Engine/Transmission (1994 - 1998) '97 12V Oil Pump Capacity?

[BCraig]

I have heard the '97 12V oil pump does not have the reserve capacity to supply a bypass filter and the engine at the same time. Does anyone have any info on this? Thoughts are appreciated.

Bruce

 

[CSnyder]

Seriously? LOL!!!

 

[BCraig]

Seriously! I was investigating the different bypass filter systems for my Ram and ran across that statement. It stated something to the effect of the pump flowing approximately 2 gpm to the engine and a bypass filter would siphon off some of that flow and potentially reduce the needed supply to the engine.

I had never heard that statement before, therefore my question!



Realistically, any pump would need to be sized for not only pressure but flow capacity as well, for durability. I am new to diesels and was not sure what the engine requirement is for flow rate. Pressure is developed by restriction to flow, to the limit of the pump system. Adding items (filters) to this system affects the flow rate and needs to be designed with that in mind.



This information is not readily available nor readily discussed on filter system pages. Just trying to get some answers is all.



Thanks

 

[thomasrmmr]

if you use a restricter say 1 mm opening and put on a direct oil pressure gauge factory gauge is computer , not actual pressure should idle no less than20 psi and go to 60 to 65 at 2100rpm if you can get a valve inline that opens at 30 min or 40 max that would be ideal if you know where to get the check valve let me know please

 

[BCraig]

Thanks Thomasmmr. That is a good place to start. Is there a preferred location to tap into the oil galley, such as the current sending unit? Or, does that need to be retained? I will look into that valve idea, sounds interesting.

I do have a spot open on my A Pillar panel to install the gauge.

Bruce

 

[ata]

I don't know why just the 97 would have a problem. As far as I know the oil pump and Bi-Pass valve are the same on 89 to date. (6. 7's) If you look at the oil filter housing on the front side (front of engine) there is a Plug cap that takes a 19 or 21 mm wrench. You can take that cap off and shim the spring under it and make what ever oil pressure you want. That valve regulates the oil pressure and or flow of oil that goes to the engine and the over flow goes back into the pan from there. On my 97 it held 73 pounds running warm and 36 at idle. This is with a real gauge. When I put the Bi-Pass filter on my oil pressure was still the same. On the oil filter housing you will see a 1/8 inch pipe plug. (next to the turbo oil supply line) That is the best place to tape for the Bi-Pass filter.

 

[thomasrmmr]

shimming the spring can get you too much oul pressure in the winter cold start ups running at high rpms at idle it will not do much if anything fully warmed up at 2200 running on the hwy aft 15 minutes to 30 minutes will show where your oil pressure is HOT when the oil thins out from the heat say 200 plus degrees oil temps but if you get too much on the spring you could turn the oil pump into a hydraulic pump n blow the filter off the block or bend the mating surface enough to blow the oil sealing ring out n drop your oil on your nice clean driveway in about 30 seconds !

 

[thomasrmmr]

you have to restrict the flow with a hole in the line and or a pressure check valve so your engine gets at least 20 to 30 psi inside ,

 

[thomasrmmr]

the oil sender has an o ring and straight threads its much easier to take out the 1/8 pipe plug on top of the filter housing just remember not to tighten the hell out of it [its only aluminum and not that thick , you can crack it !

 

[Vaughn MacKenzie]

According to this oil pump output is 20 gal/min 96-98 engine specs

 

[ata]

you have to restrict the flow with a hole in the line and or a pressure check valve so your engine gets at least 20 to 30 psi inside ,

Yes your right if your making up your own Bi-Pass kit. But all after market kits come with an oil restriction plug built in the filter head.

 

[ata]

the oil sender has an o ring and straight threads its much easier to take out the 1/8 pipe plug on top of the filter housing just remember not to tighten the hell out of it [its only aluminum and not that thick , you can crack it !

89 to 98 12 valve cummins oil sending units have 1/8 NPT (tappered) I do know they went to Straight threads on the 24 valve engine but not sure what year.

 

[BCraig]

Thanks very much for this link! I have now got it bookmarked for further reference.

It sounds like the pump will handle the bypass without problem as long as care is taken to verifly flow rates.



Thanks to all for your comments. Personally I never doubted the capability but I have to do my research and validate decisions when this much money is involved. Can't afford to replace this engine. You guys are very knowledgeable and willing to lend a hand with answers. That is very much appreciated. Maybe one day I will also be able to assist others. Thanks again to all!

 

[fest3er]

As others have said, your initial research is correct: the stock pump will not produce enough oil pressure for the engine if too much oil is siphoned off through the bypass filter. If you restrict bypass flow so that you have not less than 35 PSI oil pressure (if I recall correctly), then you'll be in fine mettle.

