Cat 3208 Injector Pump Bench Testing

[CrispyCritter]

I'm running some injector pump bench flow tests to check the fuel amount outputs from all 8 plunger pumps.
I'm using a new set of injectors attached to the pump.

Would anyone know what the maximum allowed difference between all 8 outputs is ?
I've done a rebuild and spent a lot of time trying to get all the metering sleeves as close as I can to the
CAT specified +- 0.050 mm (max) difference. But when running a bench test with fluid, i've got a difference of up to 12% between all 8 outputs!

Looking at some videos on YouTube of 'professional' rebuild tests, I can see fairly different levels in their fuel
collection tubes. So I'm guessing these pumps are a 'swine' to set up perfectly.

Bottom line, how much difference would be noticeable on a running motor?

Thanks for any input here.

 

[Coaldust]

It would be interesting to see your outputs.
Are the LH and RH outputs all randomly different? Or, is the main difference LH vs RH? I was just wondering about the crossover levers.

Are these new P&Bs ?

What is the engine serial number?

 

[CrispyCritter]

Hi CoalDust,
This pump is from a Ford truck. Probably 7000 or similar with a turbo as it had the fuel trim vaccuum unit on it. No idea of s/n. The pump does have two 'dog tags' .... OR3193 -NKDE and OR2373 1150-0977 and another number which maybe 7C8931 (corroded label)
It's going on (what should be) a 250hp Turbo motor in 1984 Thomas bus. (bus service record states 'rebuilt motor with 70k miles since) The pump in that had an issue with 'gummed' and seized sleeve pumps which dissabled the motor running (sitting for years). Inspection inside the pump revealed the head of a Lever Cap Screw had broken off a seized Pump Lever.
As This is just a 'hobby bus', i've embarked on a sort of Diesel Mechanic crash course to attempt an inexpensive fix in my retirement. I bought this other pump to tinker with and learn all about them as the 'fixed up' pump on the nus was clearly not set up right.

Anyways ..... Balance between left and right banks indicate no crossover lever missadjustment.
P&B's ?. Not sure what you mean by that, but i'll assume you mean the sleeve pumps. No not new.
I used the Dipaco D6V4141 calibration tool and was super careful to torque the cap screws exactly to specs. Finally using digital guages to confirm adjustment of the Sleeve Control Levers relative to the Sleeve Pump bore Land.
Bench test .... see my 'poor mans' nench test setup pic.;-/
I run around 100cc into the bottles thru the attached new injector set. Then measure the contents of each injector. Last run had a ~10% max difference between all.
I'd really like to know what CAT specifies as a max difference?
Thnx

 

[Truck Shop]

I would be concerned using that type of testing that each bottle drained every last bit
for accurate test. I suppose it would work.
*
reminds me of my days in the milk barn, lol.

 

[Coaldust]

10/10 for creativity.

 

[CrispyCritter]

Thnx for milk barn ref.
..... made me laugh.
Lacking an answer on the forum about variance specs., i'll visit my local injector pump rebuilder and enquire about what their spec on rebuild/test is.
Hopefully they'll accomodate my question civily not tell me to 'sling my hook'! (for all the ole mariners out there)
Report to follow if solved.
Happy thankgiving all

 

[Coaldust]

I had to ponder this for awhile. Caterpillar provides a volume spec in the TMI. You use the “OT” number on the valve cover to look that up. That’s how it’s approached.

There is no percentage max difference spec. I guess you could calculate one, once you had the OT information.

But, rule of thumb is roughly 2% max, when spinning a pump on a stand. That’s from my notes from when I went to sleeve metering class.

How will you even measure that by draining a few cc’s from a water bottle? 2% will stick to the sides?

 

[CrispyCritter]

Now I'm seeing numbers ..... 2% eh? Is this probably my target numbers?

I understand your skepticism on my thoroughly 'scientific' method (ahem) but
i'm pumping at least .4 cup (3.5 oz - 100ml) then draining every bottle equally.
All bottles will have a very similar amount of residue and all bottles are the same type and drained vertically into the measuring tube over the same time until no further drips occur.

I don't have access to the TMI and as mentioned before, I don't have any numbers from the 'donor' Ford this pump came from.

My lifetime engineering experience tells me there 'should be' a spec for a pump with 8.5mm dia plungers whatever the CAT setup for a particular application says. (i.e. rigid cam pushes up plunger pump x8 .... no other adjustment than sleeve position). maybe, depending on the hp output of any particular motor, they may allow more or less difference.

I'll experiment swapping the injectors around and see if my numbers change. Could be this fabulous new injector set is not so fabulous. Could even be knockoffs? (CAT boxes which clearly state Made in ....... you guessed it .... Chynaaaa)
Anyways ..... thanks for your comments

 

[Coaldust]

I think your set up is pretty cool.

