Need help with 1.5jz build

The Reaper

Single, and lovin' it!!
Jan 10, 2006
1,909
0
0
Florida
Jay the more i look at it the more im leaning towards a poor tune.

Justin and i were talking about it on a break at work, and the AF's were tune but something may have been wrong with the timing map
 

tlo86

Ninja Editor 'Since 05'
Jul 24, 2005
3,914
0
0
38
Colorado
detonation? saw the same damage to my friends pistons but it was his 4cyl. every piston... he ran lean 24/7
 

suprahero

naughty by nature
Staff member
Aug 26, 2005
14,971
0
36
54
Roll Tide
My car was tuned by a trained professional and it ran perfectly with his wideband and mine so I don't think it was the tune. My timing map was messed up according to Aaron, but now it's right even though it doesn't do me any good. I'm still not sure which route I'm going to take, but I'm not giving up.......yet!!!!

George, I've got my eye on a Baltic Blue '94 with a T67 already installed.
 

IJ.

Grumpy Old Man
Mar 30, 2005
38,728
0
0
62
I come from a land down under
J: Ok if you're sure it's never leaned out on power that narrows it down some.

Bent/stuck/incorrectly adjusted valve is my guess.

Can you post your fuel and ignition maps?
(hi res screenshots will do)
 

jugodegolf

Supramania Contributor
Apr 5, 2005
2,369
2
38
Phoenix,AZ, United States
suprahero;975079 said:
My car was tuned by a trained professional and it ran perfectly with his wideband and mine so I don't think it was the tune. My timing map was messed up according to Aaron, but now it's right even though it doesn't do me any good. I'm still not sure which route I'm going to take, but I'm not giving up.......yet!!!!

George, I've got my eye on a Baltic Blue '94 with a T67 already installed.

Don't think you'd be happy any anything other than your car, Jay. You still owe me a rematch...let me know how the lesson went.

I find it hard to believe it was the tune...car ran too well. IJ might have it right.
 

rakkasan

Currahee!!
Mar 31, 2005
2,997
0
36
55
Fort Campbell, KY
IJ.;975118 said:
George: This is why I asked to see the maps, all this speculation is useless without some data/evidence to go on.

Jay sent me a copy of his tune file, nothing looks out of whack, but I think the copy he had sent me was post Aaron changes....
 

IJ.

Grumpy Old Man
Mar 30, 2005
38,728
0
0
62
I come from a land down under
Mark: I'd like to see the maps in use when it died.

Anything else is useless.

Motor's don't just eat parts for no reason and it would be nice for J to have a 100% answer so it doesn't happen again.
 

tissimo

Stock is boring :(
Apr 5, 2005
4,238
0
0
40
Melbourne, FL
IJ.;975130 said:
Motor's don't just eat parts for no reason

+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
 

p5150

ASE and FAA A&P Certified
Mar 31, 2005
1,176
0
36
Central Idaho
Here is a pic of the GE head: http://www.clublexus.com/gallery/data//500/medium/IMG_0045.JPG

Now here is one of the GTE head: http://www.clublexus.com/gallery/data//500/GTE_combustion_chamber.JPG

The point im getting at with these pics is that the 1j, im certain, is different as well; I just dont know the specific measurements.

I dont have any pics of the 1j CC but from what I have read on other threads it is a bit smaller. I also dont know the deck height of the motor Jay is running, but it would be pretty easy to measure the valve protrusion and compare it to the deck height of a piston at TDC to see if it was possible that the valves struck the pistons.

This should be a non-interference motor, right? Im leaning away from a mixture problem because the damage looks pretty consistent. Im putting my money on the valves just BARELY hitting the edge of the pistons when the rpms and heat started taking effect.
 

rakkasan

Currahee!!
Mar 31, 2005
2,997
0
36
55
Fort Campbell, KY
p5150;975189 said:
Here is a pic of the GE head: http://www.clublexus.com/gallery/data//500/medium/IMG_0045.JPG

Now here is one of the GTE head: http://www.clublexus.com/gallery/data//500/GTE_combustion_chamber.JPG

The point im getting at with these pics is that the 1j, im certain, is different as well; I just dont know the specific measurements.

I dont have any pics of the 1j CC but from what I have read on other threads it is a bit smaller. I also dont know the deck height of the motor Jay is running, but it would be pretty easy to measure the valve protrusion and compare it to the deck height of a piston at TDC to see if it was possible that the valves struck the pistons.

This should be a non-interference motor, right? Im leaning away from a mixture problem because the damage looks pretty consistent. Im putting my money on the valves just BARELY hitting the edge of the pistons when the rpms and heat started taking effect.

I wonder if Jay was running stock valve springs which could cause valve float at high rpms......
 

suprahero

naughty by nature
Staff member
Aug 26, 2005
14,971
0
36
54
Roll Tide
I thought it was a non interfering engine as well, but apparently not. IJ, I'll find a copy of my map before Aaron corrected it and try to post it up.
 

suprahero

naughty by nature
Staff member
Aug 26, 2005
14,971
0
36
54
Roll Tide
The guys at the machine shop tested the springs and said they were as good as new.........:dunno:

Try this link out for the tuning files.
www.msnusers.com/tuningfiles

I don't know if that link works for you guys or not, but click on the documents and see. I'm having problems with it, but I'm trying to solve them.
 
Last edited: