990 Case injector pressure and push rod length

gwayne919 · Jun 21, 2020

Well, my 990 Case is 40 years old and the tank leaked and after epoxying the bottom water was entering the defective fuel sender unit so I sealed it with epoxy also. Had the injector pump rebuilt and a new lift pump will be installed once I fabricate a new push rod out of drill rod as the old one was concave on the cam side and the fuel pump lever had made a groove in that side, I can only imagine what the camshaft looks like. I think the push rod is 36MM long??? I'm making an injector adjusting device using an old but good bottle jack, just need a few more pieces so I can adjust the injectors to 1750 PSI if that is correct??? I had to rewire the whole system except now the key will not energize the starter solenoid. Maybe I need another switch as water could have gotten inside the old one and you know the story. I'll have to wait till the tractor is running to determine if the radiator will need some work as the cores look like they have calcium buildup from what I can see from the raditor cap opening. Can anyone help me with the length of the push rod and the set pressure of the injectors?

joestewart · Jun 21, 2020

Regarding the push rod length, here is a useful thread:

https://dbtc.co.uk/phpBB3/viewtopic.php?t=17992
Thread

Dieseltech · Jun 21, 2020

New spring opening pressure 2572, with used spring 2400-2500 will be fine. 1750 is too low for direct injected diesels, energy cell/Lanova did use a lower setting.

gwayne919 · Jun 21, 2020

I thank you for sending me the useful link and after sticking a tiny cam down the hole I was not surprised at how much wear the cam had suffered and what I only suspected after seeing the concave end of the push rod. The usual chamfered sides of the rod weren't even evident and the wear on the camshaft must be at least .050" deep. I'll be adding .040" to the 36MM length to compensate a bit for the loss of cam lift. That shouldn't be too much to damage the diaphragm. This engine had suffered with a power steering leak into the crankcase for a long time before I bought the tractor of which I replaced the seal. I'll keep an eye on the oil and pwr steering fluid levels until I know there is no longer any problems there. Poor design. Maybe the injection pump also leaked internally as it did externally. When I got the tractor home I operated it for a half hour and the crankcase oil level was up very high from acceptable when I tested it. Thanks again.

gwayne919 · Jun 21, 2020

I appreciate the information about the pressure setting of the injectors. I am almost finished with a bottle jack modification into an injector testing apparatus. I've already taken the spray heads off and cleaned them and they have a good spray pattern with expected wear to a minimum. One of them was a bit stuck but freed up easily and washed and reassembled. I saw several YouTube videos about converting bottle jacks into injector testing rigs and I had several bottle jacks that I never use so it was easy with a 3000PSI Ashcroft glycerine-filled gauge and a S/S 6000PSI valve and some high pressure weld S/S fittings, just needing a 1 1/2" X 1/2" solid steel reducing bushing and a single inverted female fitting that will fit the injector line that I will use to test the injectors with before reinstalling it. Always saving things pays off someday if we live long enough. Thanks again and the forum is a really great site with great information to compliment anyone trying to fix most any tractor as I see it.

990 Case injector pressure and push rod length

gwayne919

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joestewart

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Dieseltech

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gwayne919

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gwayne919

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