Hello friends.... Let me introduce myself, a caterpillar enthusiast since my childhood, I bought a 1974 D7F (with the new, more reliable reduction system!!!). To terrace and level a wooded area. my problem and the following: the engine runs on 5 cylinders vergicles remain stopped for a long time (acceleration and normal engine shutdown), I dismantled the injector lines and I noticed that piston n°3 of the injection pump does not provide fuel. My question is the following: is it possible that the piston remains blocked at the top and how can I unblock it? or how to change the piston of the injection pump without dismantling it, with specific tools in particular the grooved socket to remove the upper nut and therefore change the piston? How to stall the injection pump at maximum acceleration by dismantling a minimum of parts to be able to insert the new piston without having a timing problem? I would be really grateful for advice and a procedure (especially after reading several posts from Nigeria) with plans or other photos. Waiting for a response, a big hello to all caterpillar enthusiasts
Do you mean the newer style of transmission.? To obtain detailed information regarding the fuel injection pump on your engine will require the engine Serial Number. I imagine it will be 3Nxxxxx. There were a lot of changes made to fuel injection system design during the production of the D7F. It is important to know which generation of fuel injection system you have. Some photos of the fuel injection pump and governor would also be useful. Question: Does the engine run on all 6 cylinders at any time or under certain specific conditions.? Disclaimer: I am not a fuel injection specialist but when they see this they will require answers to the questions above plus photos in order to offer you advice or suggestions.
Good morning thank you for your answer indeed the engine does not run on 6 cylinders but on 5 cylinders since by dismantling output number 3 (engine on the road no fuel came out) The engine number is 3N71762 it is a 3306PC. What do you think, can I unseize piston number 3 by dismantling the upper part (discharge valve) and tapping lightly with a mallet and a 5mm thick rod on the piston head to bring it back down? Do you think this would be possible without damaging the assembly by placing the camshaft of the injection pump in the low position on cylinder 3? Thanks
Thank you for the information above. Can you supply 1 or 2 photos of the fuel injection pump please.?
My bad attached the photo of the injection pump
That should be enough information. Now you have to wait for the fuel injection specialists to offer opinions/suggestions.
Thank you Nigeria I look forward to the reviews
LoL
It’s possible to replace it on the engine..BUT.. you’ll have to get eyes on the problem..which means cleaning the heck outta the big flat panel where the filter is.. When u pull it off, pay attention to an overflow valve and spring in one of the corners.. So go getcha a pressure washer and a case of brake cleaner and a scraper.. There’s several different problems it could be, so get eyes on it..
Good morning Thank you for your response, I will actually remove the protective sheet and see what is stuck behind it. As the bulldozer was stationary for a long time, I think it was condensation in the fuel tank which would have put a little rust in the circuit. I will try to lower the piston if it is stuck, and then do a global overhaul of the injection system (taring the injector etc.) thanks again
U can buy a “Bonnet” removal tool online or at your local Cat house for about 30-35.00..
thank you the pump guy for information I will try to dismantle the upper splined nut and separate the valve from the piston to exert light pressure on the piston head (by spraying copiously with brake fluid) and force it to go back down into its housing (of course by putting the piston cam in neutral on piston number 3) I will try to go slowly so as not to remove the whole thing so as not to miss a timing tooth on the rack since the pump is still on the engine Do you think this operation is feasible?
Stop guessing at it.. u won’t know what you’ll need UNTIL u get the cover off..AFTER ITS OFF, post a picture and we can go from there..
If it sat for a long time and only 1 hole isn't pumping fuel consider yourself lucky. The size hammer required to free the piston in the bore may scare you.
3N1762 Engine should have a compact scroll injection pump but your picture shows a sleeve metering pump?????
old magnet that's the engine number I'll post a photo of the plate
It looks like 3N71762.
old magnet the injection pump looks like a 3306 Di?
Is that a mango worm borrowed into your arm? I’d wash that engine before taking anything apart.
