Oil squirters for n/a build
 

Keep them or block them off?

~1.9 VVT motor, 11:1 CR, rods, SUB lifters, BE VVT pump, 949 superdamper etc.

What say you?

I am leaving them out for my new motor. It is supposed to make a tad more power.

To clarify, this motor will run for more than 14 consecutive seconds at a time and a planned MTBF of ~10k miles on trackduty.

Yes I am aware of that. And so you know, I plan to do some Sebring tracking with my motor and not just jaunts down the quarter mile.

It is a common mod to tracked BP motors.

Reliability says, leave them in.
Power goals say, leave them out.

If I were you, I'd leave them in. In that way, you can always say "I kept the oil squirters" when you lap times suck.

Laptimes will suck anyway, might as well go for broke this time

Id say leave them out. But I do believe using ceramic coated piston tops are an important part of the equation when doing so.

Even in a naturally aspirated motor? There are a ton of high reving motors that do not have oil squirters out there. And I doubt that ceramic coatings are on a healthy percentage of them.

I was under the impression that the oil ring grooves on a stock bp piston was specifically designed for squirters, and that a typical aftermarket piston's ring groove is designed in mind for motors without squirters.

I believe the thoughts on aftermarket versus stock pistons is correct.

I also think the ceramic coating significantly changes how heat is transferred from the combustion chamber to the piston and the need for removing heat from the bottom of the piston.

I suspect the coating could be worth more power wise than just blocking off the squerters for several reasons.

No way no how would I leave them in. You will have less "windage", your oil pressure will be better, if you are NA you have ZERO need for "piston cooling" anyway.

Based on my witnessed change in engine running on the track behavior I think removing oil squirters and ceramic top pistons did more for keeping the thing from running without overheating than any cooling mod I ever did.

My reasoning comes to these points.

1) Less combustion heat is transferred to the engine by way of the pistons.
2) The pistons don’t develop hot spots as easy thus you get better knock resistance.
3) Better knock resistance means you can run more timing which means lower waste heat is generated to begin with.

After spending years trying about every trick in the book to try to keep 200-250 hp 1.6l then 1.8l engines cool on the track currently My car will run pretty much continuously without going thermally unstable whale making ~350 hp. And it made a big difference with the 2.0l engine when I swapped to ceramic pistons and took the squirters out with basically no other changes in setup.

Another benefit in my book is the engine maintains higher oil pressure for added safety.

On an NA engine I still think you will gain some knock margin and be able to add some more timing, make more power. Might also be able to loose some cooling system weight. Possibly go to a little Honda Civic size radiator that would keep things stable.

How do you plug the oil ports after removing the squirters? I have a 2001 engine on the engine stand now, waiting to go in my 95 R-Package.

C

I went to the hardware store and bought flange head bolts with the same thread and installed them reusing a crush washer plus red locktite.

Exactly how I did mine too. ACE Hardware racing supply.

Thanks guys.

And thanks Oscar for bringing up the subject. Your timing was on the money. :)

C

I left mine in, but it's my first build.

Fifth build and beyond however... :)

I’m curious how well it works without the ceramic coated pistons.

Obviously the extra oil was meant to pull heat out of the pistons. But I might suspect the ceramic barrier coating on the top of the piston prevents more heat transfer than the extra oil ever was taking away. Some scientific studies suggest the ceramic might be reducing the amount of heat transfer through the piston by 15% or as much as 40%.

I will not have the slugs coated. I was asking since apparently only the FM wisecos are clearanced for the squirters and off the shelf wisecos would hit them. Not sure if entirely true, but if removing them frees up some power I figured why not.

Last I checked FM's don't work with stock squirters.

In the FWD SR20 world, USDM engines don't have squirters, while SR20VE's do, and their oil temps run allot hotter on the track. That heat your taking out of the pistons has to go somewhere, and it goes into the oil.

C

Anecdotal evidence of why I think coating the tops of the pistons is part of the equation.

