Oil Cooling Jets for Pistons Anyone?

[Josh280z]

I want to see the results, looks like its an interesting mod; very plausible for any engine build. Seems like it would need the high pressure oil pump and a bigger reserve.

 

EDIT: maybe also a oil cooler to be even more effective.

Edited June 26, 2012 by Josh280z

[TimZ]

Who says you can't convey tone on the internet?

[Gollum]

Maybe I'm just sticking out like a sore thumb here, but has anyone done some basic research comparing bearing tolerances on factory engines with and without piston oil jets? Seems to me that since so many high level race groups ignore them altogether that they look more like a solution forthe trend in modern engines to run tighter and tighter tolerance with thinner and thinner oils.

I'll never say what Tim did is pointless and I commend him for doing it, I just feel like there's an elephant in the room that nobody wants to spend the time looking into. If I was 15 again, living with my parents with nothing but time on my hands I'd just go whip up a spreadsheet. Alas that's not the case for me anymore. Maybe I'll find a way to make the time if nobody else jumps on it.

In the end, as long as the pump has the capacity to support it I'm all for it. I've just been curious why we've seen these jets on non-performance minded engines for so long with very little hardcore data put out there for everyone to see. Due to the lack of precedence in the racing world I've just felt/assumed they were just kind of a bragging right of Honda boys reading the spec sheets of their engines...

Edited June 28, 2012 by Gollum

[SleeperZ]

 

In the end, as long as the pump has the capacity to support it I'm all for it.

That's all that matters in the end. If Tim can keep sufficient oil pressure, this mod will keep piston temps down and make them more reliable. And of course additional oil cooling will help shed that heat load as well.

[TimZ]

Due to the lack of precedence in the racing world I've just felt/assumed they were just kind of a bragging right of Honda boys reading the spec sheets of their engines...

 

Maybe I'm misreading what you are saying, but I think there are plenty of examples of piston oil jet cooling being used in performance applications. Are we not counting F1, WRC or Winston Cup as part of the racing world?

 

Also, I'm not running particularly big bearing clearances - I'm right at .002" for both the main and rod bearings. That said, I will be watching the oil pressure pretty closely...

Edited June 29, 2012 by TimZ

[Gollum]

Yes we might see these cooling jets in a lot of those racingw series today, but from all I've seen they've kinda followed the OEM market in many ways. Though not the case for formula 1, wrc, gt1, jgtc, etc have very close ties with production engines as a base. Now, who leads who is tough for me to tell from the outside, but considering how many engines with almost zero racing interest suddenly started popping up with oil jet piston coolers really has me wondering how much race teams really cared about them.

And honestly I'm not that knowledgable about f1 history, but didn't the oil jets not get put into use until the high output turbo years? Which is relatively recent for the age of the technology.

And I don't think it's just NASCAR that doesn't use them to this day. I don't think they're used at all in NHRA top fuelers, and I can't find concrete use in many areas like Dakar/Baja which makes me think it's not a huge concern.

And you're right, you ARE running tight tolerances. You're also producing plenty of heat. Of the L motors on this site yours is definitely one of the better candidates to maybe benefit from this mod.

[PMC raceengines]

For the last 5 years all out big rpm RB26 engines we have removed the oil jets , its helped keep the mains and big ends alive and we have not lost a piston yet and we are making well over 1000hp and 10000 rpm. We were rebuilding them every time we raced and now every seasion, and also our turbos are not failing as often . pmc

[Tony D]

" I don't think they're used at all in NHRA top fuelers, "

Possibly because they throw the pistons away after each run?

"And honestly I'm not that knowledgeable about F1 history, but didn't the oil jets not get put into use until the high output turbo years? Which is relatively recent for the age of the technology."

I believe this is exactly the conditions we are talking about, isn't it? 200HP/Litre+ Even though the F1 was more like 1000HP/Liter+ they were also Damocles Engines ready to blow at any second. This adaptation at a relatively low output comparatively is aimed solely at Longevity in an OEM application expected to last 300,000 miles. And if by 'relatively recent' you mean 30 years ago... Stationary Turbocharged Engines (or mechanically supercharged engines) have run cooling jets on the bottoms of the pistons since the early 1900's...

