Guest Delbert Stallings Posted June 14, 2016 Share Posted June 14, 2016 My 1926 Buick Standard has 25# oil pressure cold that drops to 0 when hot. I have the oil pan off and the pump apart but I see nothing wrong. Could any one tell me what I could possibly do to help this problem??? Delbert Stallings Link to comment Share on other sites More sharing options...
Vila Posted June 14, 2016 Share Posted June 14, 2016 (edited) What weigh oil are you using and what RPM do you have when the oil pressure is reading 0 hot? My 1933 Chevrolet used to read 0 at idle after it warmed up and I was using 10W30 motor oil. With the original oil spec of straight 30W I switch to 20W50 Valvoline synthetic racing oil a few years ago and now I get around 15 PSI at idle when hot. Went to the racing oil since it has a higher Zinc level. Edited June 14, 2016 by Vila (see edit history) Link to comment Share on other sites More sharing options...
Guest Delbert Stallings Posted June 14, 2016 Share Posted June 14, 2016 I was using 10w-30w Pennzoil. Don't know the RPMs but much more than needed and the pressure would barely rise when hot. I was wondering if there was anything I could do before I put this oil pan back on? Link to comment Share on other sites More sharing options...
misterc9 Posted June 15, 2016 Share Posted June 15, 2016 Maybe the oil pressure relief valve is stuck open. I don't know if it Is in the pump or the block in your car. That would cause low oil pressure especially when hot. Or it could be something else. The single weight 30 oil is a good bet though. Link to comment Share on other sites More sharing options...
Ben Bruce aka First Born Posted June 15, 2016 Share Posted June 15, 2016 3 hours ago, Delbert Stallings said: I was using 10w-30w Pennzoil. Don't know the RPMs but much more than needed and the pressure would barely rise when hot. I was wondering if there was anything I could do before I put this oil pan back on? Yeah, check the rod and main bearing clearance. Ben Link to comment Share on other sites More sharing options...
Guest Posted June 15, 2016 Share Posted June 15, 2016 (edited) 52 minutes ago, First Born said: Yeah, check the rod and main bearing clearance. Ben Bingo! Especially since you've already got the pan off. The rod bearings in these old long stroke engines take a pounding, especially when people push them too hard trying to keep up with modern traffic. There's a good chance you won't even have to actually check clearances because you may find the babbit bearings fretting away in chunks. Pull a few caps and see what they look like. If they look ok, it's a simple thing to buy a few strips of plasti gauge and see what the clearances actually are. Hate to paint a gloomy picture, but now's the time to find out. I've been there more than once. Certainly heavier oil will tend to help, and you should check the oil pressure relief valve for a broken or weak spring and for sludge as previously mentioned. But while you have the pan off........... Edited June 15, 2016 by Guest (see edit history) Link to comment Share on other sites More sharing options...
cahartley Posted June 15, 2016 Share Posted June 15, 2016 How much clearance is there between the pump gears and the face of the case cover? Also between the gear teeth and case? Link to comment Share on other sites More sharing options...
Guest Delbert Stallings Posted June 15, 2016 Share Posted June 15, 2016 The pressure relief valve has such a strong spring in it I doubt it would ever open. Link to comment Share on other sites More sharing options...
Spinneyhill Posted June 15, 2016 Share Posted June 15, 2016 Before doing anything too drastic, ensure the oil pressure gauge is functioning properly! Link to comment Share on other sites More sharing options...
Guest Delbert Stallings Posted June 18, 2016 Share Posted June 18, 2016 This is the bottom plate of the oil pump, there is some vey lite wear from the gears that lay right on the plate. Are the gears supposed to lay right on the plate? The plate is brass although the picture doesn't show it. Link to comment Share on other sites More sharing options...
cahartley Posted June 18, 2016 Share Posted June 18, 2016 There must be as little clearance as possible between the sides of the gears and the bottom plate. Lay a straight edge across the cover plate to see what's what.......it may require facing or getting surfaced on a surface grinder. If the bottom shaft bushing is loose there may also be excessive clearance between the gear teeth and housing. Check it with a feeler gauge. With hydraulic pumps tooth to case clearance exceeding .005" will not develop rated pressure. You aren't dealing with anywhere near what a hydraulic pump must develop though the principals are identical. The fact it pumps when the oil is cold could be a badly worn pump or main/rod/cam bearing(s) that need taking up. Link to comment Share on other sites More sharing options...
37_Roadmaster_C Posted June 18, 2016 Share Posted June 18, 2016 Cahartley has it exactly right. Any 'slop' in the gears will greatly reduce pump effency to the point of non-operation. As the oil warms up it thins and the problem is worse. On your top photo of the bottom plate the wear marks are obvious and in my opinion the plate should be faced smooth. Another thing I think I see is a slight ovaling of the lower shaft guide hole. If this is the case the clearance between the gears may be excessive and/or the main housing may be warn from the gear riding on the lower side. Either of these things is a big problem and needs attention. Robin Link to comment Share on other sites More sharing options...
