gbs

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I've found that ih used 3 different sizes of oil pumps on the 414 436 466 engines 7/8" on non turbo, 1" and 1-1/4" on turbo engines I'm assuming they had some type of volume issues to increase the pump size I'm aware of the fact it takes more volume to supply a turbo and a engine with oil cooled piston system how much more gpm flow did they gain going from 1" to 1-1/4",i realize it should be somewhere in the 25% range but I would like to know the approx. gpm of both pumps
 
Acctually the 1 1/4 was probably TWICE the volume of the 1".I never 'figured' it,dont know the math.... example: a 2" syphone tube will flow over DOUBLE the amount of water of a 1 1/2" tube.The outer circumfrence is where the most volume comes from. OK you math wizzards....Am I close,or am I full of $#!+?
 
(quoted from post at 21:01:24 02/16/15) Acctually the 1 1/4 was probably TWICE the volume of the 1".I never 'figured' it,dont know the math.... example: a 2" syphone tube will flow over DOUBLE the amount of water of a 1 1/2" tube.The outer circumfrence is where the most volume comes from. OK you math wizzards....Am I close,or am I full of $#!+?


1-1/4" tube will flow 1.5 times the volume as a 1" tube. A 2" tube will flow 1.77 times as much as a 1.5" tube. Radius of a circle squared times Pi equals its volume.
 
the reason I asked is I've got a low oil pressure issue at idle with a 1086 no telling how long it's been this way because the electric gauge isn't too accurate,engine runs fine so far no apparent damage has been done that I can find,I don't mind rebuilding it but I would like to find out what the problem is before I spend in excess of 3 grand in parts and machine work, not including my time and still have the same problem,i know if there is enough volume even with low idle pressure it won't hurt ,because I've seen several old detroit's that would hardly move the gauge at idle give no problems, I was wondering if someone previously installed the wrong pump, I mentioned in another post about a 396 chevy after rebuild that had no oil pressure at idle being a galley plug missing but after over 40 years I got my wires crossed it was actually a sand casting hole that opened up in the oil galley after vatting
 
First thing is to get a mechanical gauge and test/find out for sure.Hook to the pressure port in the side of the block.Are you sure the pump isnt just worn?Is this a 'high hour' tractor?
 
If it is a high hour tractor like over 10,000 it probably needs cam bearings as bad as a pump to see significant amount of improvement. Could also be the pressure control valve is getting weak.
 
I don't know if the dimensions are the gear diameter or the gear width. If it is the gear diameter then the other posts are correct, but if the difference is the gear width then a 1.25" pump would give 25% more flow than a 1". That seems to be a more logical scenario as all that needs to be done is put in a wider center section and gears in the pump to increase the flow. Everything else could remain the same. IMO
 
(quoted from post at 06:12:56 02/17/15) I don't know if the dimensions are the gear diameter or the gear width. If it is the gear diameter then the other posts are correct, but if the difference is the gear width then a 1.25" pump would give 25% more flow than a 1". That seems to be a more logical scenario as all that needs to be done is put in a wider center section and gears in the pump to increase the flow. Everything else could remain the same. IMO
Phil is almost certainly correct. I have ever been inside of the motor in question, but every high volume pump I have seen was changed exactly that way. When I checked the parts catalog, I found 4 different parts numbers for rotors and center section package and no changes in the rest of the pump.
 
I got concerned about the gauge and installed two different manual ones, they both show very little pressure at operating temp. when at low idle, any speed above that is reasonable,I check the relief valve and added a .060 shim no difference, then installed a new pump basically the same results,pulled a couple rods and mains the bearings shells had very little sign of wear, crank journals are slick as glass I realize that doesn't mean it's not out of round or undersize,but in an old engine it's a pretty good indicator of it's condition,I checked the oil clearance with plastigage laying in the worn part of the bearing shells, mains were .002 ?? not thinking until someone mentioned it due to weight of the crank that is off somewhat,rods cleaned and dry check .003,I'm going to recheck the crank with a mic,another possible dumb thought, would it be remotely possible to check the cam bearing clearance by removing the rocker arms and using a dial indicator to check movement while lifting the cam? I don't mean to ramble on about this problem but as I have grown older I am more inclined to find the cause of a problem before spending a couple days tearing something down and putting it back together when it would have took very little time to fix it to begin with, let alone the extra expense of parts,if I had only known what was causing the problem to begin with, BTDT to many times, thanks for all the inputs never know when a seemingly insignificant thought is the answer to a complex problem, thanks again for all the help
 
that is correct the only difference is rotor width,i was courious about the gpm of the 1" width and the gpm difference between the 2
 
A couple of things here, I am sure you will not be able to get the old 7/8th wide pump and not even sure about the 1 in. They may have all gone to the larges one now, hard to tell from parts book. But at any rate, the pump housing changes also with the width of the rotor. Those rotors do wear out badly occasionally and can cause low pressure at low speeds. Also, the gear on the crankshaft that drives the pump wears badly. You can put new rotor onto unused splines if there are any left or replace gear in chassis. The camshaft, being enclosed in the block is really a tough one to replace bushings and you cannot get ahold of the cam from underneath to check for movement. Fortunately, the cam bearing seem to last really well on those engine. We had a lot of problems with the pressure regulating valve. Especially in later 86 series and 50 series tractors. Luckily they are easy to replace. Another thing that uses quite a lot of oil is if it has the very latest rocker arm supports. They each have a jet in them to spray down on the camshaft. That engine should carry good oil pressure at low idle speeds if all is well.
 
Originally the rotor width was 5/8" for NA engines and 3/4" for turbocharged engines. The turbocharged engines were soon changed to 1" wide rotors and the NA engines were updated to use the 3/4" rotor.
 
I guess I should have said I don't know what the width is but that they have increased them and doubt the smaller ones are available. Speaking of them oil pumps, had a customer cruising down the road with almost new 986, wham, engine stuck, wheels slid on ice. It was the oil pump that had seized. There was one other one in this area that seized and killed engine while warming up.
 
Question for all you, I just registered to this site after seeing this thread. We are in the process of rebuilding a 966 after scorching #5 piston due to lack of lubrication as the block did not have any piston coolers and we were told that if you have both piston coolers that the 1" rotor oil pump will give a low oil psi reading at operating temp and the reason for this is something to do with Navistar having issues with the pumps locking up so they opened the specs of the 1" and at an idle will not have much oil psi. Now there's the 1.25" that is supposed to solve this low oil psi issue, so we bought the 1.25" pump and now the original harmonic balancer tightened to spec the engine will NOT move but as soon as we loosened the 3 bolts up to finger tight the engine moves freely. We found that the balancer is hitting the casting that separates the seal from the rest of the pump, has anyone had this problem that has used the 1.25" pump???? We are thinking about turning the surface for the ware ring from the ware ring down to the tapered thickness to gain clearance will this work?? Planning on calling the place we purchased the pump and see what their solution is.
Thanks!
 

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