The thing about looking at 'racing' engines is that compared to OEM Streeters, they can remove some things because they want others to last (see RB26 engine example from PMC, sacrifice piston cooling to keep bearings alive in race conditions)... Racing is a balancing act, and if your engine only has to last one pass...or one race of one or two hours duration---does it become important?

If you plan on running 300K...you start looking at long term fatigue cycles and what you can do to lessen their severity.

Edited June 29, 2012 by Tony D

[Gollum]

have run cooling jets on the bottoms of the pistons since the early 1900's...

 

Which is relatively recent for the age of the technology.

 

 

Which is exactly what I was eluding to. This isn't a "new" technology just like hOnDA VTEC isn't anything new really either. Honda simply popularized it, and it's ironic that they're the same exact company who made these oil jets all the rage as well.

 

Again, never once have I discounted the idea. I'd just like to see more hard data out there instead of speculation. "So and so does it so it must be a good idea" rarely flies for me, and was very much the tone of MUCH of this thread. TimZ has the right attitude about it and I'm glad to see someone who might actually need them doing it. I never once in any of these posts set out to say he was making a mistake, just that there's lots of assuming going on which we all know can be quite dangerous.

[TimZ]

Which is exactly what I was eluding to. This isn't a "new" technology just like hOnDA VTEC isn't anything new really either. Honda simply popularized it, and it's ironic that they're the same exact company who made these oil jets all the rage as well.

 

Again, never once have I discounted the idea. I'd just like to see more hard data out there instead of speculation. "So and so does it so it must be a good idea" rarely flies for me, and was very much the tone of MUCH of this thread. TimZ has the right attitude about it and I'm glad to see someone who might actually need them doing it. I never once in any of these posts set out to say he was making a mistake, just that there's lots of assuming going on which we all know can be quite dangerous.

 

Thanks for the kind words and I'm not taking offense. However I am have trouble following your line of reasoning. This method of stabilizing piston temps is really well established and is becoming pretty much ubiquitous on high specific output engines. Plenty of OEMs use them, not just Honda. And I was having trouble understanding the assertion that they don't have precedence in racing when it seems to me like organized race series that don't have teams that use them seem to be more the exception than the rule. The latest NASCAR engines _do_ use them, btw.

 

As we've already discussed, I'm more interested in the potential longevity aspect of these, rather than trying to get a horsepower gain out of them. I'm already using ceramic coatings on my pistons and they appear to be working, in that I'm not getting any discoloration, coking or sludge buildup on the underside of the crown. However, ceramics are a heat insulator and while they significantly slow the flow of heat into the piston, they won't stop it. This will work great for short bursts, but I have no idea of how long they will stave off disaster by themselves. It seems logical to me that the combination of the coatings with the squirters should allow the oil squirters to remove the heat that does get through pretty much indefinitely, assuming nothing else craps out.

 

My main concern right now is whether the oiling system can accommodate the additional flow required, which should become apparent pretty quickly.

[Tony D]

" they're the same exact company who made these oil jets all the rage as well. "

I'm sorry, but that IS discounting the exact strong science behind them being added. I didn't know Honda did it. I knew Cooper Bessemer did it back in the 1900's.

As Tim says the engineering basis for these modifications is sound, and well proven.

Frankly, I had no idea WHAT Honda is doing, nor do I care. I'm not doing it 'because Honda now does it' nor am I doing it because Cooper Bessemer does/did it for over 100 years.

I did it and was curious about it's application to THE NISSAN L-ENGINE because I haven't seen anybody do it, despite increasing the engine output 10X. We didn't do it in the VW air cooled engines because of the configuration and clearances involved. But (as I stated at the top of this page in fact) I inquired about this SOME TIME AGO but nobody else could answer specific application enquiries so I'm watching this thread for APPLICATION INFORMATION.

For the ENGINEERING BASE, go to the Cooper Bessemer Engine School and you can spend half a day on thermodynamics equations and WHY they did it. I was there, they convinced me WHY it should be done. I don't need to revisit it. If you want to know why...read some more. it's all out there! They 'hard data' is in the equations and over 100 years of operational history.

Hard fact of the matter is it becomes DAMN HARD TO APPLY in smaller engines operating at higher RPM's with limited oil pump capacity.

