Oil Cooling Jets for Pistons Anyone?

[TheSwede]

Well as the title says.....

 

Has anybody put cooling jets for the pistons in there L28 engine.... like the types in BMW,Saab,Volvo,newer Nissan turbo engines.

 

Its just a thought... considering that the ones from SAAB or BMW comes at no cost at all. (Well at least if live in Sweden).

 

Thinking about doing a turbo conversion....and it whould be a good way to keep the pistons a little bit cooler. But it does require drilling and tapping the enigne block if you use the type from Saab or drilling and tapping the main bearing cap if you use the type from BMW.

 

Most types of oil jet has a valve that opens att a certain pressure, but the question is if the oilpump/flow will be up to the task... so you dont loose the much oil at other areas when they open.

 

And where to drill.... would suck to hit the water areas of the block instead of the oil mains...hehehe

 

 

 

Any ideas, previous experiences....?

 

 

Cheers

[ctc]

This could be interesting. I have had the same thoughts myself. Might need to breakout one of my scrap blocks and have a look.

 

I do remember Tony D alluding to mods that JeffP did to his oiling system in the context of cooling, so maybe he knows something about this topic.

 

Can you get sizing specs on the Saab squirters?

[johnc]

I think a good high temp coating on the top of a forged piston will do a lot better job of keeping the pistons cool:

 

http://swaintech.com/race-coatings/

[TheSwede]

Well coating in all its glory...

 

But there must be a reason to why all car builders with good performance turbo engines use them....instead of coating. (Cost and logetivity)

 

 

Dont know what the cost for coating is around here.... but I bet building oil jets will be cheaper.

The ones from BMW is about 14 us dollars a piece (in sweden) times 6.... and the machining.... cant be that much. (Get back to you on that)

[Josh280z]

It would be interesting to see, but I'm with john on this one. I think ceramic coating would be your best bet.

[TheSwede]

This could be interesting. I have had the same thoughts myself. Might need to breakout one of my scrap blocks and have a look.

 

I do remember Tony D alluding to mods that JeffP did to his oiling system in the context of cooling, so maybe he knows something about this topic.

 

Can you get sizing specs on the Saab squirters?

 

 

Jupp.... I´ll have a look at it. Just give me a day or to... a buddy of mine has a company that only works with the Saab engines.

 

And if you could take one of thoose scrap blocks and put a drill to... it would be great. Since there just aint no scrap blocks laying arround in this country.... hehe.

[TheSwede]

It would be interesting to see, but I'm with john on this one. I think ceramic coating would be your best bet.

 

 

 

Well as john said a coating on top of a forged piston.....while this could be a good way to make your stock pistons a bit safer at a lower cost.

 

As I said before.... they come stock on modern turbo engines for a reason.

[TheSwede]

Here´s a link to spice it up a bit....

 

http://www.turbo-mini.com/44648/23109.html

[HowlerMonkey]

Don't the stock rods squirt oil on the bottom of the pistons.

Edited May 2, 2012 by HowlerMonkey

[duragg]

Did the Ceramic top and teflon side on the M14 (Supercharged).

 

If I recall doing 9 of them was maybe $300 bucks for both coatings and it just seemed like a neat thing to do.

 

 

Probably all burned off in the first 2 hours.

[rsicard]

Coating the piston is doing just HALF the job. How about valves and cylinder heads also as they take just as much heat as the pistons do?

[ctc]

Don't the stock rods squirt oil on the bottom of the pistons.

 

Yes, they do. In How to Modify Your Nissan/Datsun OHC Engine, it says to close the oil hole in the rod because the excess pressure will spray too much oil onto the piston and cylinder wall. Let me look at the geometry, but the oil squirts being discussed would would give a more direct consistent spray onto the piston not cylinder wall. I think the stock hole, being on the rod end, changes angle relative to the piston during a rotation of the crank and it would only oil one side.

 

Just checked a set of stock rods and pistons. The oil hole in the rod is directed such that only one side of the piston gets the oil spray. Also the angle looks like it will spray only on the skirt and maybe below. Definitely not on the underside of the piston crown. Maybe the crown would get a little spray but nothing consistent, I don't think.

 

On a plus note, the underside of the block at the bottom of the cylinder bore is pretty flat. Would be pretty easy to machine a flat to mount the squirter. Now just have to find an oil source. The main bearing feed is right there, but I would hesitate to tap pressure from the main bearings. Need to find my copy of the oil system diagram. That has the oil flow in the block if I remember correctly.

Edited May 4, 2012 by ctc

[josh817]

Don't the stock rods squirt oil on the bottom of the pistons.

I would have to agree. Granted, I never looked into at what angle it would squirt because I shaved mine off...

 

 

I'm curious about it but I'm with John, I would just as well get the coating and be done with it. Why argue that coating the pistons is not cost effective and "that's why the big names don't do it" when making a system to actually squirt oil on the bottom of the pistons could very well be over $300; not to mention you won't have Teflon coating on the sides it that is what duragg had done too.

 

 

Coating the chamber and the pistons and isn't there methanol or water injection too? There has to be a reason why people here are making plenty of power without burning out their pistons. Maybe a good tune...?

 

 

Perhaps if you find a nice spot on a rod to drill a hole, like the stock rods have, and then make a hole in the bearing to correspond, you can get away with it! Otherwise I can't think of a spot to even place squirters. Or take a look at that link, pretty cool but I see no solution as to where you are suppose to pull the oil pressure from as far as Datsun is concerned. The mini has an oil galley running right in there, ours is on the side of the block.

