Here are pictures of what I found today on this new motor, a LS6 all forged motor from a big engine supplier:
The combustion chamber on #2 cyl shows an awful lot of build-up for only 1500 miles....Also, the lack of carbon in the burn area shows leaking coolant.
Piston top is "steamed clean" compared to #4....but notice each show some coolant leakage into the cyl (where the piston top is clean).
Effects of the reversion pulse that carried the coolant steam up into the intake port & further into the intake manifold. The coolant was only leaking into the cylinder, but the reversion pulse carries some back into the intake (and can with oil as well).
And the intake port for #4 right next to it shows oil build-up and very little steam reversion.
Only #2 was leaking real bad, but all 8 show signs of some seepage.
I also found that the piston to cyl bore clearance is excessive a .0055 when .0035 is the max I like to see so it allowed the rings to flutter and #2 top ring was stuck in the groove and allowed the oil consumption.
Other than these issues, it was a forged build with top quality parts and the rod & main journals & bearings show very little wear so I would attribute this to a "production" builder that puts out qty to be price competitive since the time it takes to check & double check tolerances, and then to order an oversize piston/ring set when the machining was done more than expected does not allow a builder to compete price wise with the other volume builders.
This is NOT real common, but is seen far more than it should be and NO, I will not post the name of the builder as I see some great builds come from them.....and rarely see this.
This is seen more with the low-priced bargin advertised engines & short blocks from the big-name volume builders or the shops that have regular techs attempt to do the engine building.
This post is only to show an example of what can cause some of the issues this thread is dealing with. This engine shows clearly the reversion pulses you here me talk about and leave some thinking...what???
The combustion chamber on #2 cyl shows an awful lot of build-up for only 1500 miles....Also, the lack of carbon in the burn area shows leaking coolant.
Piston top is "steamed clean" compared to #4....but notice each show some coolant leakage into the cyl (where the piston top is clean).
Effects of the reversion pulse that carried the coolant steam up into the intake port & further into the intake manifold. The coolant was only leaking into the cylinder, but the reversion pulse carries some back into the intake (and can with oil as well).
And the intake port for #4 right next to it shows oil build-up and very little steam reversion.
Only #2 was leaking real bad, but all 8 show signs of some seepage.
I also found that the piston to cyl bore clearance is excessive a .0055 when .0035 is the max I like to see so it allowed the rings to flutter and #2 top ring was stuck in the groove and allowed the oil consumption.
Other than these issues, it was a forged build with top quality parts and the rod & main journals & bearings show very little wear so I would attribute this to a "production" builder that puts out qty to be price competitive since the time it takes to check & double check tolerances, and then to order an oversize piston/ring set when the machining was done more than expected does not allow a builder to compete price wise with the other volume builders.
This is NOT real common, but is seen far more than it should be and NO, I will not post the name of the builder as I see some great builds come from them.....and rarely see this.
This is seen more with the low-priced bargin advertised engines & short blocks from the big-name volume builders or the shops that have regular techs attempt to do the engine building.
This post is only to show an example of what can cause some of the issues this thread is dealing with. This engine shows clearly the reversion pulses you here me talk about and leave some thinking...what???