Prevent the heat from getting to and building up in the piston and then you don’t have to worry about pulling it out in a manner where the cooling system has to deal with it.

Wouldn't the higher compression give a lot less heat in the compression chamber (and thus the piston) with its more effective burn? They're 10.5 static and whatever it ends up being after headwork etc.

If it matters, I have a 13 row oil cooler and a shimmed VVT BE oil pump. Will discuss with my builder too of course.

The opposite is true. The more power you make the more heat you make. Also, physics has shown that the simple act of compressing a gas creates heat.

Also more compression will require a bit more retarded timing to avoid knock = more heat.

On my dodge diesel with a compression ratio of 17:1 I can generate higher egt engine braking downhill with the exhaust brake and no fuel at all than I do cruising down a flat road burning fuel. Purely heat from compression.

more squish = more heat.

But 10.5 really isn't that high Plus I believe in the Netherlands you get a lot better pump gas than we get here in the states so you can probably optimize your timing a bit more assuming you are not running race gas.

I do not believe what you are building will be bad or problematic.

Thanks for the replies, keep 'm coming. Will be using ron98 (your 93 I think). The nearest E85 pump is 1+ hours away, so for now that's not an option unfortunately

For poops and giggles I looked around for ceramic coatings and the most decent option was in the uk and would cost €500 at least. That would buy me a fresh set of wisecos....

California gas premium is 91. And I think it is optimistic to call it 91. Some states get 92 or 93. 98 is basically like our race gas that cost ~3X as much as pump gas. I don't even understand why we get different gas quality across the country but it all pretty much sucks compared to most places in the world.

mon+ron/2 != ron

I've never been to a state where I cant get 93. Actually come to think of it I know of a few places I can fill up with 110 octane CAM2 (leaded) straight out of the pump that isnt a race track... Just dont let the attendant see you put it straight into a street car, off road only. :jerkit:

92 here in Washington. My car wouldn't run well on track at all on the pump gas in California the last time I tried it. Luckily I was at a track where I could get VP100. I have found there are risks with retarding the timing in that egt’s go way up and you start having more issues like burning exhaust valves, turbo manifold connections developing issues, or turbo manifold cracking. At 350 hp the margin of reliability is not very wide for a lot of issues under heavy track use.

I'd remove them and not think twice about it. At the very least, you'll get better oil pressure out of it.

Not entirely related, but the KL i'm building to replace my dun blowed up one has no oil squirters. Mazda themselves removed them later in the engine's life.

And i'm going to spin that fucker to 10krpms or more.

We are lucky enough to get 100 Sunoco at the pump, and genuine 93 on almost any gas station here in north FL.

In no way the gasoline is the same in CA. have seen plenty of nasty cylinder heads on CA jun yards, insane amount of additive is added to the gasoline. Once I came here to FL, most blocks I would strip open had nice clean valves top end.

Discussed with my builder today and decided to leave the squirters in. Oil pressure shouldn't be an issue with the shimmed VVT pump. He will clearance the piston skirts if necessary. Thanks for the input.

I am really surprised by your decision. What swayed it?

His experiences mainly. He's building the IL motorsport endurance car's motor too and they too decided to leave them in. Pressure should be more than ok with the BE pump, temperature should be kept in check easily with my 13 row oil cooler and big rad. Running the squirters would also allow to use the tighter end of the piston-to-wall clearance and reduce noise/wear. The spraying on the piston bottom would also help lubricating the small end (wrist pin?) and help cool the piston crown, especially when it's not coated. If I were to coat them, deleting the squirters would probably be ok.

Now we're waiting on rods so machine work can be done and bearings (ACL race) can be ordered.

I keep coming back to this myself.

I just pulled my motor out to fix my oil leaks(wrong RTV) and ordered the IJ crank scraper and was debating plugging mine. Non coated pistons and still an idea in the back of my head that i might boost it, someday, swayed me to keep them.