#5 1jz's weak point?

[tissimo]

Well this weekend I was helping a buddy swap his bottom end that he fried with my old 1j bottom end that I had in my car..

My buddy did a highway pull and it ran rough afterwards, smoke out of the oilcap, the engine was done. Didn't bother to find out which cyls were low and what the compression numbers were (though should of) but pulled it apart and found #5 was ate up pretty bad (just scoring on the walls, pistons looked fine from the top) and # 2 was also ~ 40-50% scored as well...

I pulled off my old 1jz apart (using the head for the 1.5) and noticed my #5 was a tad scored to.. my #2 was a Very small amount near the top front.. On my engine I was down 5-10 psi in #5 (165-170 and 160 in #5).. My engine was running 400+ whp on it when I took it apart.. I say it was probably closer if not more then 450 whp @ 18psi on 93. The previous owner dynoed 480whp on it.. so it hasn't had an easy life..

Anyways on both engines the majority of the scoring was at the front and rear of the cyl wals (at least the worst portions on his).. It seems #5s seem to be the weak point of the engines.. I've read a couple threads where #5s went out.... #2 seems to be related as well at least in my exeriences... I think this has to due with the small exhaust ports on the 2 and 5 ports. I assume the ports are causing more back pressure in those cyls and more prone to detonation because of this. Not sure why #5s seem to get it the worst though. Maybe due to coolant flow (not sure how the coolant flows through the block).

Any thoughts on this?

 

[soapra]

I have the same issues on my old 1jz. but it has high miles and it ran lean. That's the only way the cylinder walls end up like you explained.

 

[Evilempire1.3JZ-GTE]

Are all the cylinder walls scored a little though ? If so you might have crank walk ?

 

[RazoE]

uh oh, time go to 7m....

 

[bigaaron]

I wouldn't consider it an inherant problem with the engine as much as a problem with people trying to run too much boost on pump gas. If you run any engine too lean or too rich it's not going to be good for the rings. Jose beat the crap out of his for 275k miles, and it was purfect up until the very end. It's completely proven that you have to do something that's borderline retarded to blow up a 1jz.

 

[Yellow 13]

uh oh, time go to 7m....

:werd:

 

[OneJoeZee]

It's completely proven that you have to do something that's borderline retarded to blow up a 1jz.

Now who would do something like that?

:hsugh::hsugh::hsugh:
:hsugh::hsugh::hsugh:
:hsugh::hsugh::hsugh:

 

[bigaaron]

Now who would do something like that?

:hsugh::hsugh::hsugh:
:hsugh::hsugh::hsugh:
:hsugh::hsugh::hsugh:

We all have our moments. :icon_bigg

He who is without sin, cast the first stone. :biglaugh:

 

[soapra]

I'll take pics of my boost induced retarded moments!

 

[ropadopa]

# 5 seemed to be a problem with the 7m too.

 

[tissimo]

Not on all cyls just 5 and 2 on both engines..

I havn't ran that much boost on my engine.. I've never ran over 18 psi on my engine.. and only 18 psi for the last couple months I had it w/ the single.. and always a rich concervative tune.. I dont remember when I first noticed the little bit low on #5 when doing compression tests.. might of been before I got it, dont remember 100%.. it was only 5-10 psi so didn't pay that much attention.

Not 100% why my buddys engine went.. he was running 18 psi on the twins doing a highway pull.. only thing i can think of was timing was too high for 18psi + a long highway pull and melted the pistons a bit.. (has 550s and no afpr so pulling like 32-35% in upper ranges..) was tuned ~ 11.0 as well

 

[The Reaper]

damn that sux

pretty interesting tho that it seems #5 and #2 take a beating...

 

[Ric]

Here's the problem:

You bought an unrebuilt salvaged junkyard motor from a crashed or recycled car thats been sitting in a field for 10 years, then started it up and ran the piss out of it.

 

[csnow]

Here's the problem:

You bought an unrebuilt salvaged junkyard motor from a crashed or recycled car thats been sitting in a field for 10 years, then started it up and ran the piss out of it.

That adds alot to the thread. Let me guess, you rebuilt your 1J when you got it right? Thats what I thought. I am willing to guess there are only a few people, if any, who actually rebuilt their 1J. When it goes, they get another longblock and run it.

 

[OneJoeZee]

Here's the problem:

You bought an unrebuilt salvaged junkyard motor from a crashed or recycled car thats been sitting in a field for 10 years, then started it up and ran the piss out of it.

Right, because a rebuilt engine would stand up to knock and detonation any better?

It doesn't matter how rebuilt or strong your engine is. Detonation kills engines.

 

[Ric]

That adds everything to the thread. 1JZ's have been proven to do over 1000whp on stock internals. If your blowing it up on stock twins, you've done something wrong.

My buddy did the same thing 3 months ago on his 1JZGTE. 18psi long highway pull on stock twins, SAFC2, FCD. Roasted #5 and hurt a front one. It ran lean on just those, everything else was fine. We concluded that it was a 100% fuel injector firing error, the injectors tested fine. The 1JZGTE is batch fire, so that leads to only one thing that happened....

Our friend the ECU goofed, whats new. He's on stock caps, and about 4 of us agreed that was the problem

 

[ropadopa]

Here's the problem:

You bought an unrebuilt salvaged junkyard motor from a crashed or recycled car thats been sitting in a field for 10 years, then started it up and ran the piss out of it.

Thats why you buy engines from a running car in Japan do these look like they were sitting in a field for ten years?

Justin, im sure its just a reality check as that 1j started life in a heavy supra then came here for another ride in a heavy supra then another.

 

[drewgo]

2 months ago I blew my 1j, same scenerios long highway pull and boom.
melted 1 3 4 5 & 6, #2 servived.

 

[The Reaper]

yea it was definitely detonation that killed it

i told the owner....he didn't listen....bye bye 1J

 

[bigaaron]

Stock 1jz engines have stock Toyota pistons, not magic pistons that can take unlimited cylinder temps without damage. Melted pistons are caused by a tuning problem or bad injectors. Another thing is that rich does not equal conservative. Conservative equals turning down the boost. Overly rich conditions can wash out the rings and cause cylinder scoring and then blowby. Running rich is not a substitute for octane.