at 500 cc's, that pump (if accurate) will flow 500 cc's in 1000 strokes (or revolutions)

So to answer your question, it is measured in cycle, not time...because rpm could alter the measure if time was used :Cheer:
 
CTDYoungGun said:
Fuel "flow" is universally stated in cc's flowed per 1000 strokes. So if someone says they have a pump set at 500 cc's, that pump (if accurate) will flow 500 cc's in 1000 strokes (or revolutions)

So to answer your question, it is measured in cycle, not time...because rpm could alter the measure if time was used :Cheer:
Click to expand...

I always thought that it was measured in Cubic Milimeters per 1000 strokes.... Not to say it couldn't easily be converted, but on the test benches I've seen its always been cubic milimeters....
 
XTrEmE9156 said:
I always thought that it was measured in Cubic Milimeters per 1000 strokes.... Not to say it couldn't easily be converted, but on the test benches I've seen its always been cubic milimeters....
Click to expand...

Looks like the mm3 is used to indicate the displaced volume of one stroke... from the Bosch book.

Well my barrels are fully rotated and balanced now.... so no messing with them anymore. Thanks for all your inputs!
 
Ok, novice question time.

On the data plate for my '94 175hp engine, it says at rated hp, fuel consumption is 83 mm3/stroke. Which is the same as 83 cm3/1000 strokes. Is that for a single barrel, or for the entire pump? When pumps are rated at 400, 600, 800, etc. cm3, is that for the entire pump, or single barrel?

I really need to pick up that Bosch inline pump book.:bang
 
When a pump is said to have 500cc's it will pump 500cc's per cylinder, not total...

as far as fuel consumption on your pump, I don't know how they figure that, because a stock pump has a lot more then 83cc's...more like 140-160
 
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