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.
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?
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
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.
10/10 for creativity.
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
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?
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
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.
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.
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!
Test Stand results.
Does anyone know if serial #'s are 'stamped' anyplace? My motor does not have a valve cover label
HeavyEquipmentForums
Then, check out this thread. HeavyEquipmentForums
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.
Any chance you could be more precise?
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.
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.
They had to, jimmy had the detroit, Ihop had the DT, dodge didn't care.
Nope, I used all my precise at 12:32 pm.
Interesting beast. That fits a 3208T?
At one point it did. Might need a front cover from a 3150. 1100 series engines are like Pokémon. You have to get them all!
I agree, 10/10 for creativity, but remembering back from diesel school, you will never get that pump dialed in like it needs to be with your setup. No offense, but a test bench uses calibration fluid for starters, and the fluid goes into graduated cylinders, marked in CCs. Find a diesel shop to set it up.
Thnx for comment. Admittedly, i'm using std. dot diesel for my test but i do empty individual bottles into a ml graduated tube and record the volume from each injector following each run. My original post was an effort to discover what the 'official' acceptible fuel % varience between cylinders was! I've got the mechanical setting info but cannot find bench test info.
What is the engine going into? If it's nothing special just get it close and install. I doubt you'll feel the diffence.
@thepumpguysc is probably still rolling around on the floor.
A Strong possibility as I haven't seen any comment from him! ...... very glad to provide you folks a good laugh though, especially in these strange times.
Lol. I get it, I like to do things myself whenever possible, but calibrating a fuel pump is pretty exacting. Getting them even is really only half the battle, a specific amount of fuel at a specific RPM is the true goal. There's also the matter of high idle, no load RPM. I don't know if you messed with the governor yet.
I haven't messed with the govenor (haven't dared nor want to) Or ... the Torque control (set point) Nor the Fuel Ratio Control. What i did do is make a 'calibration pin' which was 15.94 mm long (+-.01) and set the low idle lever to 9mm for the pump calibration process. I bought Dipaco calibration tool (calibration pump substitute) and used to set the pump control levers. Following setting all levers, i used a dial guage setup to verify lever position relative to each pump 'land'. I certainly got them all within .050mm (CAT doc i read). I've seen several professional pump rebuild shop videos (youtube) demonstrating a fluid bench test. Fluid levels in their collection tubes look far from equal. How unequal is the question. Finally, if a me hanical calibration process is all that is required, why conduct an actual fluid test after. Hmmmmm. My logic tells me they must be qualifying their adjustments ..... and therefor must fail or pass a 'tollerance'. What is that tollerance? There must be some published numbers someplace. I'm putting this on my 3208T1984 Thomas school bus to see how it runs but this pump came off a ford 3208T truck. It has two tags .... pic. OR2373 and OR3193
Those numbers you're looking for are available for purchase, if you're running a fuel injection pump repair business, probably since the EPA started mandating emissions. Chances of finding them on the world wide web are pretty slim.
So i'm discovering. My hope was to get an answer from this blog. Alas, not to be
There's only one guy on here that would know, and you aren't getting them from him, I guarantee it, haha.
Are you refering to 'SC' or Ronnie Barker?
I have a friend, 25 years at cat mainly working truck area, he has rebuilt countless pumps of 3208, 3406. He still does one now and then at his farm, his never were run on test stand, best cat pump guy I've dealt with.
Ok, two maybe. I guess I didn't take into account you might be able to find it in a Cat bible somewhere.
Don't bother trying to set one up, just buy a good running engine for cheap and swap the whole engine over.....lol
It’s not a secret. Pick a OT number and look it up. Or, have someone look it up in SIS in TMI. Or, go to eBay and get the microfiche.
I rebuilt many 6cyl sleeve metering pumps and new scroll without spinning them. The high-horse, E-rated ones, I occasionally had Seattle do them. Because that’s much more critical. It’s been a long time since someone asked me to work on a 3208. Occasionally, NC Power System gets one from a government entity, or from Bristol Bay. The fuel systems were a money maker. Those cheezy Stanadyne Pencil nozzles and crappy sleeve metering pumps were seizing up from water contamination, all the time. Good times. I liked them. Lots of smoke and noize. Loved the pre-combustible chamber chorus.
