Breaking a GZE piston or rod

[30psi 4agte]

Has anyone or know of someone (not rumors) that has managed to break a GZE rod or piston ( later version stuff. Ceramic coated pistons/ big rods) I have read plenty of info that says they are good for about 450-500 hp but havent been able to find any proof that they break after this! I thought id put my feelers out and see what you guys come back with.
The reason i ask is a little while back i had a major engine faliure after making 283rwkw numerous times we decided to give the Nos ago. Lets just say it didnt go too well!! I ended up melting the head in the no. 4 cy and having 30 psi go into the cooling system and blow the header tank clean off the radiator!. After pulling the engine down i found that the piston and rod were still perfect!! ( could not believe it)
This has started me thinking what the hell will it take to break one of these suckers?

[mrshin]

I broke one a few years back - but that was the result of revs causing a rod bolt to fail...

[fixeruperer]

i broke a gudgen few months ago

[30psi 4agte]

I have herd gudgeon pins can be a issue. how did it break? detonation?
What was te piston like? Its still amazing though that you can break a gudgeon before just the piston will let go.

[fixeruperer]

the piston and rods were fine i was suprized i broke a gudgen rather than a bearing ,never pinged only thing it did that i didnt like was the compressor surge just before it would start boost high like from 5 psi to 25 psi becuase it was a quik change the turbo would stall and go cho cho cho cho till the revs were up.

[30psi 4agte]

Toyota engineering at its greatest! can break a gudgeon but the piston and rod is fine!

Off subject a little what turbo u using to have comp surge?

[fixeruperer]

its a 550 hp "ITS" turbo
.6 front a/r 57mm front wheel
.64 rear stage 3 rear wheel
i got bigger cams and diff pistons nows so should cancel the surge hopefuly.

[oldcorollas]

it very very much depends on the tune. you could break one with 100hp if you tried

but as for rating, there was guy in? finland? with some stupid amounts of power (400+) on stock bits, but different bolts.

if you don't detonate and break the rings/ringlands, there is very little reason for a piston to fail.

rod bolts stretch and let go from excessive rpm, but rods are very beefy.. compare to many V8 rods which hurl much larger pistons around...

i hope to try and break some in a year or so.. using gas to reduce det probs perhaps...

[Cameron_Datto]

Which compression ratio 4agze engine are you guys using ,, 8.1 or 8.9 ? Oil squirter piston Block ?

[fixeruperer]

im using 8:1

[30psi 4agte]

Im using the 8.9 with oil squirters. comp has been dropped to 8.1 though

[Cameron_Datto]

Also what is your max ignition timing under boost ,, and what fuel ?
Keep the info comming :>)

[30psi 4agte]

Max ign is about 25 on full boost but will have to check that ( i think its more) pump fuel up to 23 psi and turbo max at 30 psi

[RonRob]

Max ign is about 25 on full boost but will have to check that ( i think its more) pump fuel up to 23 psi and turbo max at 30 psi

I know the thread is a bit old but I am very curious as to how much timing you are running at full boost. I am also running the small port gze with stock internals. I have yet to adjust timing at 21psi, but as it stands I am running 20 degrees timing with no detonation. I know every engine is different, but from what I have been told the Gze can handle heaps of timing up top as long as your intercooling is completely up to the task. Ideally I like my temps to be no higher then 100f or 38C. Most I have seen timing wise was 28 degrees up top at 18psi and no detonation. I believe this is kind of high, but when you mentioned you are running 25 degrees maybe more at full boost makes me think I may be a bit retarded timing wise up high.

Thanks
Ron

[30psi 4agte]

Im using big port head on GZE bottom end. Its is still STD but then again its not Depends on what you would call std

My motor seems to love timing. I had run more than 30 deg on full boost at one stage but it doesnt make any more power than if it is on 25 deg.
My comp is at 8:1 so i can get away with running lots.

Best thing to do is have a play on a dyno and see what it likes. There is no point running more timing than you need!