Whats your take?

[Accelerator]

Basically you are starting a thread with either the intention of selling something, or the intention of attacking somebody. You have been warned about both issues.

I've basically had enough of you trying to wreck our tech area. See you in 7 days.

Wrong!, the thread was to ask a question!, hence "Guess the tune".

Ass-ume....

Anyway, This engine was a complete LBZ that i had a while ago, but i have parts for the engine laying around. so i started to look closer at the pistons for this motor, it looked like it had Gobs of timing added to the tune, but im wondering how much? Then i noticed the injector patturn was not in line with the model, some of you noticed that right away!, and when the engine was dissasembled i noticed that a valve hat been playing catch with one of the pistons too.

So the question were.

How much timing would cause it to spray that far out of the bowl?

Why is the injector patturn looking like a lmm

Would have the added timing caused a valve to drop?

Also i know for sure that this was a 06 LBZ and not a lmm, maybe the factory was testing the lmm nozzels on there like i see some of you have asked about?

II told me that the nozzels had a different spray angle than what a lmm or lbz normally have and the washers were a different thickness????

Any speculation?

 

[JoshH]

Are there supposed to be pictures in the first post? If there is, I don't see anything.

 

[Accelerator]

Are there supposed to be pictures in the first post? If there is, I don't see anything.

sorry about that.

here ya go

 

[SteveFord]

Seems like some people run alot of timming like the way you would tune a gas motor. I've seen one of the top tunners of the duramax post awhile ago that running over 28 degrees of timming showed no real gains on the dyno.

 

[racinmike77]

ever think it has more to do with PW than timing?

 

[racinmike77]

Wrong!, the thread was to ask a question!, hence "Guess the tune".

Ass-ume....

Anyway, This engine was a complete LBZ that i had a while ago, but i have parts for the engine laying around. so i started to look closer at the pistons for this motor, it looked like it had Gobs of timing added to the tune, but im wondering how much? Then i noticed the injector patturn was not in line with the model, some of you noticed that right away!, and when the engine was dissasembled i noticed that a valve hat been playing catch with one of the pistons too.

So the question were.

How much timing would cause it to spray that far out of the bowl?

Why is the injector patturn looking like a lmm

Would have the added timing caused a valve to drop?

Also i know for sure that this was a 06 LBZ and not a lmm, maybe the factory was testing the lmm nozzels on there like i see some of you have asked about?

II told me that the nozzels had a different spray angle than what a lmm or lbz normally have and the washers were a different thickness????

Any speculation?

Ever think the extra thick washers caused the problem?? or are you just making shit up?

 

[The Neens]

Seems like some people run alot of timming like the way you would tune a gas motor. I've seen one of the top tunners of the duramax post awhile ago that running over 28 degrees of timming showed no real gains on the dyno.

Pat and I made over 25 pulls with my Dad's '02 Ca. Emissions truck a few years ago...Anything over 28* did not yield any improvements...That was that truck on that day, Superflow dyno...Other models may like more timing, that LB7 didn't...

 

[LBZ]

I thought the washers were the same through all years? Maybe someone put two on?

 

[TheBac]

Could the engine have been a test motor from GM? Maybe thats the reason for the odd injector patterns? Guess we'd need some more background info.

 

[JOHNBOY]

Wrong!, the thread was to ask a question!, hence "Guess the tune".

Ass-ume....

Anyway, This engine was a complete LBZ that i had a while ago, but i have parts for the engine laying around. so i started to look closer at the pistons for this motor, it looked like it had Gobs of timing added to the tune, but im wondering how much? Then i noticed the injector patturn was not in line with the model, some of you noticed that right away!, and when the engine was dissasembled i noticed that a valve hat been playing catch with one of the pistons too.

So the question were.

How much timing would cause it to spray that far out of the bowl?

Why is the injector patturn looking like a lmm

Would have the added timing caused a valve to drop?

Also i know for sure that this was a 06 LBZ and not a lmm, maybe the factory was testing the lmm nozzels on there like i see some of you have asked about?

II told me that the nozzels had a different spray angle than what a lmm or lbz normally have and the washers were a different thickness????

Any speculation?

Well hard to say. Timing of injector open and injector can cause that. I keep preaching that just knowing Main shot timing is not enough. You need to know RPM and pulse width also. Another thing is reading piston like that is for old Mech. pump stuff. With pilot and post injection trying to read a pattern like that is pointless. I have two stone LB7s here that show considerable patterns outside the bowl. But I know that neither ever had more than 20* main shot timing which is well with in the bowl. But if you look at pilot you can see what made the patterns.