3N71762 would have the sleeve metering pump. Can't find anything on a 7N1533 arrangement. Odd that it would be a PC engine
7N1533 is (or was originally) a 3306 engine arrangement for an 81V-prefix 140G motor grader built some time between October 1978 and March 1980. Before & after those dates the engine Arrgt Numbers were different. For a D7F installation the original 3306 engine Arrangement Number was 2P6806 for engines with S/N up 3N18568 (tractor S/N 94N5192-7184) and 6N0484 in engines with S/N above 3N18569 (tractor S/N 94N7185-Up). So what the OP has could easily be a Frankenmotor....... who knows how it has been "altered" to install it in the D7F.? Differences between the 7N1533 and 2P6806/6N0484 include (but not limited to) the crankshaft, piston/rod group, rear gear group, & cylinder head/valve mechanism. I fear that a can of worms may have just been opened.
maybe it’s a DI then?
It appears to be a PC injection system. Take a look on the gine itself. Does it have glow plugs.? It's PC if it does.
I will take a look and keep you informed, is there any impact with all this mixture on the functioning!!!???
Potentially enormous........ Possibly different compression ratio. Was a "D7F compatible" turbo installed.? Were the fuel injectors replaced and the adjustments made to the fuel injecton pump/governor settings to achieve the power and torque required for the D7F from the donor engine.? The 7N1533 engine when it was installed in the grader was rated at 150 BHP. The D7F installation is 180 BHP. The list is endless. Can you supply a machine Serial Number please.? It would help with investigaton.
Thank you for that information. So the original engine in the tractor was a 3306PC of Arrangement 6N0484 and Serial Number 3N28471.
hoping that all the modifications were made by professionals!!!
In my experience that is high unlikely but I have my fingers crossed for you.........!!
so which manual should I order to order parts if necessary??!!!
The D7F Parts Manual UEG0735S will cover all of the tractor and might possibly also cover the engine depending on how the grader engine was converted to fit the D7F. Failing that you may need a 140G grader Parts Manual SEBP1092 that covers the range of 81V-prefix 140G machines that used the 7N1533 Engine Arrangement.
thank you nige for this professionalism, hoping that it was your inspiration to change this engine!!!! for information power part it is present when turning on 5 cylinder it is already pushing hard!!! I will keep you informed of progress!!! in particular the injection pump thank you again for this clarification
Please post any Part Numbers that you find on the fuel injection pump. It could help to identify exactly where the pump originally came from (140G or D7F) that is currently fitted to the engine. If you are lucky maybe there will be a Caterpillar data plate under all that grease that would help tremendously with identification.
Would 3N71762 be the proper serial number?
Can you give any other explanation for the photo attached to Post #18.? It clearly appears as 3N71762 and the plate looks oriignal. 81V-prefix 140G grader engines of 7N1533 Arrgt are listed as below, so IMHO based on that then 3N71762 is a kosher S/N.
hello gentlemen After removing the inspection plate at the front of the injection pump, we find piston number 3 which does not go back down into its housing. What do you think, I will try to remove the nut on the upper part of the injection pump and remove the delivery valve, do you think I can just remove the valve without removing the piston with its adjustments on the rack? Then I would tap gently on the piston head while leaving the pusher at the bottom?
Have you first tried soaking all the mechanism in that area in penetrating oil and leave it for a few days.? After that some light taps with a hammer and a brass drift might well loosen things up.
I have already done the soaking with penetrating oil, will the lower part of the piston move if I remove the discharge valve once the grooved nut has been removed?
I would suggest that if you can get hold of something like this automotive trim tool you should be able to carefully move the mechanism provided that you first turn the engine to a position where the camshaft inside the injection pump is in the "down" position for that cylinder.
Thanks
Seems the plunger is stuck in the barrel. Remove the bushing and bonnet and you can access the plunger and try pushing it back down.
Merci pour les plans ça va mettre très utile
"Thank you for the diagrams. They will be very useful."
Bonsoir Messieurs excusez moi du retard de news mais je voulais vous informer que le piston n3 à pu être débloqué avec de huile de frein et des levier bras de force merci
Remember you have to post in English......... "Good evening Gentlemen excuse me for the delay in news but I wanted to inform you that piston #3 could be unlocked with brake fluid and a bit of force. Thanks."