Piston oil squirters in NASCAR engines

[hoffman900]

Many high performance Japanese engines also use multiple slots on both side of the rod cheek . I figured it was to "leak" the oil in a specific direction instead of just letting it sling off where ever it goes naturally.




These are on the bottom of Honda production engines.



https://www.ebay.com/itm/00-08-Honda-S2 ... 3274366270

A bunch of engine builders block them off to increase oil pressure. Doesn't seem like a good idea. Honda spent a bunch of production money to put them in the engine. Not sure how a race motor would survive without them.

All the Honda and import racers I've seen eliminate the oil squirters....and then wonder why they trash pistons so quickly and they're black on the underside, I don't even bring it up anymore, they obviously know better.

Unfortunately it's rubbing off onto the LS crowd and even though I go to great lengths to retrofit in pressure activated (OE BMW) in many endurance builds and have seen without a doubt that there are great benefits to doing so in piston life, power, etc....many come in wanting their OE squirter equipped blocks (LSA, LS9, LT4, etc) to be blocked off because that's what they see done on the internet.

Piston oil squirters are a very good thing as long as you do it properly and don't starve the system as a whole.

Classic case of not seeing the forest for the trees. Also, just because one can assemble an engine, doesn't mean one understands how they work or how to improve them.

My guess, if they took advantage of what the squirters allowed them to do, they would gain way more than any windage gains they would see, let alone the reliability.

[Fusion Works]

I'm wondering if there is a way to add a nozzle to the stock squirters? Like drilling a small hole and then brazing on an additional squirter?

Another option might be to come in from the opposite side of the block and feed them with a four AN line or some sort of stainless hard line with AN flare nuts. Then tap through the block into the underside of the cylinders to feed some squirters.

[Kevin Johnson]

Anyone had a look inside a newish NASCAR engine? I hear they have four or five piston oil cooling jets per cylinder. Which spots in the piston underside do all those four or five jets spray?

This might help:

The R07's camshaft resides higher in the block than the SB2's, thus allowing for a shorter/stiffer pushrod to be used. This dramatically improves valvetrain geometry at high rpm. The raised camshaft allows room for inboard piston squirters, which spray the underside of the pistons for additional cooling.

[j-c-c]

I broached this question before, not sure if i got much of a response.

If piston cooling is so beneficial, why not incorporate a separately extra cooled, pressurized (?), and plumbed oil delivery circuit just for the squirters?
Its main goal is cooling, right?
It would likely feed off the central oil tank, and return with the normal DS pickups.

[Kevin Johnson]

I broached this question before, not sure if i got much of a response.

If piston cooling is so beneficial, why not incorporate a separately extra cooled, pressurized (?), and plumbed oil delivery circuit just for the squirters?
Its main goal is cooling, right?
It would likely feed off the central oil tank, and return with the normal DS pickups.

But seriously, I was told by a factory engineer that an oiling solution for a known performance car was vetoed because it would have added $1000 to the sales price. I expect that a separate circuit and cooling system would exceed this.

[naukkis79]

I broached this question before, not sure if i got much of a response.

If piston cooling is so beneficial, why not incorporate a separately extra cooled, pressurized (?), and plumbed oil delivery circuit just for the squirters?
Its main goal is cooling, right?
It would likely feed off the central oil tank, and return with the normal DS pickups.

Why add complex things that won't bring any benefits? Piston cooling with oil from main galleries works just as fine. Suzuki build motorcycle engines where also cylinder head is totally oil-cooled, there was a additional low-pressure oil pump to circulate oil in head and oil cooler - but even in that configuration piston squirters are fed from normal high-pressurized side of oil pump.

[ptuomov]

Shooting straight:



The piston is a more modern design than the ‘87 piston, so the jet angle and location was adjusted.

[modok]

The majority of high output gasoline and diesel engines spray oil at the pistons.

Now with direct injection, there is really less difference than ever. gas and diesel are almost the same mechanically.

[j-c-c]

I broached this question before, not sure if i got much of a response.

If piston cooling is so beneficial, why not incorporate a separately extra cooled, pressurized (?), and plumbed oil delivery circuit just for the squirters?
Its main goal is cooling, right?
It would likely feed off the central oil tank, and return with the normal DS pickups.

Why add complex things that won't bring any benefits? Piston cooling with oil from main galleries works just as fine. Suzuki build motorcycle engines where also cylinder head is totally oil-cooled, there was a additional low-pressure oil pump to circulate oil in head and oil cooler - but even in that configuration piston squirters are fed from normal high-pressurized side of oil pump.

1. benefits:
Cooler supply of oil, if as reported here a reduction of 77F ipiston temp is worthy, it seems like cooler oil would assist in gaining that goal
ability to modulate volume of oil as needed or fine tune oil spray
reduce stress on main oil system, whose failure leads to catastrophic failure normally, a squirter system does not have the same criticality, IMO
2. If Suzuki figured it it out as worthy bang for buck, seems like it should be doable
3. I agree, "Fine" is good enough for some
4. Might even go a step further and use a diesel injector pump style solution, very high pressure, and timed for best use of the oil striking the piston if there are benefits to found there I can't imagine much oil remains on a piston as it starts it upward trajectory.

[Kevin Johnson]

...

1. benefits:
Cooler supply of oil, if as reported here a reduction of 77F ipiston temp is worthy, it seems like cooler oil would assist in gaining that goal
ability to modulate volume of oil as needed or fine tune oil spray
reduce stress on main oil system, whose failure leads to catastrophic failure normally, a squirter system does not have the same criticality, IMO
2. If Suzuki figured it it out as worthy bang for buck, seems like it should be doable
3. I agree, "Fine" is good enough for some
4. Might even go a step further and use a diesel injector pump style solution, very high pressure, and timed for best use of the oil striking the piston if there are benefits to found there I can't imagine much oil remains on a piston as it starts it upward trajectory.

When I did the pattern for the RB26DETT I noticed that the pistons had squirters that fed into a chamber. When I returned the core to the customer after measuring I knew he was going to throw them away so I asked for one to keep. I even looked up the Aisin Seiki patent for it at the time. (This is a type of "cocktail shaker" piston cooling.)

The same engine had a wetsump that obviously had a great deal of thought put into oil flow.

The same engine had an inward protruding "hump" in the sump to allow easier external access to torque converter bolts. Nissan had started adding this feature to their engines. This was something that you would likely only notice if you had to design parts for families/types of engines for a marque over many years/decades. It was significant because the oil witness marks in the sump showed the severe disruption to windage flow and this costs power and heats up the oil. The oil control engineers had this forced upon them. Clearly, if they could have changed it they would have. It is an example of the frustrating constraints that engineers have when working out solutions.

Another engine that I designed parts for unceremoniously dumped draining oil from the head directly onto the rotating assembly -- that heats up the oil and aerates it. I corresponded with an engineer involved with the design. He said that they had met the target power output in the first iteration and there was no reason to do further improvements -- that all costs real money. He also explained that additional power output could be an issue in certain markets due to taxing schemes.