Since that is an OR pump, good reason to believe it wasn’t set up properly to begin with. Those are shipped with genetic calibration, set point, hi idle/ Low idle and I’m sure the governor spring is incorrect.
Same for the torque spring stack.

You might get the delivery balanced, but you don’t have any idea if the governor is set correctly for your application.

If you are taking this project seriously, research an appropriate AR# number and a OT# and set the injection pump up for that.

 

[CrispyCritter]

Thank you again for your input.
As mentioned, this pump was to fiddle about with to get an understanding on these things.
I'd understood the Ford 7000 with 3208T was also 250hp so thought the governor stuff was compatible.
However, I'll probably swap it out with the existing pump just to see how it runs at low idle etc. and how clean it runs.
The original pump is going to get a good work over WITHOUT touching any of the 'Torque Setting' stuff but I'll just attempt to set up all the plungers to spec then reinstall and see how it works.
If it runs better, that'll probably be it, but if still rough, install the injectors and check valve stuff while the covers are off.
Unfortunately, as that motor has been replaced and there are no labels on the valve cover nor 'dog tags' on the pump, I probably won't be able to narrow down any specs.
All I know is it is a 3208T and should be a 250hp model.
I'll probably end up to just advertise it for sale with the Alison trans and see if anyone wants it. (as a bonus, with a free bus to transport it in!
(my original plan was to turn the bus into an RV 'schoolie' but that whim has long since expired)
Finally.......
Q. Would you know if there usually are serial numbers stamped on the 3208 blocks anyplace?
Regards

 

[Coaldust]

Thank you again for your input.
As mentioned, this pump was to fiddle about with to get an understanding on these things.
I'd understood the Ford 7000 with 3208T was also 250hp so thought the governor stuff was compatible.
However, I'll probably swap it out with the existing pump just to see how it runs at low idle etc. and how clean it runs.
The original pump is going to get a good work over WITHOUT touching any of the 'Torque Setting' stuff but I'll just attempt to set up all the plungers to spec then reinstall and see how it works.
If it runs better, that'll probably be it, but if still rough, install the injectors and check valve stuff while the covers are off.
Unfortunately, as that motor has been replaced and there are no labels on the valve cover nor 'dog tags' on the pump, I probably won't be able to narrow down any specs.
All I know is it is a 3208T and should be a 250hp model.
I'll probably end up to just advertise it for sale with the Alison trans and see if anyone wants it. (as a bonus, with a free bus to transport it in!
(my original plan was to turn the bus into an RV 'schoolie' but that whim has long since expired)
Finally.......
Q. Would you know if there usually are serial numbers stamped on the 3208 blocks anyplace?
Regards

These 3208 threads pop up every six months or so. We have gone over the process of playing detective to match major components to the appropriate serial number prefix .

Check out some of the other threads. Maybe Nige or OzDozer will chime in. OzDozer has a huge microfiche library.

 

[Megawatts Part]

Those 3208 sleeve metering pumps can be tricky on the bench if you don't have the specific Caterpillar fixtures. The governor settings are critical and easy to mess up without the right tooling.

If you're seeing inconsistent fuel delivery, double-check the advance unit as well those are notorious for sticking on older units. Good luck getting it dialed in!

 

[Truck Shop]

Test Stand results.

 

[CrispyCritter]

Does anyone know if serial #'s are 'stamped' anyplace?
My motor does not have a valve cover label

 

[Coaldust]

https://www.heavyequipmentforums.com/threads/help-identify-cat-marine-engine-please.41293/

 

[Coaldust]

Then, check out this thread.

https://www.heavyequipmentforums.com/threads/3208-identification.98165/

 

[Truck Shop]

One small but notable fact with the 3208 and it's 2 ring and three ring circus pistons.
The 3208 requires a 42* angle for cylinder honing cross hatch only achieved in a wet
tank honing machine at a 125 rotation speed and stroke per minute at 37. 3208 uses
a shallow hatch angle unlike most other engines at 45*. trivia.

 

[CrispyCritter]

Any chance you could be more precise?

 

[Coaldust]

It’s a long, sad story. Ford had a significant role in the design of the 3208. Caterpillar, excited to pursue the on-highway market, capitulated to Fords cost-cutting demands.

Backing up, to understand the 3208, a basic awareness of the 1100, 4.5 bore family is required. The 3150, 1160, 3160, 1140, 3140, 1150, 1145, etc…….

it was plagued with problems, updates and re-design until it was discontinued.

Any chance you could be more precise?

 

[Coaldust]

This is what you need. Toss that sleeve metering pump and use the in-line, scroll style 1100/3208 fuel pump.

Now, you have something to work with.