The issue isn't WHY you do it, but far more geared towards "HOW" you can do it within the existing engine package. Generally these setups are done on engines DESIGNED to incorporate the provision. RETROFIT applications merely take KNOWN engineering principles and apply them to an EXISTING design.

In this instance HOW is the only issue, as the WHY has been proven in too many other applications...

As TimZ states in his last paragraph, the DIFFERENCE between Ceramic Coatings and Oil Jets is the difference between BURSTS of speed, and something operating CONTINUOUSLY at peak HP.

My interest stems from the fact that the Bonneville Run will be at least 5 minutes each way at FULL HP. It's one of the reasons JeffP and I were running 5 minute runs on the engine dyno at 475HP to see what oil temp stabilization we got with cooling mods. Now, double that HP and you can see for a season of running, dyno tuning, etc you want all you can get in terms of longevity.

The stationary engines run them because they run 100% load 24/7 and they don't want excessive heat in the pistons (even if they ARE cast iron, and already have been retrofitted with ceramic coatings...)

The first step is getting them to fit.

The second step is deciding if the stock pump will handle the additional flow, or if you have to go external-pickup or dry sump.

The LAST step is to monitor and gauge benefits long term.

The "WHY" that initiated the project really doesn't enter into the matter, that's pretty much black-and-white understood that the engineering basis for having them versus not having them tilts strongly towards having them when you can.

When the L-Engine was designed in the 50's, there was no projection to have more than 1HP / CID. At that level, engineering economics don't dictate the necessity of the item. 2HP / CID, 3HP / CID, close to 4HP / CID---might want to consider it for OEM 300,000 mile reliability.

Think of how many modified L-Turbo engines you hear of long-term 100K +, I'm only halfway there at the 2HP / CID and I know I made compromises in the build simply because of time... My next build I plan on having 100K + clearly in my sights and beyond with more HP. To do that, heat management on delicate aluminum parts seems to be a no-brainer!

It doesn't have anything to do with what the Honda Boyz are doing. It has everything to do with what the Engineers at Cooper Bessemer worked out and proved on paper 110 years ago, and subsequently confirmed in that period in the field that does it for me.

[Tony D]

In short, what all that says is "BECAUSE they exist in so many applications means the ENGINEERING BASIS for them is SOUND"

 

What Gollum seems to be doing is discounting that engineering basis as "because so-and-so is doing it"....

 

Did you ever stop to consider that the reason so-and-so does it would be because it works for them?

 

The only way to know if it works for you is NOT to question why THEY do it---because THEY have something different that YOU!

 

The only way to know if it works for YOU is to DO IT!

[TimZ]

In short, what all that says is "BECAUSE they exist in so many applications means the ENGINEERING BASIS for them is SOUND"

 

What Gollum seems to be doing is discounting that engineering basis as "because so-and-so is doing it"....

 

Did you ever stop to consider that the reason so-and-so does it would be because it works for them?

 

The only way to know if it works for you is NOT to question why THEY do it---because THEY have something different that YOU!

 

The only way to know if it works for YOU is to DO IT!

 

Thanks Tony. You always seem to save me a bunch of typing.

 

Now just pray that the oil pump holds up.

[Tony D]

Remember the flow available increases quite a bit by the -10 external oil line modification to the standard Wet Sump Pickup and Pump!

 

And after that, there's Cleve's idea about that external mount Gilmer-Drive Wet Sump Pump arrangement!

[TimZ]

Remember the flow available increases quite a bit by the -10 external oil line modification to the standard Wet Sump Pickup and Pump!

 

I'm already part-way there - I have an external feed from the pan that taps into the pump feed galley in the block. The original pickup point in the block is blocked off. This was done out of necessity at the time as I had an early AZ ZCar cast pan tht did not accomodate the stock internal pickup. My external line is a -12 that runs for maybe 10" to the point where the block was tapped. The internal passage ID isn't too bad, but there are a couple more sharp corners in there than I would like. I've taken a die grinder and opened up the internal, somewhat tortured paths in the front cover, so that should be a bit better, but I suspect a -12 line straight to the pump would still be better.

 

I've seen a mod that involved an adapter block placed between the pump and front cover - is that the mod you are speaking of, or is there a simpler way that wouldn't involve relocating the sway bar? I was thinking of having another look at the front cover to see if it would be possible to mod it directly with a fitting...

