190xt Engine Oil Pressure issue
Printed From: Unofficial Allis
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=184355
Printed Date: 08 Sep 2025 at 8:47am
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Topic: 190xt Engine Oil Pressure issue
Posted By: A&Sfarms
Subject: 190xt Engine Oil Pressure issue
Date Posted: 02 Nov 2021 at 2:05pm
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A couple months ago my brother and I bought an early 190xt. We bought it with a known injection pump issue. We could run it, but the return was disconnected so we didn't run it very long. We had the injection pump and injectors rebuilt and replaced the turbo. It runs now and sounds good, but the problem is the oil pressure. This tractor has an actual pressure gauge already on it in place of the sending unit. When we start it cold, the pressure jumps right to around 50psi but as it warms up the pressure drops. It eventually gets below 5psi and doesn't come up over 10psi when the engine is revved up. We have been chasing this problem for a while and what we have tried so far is as follows: -New 15w40 oil and filter -Tightened oil pressure regulating valve (did not increase pressure, tightened all the way) -removed and inspected oil pressure regulating valve. Seems Ok -double checked gauge with a second gauge. -put second gauge on oil gallery port close to engine oil filter (reads within 3psi of second gauge) -removed turbo and ran engine with turbo feed line plugged -dropped pan and cleaned some sludge out of the pan -removed oil pump and inspected. Didn't notice much wear. Seems tight -Plasti-gauge #3 main bearing. about .006" clearance We went and talked to our local Agco dealer and they didn't have much help. They said they didn't like the 6 thou of clearance on the main bearing, but the book says to rebuild the engine at 8 thou. Are we missing anything? Is 6 thou enough to drop oil pressure that much? We are basically out of ideas other than source a different oil pump to try and a rebuild if that doesn't do it.
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Replies:
Posted By: DrAllis
Date Posted: 02 Nov 2021 at 3:50pm
| Decent oil pressure when cold and drops when warmed up indicates a worn out oil pump (doubtful) or worn main and rod bearings (probable). I'm guessing .003" is a good bearing clearance, but I'm not looking at the service manual. |
Posted By: DrAllis
Date Posted: 02 Nov 2021 at 6:54pm
| I've never seen it, but your pressure regulator seat or plunger could be worn funny causing a massive leak there. You'd have to remove the plug and spring and plunger from behind the injection pump to see those parts. Your plasti-gauge in chassis may not be what you think it is. Ideally, the block should be upside down with a dry crankshaft and bearings. Any oil on them or in your case the weight of the crankshaft laying on the plasti-gauge may be giving a tighter reading than it really is. Your number of .006" is out of spec and I think its more than that. |
Posted By: A&Sfarms
Date Posted: 02 Nov 2021 at 7:05pm
| We pulled the plunger out. We weren't really sure what it should look like, but it did seem like it might be seating unevenly. There's a local guy that might let me pull his to compare and he might have a different oil pump to try. It looks like we are pointing towards a rebuild though. When we did the plasti-gauge i didn't think about the motor orientation being a factor, but I could see it. We were really hoping that an injection pump was all this tractor was going to need. Thanks for the help |
Posted By: Lars(wi)
Date Posted: 02 Nov 2021 at 10:20pm
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Try straight 30w diesel oil. What have you got to lose? ------------- I tried to follow the science, but it was not there. I then followed the money, and that’s where I found the science. |
Posted By: ACjack
Date Posted: 03 Nov 2021 at 9:42am
| Back in the 70's the factory fill was straight 30w Shell Rotella. |
Posted By: Ky.Allis
Date Posted: 03 Nov 2021 at 9:58am
| Don't these engines have cork plugs in ends of rocker arm shaft? Maybe one or both are missing. I would think it would cause very low oil pressure. |
Posted By: injpumpEd
Date Posted: 03 Nov 2021 at 10:48am
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to me if it were worn bearings, it would not have good oil press ever. ------------- 210 "too hot to farm" puller, part of the "insane pumpkin posse". Owner of Guenther Heritage Diesel, specializing in fuel injection systems on heritage era tractors. stock rebuilds to all out pullers! |
Posted By: ACjack
Date Posted: 03 Nov 2021 at 10:49am
| Yes, they did use cork plugs in the ends of the rocker arm shaft at the Harvey engine plant. |
Posted By: DrAllis
Date Posted: 03 Nov 2021 at 12:02pm
| It really doesn't have good oil pressure when cold. With the pressure regulator bottomed out, I would xpect to see 75 or 80 psi for the first few minutes and gradually fall as it warms up. Spec is 35 psi (hot) to 55 psi (cold) wide open throttle. |
Posted By: tbran
Date Posted: 03 Nov 2021 at 9:00pm
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as we have suggested before - put air pressure in the oil galley - we use a air chuck brazed to a 1/8" pipe male thread coupler- wish we had had the oil pan off when doing this. Put air in starting at about 30 psi and increase and listen /look where the sound of escaping air comes from - turn the crank over in the process - has saved us a lot of grief in the past.