Oh, and those sheet metal oil pans soaking in the salt water bilge brine. R&R engines just to replace an oil pan, many times. Labor intensive jobs. And, while we are here, let’s do this and this and this, since we have access. lol
Holy shlt, this sounds like misery times a million...
Easiest way to replace the oil pan is when the engine is tits up after all
A young feller doesn’t know any better. Soaking up that over-time and double-time on Sundays. Sometimes, the tricky part was aligning the shafts and dealing with the inevitable new vibrations. Waiting for the hull to settle, weather, humidity. Making shims, sea trials. That soaks up the labor.
Just to rule any differences out, maybe it's worthwhile swapping injectors between the lines to see if the outputs stay the same. I've had some new pencil injectors recently that didn't work properly.
I did swap 3 of the injectors around between high and low delivery ports. Numbers changed and became more balanced. So ..... Just researching what 'Pop Testing' is all about. Going to get a simple tester and compare these 'new' injectors for adjustment. Hopefully won't destroy them altogether, but, heck; just gotta FAFO. It's never too late to learn! (good stuff I hope)
When testing the pencil injectors if they are the ones with the caps on top, they need to be removed while testing or on other types, the little screw on the side needs to be removed, otherwise the injectors hydraulic lock and the needles won't open. I never worked out why they don't do that while running normally, must all happen too quickly I suppose.
Update. Thanks for the injector suggestion. I got a Pop Tester and sure enough ...... couldn't figure why they hydraulic locked after a few pumps. Must have missed your last message about removing the caps when testing. DOH! Had to adjust a couple , but not by much. My CAT book says to set the 1W5829 injector to 2500psi then open the 'stop' 3/4 turn ....... generally found them all originally opening around ~2300psi but several had the stop setting way over 3/4turn! Anyways, they all pop n chatter 'lovely' with good spray pattern. Back on the pump, I've got pretty good at stripping down to set the sleeve levers and swapping pumps around to test whether my bench runs change. No significant difference tho. except #5 seemed to result in the lowest volume dispensed even after swapping pumps around. So, moving onto the cam and followers, checking dimensions of cam follower lift revealed no significant difference (+-.0005") between #5 and adjacent pump followers (measured to pump seat). Checking and re-checking sleeve lever adjustment didn't solve the different volume dispensed (all within .0005" of each other) Tried re-setting the levers with the shaft play pressed down then up etc. etc. However, and this is a tad strange, depending on the rpm's and govenor position of the bench test, the % variance of fuel delivery between between pumps changed. Repeatability at the same settings also does not appear constant (i.e. 400rpm at 1/3 govenor for 4 minutes ..... not exactly same results each time!). Anyway, I got the TMI for the application this pump was assigned to (from CAT) and have checked the Fuel Setting (0.157") and Air/Fuel Ratio (0.122") as per CAT data. It's going in a 1984 Thomas School Bus which is reported as a 3208T-250hp. This pump came from a Ford Truck also a (3208T-250hp) so ............ should be ok??? (please correct me if I'm wrong tho) (Bus motor has no Valve Cover tag and I haven't found a stamped s/n anyplace yet so cannot research Arrangement.) I'll follow up how it runs when this years snow has gone. To conclude ..... maybe parts in this pump have too much wear? Sleeves and pump shafts all look good, as does the camshaft and followers. I did read someplace however that the cams can get a little 'hollow' on the lifting face , but I don't see any significant wear here. Maybe ..... and this may be the answer about different fuel delivery versus rpm, is wear on the sleeve operating levers. There is a fair amount of 'play' in all of the lever-to-sleeve grooves ...... and although the levers are adjusted to press on the bottom of the sleeve groove, maybe the sleeves kind of 'rattle around' at different rpm's and 'choke-off' the 'bleed port' with some variance? .....anybody care to comment? OK .... this old Brown Jersey Cow is done for now
Oh ..... and happy new year!
From memory, while testing the pumps on the test bench the governor was only held at full throttle. I don't think there was any tests for different throttle positions. This was about 40 years ago, so that may not be the case. I would think that your pump would be fine for your application. Sometimes the sleeve levers on the rack used to wear where they engage with the sleeves & need replacement, but I think that was rare. Happy New Year to you too.