Guest Posted June 18, 2016 Share Posted June 18, 2016 You can reface it yourself. All you need is a piece of glass on a bench, some valve grinding compound and circular motion. I doesn't take long. Link to comment Share on other sites More sharing options...
Guest Delbert Stallings Posted June 20, 2016 Share Posted June 20, 2016 I DONT UNDERSTGAND. HOW DO USE THE GLASS AND COMPOUND??` Link to comment Share on other sites More sharing options...
hchris Posted June 20, 2016 Share Posted June 20, 2016 (edited) A sheet of flat thick glass, such as in your side windows, gives a nice flat surface on which you can lay a sheet of fine grade wet and dry abrasive paper, or grinding paste. Put the scored surface of the oil pump plate on the abrasive surface and move it firmly in figure 8 movements, to wear down the grooves, to the point that the surface of the plate is nice and smooth, wipe the plate surface regularly to remove any residue. Make sure all the pump surfaces are nice and clean prior to re installing. Clearances within the pump are critical if you want to maintain good oil pressure, as mentioned .005" clearance would be the maximum acceptable between gear and wall of the pump, .003" between the gear teeth and .005" between the end plate and gears; given that you have what I would consider excessive wear on the end plate, you probably need to go through the whole of the pump or perhaps find an acceptable replacement. Edited June 20, 2016 by hchris add words (see edit history) Link to comment Share on other sites More sharing options...
Restorer32 Posted June 20, 2016 Share Posted June 20, 2016 As an illustration. We recently completed restoration of a '49 VW. Upon startup of the newly rebuilt engine it had virtually zero oil pressure and this with a new pump. After a lot of head scratching and measuring, difficult on this car, we realized that from the factory the NOS oil pump had accidentally been fitted with 2 thin paper gaskets instead of the 1 it should have had. That extra paper gasket reduced the oil pressure to almost nothing. Oil pump clearance is critical. Link to comment Share on other sites More sharing options...
ckowner Posted June 23, 2016 Share Posted June 23, 2016 I am having the same issues with oil pressure as described above. The engine was completely rebuilt, new babbitt, pistons, rings etc. All bearing clearances were meticulously checked. The oil pressure starts at 30-35lbs and drops to under 10lbs when warm. Now I am starting to think that the gasket on the plate of the pump is too thick. I made the gasket from the thinnest material I had, but it is probably too thick. What would be the proper material to use? Thanks for your help Rick VanOene 1930 DeSoto CK 6- 6 wheel rumble seat coupe(Canadian) 1 Link to comment Share on other sites More sharing options...
cahartley Posted June 23, 2016 Share Posted June 23, 2016 There are cases where a piece of wax paper is sufficient for a gasket which I have experienced. You want things to fit that closely especially if there is some wear between the gear teeth and housing which there undoubtedly is. Link to comment Share on other sites More sharing options...
maok Posted June 23, 2016 Share Posted June 23, 2016 43 minutes ago, ckowner said: I am having the same issues with oil pressure as described above. The engine was completely rebuilt, new babbitt, pistons, rings etc. All bearing clearances were meticulously checked. The oil pressure starts at 30-35lbs and drops to under 10lbs when warm. Now I am starting to think that the gasket on the plate of the pump is too thick. I made the gasket from the thinnest material I had, but it is probably too thick. What would be the proper material to use? Thanks for your help Rick VanOene 1930 DeSoto CK 6- 6 wheel rumble seat coupe(Canadian) My 1928 Chrysler was similar, at start up the oil gauge would go all the way up to 50psi, as the engine warmed up, the pressure would drop gradually to 10psi and stay there. I always thought this was strange, that it would not increase in psi with engine rpm. But recently something has happened, probably in the relief valve but I am not sure, it will still start up at 50psi but now at operating temp will range from 10psi to 25psi depending on temp and engine rpm. Its a worn engine and I use 40w Penrite oil Link to comment Share on other sites More sharing options...
AzBob Posted June 23, 2016 Share Posted June 23, 2016 Delbert, FWIW, my 1926 Buick has 22 psi on startup then drops down to 20 psi when at normal operating temperature. Never seems to vary much from this. I am running 15W 40 Rotella t. Link to comment Share on other sites More sharing options...
Guest Posted June 24, 2016 Share Posted June 24, 2016 Kitchen type parchment paper is about the right thickness, oil resistant as well. Link to comment Share on other sites More sharing options...
