bbundy

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.

Oscar

iTrader: (2)

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.

miata2fast

iTrader: (2)

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.

bbundy

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.

bbundy

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.

Oscar

iTrader: (2)

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....

bbundy

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.

Savington

iTrader: (31)

mon+ron/2 != ron

Leafy

iTrader: (1)

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.

bbundy

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.

concealer404

iTrader: (3)

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 ****** to 10krpms or more.

psiturbo

iTrader: (1)

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.

Oscar

iTrader: (2)

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.

miata2fast

iTrader: (2)

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

Oscar

iTrader: (2)

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.

doward

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.