Oil Viscosity and Oil Starvation Issues.

[Idrinkmotoroil]

If you had an engine that "might" be prone to oil starvation issues what can you do to help protect things as best as possible ?. There have been a few people with my engine that have recorded low oil pressure and then a subsequent connecting rod bearing knock. I'm thinking it's an oil starvation issue.

Should we keep viscosity on the thinner side and possibly using an oil with higher amounts of Moly ?, that's about all I could think of. This engine has a balance shaft system, not sure why but it seems that some engines with balance shaft systems seem to be more prone to oil starvation issues. I could be wrong but that's what I've seemed to notice. The engine is also factory turbocharged but I don't think that has anything to do with the issue.

Any suggestions on ways to keep things as safe as can be ?

thanks

 

[427Z06]

Under what conditions does the suspected "oil starvation" occur? What engine are we talking about? Mileage, history of use, modified/stock etc?

 

[Idrinkmotoroil]

quote:

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Originally posted by 427Z06:
Under what conditions does the suspected "oil starvation" occur? What engine are we talking about? Mileage, history of use, modified/stock etc?

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it's hard to get straight answers to those questions, but most people will say non-modified low mileage street use. I'm referring to a Dodge SRT4 2.4L turbo engine. I know Nissan Spec V's had similar issues sometimes attributed to their balance shaft system. not sure if this helps.

 

[BrianWC]

How would the balance shafts affect oil starvation?

Saabs have problems w/ low oil pressure but it's due to a poorly made oil pump that wears prematurly.

 

[Idrinkmotoroil]

quote:

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Originally posted by BrianWC:
How would the balance shafts affect oil starvation?

Saabs have problems w/ low oil pressure but it's due to a poorly made oil pump that wears prematurly.

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yeah I agree with the oil pump theory as well, but with balance shafts sometimes their bearings crap out due to oil starvation, then the loose material clogs major oil passages and that in turn kills the rod bearings and related parts.

 

[427Z06]

There's tens of millions of engines with balance shafts that don't suffer from this problem. Must be a design defect or poor quality control if it effects a particular engine design.

 

[Curious Kid]

The following are just thoughts mind you.

My mind keeps thinking that it's something in the design - oil pump of too little volume, for as long as inflow exceeds outflow from around all the bearings and so forth, than pressure will be maintained. Using a heavier weight will present higher pressures closest to the pump outlet, but also lower them further down the line due to flow resistance - increasing effect with smaller cross sectional area supply lines, high bleed off, and increased distances..or so I think.

Other things like too low a oil bypass setting for limiting line pressure (also tied in with most recent idea), bearing load/surface area/clearence w/general visc. range imbalanced. There could have been an error in the oil feed distribution network, with a given line being asked to flow more than it's capable of, thus resulting in lower than desired pressures at the final point of use (another way of explaining the end of the 1st paragraph) - this may be where the required lubrication source for the counter balance bearings plays an effect, with the added bearing clearence area presenting further
bleed-off.

From what I have read from a person or two around here, it doesn't seem that the oil flow network is something that is as thuroughly followed through as I first thought. It seems to have been more of a trial-and-error sort of thing!?

 

[Shannow]

chuck in a few balance shafts, and you've got quite a few more bearings to feed also.

 

[UncleS2]

The 2.0 Liter Neon engines are known to sometimes starve for oil when pushed to the extreme through hard right turns. Usually it's the hard-core racers who experience this. Reason is because the oil pickup is in the RH end of the oil pan.

Could the problem in the SRT-4 be similar to this? Just a thought. Also, check over at neons.org, they even have a forum especially for the SRT-4's.

 

[427Z06]

quote:

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Originally posted by Stuart Hughes:
...engines are known to sometimes starve for oil when pushed to the extreme through hard right turns. Usually it's the hard-core racers who experience this. Reason is because the oil pickup is in the RH end of the oil pan...

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A lot of engines are susceptible to this type of starvation when high lateral/longitudinal G's are involved. And even when the engines are installed longitudinally, oil can pool in other parts of the engine and the oil pickup can be uncovered.

 

[Curious Kid]

Continuing with quote reference - could this be one of the reasons people go with dry-sump oiling systems?

 

[BrianWC]

I'm glad to hear some thoughts on the balance shaft theory. A saab mechanic told a member of the forum I moderate that his low oil pressure was due to the balance shafts. But seems like someone would say the pickup was clogged instead....

 

[1sttruck]

Depends upon what the cause of the low oil pressure and/or low oil flow is. The old air cooled VWs had a simple oil pump which would often exhibit wear between the cover and the gear faces, between the two gears, and between the gears and housing. One needed to either replace it with a new one if there was too much slop in the gears, or just lap the cover flat and then the gears when installed in the housing, where clearance would be provided by the gasket. In this case a thicker oil would probably help to improve oil pressure due to excessive clearance, and is a general case for 'worn engines'.

With a higher perfomance engine that has seen high loads, or a 'regular engine' with a lot of miles, you may have more wear in some systems than others. You need to be careful about loads placed on cold engines as clearances may not have reached operating values, and a thicker oil being used for higher clearances and/or higher expected operating temperatures may not be flowing as needed. A stable, suitably rated synthetic with a wide operating range might be called for, to provide good flow when cold and yet adequate protection when warm.

If you're using too thick of an oil, say a 20w50 because you have a high performance engine but a 5w30 was recommended for general use, and your vehicle doesn't see much but lots of cold starts and city driving, you're also setting up conditions for lots of wear and are more prone to scuffed/scored surfaces due to inadequate oil presure and /or flow.

 

[1sttruck]

"The 2.0 Liter Neon engines are known to sometimes starve for oil when pushed to the extreme through hard right turns. Usually it's the hard-core racers who experience this. Reason is because the oil pickup is in the RH end of the oil pan."

Aren't 'baffled' oil pans / sumps are typically used to address this ? An oil presure gage can help to diagnose the problem.

 

[Idrinkmotoroil]

thanks for all of the replies. This isn't a widespread problem on this vehicle but I have seen in happen to two people in recent times which just gets me thinking. The oil pump is an issue on this vehicle for extreme racing conditions, something about not flowing enough in certain conditions. The other issue is that the oil pan has absolutely no baffling, it's just wide open, not even a windage tray.

These aren't two things I'll ever get around to fixing so if there is a better fluid to use I'd consider it. The engine is recommended to use 10w-30 Mobil1 under hard driving conditions. I'll probably stick with a 10w-30 viscosity, unless someone thinks a 40 weight might be more helpful.

 

[Leo]

Just fill her up by another half a quart and that may help any oil pickup starvation...