I thought the washers were the same through all years? Maybe someone put two on?

Is he talking about the sealing washer that seal the injectors to the head or is he talking about the washers that shim the pintle spring in the injector? With out know for sure what washers it is hard to say.

Seems like some people run alot of timming like the way you would tune a gas motor. I've seen one of the top tunners of the duramax post awhile ago that running over 28 degrees of timming showed no real gains on the dyno.

Depends on what your looking for and your setup. If your looking for peak power and your stock turbo. Than I can buy that. But if your trying to make a wide curve then your giving up power past 3500rpm with that timing. I was still making over 400rwhp at 4000rpm with a stock turbo turbo. With 28* max you will give up a lot of topend pull but you still have the nice pretty peak number. But the only thing peak numbers win are dyno trophies.

Now build an engine, add big air and rpm your going to need timing. High timing is fine if it is the right place. It is all about figuring out the curve that works for you.

 

[Accelerator]

Well hard to say. Timing of injector open and injector can cause that. I keep preaching that just knowing Main shot timing is not enough. You need to know RPM and pulse width also. Another thing is reading piston like that is for old Mech. pump stuff. With pilot and post injection trying to read a pattern like that is pointless. I have two stone LB7s here that show considerable patterns outside the bowl. But I know that neither ever had more than 20* main shot timing which is well with in the bowl. But if you look at pilot you can see what made the patterns.
Thanks i did not spend much time thinking about the pilot shot, that makes sence
Is he talking about the sealing washer that seal the injectors to the head or is he talking about the washers that shim the pintle spring in the injector? With out know for sure what washers it is hard to say.
The washer in the injector bore is what im talking about, it was 12 thou thicker... also yes this was a GM test engine. before the testing sheets were thrown away, the specs were LBZ 410HP @3600rpm??? Test procedure was "sustained Peak HP" Duration 11 hours. Other than the ding in one piston everything else looked brand new, so it did not get hurt.


Depends on what your looking for and your setup. If your looking for peak power and your stock turbo. Than I can buy that. But if your trying to make a wide curve then your giving up power past 3500rpm with that timing. I was still making over 400rwhp at 4000rpm with a stock turbo turbo. With 28* max you will give up a lot of topend pull but you still have the nice pretty peak number. But the only thing peak numbers win are dyno trophies.

Now build an engine, add big air and rpm your going to need timing. High timing is fine if it is the right place. It is all about figuring out the curve that works for you.

:happy2:

 

[SteveFord]

Well hard to say. Timing of injector open and injector can cause that. I keep preaching that just knowing Main shot timing is not enough. You need to know RPM and pulse width also. Another thing is reading piston like that is for old Mech. pump stuff. With pilot and post injection trying to read a pattern like that is pointless. I have two stone LB7s here that show considerable patterns outside the bowl. But I know that neither ever had more than 20* main shot timing which is well with in the bowl. But if you look at pilot you can see what made the patterns.

Is he talking about the sealing washer that seal the injectors to the head or is he talking about the washers that shim the pintle spring in the injector? With out know for sure what washers it is hard to say.



Depends on what your looking for and your setup. If your looking for peak power and your stock turbo. Than I can buy that. But if your trying to make a wide curve then your giving up power past 3500rpm with that timing. I was still making over 400rwhp at 4000rpm with a stock turbo turbo. With 28* max you will give up a lot of topend pull but you still have the nice pretty peak number. But the only thing peak numbers win are dyno trophies.

Now build an engine, add big air and rpm your going to need timing. High timing is fine if it is the right place. It is all about figuring out the curve that works for you.

I figure with a stock setup whats the point other than maybe sled pulling to run the motor past 3500 rpms. I can tell you my truck gives nothing up on top end with the timming it runs and it dosen't see 28 with the tune I run. Than again it does have a nice power curve.

 

[JOHNBOY]

I figure with a stock setup whats the point other than maybe sled pulling to run the motor past 3500 rpms. I can tell you my truck gives nothing up on top end with the timming it runs and it dosen't see 28 with the tune I run. Than again it does have a nice power curve.

Frankly with your trans and the way it works your are far less likely to notice. At 4000 rpm the Allison is eating around 80rwhp on the dyno. I do have that issue so it will show up more for me.

 

[SteveFord]

Frankly with your trans and the way it works your are far less likely to notice. At 4000 rpm the Allison is eating around 80rwhp on the dyno. I do have that issue so it will show up more for me.

As far as your posts about tuning and pilot injection that I have seen you post is something I would like to hear more about as I belive you have some good info and or ideas to share