3500 Fuel Issue

jaluhn

Member
Got an issue with a Ford 3500 tractor I'm rebuilding and wanted to get some thoughts.

It's a 65 3500, 172 diesel with a inline injection pump (Simms Minimec) I bought it as a basket case with the head off and significant rust in the bores. Seems the head was pulled about 10 years ago and then owner deployed and while he was gone the cover blew off and it got rained on. Wound up needing sleeves in all 3 cylinders. The injection pump also looked like it was exposed to water. Injectors had some rust but mostly surface. I've got the engine back together and in the tractor now but I cannot get it run - as far as I can tell it's not actually injecting fuel.

I've got clean fuel to the pump, good life pump pressure and the low pressure side has been bled multiple times. I'm getting fuel delivery and I've bled the injector lines several times and cranked it a ton, even to the point of having it running on starting fluid for a bit. Still no sign of any fuel actually getting injected. With the lines loosened I get a good squirt of fuel from each line.

The injection pump did have rust problems in the delivery valves and I wound up having to disassemble the hydraulic head, clean the delivery valves and seats and lap to the valves. The actual plungers and bores were clean with no signs of rust or damage. They felt tight in the bores and all of the fuel flow ports were open and clean. All of the parts were put back in their proper locations and the plungers are engaging the rack properly. The rack moves freely and the governor seems to be working properly. After fixing the delivery valves I get a nice clean squirt of fuel from each port and the shutoff lever does stop fuel flow. The quantity of fuel *seems* about right though it's hard to say for sure. Should be enough to at least make some smoke anyway. The cams did have some rust on them when I checked but I can't tell if it's new or not and there doesn't seem to be enough damage to cause problems.

I also removed the nozzle holders on all 3 injectors and cleaned and inspected the nozzles and plungers. All were clean, seemed to fit well and were free. I don't have a pop tester yet so I can't fully verify proper function, but I didn't see anything that looked horribly wrong.

When cranking I get no smoke or evidence of any fuel injection. I even tried connecting on of the injectors sideways so I could see the tip and I saw no evidence of fuel.

So, any thoughts? Everything I've looked at has seemed ok. It would not surprised me if it was a bit off somehow, either from damage or from me messing up putting something back together, but I can't think of anything that would fit the symptoms. I'm definitely getting flow to the injectors, and it's making enough pressure to lift the delivery valve (1-200 psi???) and delivery a healthy slug of fuel, but yet apparently not enough to lift the injector. About the only thing I can think is I still have air in the system somewhere. However, with a much as I've played with it (probably close to 30 minutes total cranking time) I find it hard to believe there's not something else going on. On the pickup (ford 6.9L) with a new pump, blown out lines and new injectors I don't recall it taking more than 1-2 minutes.

This things seriously starting to make me pull my hair out... and I don't have enough left to do much of that!

Thanks,
~John
 
maybee a 175 anyway.. :)

if you have good fuel all the way to te injectors.. and it will run on go juice.. I'd pull the injectors and have them rebuilt...
 
Meh, what's 3 extra CI? It's the economy version... :D

It'll run on starting fluid but it dies as soon as you stop squirting it. So still no fuel. It all come back to not actually injecting fuel, which to me means either the pump isn't making enough pressure or something's keeping it from getting to the injectors. About the only thing that makes sense to me is I've still got air in the lines somehow.....

I am in process of fabricating a homemade pop tester, that's going to be the next step.
 
i pull gear tractors to bleed them.

pop test them on cardboard right at tractor.. see if you are getting any spray...
 
SOS trans, so pull starting is a no go.

I have tried checking on the tractor and I'm not getting any spray.
 
You're not going to like to hear this.... but if you had the head off the pump and the delivery valves removed from the head... you need to have the pump spill timed. The issue being that number one needs to be timed to a reference and 2/3 need to be degreed off of #1. This way you know with confidence when you install the pump to the flywheel timing marks that the time is right so to speak.
Second issue... your injectors, for whatever reason... are not firing.
This is probably one of those times where you're best off to pack the whole works in a box and send it off to an injection shop. Be up front with them about what you've doen so they take the time to go through it and get it right... and just have them install new nozzles in the injector bodies.
When you get it all back make sure you install the pump on the correct stroke on the engine if you're not already positive that it isn't 360 degrees off...
Again, I say this... I know you probably don't want to drop that kind of money on having the pump spill timed... but IT WILL BE CHEAPER THAN A MELTDOWN or cracked piston if you do succeed in getting her running with improper timing.

Rod
 
Understand the point you're getting at, but why would you have to redo the timing just for having removed the head? I did not do anything that would have changed the pluger or sleeve positions in the head and was careful to retain all of the shims in the proper positions.

I'll admit I've never heard of spill timing but I was able to find some info on it, and it does make sense.

However, that still leaves the main issue - the lack of any injection. My guess is that I've still got some sort of delivery valve issues.

Next step is going to be probably pulling the pump back off and doing some more bench testing. I should have a pop tester setup in the next few days, and I should be able to use that setup to bench test the pump output pressure too. I'll probably also try to do a spill timing procedure on it now that I know about that.

I understand the point you're making about the cost of messing up the fuel system, however I don't have the budget to do the full professional rebuild and nothing that complicated about working on these.... just need to be very careful, cautious and meticulous. For a backyard ranch tractor I serious doubt it's ever going to get run hard enough to cause serious damage even with the timing off a bit. Turns out my pickup was running about 5* advanced for over 10k miles and it doesn't seem to have hurt that motor.

Beyond that, honestly it'd cost me less to rebuild the motor again than getting the injection system overhauled.
 
