Series 1 D17 Diesel low oil pressure
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Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=207581
Printed Date: 28 Jul 2025 at 5:02am
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Topic: Series 1 D17 Diesel low oil pressure
Posted By: Allis58D17D
Subject: Series 1 D17 Diesel low oil pressure
Date Posted: 27 Jul 2025 at 2:21pm
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Hey all I’ve got a 58 series 1 D17 Diesel. Fresh rebuild on the motor. Only thing not replaced was the rockers and the oil pump. All new bearings, camshaft bearings, rod bearings and main bearings. Cold start oil pressure is at the “L” in normal but by the time the engine reaches temp it’s in the middle of the non labeled section of the gauge. Also it’s a new 0-80 gauge and I’ve checked it with a numbered gauge as well. New oil pressure relief spring below the injection pump. With this once the oil is warm at full throttle I hear what sounds like a knock but I’m not able to pin point if it’s high or low. First I’d like to solve the oil pressure issue first and see if it goes away with that. I’ve got about an hour on the rebuild accord to my tach.
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Replies:
Posted By: DrAllis
Date Posted: 27 Jul 2025 at 5:41pm
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What kind of oil pressure did it have before you overhauled it ??? The last engine of that model with poor oil pressure after an OH ( that I was involved with) had .010" mains or rods when it should have had .020". What is the p/n on your old bearing shells ??? Pretty good oil pressure when cold and poor oil pressure when warmed up is pointing to wrong sized bearings.
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Posted By: Allis58D17D
Date Posted: 27 Jul 2025 at 5:45pm
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It is about the same. I can’t remember the part number off the top of my head but they had STD stamped in them. Had the crank measured and it was in spec for standard size so that’s what was put back in it.
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Posted By: DrAllis
Date Posted: 27 Jul 2025 at 7:15pm
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Poor oil pressure when warmed up was how it was before the OH ?? Did you plasti-gauge all the main and rod bearings when dry ?? Measuring the crank is one thing. The only way to ensure the bearing shells are correct is to plasti-gauge them one at a time when assembling. What condition is your oil pump internally ?? You knew there was an issue and should have been looking for the cause while it was apart. Without looking the numbers up, I'd say anything over 35 psi when hot at full throttle would be fine and no less than 15 psi at a hot low idle with 15W-40 oil. A numbered 80 psi gauge would be a bit big for me to use.
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Posted By: Allis58D17D
Date Posted: 27 Jul 2025 at 7:24pm
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All of it was plastigauged and checked out. I didn’t intend on overhauling. I had the low oil pressure and pulled it out to do a rear main and front main seals and found a crack in a sleeve so I overhauled it. I’ve replaced the spring under the pump and it seemed to help some. Not sure what condition the pumps in confidently but I removed the screen and it all looked okay but I’ve never seen what a new one looks like to say it’s wore out. Correct me if I’m wrong and I feel I may be but would my tolerances get tighter when warm vs cold thus making a knock at cold and not warm? Maybe I’m thinking of that wrong. I also checked the rockers while it was running and quite a few were pushing more oil around the rocker pivot than others. Some dropped some were a solid stream.
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Posted By: DrAllis
Date Posted: 27 Jul 2025 at 7:58pm
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I just looked at my service manuals and I'll stick with my 35 psi and 15 psi numbers for actual oil pressures when hot. Get a 50 psi gauge to get accurate readings.
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