Valve spring oil cooler?

[jean genibrel]

I would like to know if anyone out there knows how to plumb a valve spring oil cooler.
Are they gravity activated, do they need a pump like for gearboxes and diffs?

Thank you

 

[SwinnyGG]

I would like to know if anyone out there knows how to plumb a valve spring oil cooler.
Are they gravity activated, do they need a pump like for gearboxes and diffs?

After following your link, the answer becomes clear. Note that the series of Setrab coolers you have linked to are noted for use as 'Valve Spring' AND/OR 'Power Steering' coolers.

Of all possible cooling loads you could create in an engine system by plumbing a separate cooling loop, valve spring cooling and power steering cooling are going to typically be by far the smallest cooling loads. Meaning they would require very small heat exchangers compared to, say, a transmission cooler.

If you wanted to cool valve spring cooling oil separately from everything else, there is only one way that I can see it being possible; you'd have to have a separate dry sump pumping stage for the valve spring oiler supply, plumbed with the (tiny) heat exchanger in line between the pumping stage and the supply on the cylinder head(s).

You can't separate the valve spring cooling oil from the rest of the stream, because once you spray it inside the valve cover, it's getting mixed with other sources (ie lubrication for flat tappet lifters or whatever else is in there) as it drains back to the sump. So cooling prior to spray is your only option.

This is why the other guys are talking about dry sump pumps - because having a dry sump pump with a dedicated stage is the only way to provide cooled oil to the valve spring oilers and the valve spring oilers only.

With all that said, even in the most demanding applications, I can't imagine the flow required to properly supply valve spring oilers for cooling is so gargantuan that you would dedicate an entire dry sump stage to it. Maybe I'm wrong about that, but I don't see it. If I were building an engine and felt that spring oilers were necessary, I'd probably source that oil from a dry sump stage that is already supplying oil to other relatively low volume destinations - like piston skirt oilers, cam bearings, whatever.

In short, I'm pretty sure Setrab calls these 'valve spring/power steering coolers' because the heat exchangers in that particular series are so small, that those little cooling loads are all people ever use them for. But the coolers themselves aren't 'special' in any way.. they are just a smaller version of the standard Setrab cooler you'd use to cool a transmission or a rear end or whatever. That fact is obvious from reading the catalog. They're like normal Setrab heat exchangers, just tiny.

 

[TugboatEng]

With all that said, even in the most demanding applications, I can't imagine the flow required to properly supply valve spring oilers for cooling is so gargantuan that you would dedicate an entire dry sump stage to it.

The benefit of dry sump oiling is the variety of pressure circuits, not just more capacity. If valve spring cooling requires a higher pressure than piston cooling it starts to make sense to run separate stages, regardless of flow requirements.

 

[SwinnyGG]

The benefit of dry sump oiling is the variety of pressure circuits, not just more capacity. If valve spring cooling requires a higher pressure than piston cooling it starts to make sense to run separate stages, regardless of flow requirements.

I agree, that's one of the benefits of a dry sump system. What I was getting at is that unless I'm missing something (which, maybe I am) the demand for a valve spring cooling system would not be high pressure, meaning it would be easy to bleed it off somewhere else without adding the weight/cost/parasitic loss of a dedicated dry sump stage.

 

[gruntguru]

What's the goal here?
- Extra oil flow to cool the valve springs? Arrange some squirters using the existing oil system.
- Colder oil to the valve springs? A very small oil/air cooler added to the above squirter circuit.

je suis charlie

 

[TugboatEng]

As I said earlier, this would make sense on a system that doesn't have oil drain back holes from valve spring area. The valve lubrication would have it's own separate oil system thus the need for cooling.

On marine slow speed diesels, the camshaft has it's own lubrication sump and pump. This is prevent contamination of the main sump from fuel leakage.

For more conventional engines, I do believe nearly all of the blow-by into the crankcase comes up the valve guides. I know this to be true because our 2-stroke diesels with an air box between the combustion chamber and crankcase still blacken their oil at the same rate as the 4-strokes. The combustion gasses must be coming through the guides. A separate oil system for the valve gear may prolong oil life.

Finally, if the engine operated upsidedown it may also need additional pumps and coolers.

 

[SwinnyGG]

I mean I'm not saying you're wrong... but you're talking about a very, very minor subset of engines as a whole.

This bit:

I do believe nearly all of the blow-by into the crankcase comes up the valve guides.

Is, I must say, not the case. If it were every valve cover you ever took off would be chock full of carbon.

 

[TugboatEng]

On diesel engines you can see the soot sprayed on the inside of the valve cover. Gas engines don't make so much carbon, they do varnish instead. But the oil has dispersants so the accumulations of carbon should be minimal. It mostly gets removed during the oil change.

Some of our engines have valve covers like engine hoods. You can open them with the engine running. You can see the smoke coming up the guides during cold starts. Turbocharged engines are worse because they have higher exhaust pressures.

 

[SwinnyGG]

I'm not totally unfamiliar with large format diesel engines.. I worked at the Redford, MI Detroit Diesel plant in R&D for a number of years.

There's certainly leakage through valve seals, but it's not a major portion of the total. This is a thing we studied.

 

[Demented]

Could it be that they're referring to a transmission oil/fluid cooler as a valve oil cooler? Especially with a lot of power steering systems use transmission fluid. Seems like an awful silly idea to try and specifically cool the oil spraying on the valve springs in the engine head.

 

[SwinnyGG]

Could it be that they're referring to a transmission oil/fluid cooler as a valve oil cooler

See my post above.... this is exactly it. They're listing a series of heat exchanger sizes typically used for power steering or small transmission cooling applications, and saying 'oh by the way sometimes people use these to cool valve spring oil too'.

This whole thread is the result of a weird marketing listing by Setrab as far as I can tell. Nothing really to see here.