450-C Injection pump and timing questions

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sbfd1287
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450-C Injection pump and timing questions

Post by sbfd1287 » Tue Apr 07, 2020 9:11 am

Sorry for posting in both early, and late forums...I made a mistake.

Hey guys, Im working on a 450C...It has the notorious "starts, idles. dies" issue. After searching around i saw to loosen the two screws on the timing window. I did that, and the customer was able to start, and rev the machine..Leading me to believe the plastic governor ring has come apart.

In lieu of blowing out the return line and the such, before i go back out there, is it something im able to overhaul on location? im not worried about my ability on rebuilding it, the issue is location of the dozer, and distance to the customers location from my place. Its about 70 miles one way, and then about 400 yards off in the woods.

Lastly, and the most important question i have is, does anyone have an easy write up on re timing the pump to engine? Customer supplied the technical manual for it, and its quite vague...

I saw you need to set the engine at TDC on cyl 1, and then time in the window of the pump..Thats about it.


Sorry for the questions, as we're not specializing in dozers, i run all types of service.


Tony Hemen

B Town
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Re: 450-C Injection pump and timing questions

Post by B Town » Tue Apr 07, 2020 11:37 am

Welcome to the crawler board.

Did you witness break down of the ring in the window? Mouse turds? I would look at the entire system before resigning to a IP rebuild. The check valve on the IP solenoid cover. The vent on the fuel tank. Fuel filters. Fuel supply from the tank. These all can cause similar problems.

The left rear of the engine/bell housing should have a small tear drop shaped tin cover over an opening into the flywheel. There should be a locate pin screwed into the bell housing. This locate pin is turned and placed through the access hole into a hole in the fly wheel to find/hold at TDC #1.

Best regards, Bruce

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gregjo1948
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Re: 450-C Injection pump and timing questions

Post by gregjo1948 » Tue Apr 07, 2020 1:28 pm

It might be the check valve in the fuel return line. It should be coming right out of the pump. It will be in the return fuel line and is about a $10.00 part which a 10 minute job to change out.
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original possum
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Re: 450-C Injection pump and timing questions

Post by original possum » Tue Apr 07, 2020 4:11 pm

Line up the two lines in the window you opened. This should be numbehr 1TDC . The timing pin hole should be close now.
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Jim B
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Re: 450-C Injection pump and timing questions

Post by Jim B » Wed Apr 08, 2020 5:56 am

Like B Town posted inspect closely, check tank venting, etc. Diagnose fully before pulling the pump.

Check closely when you remove the window for the mouse turds. Inspect the check valve to see if it has mouse turds in it. They do sometimes fail, as gregjo1948 posted, without being plugged. It should allow fuel out of the pump to the tank, but not let fuel back into the pump.

As original possum posted line the marks up in the window and you should be close as far as installing the timing pin into the flywheel. The pump turns at 1/2 engine speed so if it runs the marks will only line up on #1 compression. This is where it should be to remove the pump if you get to that point. Also, I would unhook the batteries to prevent anyone trying to turn it over.

To move these to a more suitable place to work on a machine, some people have knocked the guts out of the check valve (replacing it with a new one after the pump was rebuilt) so the material can pass through without plugging. That allowed it to run so they could get it "out of the woods", loaded, and hauled home to work on. That is up to you and the owner if you want to go that route. I won't recommend leaving the timing window loose like one guy did to get it home, what a mess he made.

As to whether or not you can rebuild the pump. My choice is to send any pumps I have, that need work, to a pump shop. I have worked on pumps and can do it. I would have to order parts which could delay repair if I miss something in the order or damage a part during repair. I do not have the specialty tools nor the equipment to properly test and calibrate a pump. So why do half a job if I pull it off? Again that is my choice, I know others will say they do them and they run after with no problem; that is their choice and I accept that. Either way, if you pull the pump, I would suggest getting a spare set of the umbrella seals for the shaft in case you damage one putting it back on, they are cheaper than the time and trip to get another if that does happen. The timing marks should be lined up, ready to install, when the pump rebuild is complete regardless of who does it.

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DrLoch
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Re: 450-C Injection pump and timing questions

Post by DrLoch » Wed Apr 08, 2020 6:55 am

2nd that on the umbrella seals. Get extra's, it's better to have them and not need them than need them and not have them.

Getting the engine to TDC is the correct way, but once your pull the pump you will notice a dot on the end of the tang shaft. There is a corresponding dot on the Distributor rotor inside the pump, they need to line up for the timing to be close. If you intend to do it this way, the pump and twists on the mounting surface so you will need to mark the pump housing and the mating surface so you get the correct rotation twist correct if you understand what I'm saying, I've done it both ways.

Also when installing the pump back onto the shaft after replacing the umbrella seals either use the seal compressor (JD256 or 13371) or have some wireties handy to compress the seals until they get into the pilot tube. If you tear or turn one inside out you will have diesel in your engine oil.
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