------------- When told "it's not the money,it's the principle", remember, it's always the money.. |
Posted By: 6080fwa
Date Posted: 04 Nov 2021 at 8:45am
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when you plasti gauged the bearings out was there any copper showing? if there was i would change all main and rod bearings, and slide in all new bearings. Better yet pull the crank out and get it ground new bearings and resize the rods. I slipped in new bearings with my d-19 diesel and it helped alot without grinding the crank, my crank was not badly oblong on the journals. you could also see how much play is in your rocker arms /shaft and if those corks are still there doing their job. you could run it wth the valve cover off and see how much oil is leaking out of the rocker arm/shaft. each worn part looses more pressure. I like the idea of air pressure. you loose pressure as the oil heats up. your oil pump spring might also be worn out. your air pressure will tell u what psi the pump will bypass at. ------------- d19d d19lp 175d 190d 190gxt 190dxt 200 6080 7000 8010 9150 9190 |
Posted By: A&Sfarms
Date Posted: 04 Nov 2021 at 1:18pm
| There wasn't any copper showing on the bearing when we pulled it. I haven't pulled the valve cover yet, so I don't know about the corks. If they weren't there, would it build any pressure at all? I can rig an air regulator up to it pretty easy, so I will definitely try that |
Posted By: DrAllis
Date Posted: 04 Nov 2021 at 1:35pm
| You've got bigger issues than rocker arm shaft corks. |
Posted By: MACK
Date Posted: 04 Nov 2021 at 9:45pm
| I would pull all main caps (one at a time) . .006 is too much clearance if all are .006 or more with a stock pump. You don't say what rod clearance is. MACK |
Posted By: A&Sfarms
Date Posted: 08 Feb 2022 at 10:13am
| I finally had some time to work on this again. I pulled the valve cover off and found a bent pushrod. I replaced it, reset the lash and started the engine up without the cover on to watch it for a while. Oil pressure behaved the same. As far as I could tell, everything else in the valvetrain was functioning as it should. I am now to the point of an overhaul. Is there anything else I should look into/replace while I'm in this far? |
Posted By: Alvin M
Date Posted: 08 Feb 2022 at 10:41am
| Check if the insert is in the block where the relief piston seats on part# 74507673 when I sent to the machine shop I always take it out or it will fall out when clean the block |
Posted By: Joe(TX)
Date Posted: 10 Feb 2022 at 10:19am
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Another thing to look at is to see if the engine has rods that have the piston cooling jets along with the rod bearing with the holes for them. I have run into this problem before. The 190 oil pump way not supply enough oil to maintain pressure. The piston cooling requires the crank driven oil pump. ------------- 1970 190XT, 1973 200, 1962 D-19 Diesel, 1979 7010, 1957 WD45, 1950 WD, 1961 D17, Speed Patrol, D14, All crop 66 big bin, 180 diesel, 1970 170 diesel, FP80 forklift. Gleaner A |
Posted By: DrAllis
Date Posted: 10 Feb 2022 at 10:44am
| 301 engines don't have piston cooling thru the connecting rods. Only the late model 426's from 1979 or so have rods like that. |
Posted By: jlackman
Date Posted: 23 May 2022 at 9:36am
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I have a 190 XT trying to get back to life. Had low/no oil pressure. Where is this "oil pressure regulating valve"? I've already got the pan and oil pump pulled. Is there anyone who rebuilds these oil pumps? |
Posted By: DrAllis
Date Posted: 23 May 2022 at 9:40am
| The oil pressure regulator is built into the block behind the injection pump and is adjustable with a 3/4" wrench. It is to see to it 55 psi is the maximum pressure in the main oil galley. There is an 80 to 100 psi relief built into the oil pump which does NOTHING except see to it on a very cold start and too much throttle the oil pressure at the pump doesn't exceed that amount to save the drive gears to the oil pump. |
Posted By: 6080fwa
Date Posted: 23 May 2022 at 10:18am