 

And after that, there's Cleve's idea about that external mount Gilmer-Drive Wet Sump Pump arrangement!

 

[Tony D]

The mod I was thinking of you blocked the pickup line in the block, and the suction and discharge of the pump screwed into a new pump end cover.

 

Any clearance you might need for the swaybar is gained the same way as when you lower the engine in the chassis: Make a block that goes under the mounting point on the frame rail, and shorten the end links appropriately. You can easily gain 2" doing this.

[87pyro3]

I have ben reading and following this particular thread with some real interest. There is only 1 thing that pops into my mind over and over again. Why so much time and money into a "possibility" of this truly working without major modding nessary? To me refineing air flow, OIL flow/cooling, and water temps, would accomidate colder temps across the board. Why the main concern for pistions?

[Gollum]

I'll reply so tony can correct me later. (you know I love to tease)

You can gap rings and piston clearance as loose as needed for a given piston temp and be fine. As long as when under power at temp your pistons are in the right tolerance window then there's not an issue with piston temp, per say. The issue comes when you start looking at the fact that oil likes to get gummy at elevated temps and the oil surface on the bottom of the piston starts getting caked, and now you have an oiling issue. Keeping the pistons cooler will help prevent this heat driven sludge. Then there's the other benefit in that if you can keep the piston a bit cooler then you don't have to clearance for quite as much gap, meaning slightly better cold running condition. It might not sound like a bit deal, but I've raced 9 (daily driven) second Hondas and at that level every .001 of less gap needed is very welcomed.

[Tony D]

"I have ben reading and following this particular thread with some real interest. There is only 1 thing that pops into my mind over and over again. Why so much time and money into a "possibility" of this truly working without major modding nessary? To me refineing air flow, OIL flow/cooling, and water temps, would accomidate colder temps across the board. Why the main concern for pistions? "

Because your main premise for this logic line is incorrect. If you cool the oil, what do you gain? Colder oil. You do not take any heat out of the pistons. With refining of airflow (which I can only think means porting the head) would increase BMEP, meaning more heat in the combustion chamber. While it's true that thermodynamically ceramic coating the piston crowns will retain heat in the chamber where it can better drive a turbine or whatever... you have in some cases DOUBLED the heat load on the crown of the piston.

Now, if you could REFINE THE OIL FLOW TO DIRECTLY COOL THAT AREA do you see a benefit at 2X heat load? What about 3X? What about 4X stock HP loading? Tim's at 4X BTU Throughput on his engine at around 600+HP. That's about HALF the most I've heard of for an endurance engine, and nobody I know has revealed what is inside that engine---but let it be said the 1100HP L28 was built around RACING BODY SANCTIONING RULES which indeed may preclude such modifications.

On the street, absent of rules like this, it can be pursued.

Now, the "Why so much time and money" and your use of the word "POSSIBILITY"---read the last few posts over again and then it only becomes "How MUCH benefit" not "possibility"... It is widely done---it's not a theory, it's a fact. There is no 'possibility' about it. It was just a matter of time before someone had the time and inclination to see if it would FIT.

As I said, FITTMENT is the LARGEST HURDLE to implementation of this technology, the second is engineering imperative. Seemingly the RB Engine has them, at only around what...240HP for an RB26DETT? So making 3X the power of that....the question becomes "WHY NOT?" The L-Engine was not envisioned to have 240HP continuously, and those L-Engines that DID has RADICALLY RECAST heads and cooling water flows (look at Alan Thomas' FIA Six Cylinder Head Photos.)

Indeed, read more, investigate and the logic becomes 'why not', and not 'why'!

[Tony D]

Also, you do not necessarily want 'colder temps across the board'---you want some areas hot, other areas cold.

 

In terms of pistons, you want them as cool and thermally stable as you can get them. If you truly read the thread, you would see the jets are check-controlled. They will turn off at idle when not needed. VERY utilitarian, and a 'relatively recent' development as usually they are 'always on'...

 

No wasteage of oil when idling and the pump is putting out less flow, on and cooling when the engine needs it most: higher rpms and likely more load from throttle position.

 

Comprende, Newbmigo?

 

Did I coin another Signature Phrase for the Tagging Moderators there, or what?