I installed an Amsoil dual remote bypass on my '98 at 60K miles. I have not taken it off since, nor have I drained the oil since (though with the many leaks, I've *replaced* the oil frequently over time). I now have 275K miles on the truck/engine and it still starts most of the time with about a 1/2 second starter contact.

 

[BCraig]

As others have said, your initial research is correct: the stock pump will not produce enough oil pressure for the engine if too much oil is siphoned off through the bypass filter. If you restrict bypass flow so that you have not less than 35 PSI oil pressure (if I recall correctly), then you'll be in fine mettle.

I installed an Amsoil dual remote bypass on my '98 at 60K miles. I have not taken it off since, nor have I drained the oil since (though with the many leaks, I've *replaced* the oil frequently over time). I now have 275K miles on the truck/engine and it still starts most of the time with about a 1/2 second starter contact.

fest3er, what kind of oil leaks did you have? Normal age stuff or possibly from the bypass system and pressure? Sorry, hope you don't mind my asking

 

[fest3er]

fest3er, what kind of oil leaks did you have? Normal age stuff or possibly from the bypass system and pressure? Sorry, hope you don't mind my asking

Age. The front seal was non-existent; it had completely disintegrated. There's enough blow-by in the crankcase to exceed the capacity of the vent tube; I opened the oil filler to provide extra venting which alleviated much of that oil loss. At present, it seems the side gasket (tappet cover?) is leaking; since fixing it requires removing the p-pump, it's going to wait until I have the funds to rebuild the pump at the same time. It's possible the pan gasket is leaking.



The Amsoil unit at the stock filter fitting leaked a bit until the fittings were greatly tightened; that's been OK since. The Amsoil filters weep just a little, possibly due to imperfect machining at the sealing surface. The hoses I made with Amsoil's supplied parts have never leaked; I took my time and made them right, and took care to shield the hoses from abrasion where it was likely to happen.

 

[Kirwin]

So I have to ask????

fest3er Why does your truck have excessive blow by? Your statement implies that the engine uses enough oil that you haven't needed to changed it in 200k miles is at the very least misleading. The front seal both keeps the oil in and keeps the dirt out of the crankcase. Any indication of external leakage of engine oil also implies an entry point for abrasive dirt to enter the crankcase. There are reasons that oil must be changed and one is the accumulation of chemical impurities that cannot be removed by filtering. Acids are produced during combustion that are neutralized by the additive package in the oil. To most of us excessive blowby is a sign of a worn out engine. If you have enough blow by that you have had to (decided to) remove the oil fill plug that tells me that you have a serious engine problem. The only way to wear out a Cummins engine (especially a 12 valve one) with normal routine maintenance is to put a lot of miles on one. Some get over 1,000,000 miles. Please explain this to me. Ken Irwin

 

[fest3er]

Wish I knew. The engine has never been worked hard for very long; perhaps the rings never seated quite right. At some point, the thermostat was malfunctioning. The gauge never showed the temp becoming alarmingly high. When I noticed that it was climbing higher than I thought it should (uphill with a light-ish trailer), I had Cummins Atlantic take a look. They found the internal temperature was exceeding 230F, even though the gauge was indicating 190 or so. I would imagine this 'overtemp' heated and hardened the seals, causing them to fail sooner. When I was made aware of the completely failed front seal, I had it replaced.

I believe I said that I haven't changed the oil in 200K miles. When I change the filters, I add makeup oil to replace that which is in the filter(s) (about 1 qt. each). That's enough to replenish the additives. Replacing oil lost to leakage further replenished the additives.

When the crankcase was 'overpressured', oil could not return from the top and found different ways to 'escape'. Relieving the pressure allowed the oil to return to the pan; this dropped my oil consumption from 1 quart per 500 miles to 1 quart per 2000 miles or so.

As I understand, some engines simply have more blow-by. I believe the excessive blow-by happens mostly during high boost (15-28 PSI). I am quite aware that the engine has problems; I hope I didn't insinuate otherwise. If I had the funds, I'd pull the engine and rebuild it; alas, I'm still in a financial hole from a failed business venture a few years back. Until I have the money, the truck gets driven the way it is.

 

[Bob4x4]

89 to 98 12 valve cummins oil sending units have 1/8 NPT (tappered) I do know they went to Straight threads on the 24 valve engine but not sure what year.

FYI later 98 12 valves also had straight threads

 

[ata]

FYI later 98 12 valves also had straight threads

Just wondering what a later 98 12 valve is. The 12 valve was only available (production wise) until Dec. 31 97. Cummins Northwest only show one oil sender for 98 12 valve.