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if you have too much bearing clearance you will loose alot of oil pressure there and sometimes in the camshaft and the rockers too, it all adds up. Reliance power parts https://reliancepowerparts.com/Products?partListId=3104&isListView=False" rel="nofollow - RELIANCE (reliancepowerparts.com) has a oil pump listed, you could start there. It depends if you want to keep the tractor you could replace the rod and main bearings paying attention if they are oversize or not. the crank can be oblong from wear so it may not fix the problem entirely, but if its it not too oblonq should help the problem. It is a gamble without measuring how out of round and worn your crank is. |The only way to get it down to factory specs is to pull the motor and get the crank ground so it is not oblong and put oversize bearings in on the mains crank, rods and camshaft. .0016-.0043 is the crank specs. rods .0009-.0034 camshaft .002-.005. Another option is you could also look for a donor motor out of a combine and just swap the motor out , inj pump may be different, other things too, but then u have a motor with low hours and should hopefully last a while. I think gleaner L's had a 301?. ------------- d19d d19lp 175d 190d 190gxt 190dxt 200 6080 7000 8010 9150 9190 |
Posted By: jlkansascity
Date Posted: 23 May 2022 at 6:28pm
| thanks! You've given me some things to check up on. Do you know if the 190 had the riser pipe in the oil filter like some of the other Allis Chalmers did? |
Posted By: jlkansascity
Date Posted: 23 May 2022 at 7:28pm
| I can't see the Reliance part without logging in so I applied to be a "dealer" and we'll see... |
Posted By: 6080fwa
Date Posted: 23 May 2022 at 9:54pm
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474622581 under tractor allis 190xt 301 engine ------------- d19d d19lp 175d 190d 190gxt 190dxt 200 6080 7000 8010 9150 9190 |
Posted By: DSeries4
Date Posted: 24 May 2022 at 9:39pm
No 190s had the pipe going up the middle of the oil filter. That was only for the gas engines with the low flow oil pressure system. Most of those were switched to full pressure lube systems in the early 60s. ------------- '49 G, '54 WD45, '55 CA, '56 WD45D, '57 WD45, '58 D14, '59 D14, '60 D14, '63 D15D, '66 D15II, '66 D21II, '67 D17IV, '67 D17IVD, '67 190XTD, '73 620, '76 185, '77 175, '84 8030, '85 6080 |
jlkansascity wrote:Posted By: A&Sfarms
Date Posted: 25 May 2022 at 11:51am
| I tried just rolling new rod and main bearings in to see if that would fix my oil pressure problem, but no such luck. If you pull the regulating valve out, it would be great to see some pictures of the needle/plunger. Mine is out and I can take some pictures for comparison. I still doubt that is the problem, but I don't know what it is supposed to look like. I borrowed a bore scope yesterday so I can try to take a look at the seat. I would also be interested in how much the oil pump would be from Reliance. |
Posted By: SteveM C/IL
Date Posted: 25 May 2022 at 9:08pm
| Dr allis and others will know. What is the deal about the galley plug in these engines for oil cooler VS non cooler? Have no idea if this could be in play. I just remember talk about it and even though this engine hasn't been converted one way or the other as far as we know it made me wonder. Seems like a huge pressure change for loose brgs but I'm no expert in that field. |
Posted By: A&Sfarms
Date Posted: 26 May 2022 at 1:57pm
 Here is my plunger. It is definitely not seating evenly and looks like it could be leaking in-between one of the sections.
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Posted By: A&Sfarms
Date Posted: 26 May 2022 at 2:00pm
 Here is an image from the bore scope. It is hard to tell from the picture, but is there a seat there?? I'm not sure what it is supposed to look like.
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Posted By: DrAllis
Date Posted: 26 May 2022 at 7:05pm
| I've never had to replace one, but I think the seat is a steel ring pressed into the block down inside the pressure adjustment hole. To remove, I think insert a tap, thread, and pull out with a slide hammer. Hard to do when engine is assembled. Where do all the cuttings go ?? inside the main oil galley. Maybe grease on the tap would work ?? |
Posted By: MACK
Date Posted: 26 May 2022 at 9:02pm
| The gallery plug made the oil go around block through a tube to oil cooler then back into block. If plug is left in with NON oil cooler block, oil cannot get to right side of block to oil mains and rod bearings. MACK |
Posted By: Albert
Date Posted: 26 May 2022 at 9:08pm
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I have two NOS seats here and took a photo with the bottom up and the other bottom down. I cant get from my phone to here but if you text me I will text the photo to someone. Albert 660 541 2029 |