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I think there is a reoccuring problem with....

DemonSVT said:
I run 0W40 on a NA car because of the rpm I hit and heat it generates.
however on a different note. I have the stock pistons and rings. Aftermarket pistons and rings normally need cutom ring filing and fitting to make sure they are not too tight. When I tore apart my 35k mile 2.5L that spung to 8200rpm for a good portion of it's life the cylinders and rings looked great. That was on 5W30 Mobil 1.

On a related and more evil note. Funny how no turbo car to date (i.e. custom forged parts) has beat the power output of a stock 3L engine with a bare bone turbo kit??? What's up folks... Heck not like the platform could handle it EVER anyway.
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uh.. did you mean 7200 rpm?
 
No, 8200... that's when the duratec is having fun.

If you've never heard a duratec at 8k rpm you're missing out.
 
what cams does that require? i'm assuming that's beyond what the stock valvetrain can do...... 8200 rpm on the bottle would be insane.... :)

and as for the hyperutectic pistons..... i'm starting to be a believer. i have a 100 shot on a wore out junk 2.5L motor, and it takes the hit like a champ. the cylinder pressure on a 100 shot should be equivalent to a considerable amount of boost. but my car doesnt have one thing that boosted cars have.... heat. i'm starting to wonder.... does the temperature of the intake air make the pistons considerably more hot? and would that make a hyperutectic piston more brittle? i would imagine a cold piston would be more brittle, but i might be thinking wrong here.....
 
TRicker said:
what cams does that require? i'm assuming that's beyond what the stock valvetrain can do...... 8200 rpm on the bottle would be insane.... :)

and as for the hyperutectic pistons..... i'm starting to be a believer. i have a 100 shot on a wore out junk 2.5L motor, and it takes the hit like a champ. the cylinder pressure on a 100 shot should be equivalent to a considerable amount of boost. but my car doesnt have one thing that boosted cars have.... heat. i'm starting to wonder.... does the temperature of the intake air make the pistons considerably more hot? and would that make a hyperutectic piston more brittle? i would imagine a cold piston would be more brittle, but i might be thinking wrong here.....
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No the heat doesn't make it more brittle if anything I can imagijne it would pit the ends or make the rings land softer since you are trying to put it back into melted state. But understand that they make these pistons under more heat than we can produce if tuned right. The pistons I believe are staged through heat levels to get it hardness and it bonding state better. There would seem to be a certain heat range or certain level of heat it would just begin to pit the pistons removing the softer metals the it would just break off due to the pores it created. But it will not swell like forged so it can take some seriuos heat but not serious impacts.
 
warmonger said:
Nope. He meant what he said.
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ah, I see!
Just wondering, since this is what he published on his webpage-



Above 7500rpm and your engine is in a downward spiral due to the weak rod bearings, crank whip, and the fact you are just physically surpassing the mechanical limit of the component's material. (roughly 7650rpm) Expect a serious increase in oil consumption and early rod bearing failure."

Then he goes on to say...

The stock components also can handle ultra high rpm (8100) and banging the rev limiter hundreds (thousands really - I lost count long ago) of times too. Like I stated it's the rods bearings that are the weak point when rpm levels are raised. Crank whip is also a factor as the destructive harmonics, when you pass 7000 rpm, are just deadly and the rod bearings suffer the most."



Well, even with clevite RB's, what are you doing at 8200 "thousands" of times? What cams were you using to need to rev that high? I am taking a wild guess, but I don't see the SVT camshafts sailing to 8200 RPM. Just wondering whats giving you the need to spin that high, CAT cams? I've had my 3L out to 7850 on SVT cams and stock rod bearings, everything is fine of course but there sure wasn't any power that high.
 
Well they were SVT cams and stock bearings. This excessive rpm over thousands of times were what eventually toasted his motor.
He already had a 3L build in the works so it was kind of his plan to test what he could.

After going there he determined that 7500 was safe. The amazing thing is not the valvetrain or pistons, but the stock rods held the tensile loads of 8000rpm. :shocked:

The cylinder wear is much higher, the rings don't seal as well and the bearings take more load. It is bad all around just due to the mass of the pistons. This isn't a motorcycle or small displacement engine.

THe valvetrain is good to go on this engine.
 
perfect. Thanks for the explain-z, that makes sense.. testing the waters with a solid backup always produces good things.
 
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