FLYER15015 Posted July 1, 2016 Share Posted July 1, 2016 Quote Here is the aluminum bottom plate off my '40 (320cid) engine just after I bought the car. 30psi cold and 0 at hot idle. I emoried it down to where there were no leak tracts, put a THIN layer of Permatex #2 round the edge, a 3/8" nut behind the pressure relief spring, and Shell Rotella 15-40 in the motor with a can of STP just for good measure. Results are 60psi at cold start, 40-45 hot cruising and 30 @ hot idle. I'm a happy camper..... And this is with a motor that has never had the head off, with 89K on the clock. Mike in Colorado 1 Link to comment Share on other sites More sharing options...
Spinneyhill Posted July 2, 2016 Share Posted July 2, 2016 I don't think it was "good measure" to add the viscosifier, STP. You have put in a good oil and then vastly increased the viscosity. Why? Link to comment Share on other sites More sharing options...
C Carl Posted July 2, 2016 Share Posted July 2, 2016 Yup. STP is a VI (viscosity index) improver. You have now increased the viscosity at both ends of the scale. More so at the top end. For example , you now may have something like a 19w/65. Or maybe a 23w/66 ? This puts your oil out of the proper temperature/viscosity envelope. Your stated oil pressure seems to be a,bit on the high side , perhaps supporting my theory. I just bailed out my '07 Mercedes-Benz E550 (really fantastic cars if you like driving) from a dealer periodic service. They have gone from 10w/30 full synthetic to 5w/40 full synthetic. I expect they have their reasons. - Carl Link to comment Share on other sites More sharing options...
Guest Posted July 2, 2016 Share Posted July 2, 2016 (edited) 14 hours ago, C Carl said: Yup. STP is a VI (viscosity index) improver. You have now increased the viscosity at both ends of the scale. More so at the top end. For example , you now may have something like a 19w/65. Or maybe a 23w/66 ? This puts your oil out of the proper temperature/viscosity envelope. Your stated oil pressure seems to be a,bit on the high side , perhaps supporting my theory. I just bailed out my '07 Mercedes-Benz E550 (really fantastic cars if you like driving) from a dealer periodic service. They have gone from 10w/30 full synthetic to 5w/40 full synthetic. I expect they have their reasons. - Carl Yep. Does seem a bit on the high side. And a "3/8 nut behind the pressure relief spring." I've heard of a washer or two and have done so on occasion... but a 3/8" nut? You definitely insured that that relief valve ain't ever gonna open, lol. Edited July 2, 2016 by Guest (see edit history) Link to comment Share on other sites More sharing options...
cahartley Posted July 2, 2016 Share Posted July 2, 2016 I agree with Caddy........running that pressure isn't going to hurt the pump but it's hard on the gears that drive it....... Link to comment Share on other sites More sharing options...
ckowner Posted July 3, 2016 Share Posted July 3, 2016 (edited) I have had some success. Checked the gasket on the oil pump. It came with the gasket kit for that engine. I cut a new gasket from kitchen parchment paper with a thin wipe of liquid gasket for good measure and to hold the parchment paper in place. I polished the bottom plate to a smooth finish. Now my oil pressure still starts at 35lbs but only drops to around 20lbs. Since the engine was completely rebuilt, could it be that the oil pressure relief spring bolt was not turned in tight enough? It is a 1930 DeSoto CK6 engine, same set up as most early mopar sixes. The oil used is Shell rotella T 15-40 oil since I have an external oil filter. Thanks for your help Rick VanOene 1930 DeSoto CK6 6wheel rumbleseat coupe Edited July 3, 2016 by ckowner (see edit history) 1 Link to comment Share on other sites More sharing options...
Guest Posted July 3, 2016 Share Posted July 3, 2016 I would think that high pressure like that could cut grooves in the Babbitt bearings pretty quick. Link to comment Share on other sites More sharing options...
FLYER15015 Posted July 5, 2016 Share Posted July 5, 2016 Considering the Buick has an 8+ qt system, one bottle of STP gives 1/2 the result of that in a modern 4-5 qt system. Years ago when I worked at a used car dealership, we always used a 3/8" nut in the pressure relief valve on "old" cars that came in with "low" oil pressure. Usually '48-'55 Chrysler products. Been driving the Buick with this set up for 5 years now and no issues. Mike in Colorado Link to comment Share on other sites More sharing options...
misterc9 Posted July 6, 2016 Share Posted July 6, 2016 With really thick oil the oil pressure relief valve probably couldn't bleed off enough oil to control the pressure when cold. Link to comment Share on other sites More sharing options...
edhd58 Posted July 9, 2016 Share Posted July 9, 2016 I recently had my 226 G overhauled. it ;lost oil pressure shortly after start up, I ended up having a machine shop machine the oil pump body to 0.015 total clearance of the internal gears and body with the paper thin gaskets. I now have at idle 30 pounds pressure and nearly 50 pounds at about 2500 rpm 1 Link to comment Share on other sites More sharing options...