Another thought - what's involved in changing over to a Cav rotary pump? I've got a 201 short block that has a Cav pump on it. No filters or low pressure fuel lines and I think it's missing one of the injection lines, but the pump and gear are there. Does the gear cover backing plate have to be changed? I know the timing gear is different which would obviously involve pulling the front cover.

Course, I have no clue if that pump is any good either - it looks just as rusty, only saving grace would be it shouldn't have gotten and water inside.
 
It's a while since I read theory on those pumps... but as I recall the settings can change with head removal....
If you intend to keep screwing with it yourself at least get a Ford service manual for the tractor that will cover the pump setup. Don't get an I&T book because it won't cover the pump.
To me tho... the MOST important thing to the operation of that engine is the pump and injector setup.

Rod
 
Agreed. Know where I can find a Simms pump manual? The manual set I have the Ford 3400, 3500, 4400, 4500, 5500 & 5550 reprint manual set off this site and has no info about injection pump work beyond R&R. It does have injector rebuild info. I have found a Dexta service manual that has good info on a very similar Simms pump.

For what they do, injection pump are actually pretty simple pieces of gear. There's really nothing much different in working on the injection pump and rebuilding an engine, just much finer tolerances and more adjustments. The tricky part is replacing parts and the calibration, but most of the adjustments you don't have to mess with. I've had good luck working on Bosch VE type pumps this is just by first inline.

IMHO injection systems are much less sensitive than the common perception. Look at how much people run waste motor oil and veggie oil in diesels.

I used to be scared to mess with injection systems at all, but once I finally got into them it turns out that things aren't as scary as they seem. The big issue is of course that it's very easy to make a mistake that bites you in the rear later. On the other hand, for a low use ranch tractor that doesn't get run hard you can get away with things not quite being perfect, and it's also hard to justify throwing the kind of money around to get it properly done.
 
I'd have to research the parts book for sure... I doubt the plate would need to be changed. Likely just the gear and all lines back to the filter. Those are not a big deal if you've got the high pressure lines.
Be sure to pop the cover off the rotary and free the metering valve before you install it if you go that route. Fuelling will also be a touch hot for the 175 but that could be adjusted down either now or later...


Rod
 
FOrd 10/30 series manuals have the full information compliment on Minimec and CAV pumps. Specs could be a bit different tho as compared to the older generation simms pump. For all that it will probably explain most of what you need to know.
Another text... "Diesel Mechanics' should cover fuel systems fairly well in general but probably doesn't give the precise setup info you need.

I agree that the mechanics of the pump are not all that difficult. The settings are precise tho.

Rod
 
NewHolland dealer... That is an expensive set. You might get away with just the first book on engines and fuel systems... or see if you can borrow one.
You might also find a simms manual on the net somewhere if you're determined enough...

Rod
 
The CAV and Simms front block plates are different. Simms might use the same plate as a gasser. It's been a couple of years since I looked at those part numbers and for some reason NH parts diagrams have been down for a couple of days so I can't verify.
I don't know if the drive gear is the same. CAV uses one with 3 bolts and a roll pin to time it.
I've got a couple of those here if you find you need one. Would send it for the price of shipping if you need one.
 
Sounds like your injectors may be rusted shut if you are not getting a spray out of them and have fuel to the top end of them.
 
And the verdict is......

The fuel screw was turned all the way down! So it was working right the whole time..... (well aside from needing delivery valves lapped) :roll:

My guess is that somehow in the process of troubleshooting whatever problem led to the head being pulled someone tried turning up the fuel but didn't realize that screwing it in decreased the fuel flow.

So after much head scratching and cussing it turned out be a very simple fix. Typical, huh? On the other hand, I learned quite a lot about Simms in line fuel pumps and how to work on them. I was able to spill time the pump on the bench and I tried to put together a calibration bench to set the fuel flow but it didn't work right. Couldn't get the counter to work and one of the injectors didn't want to seal but it did work to see the governor and injectors working.

I also learned that these pumps have an excess fuel device built in that gives you max fuel delivery for cold starting. You push in the shaft in the center of the shutoff lever with the throttle held at max and should get a click, then it'll pop back out once the engine starts and comes up to governed rpm or if the shuttoff lever is tripped.
14038.jpg
 
Well after $1100 in machine work and parts for the engine rebuilt it wasn't going to just sit there, nor was $800+ for a professional pump rebuild in the cards.

Plus it's a good way to learn how to do it. At the end of the day you learn something new, or worst case just have to pay to fix it the right way.

And these things are much simpler than folks think. It's not that hard to do. That's why this thing was frustrating me so badly... I [b:00f1c201c6]knew[/b:00f1c201c6] it had to be something simple but couldn't for the life of me figure it out.
 
(quoted from post at 22:40:15 01/22/13) Well after $1100 in machine work and parts for the engine rebuilt it wasn't going to just sit there, nor was $800+ for a professional pump rebuild in the cards.

Plus it's a good way to learn how to do it. At the end of the day you learn something new, or worst case just have to pay to fix it the right way.

And these things are much simpler than folks think. It's not that hard to do. That's why this thing was frustrating me so badly... I [b:e7a70e10b2]knew[/b:e7a70e10b2] it had to be something simple but couldn't for the life of me figure it out.

Congratulations! I am agonizing on weather to tackle my DB Stanadyne on my 971 myself or take it to the shop for $750.00 J Demaris says that they are no big deal. I have downloaded the manual, I guess that I need to study it.
 
I've got a DB2 I'm going to be tearing apart here before too long. I'm planning to take a bunch of pics and do a write up on it. That's assuming of course it actually works when I'm done.... :?

I've never been in a DB2. The Simms and Bosch VE pumps are pretty easy. DB2 type units are more complicated so we'll see how it actually works out.
 

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