Need help with 1.5jz build

[suprahero]

+1 and valves aren't stronger then forged pistons

A aggressive tune (500whp @ 17 psi with a 35r sounds aggressive) + some weak gas from the trip = boom

Justin, there wasn't any aggressive tuning done on my part. I don't like pulling my engine out because of poor tuning. I think the valves could have hit the pistons due to stock head gasket, removing material from block and head, weak valves, cut outs in pistons could have been different than the 1jz head, and a few other problems. Aaron didn't like the timing map that was on it though, so maybe the timing was the culprit. I'm really confused and agitated at the moment, but I'm trying to stay positive about the whole situation. Thanks for the help that everyone is offering.

 

[p5150]

I think its a mechanical problem man - props for staying positive. I have gone through a similar experience but it should all work out in the end.

I cant see the pictures where I am at - was the damage restricted to the exhaust or intake side of the pistons?

 

[suprahero]

I didn't think about them all being on one side, but I believe that all the damage is on the intake side. I'll have to go outside and double check.

 

[p5150]

That would point to a mechanical problem - because the intake valves are a bit larger than the exhaust side, they would be the first to strike if both of your cams had the same lift...

This is all under the assumption of proper mechanical timing, which I am sure is not an issue because you were able to drive your car!

 

[p5150]

Also, is there any way to compare the valve lash on the two cylinders that were not damaged to see if the gap was larger than the 4 that were?

 

[suprahero]

They were all within tolerance when I put them on and I really dont want to reinstall it right now. I will only put it back on when it's rebuilt and finished. Thanks for your help.

 

[tissimo]

check the flat part of head thats inside the cylinder, is it smooth or rough?

also which pistons were broken?

 

[soapra]

I know alot of you are thinking valves, but how does a valve bend 90 degrees back, to hit just the outside edge of the piston and bend back in to shape? The edges of the pistons are melted witch = detonation.

 

[tlo86]

I know alot of you are thinking valves, but how does a valve bend 90 degrees back, to hit just the outside edge of the piston and bend back in to shape? The edges of the pistons are melted witch = detonation.

exactly what i thought... the 4 pistons i have off my friends car look exactly the same brakeoffs in same spots

 

[p5150]

I know alot of you are thinking valves, but how does a valve bend 90 degrees back, to hit just the outside edge of the piston and bend back in to shape? The edges of the pistons are melted witch = detonation.

You guys are probably right if you have seen the exact same pattern before. I dont have a 2jzgte block and a 1jz head to see if the valve strike in that location is even probable/possible.

 

[WhtMa71]

^Yea thats very true.. Maybe he broke a piston and the debris went into other cylinders..ive seen that happen on a honda before and every single piston had little dents in it or was broken all because of 1 broken valve.

Jay, were the cams at 0,0?

The only logical thing i can think of is it ran lean and detonated for some reason, although i dont know how if it was tuned well. How many miles did you have on the motor before it broke?

 

[suprahero]

The cam are set as follows. Exhaust +8 degrees and the intake is -4degrees.

The car has NEVER ran lean under boost. It has ran lean under normal driving before but this was after the fact. I ran it home lean on purpose to keep as much smoke as possible from exiting my exhaust so the people behind me could see. I was told it would be fine as long as it wasn't lean under boost. The person that told me this can chime in if he wants too.......or not.

Red, the motor had roughly five hundred miles on it when it started smoking, but it was very little smoking at first. It wasn't until we got past Louisiana that it started smoking horribly.

What would the AFR's need to get to, to detonate the engine like it did?

 

[OneJoeZee]

AFRs and fuel supply could have been just fine. But too much timing, not enough octane, too much boost, or any combination of the above can = boom

 

[IJ.]

Wow wide valve centres there J!

Cylinder pressures would have been way high.

 

[suprahero]

AFRs and fuel supply could have been just fine. But too much timing, not enough octane, too much boost, or any combination of the above can = boom

Aaron said my timing map was not pretty, but I don't remember him saying it was too high. As a matter of fact I remember Chris (Gixxer) saying that it was pretty conservative.

IJ, I honestly need an interpreter........sorry.

 

[WeDgE]

I know alot of you are thinking valves, but how does a valve bend 90 degrees back, to hit just the outside edge of the piston and bend back in to shape? The edges of the pistons are melted witch = detonation.

X2 It's the same thing that happened to my 7M. Crappy gas + boost = detonation and melted pistons

 

[OneJoeZee]

Jay, what's the compression on your 1.5J?

If Aaron wasn't aware of the comp ratio, the timing he observed may truly not have been too high by the standard of typical 8.5:1 compression. But if your's is higher, then that may not apply to your engine and the same numbers may not play well with others.

 

[suprahero]

Joe, I don't know what the compression was. I know it was not correct since I used a stock 1jz head gasket and the machinist said he removed like six thousandts off of the block and he also resurfaced the head. I should have went with at least a two millimeter head gasket I think. Who knows? I plan on going with a thicker one this time though. I've also got to replace my steering rack while I have the motor pulled. Will the madness ever end?

 

[tissimo]

The cam are set as follows. Exhaust +8 degrees and the intake is -4degrees.

The car has NEVER ran lean under boost. It has ran lean under normal driving before but this was after the fact. I ran it home lean on purpose to keep as much smoke as possible from exiting my exhaust so the people behind me could see. I was told it would be fine as long as it wasn't lean under boost. The person that told me this can chime in if he wants too.......or not.

Red, the motor had roughly five hundred miles on it when it started smoking, but it was very little smoking at first. It wasn't until we got past Louisiana that it started smoking horribly.

What would the AFR's need to get to, to detonate the engine like it did?

Lean under low vac conditions is fine and will not cause any problems.

Were you beating on it when it broke? or started smoking just cruising normal?

After it started smoking was it after refilling the gas tank and boosting on it?

What timing are you running @ 17 psi @ 5500 rpms? What exactly did aaron do to the map? smooth it out (spikes?) or pull a few degrees out?

 

[suprahero]

Justin, it started smoking on the way but like I said it was minimal. It mainly only smoked on decel though and then it gradually got worse. Most of it was fuel though because it was running rich. I filled up a lot of times on the way to Texas, but I never used anything but 93 octane, or at least that's what I paid for.

My timing map that I was running is as follows:
At 17.98 psi of boost @ 5500 rpm, I was running 17 degrees of timing. Actually I was running 17 degrees of timing from 4500 rpm all the way up to 8500 rpm from 11.97psi of boost and up.