 

Then you must remember an engine, hell the entire car, is a system. If you upgrade one thing, be prepared to upgrade the next. Yes, you have oil cooled pistons now, is the oil pump ready to supply them? If not, what will you do? Perhaps better off listening to John and others who have been successful.

Edited May 4, 2012 by josh817

[Six_Shooter]

Or you can try something "new" to the Datsun world ( as far as this website is concerned) and install the oil squirters. They work, and work well. The engine I am swapping into my car (eventually) has oil squirters on a pair of pistons (due to them being hottest due to the design of the car and layout), I have bought additional OEM squirters to add to the remaining cylinders for cooling reasons.

 

The amont being sprayed is not a large amount, less than the supply to a turbo, and the stock (non turbo) oil pump has no issues supplying oil for the engine and turbo. If it was me, I wouldn't worry too much about whether the oil pump can supply enough oil or not.

[ctc]

Don't discount the way coatings and squirters work in cooling the combustion chamber. I don't want to get into a flame war with cries of where is your test data, but fundamentally oil squirters and coatings are working at the combustion heat problem from the opposite sides of the problem (pun intended).

 

Check out this link, Piston cooling and detonation, it's a lot of information, but it draws a link between pistion cooling (and mentions oil squirters) and possible reduction in detonation and potential increases in ignition timing.

 

My understanding is coatings keep the heat in the combustion chamber doing two things 1) Protecting the piston from heat (durability) and 2) higher thermal efficency for more power. A draw back is that you now need to get that heat out somewhere else (exhaust, cylinder head cooling, ect).

 

Oil squirters remove heat from the combustion directly. Just like increasing the cooling efficency of the head. The removal of this heat, while decreasing power might allow for more timing to be added and gain that power or more back.

 

Understanding there are cost, practicality and other issues with any engineering solution, I would still be interested in the feasability of adding squirters to an L engine. I would also like to continue the discussion of benifits, drawbacks, pros and cons. What I hope we don't degenerate into is a "It can't or shouldn't be done" attitude. I'm all for discussing the down side of this solution or attempt to use oil squirters, but lets not starting talking about what's better or worse.

 

I will also through this out there, heat flux (and temperature) have an effect on combustion dynamics. Cooling or not cooling the piston will effect how the combustion behaves. I am looking into squirters for the potential for more ignition timing.

Edited May 4, 2012 by ctc

[SleeperZ]

Other effects may be different, but fundamentally piston crown coating and oil squirters are doing the same thing; keeping the temperature of the piston down. With the coating, more of the heat of combustion can be used for work, where oil squirters just help conduct the heat out of the piston as waste. Minor differences unlikely to be quantified.

[rsicard]

In rethinking the piston cooling, coating the piston crown with ceramic mixture and ALSO squirting oil on the bottom of the piston would FURTHER reduce the heat that migrated through the piston crown ceramic coating. Also provides more lubrication of the cylinder walls. The best of both methods.

 

The NASCAR engine builders make exclusive use of coated engine components. They use every science that will benefit the durability and performance of engines. They want the best performance and fuel economy possible. They run their engines close to the edge of destruction.

[johnc]

There is such a thing as too much oil on the cylinder walls and the pistons. The oil rings can only do so much and oil foaming can be a problem at high rpms. If your engine is build with additional clearance on the rod bearings, oil squirters are normally closed off to prevent too much oil on the cylinder walls. The throw off from the rod bearings is more then enough. If the rod bearing clearances are built to tighter/OEM/street tolerances then the oil squirters help with cylinder wall lubrication.

 

With a race prepped oil pump and oiling system there's normally plenty of pressure and volume to handle oil squirters, spray bars, larger bearing clearances, etc.

[ctc]

Other effects may be different, but fundamentally piston crown coating and oil squirters are doing the same thing; keeping the temperature of the piston down. With the coating, more of the heat of combustion can be used for work, where oil squirters just help conduct the heat out of the piston as waste. Minor differences unlikely to be quantified.

 

I would like to steer the discussion toward combustion temperature, which allows more timing, and not just piston temperature (durability). I agreed that a coated piston is more thermally efficent, but what is the cost of that efficency? I think the increased ignition timing that a lower combustion temperature (detonation margin) will provide will definately be quantifiable.

 

Lower combustion tempertures on a stock engine L-series (EGR recuirculation), allow more timing and power. I am postulating that oil spray will effect combustion temps and timing in the same way.

[ctc]

There is such a thing as too much oil on the cylinder walls and the pistons. The oil rings can only do so much and oil foaming can be a problem at high rpms. If your engine is build with additional clearance on the rod bearings, oil squirters are normally closed off to prevent too much oil on the cylinder walls. The throw off from the rod bearings is more then enough. If the rod bearing clearances are built to tighter/OEM/street tolerances then the oil squirters help with cylinder wall lubrication.

 

With a race prepped oil pump and oiling system there's normally plenty of pressure and volume to handle oil squirters, spray bars, larger bearing clearances, etc.

 

John, I agree there can be too much oil. I think this is what the How to Mod Your Datsun book was getting at. And also why they recommended closing off the factory oil squirter.

 

To your point of too much oil, I wonder what the additional weight of oil "stuck" to the bottom of the piston does to balance and engine dynamics? Also, with your comment on race oil systems, do you think, there is enough pressure/volume that tapping a squirter off the main bearing feed would starve the main bearing?

Edited May 4, 2012 by ctc