Oil jet piston cooling and its effects on oil?

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Hey Guys,

I tried a search function but was unable to find anything of substance. Have we or anyone else discussed the effects of oil jet cooling on the oil its self? Reason I ask is my 6.2l V8 uses this technology and I'm unsure if this is in hard on the oil or not and if so should it affect my oil choice moving forward.
 
What does the operator's manual show for what oil to use?

EDIT: The piston undercrown is a place where deposits can form if the oil isn't up to snuff. At least that's what I get from the Chevron Delo tear-down videos.
 
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Break the engine in.

Motorcraft 5w20 semi syn at 1000, 3000, then 5000..then change at 5000 with same oil til you get tired of it.

Piston-cooling jets squirt oil on the underside of the pistons to keep the piston crowns cool under extreme operating conditions. The cooling jets also allow for a higher compression ratio for better engine efficiency and faster engine oil warm-up on cold starts, also improving fuel economy.
 
It's an interesting question. Does heating up a very small amount of oil for a very short period of time pollute the rest of the oil over the oil change interval.

This oil cooling process is well proven in emergency generators that I've been involved in over the years and under severe conditions, high load, long runs I've never seen anything in oil samples that would indicate such a problem.

There are other hot spots within an engine and modern engine oil appears to survive such problems. Those spots would be turbo chargers, areas near exhaust valves, boundary layer lubrication around compression rings and areas around exhaust ports.

I'd say use a good oil, drive in a reasonable manner, do the maintenance and not worry. Your engine is better off with the oil cooling devices.
 
I was really just curious more than anything else as I've not owned an engine other than diesels that did this. Its really kind of cool when you think about it. I digress...
 
Compared to what the oil that gets to the rings, circulates there for 10 seconds or so and returns to the sump, the piston squirter lube really only gets hot, before returning to the sump.

Probably spends a little more time in the blowby gasses, but probably not enough to worry.
 
When the Coyote 5.0L came out in 2011 they had them installed. Then around 2013ish or so Ford eliminated them while adding a different coating to the piston skirts. I still would rather my engine have them than not as there is no downside aside from some increased windage that can be taken care of with shielding.
 
Originally Posted By: bdcardinal
When the Coyote 5.0L came out in 2011 they had them installed. Then around 2013ish or so Ford eliminated them while adding a different coating to the piston skirts. I still would rather my engine have them than not as there is no downside aside from some increased windage that can be taken care of with shielding.
I still have no idea if my truck has them or not. So much conflicting info.
 
Based on the 3D animation above I would think that the oil squirted on the underside of the pistons would undergo less stress than the oil contacting the piston rings (which is more sheared as well as exposed to higher temperature and pressure and is doing ok nonetheless).

If there is a hot-spot under the piston, the squirted oil that contacted the hotspot will drip down quickly (heat increases oil fluidity) and be replaced with freshly squirted oil on the next cycle.

It seems like a reasonable mechanism that doesn't impose stress on the oil any worse than other parts of the engine (piston rings).
 
If not an oil jet the piston bottom would only get a little bit of oil that is flung from the crank bearings. Years ago hot rodders would drill a hole in the con rod that would do almost the same thing.
 
Originally Posted By: hatt
Originally Posted By: bdcardinal
When the Coyote 5.0L came out in 2011 they had them installed. Then around 2013ish or so Ford eliminated them while adding a different coating to the piston skirts. I still would rather my engine have them than not as there is no downside aside from some increased windage that can be taken care of with shielding.
I still have no idea if my truck has them or not. So much conflicting info.


Ya it is confusing even for me. When I look my car up in the catalog, it shows them. But when I check the block, it shows the block is one without.
 
The high horsepower Supra guys have been removing these things for years. They seem to cause damage in high output applications:

http://www.supraforums.com/forum/showthread.php?633865-Oil-Squirters-Yay-or-Nay

Even sell block off plates for them:

https://www.acceleratedperformance.com/product/2jz-Oil-Squirter-block-off-Kit

Not saying this is for everyone, just a fun fact
wink.gif
 
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They are on my sig car. In well over 100k miles not a peep of any issues.

Many pro engine builders remove them. They want more oil for the important spots. But IMO they are a great thing for an engine that may occasionally see some hard use at the track or such...
 
Honda has used them in their B series engines for ages but there are many that prefer to block them off when used in High power applications. I personally think they are a great Idea, and left them in my rather high $$$ B18C build.

I do think they contribute to oil pressure loss (albeit slight) as well as windage and possible foaming in high RPM engines.
 
The thing is, most engine builders are doing everything they can to control how oil moves in the crankcase. Piston squirters are the bull in the china shop.

I'd rather have good piston coatings than oil squirters. Keeping heat out of the piston beats trying to remove it.
 
From my literature reviews, about 20-30% of piston heat passes to the bores via the rings.

Piston squirters are spring actuated (open beyond 'x' oil pressure). The heat remaining after the energy is utilized from combustion is significant and coolant jackets around the bores are it's only source for mild operating conditions.

But the FMEP generated at higher RPMs and torque bands is so high, an oil cooling is deemed necessary.

With newer, small displacement boosted engines targeted to achieve the same power as larger engines with more cylinders, the pistons undergo ridiculous amounts of heat.

Maybe we haven't reached new avenues as far as piston R&D goes? I don't know!
But our oil intelligence is well advanced to handle most of what's thrown at it.
smile.gif
 
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Originally Posted By: racin4ds

I do think they contribute to oil pressure loss (albeit slight) as well as windage and possible foaming in high RPM engines.


Honda used them in the F20C, so they seemed happy to have them in a 9000rpm application. I'm not going to second guess Honda when it comes to the F20C.

robert
 
Just to add something (a little), here's a piston out of a 3L Toyota diesel "D4D" that had an kijection problem and ate a piston (piston is on my desk).

IMG_20151019_225944.jpg


What you are looking down into is the crown cooling passage.

The squirters are arranged such that they direct the oil at a port in the piston underside, and it circulates/sloshes in this gallery for some time before running out holes on the other side.
 
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