legacycentral bbs

#4



2.5 NA block

It's cause it's open deck...lol

dang that sucks, any plans? btw whats your mod list? just wondering since your sig says 12.5 @ 117

Are you ever going to do a EJ22T block??

Props on making a cool looking crack! How long are these NA blocks lasting with what mods?

ericem wrote:Are you ever going to do a EJ22T block??

I second this Doug, as you seem to break blocks easily.

Aaron's auto wrecking in Seattle has a 150K SS wagon that just came in.

She just couldn't handle the power Jim...

Kelly wrote:

She just couldn't handle the power Jim...

Very fitting

thats insane, what? how? did you do that douglas vincent

How was the piston? Cracked ringlands?

I wondering if some detonation is causing this. Do you have a knocklight or something like that?

Piston was in PERFECT condition.

Yeah, probably knock started the crack... Then massive boost continoually made it worse till it failed.

Have you thought about a block from Outfront? They seem reasonable for what they are.

Impressive. What year (phase) is that block? How much boost were you running?

I'm not trying to be mean but I think this comes from a fueling issue rather than a weakness in the cylinder wall.

I think doug is my hero.

Think about all the stupid threads on Nasioc debating open vs. closed deck by all the douchebag armchair tuners.

And Doug does it.

ciper wrote:I'm not trying to be mean but I think this comes from a fueling issue rather than a weakness in the cylinder wall.

Yeah it might be fueling causing some detonation. In some form or fashion, I feel detonation is making you split your walls.



Get yourself two passenger side rails and tap the FPR side for 3/8 NPT, then run what you want. Don't make my mistake and use braided line. Push-lock is where it's at.

Eventually, I plan on running -8 or -10 feed, and use the factory feed as a return.

No no no. its not detonation. Its pressure.

Somehow, doug managed to get a POS T3/T4 to spool up, and jam too much into #4, prolly early in 3rd gear. Lean woulda done something to the piston.

High Carbon Steel Sleeve(large surface area surrounded by a cooling medium)>aluminum piston(small surface area no cooling)>metric shit ton of heat>pre detonation>hot

duh.

The piston doesn't necessarily have to suffer first from detonation. I've seen connecting rods snap before pistons showed any sign of fatigue or failure due to detonation. Clean sweep of the block at 150 mph and the pistons were still usable...



Open deck blocks can and do make much more power at similar boost levels. Therefore the pressure ratio isn't very relevant. The absolute pressure doesn't matter nearly as much as the mass of the air in the cylinder. Without a temperature, the pressure is pretty much irrelevant.

What matters here is that the cylinder is cracking from one means or another. Without adequate datalogging, there is no way to know what exactly is causing it. A PP6 does not provide the means to see all these variables in action.

93forestpearl wrote:

Open deck blocks can and do make much more power at similar boost levels. Therefore the pressure ratio isn't very relevant.

This argument has no validity.

Why does Honda, Subaru, Porsche and Mitsu make closed deck versions for high output motors?

Kelly wrote:Why does Honda, Subaru, Porsche and Mitsu make closed deck versions for high output motors?

Subaru stopped in 95 because closed deck wasnt needed. Most Hondas ive seen use open deck blocks until you reach higher than 2.5 times the original power level.

Perhaps it's like the ancient builders or, a more modern example, the Empire State Building. Lacking the engineering (or construction) ability to make something just strong enough for its purpose, they overbuilt the hell out of it. Conspiracy theories aside, I've read several times that the Empire State Building would have survived 9-11 due to the heavy overengineering of the structure whereas the WTC was built down to whatever safety margin is specified for such things. The ESB did, in fact, withstand the head on impact from a B-25 (which, I'll concede is probably still less force than the wing of a 747 impacting at higher speed, but the damage was very minimal).

Subaru also designed the closed deck for 400 hp for rally, which would be extended periods of abuse. A few years later, the rules were restricted to 300 hp. Don't know if it was due to the lesser requirement or a case of overengineering until they found out that extreme wasn't necessary, but either way, it probably boiled down to cost.

evolutionmovement wrote:Subaru also designed the closed deck for 400 hp for rally, which would be extended periods of abuse. A few years later, the rules were restricted to 300 hp. Don't know if it was due to the lesser requirement or a case of overengineering until they found out that extreme wasn't necessary, but either way, it probably boiled down to cost.

I would bet 100$ that if he had an Ej257 the same thing would have happened. It has thinner walls than the 2.0 or 2.2 and its semi closed deck would have let it split in the same area. I've seen a number of them split right were the wall is machined out for the block bolt, though its usually farther down the cylinder.

I probably started the crack a while back when I was still running pump gas. Then I just aggravated it over time.... Then it finally just failed....

The pistons are running again! I simply swapped them over into reddevils old big power block, the one with the home maded pinned cylinder! Tad noisy, but it gets me around....

Kelly wrote:

93forestpearl wrote:

Open deck blocks can and do make much more power at similar boost levels. Therefore the pressure ratio isn't very relevant.

This argument has no validity.

Why does Honda, Subaru, Porsche and Mitsu make closed deck versions for high output motors?

I'm not really trying to argue. I have my theory and that's about it.


The few split blocks I've seen in person were the direct result of detonation. Phil at Element *says* he has tuned 800whp cars on a stock 257 block. Yet, a local guy has split two of them at 500whp from shit happening, like wastegate lines popping off and still raping it.


I'm not going to search for the thread itself, but a shop was making over 600 whp on a 2.5 N/A block. Granted its all internet crap, but the potential is still there. Tuning is everything, and always will be. Thick, nasty sleeves can still be effed with poor tuning. Not to say Doug is a bad tuner, but his setup limits him immensely.


I'm not trying to pick fights about about what caused the failure. I'm just skeptical about boost being the pure cause of the failure. That is all. Boost is usually an enabler to another result. Like a couple Honda owners I know. They get a tune, fuck with something, and then their cylinders end up looking like tulips.