ItalianJoe1

iTrader: (10)

Who has a pic of stock LNF pistons? Specificaly the top of the bowl.

BLAZIN07SS

iTrader: (7)

sub'd

IsItFast?

Small, but here it is:


Effectively the same as the wiseco pistons:

BLAZIN07SS

iTrader: (7)

well thats not good. lol we pulled apart a blown LNF yesterday and the piston has another set of valve reliefs next to the bowl valvetrain looked okay though. i'm wondering if there really was piston to valve contact

HHRSSouth

What was the red line on the car you pulled apart, was it factory or did he have it moved up?

BLAZIN07SS

iTrader: (7)

no idea. he was running a trifecta inifiniboost tune. so whatever he requested to redline it at

Terminator2

I need to see a picture of this.

ChevyRockstar

iTrader: (4)

i wanna see pics of what josh is talking about lol

BLAZIN07SS

iTrader: (7)

lol i'll see if i can get joe to take a picture.

Wangspeed

iTrader: (2)

Sounds like a mis-shift. Too much boost wouldn't cause contact between valves and the piston.

Matt M

I don't see how a mis-shift would either. I've pushed my motor to 8500RPM without issue. There would have to be some kind of mechanical issue prior to the piston-valve contact.

BLAZIN07SS

iTrader: (7)

matt every single piston has these recesses in them for the exhaust valves. its a little strange since the other LNF pistons i have seen dont have these recesses(neither do the wiseco's that he bought). any chance you can get me a close up picture of a stock piston you have lying around?

Wangspeed

iTrader: (2)

With stock valvetrain, or did you have a spring upgrade? I wouldn't be surprised if valve float occurs at that RPM.

ItalianJoe1

iTrader: (10)

Dunno if you can see them there. They are even on every piston and don't really look like valve contact IMO, just odd that they aren't there on the wiescos. I'll try to get closer pics next time i'm out there with the camera.

Illini_06SS

Nothing better than looking at the internals of a beautiful ICE...

ItalianJoe1

iTrader: (10)

Nothing pretty about a broken one. I'll post up a pic of another build i'm doing in a bit.

Wangspeed

iTrader: (2)

I see 4 valve reliefs per piston, like the picture that IsItFast? posted. Doesn't look like contact to me, unless it's one of the pistons at BDC.

Kinda looks like the exhaust side is gunked up. Is that just the pic?

ItalianJoe1

iTrader: (10)

Look at the top of the bowl area, where the other side of the exhaust valve would be (near the spark plug). There are 'reliefs' there as well. They look factory to me, just wondering.

Terminator2

The Wiescos are machined differently but it looks like there are 4 valve reliefs in the pic above.

ItalianJoe1

iTrader: (10)

Also, yes, everything is quite dirty. Blown piston on #4 sucked a ton of oil through the whole motor.



Now that's a pretty motor.

Wangspeed

iTrader: (2)

I'm gonna bet on ring lands. I don't see any valve to piston contact in your pics. Gettinausername sucks proposed that the ring lands cracking is a result of too small a ring gap for the boost level. The same problem that Evo X's are facing in the 4B11.

Regarding the flat top piston, all I see is unoptimized flame path in my mind.

ItalianJoe1

iTrader: (10)

It's a dish. How is it not optimal with a centrally located spark plug and 4 valves?

I know it has bad ring lands. There was no compression on that cyl and damage to the sleeve. I want to see pictures of other stock LNF pistons for verification, i'm not trying to figure out what happened to this motor, just making sure what i'm seeing is normal.

cardelino18

iTrader: (3)

thats mine i have the stock rev limiter..

ItalianJoe1

iTrader: (10)

Yep. You got my e-mail, right?

Matt M

I was running over 7000 RPM on stock springs, but yes, not as high.