herm111 Posted August 6, 2016 Share Posted August 6, 2016 On 7/3/2016 at 2:12 AM, Tinindian said: I would think that high pressure like that could cut grooves in the Babbitt bearings pretty quick. Oil won't groove Babbitt. Herm. Link to comment Share on other sites More sharing options...
herm111 Posted August 6, 2016 Share Posted August 6, 2016 On 6/14/2016 at 3:14 PM, Delbert Stallings said: My 1926 Buick Standard has 25# oil pressure cold that drops to 0 when hot. I have the oil pan off and the pump apart but I see nothing wrong. Could any one tell me what I could possibly do to help this problem??? Delbert Stallings Delbert, as I think it was a Ben has said, check your bearing clearance. If the clearance is to large, there is no fix until you do. Set at .001 thousandths per inch of shaft. A 2" crank would take .002 clearance, minimum, and plus 1/2 thousandths Maximum which would be .002-50. Run with 30Wt. summer, 20Wt. winter Herm. Link to comment Share on other sites More sharing options...
Guest Posted August 6, 2016 Share Posted August 6, 2016 herm111 Are you putting another "fact" into the category of "old wives tales" or "old mechanics facts"??? I have discovered that many many things that I was told were true forty, fifty or sixty years ago were absolutely not. My Grandfather was a fine man, a truck driver, a man who could fix almost anything. His technical knowledge was all at the school of hard knocks so I am not surprised to have found some of his theory to be false. The ones I am upset about are the "Auto Shops" teachers who have miss led so many of us. In my mid seventies, and one week retired, I am still a voracious reader and my favorite new old book is a "Machinery's Handbook" published in 1942. I suppose modern welding has surpassed the latest information in this book but is certainly a good basis for information. Of course all the mathematical tables and charts and gearing and allowances and tolerances are still valid. I once read that it's not the things we don't know that cause us trouble, it's the things that we know that aren't so. Thanks herm111 Link to comment Share on other sites More sharing options...
herm111 Posted August 10, 2016 Share Posted August 10, 2016 On 8/6/2016 at 5:23 PM, Tinindian said: herm111 Are you putting another "fact" into the category of "old wives tales" or "old mechanics facts"??? I have discovered that many many things that I was told were true forty, fifty or sixty years ago were absolutely not. My Grandfather was a fine man, a truck driver, a man who could fix almost anything. His technical knowledge was all at the school of hard knocks so I am not surprised to have found some of his theory to be false. The ones I am upset about are the "Auto Shops" teachers who have miss led so many of us. In my mid seventies, and one week retired, I am still a voracious reader and my favorite new old book is a "Machinery's Handbook" published in 1942. I suppose modern welding has surpassed the latest information in this book but is certainly a good basis for information. Of course all the mathematical tables and charts and gearing and allowances and tolerances are still valid. I once read that it's not the things we don't know that cause us trouble, it's the things that we know that aren't so. Thanks herm111 Mr. Tinindian, if there is a message in your post for me, I can't seem to find it. I do know I don't do old wives tales, but I have chased a few. Herm. 1 Link to comment Share on other sites More sharing options...
Guest Posted August 11, 2016 Share Posted August 11, 2016 herm111 I was just commenting on how many of the things that I/we were taught when we were young weren't right. Link to comment Share on other sites More sharing options...
Marty Roth Posted August 15, 2016 Share Posted August 15, 2016 On 6/18/2016 at 11:03 AM, Delbert Stallings said: This is the bottom plate of the oil pump, there is some vey lite wear from the gears that lay right on the plate. Are the gears supposed to lay right on the plate? The plate is brass although the picture doesn't show it. I agree On 6/18/2016 at 11:03 AM, Delbert Stallings said: I AGREE WITH hchris A sheet of flat thick glass, such as in your side windows, gives a nice flat surface on which you can lay a sheet of fine grade wet and dry abrasive paper, or grinding paste. Put the scored surface of the oil pump plate on the abrasive surface and move it firmly in figure 8 movements, to wear down the grooves, to the point that the surface of the plate is nice and smooth, wipe the plate surface regularly to remove any residue. Make sure all the pump surfaces are nice and clean prior to re installing. Clearances within the pump are critical if you want to maintain good oil pressure, as mentioned .005" clearance would be the maximum acceptable between gear and wall of the pump, .003" between the gear teeth and .005" between the end plate and gears; given that you have what I would consider excessive wear on the end plate, you probably need to go through the whole of the pump or perhaps find an acceptable replacement. with hchris: Link to comment Share on other sites More sharing options...
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