got a little deeper into my now dubbed "toast" 4.8L and found a lot of metal and carbon/sludge in the bottom of the pan(it was gritty not slimy) and even more metal in the K&N filter.

on various other sites... everyone is telling me my exhaust valves were getting way too hot. my dad says they look OK just a little lean ??

probably ¼" thick in there.. that is only at 4,000 miles with 5,000 mile oil changes with castrol GTX and K&N filters and a grand total of about 10,000 miles I put on the engine


pan after cleaner got dumped in it


all of the exhaust valves look like this



I'm just a little confused as to how a stock PCM can run a engine too lean like I'm being told it is. as far as I know the ONLY things done to the PCM are what I paid for which was a VATS, EGR, A/C and rear O2's disabled.
gear ratio was NOT changed to 3.73 & 29" like I ask

I still have the EVAP run from the tank to a charcoal canister to the purge solenoid on the intake. fuel trims after the exhaust leaks were running minimum light throttle -5 to +14 at 60% throttle +
(I think it's still relearning the FT after I had some bad exhaust leaks running +24 all the time)

I never had overheating problems (actually kept it at 197-202)
never got a check engine light other than the knock sensors, O2 sensor in january and temp sensor because it came unplugged.

 

Where did the engine come from?

What kind of mileage did it have on it before you installed?

Is the engine stock or modified?

 

Bought it from someone on craigslist in late 2012.
came from a wrecked silverado.

was told it had about 180k

as far as I know the engine is 100% stock aside from my "ghetto" intake tube and stainless short tubes


guess I was not clear explaining... this is the engine I've had in my S10 since 2013, that has only had about 10,000 miles put on it since.
and that oil pan, pickup tube and windage tray was BRAND NEW since I had to use a hummer H3 pan to clear my cross member.

the reason the engine came out was because it intermittently lost oil pressure.

would hold 40psi at idle in park and drive
up to 80psi revved in park/neutral
accelerating even 5% throttle it would drop to about 5psi
same thing happened at highway speed 65 trying to accelerate or go up a hill oil pressure dropped for 40-60 down to 5psi
loading the engine up in gear with the brakes applied and holding the throttle it replicated the driving problems... when I did that and let off the gas the pressure did not bounce back up like it was and the lifters started to tick and that was the last time the engine in question was started 3 weeks ago.


I've already bought a "new" to me 2004 LM7 with 142k from a legitimate shop that warranties their parts.

 

2004 LM7 means possible castech 706 heads. If you aren't aware, there was a porosity issue in the castings resulting in cracked heads. Ask how I know....

It would be worth pressure testing the motor to be sure

 

At 180K If it wasn't taken care of, I would expect excessive carbon build up. especially with 5k mile Oil Changes. The problem with High milage engines like that is, If there dirty with excessive carbon build up, You can disturb the carbon deposits and they can cause all sorts of havoc.

I.e. Sticky lifters that won't pump up, Stuck oil pressure relief on the oil pump, Oil pressure gauge not to read correctly at the sending unit as a result of a clog or blockage.

That being said, A custom intake tube and different exhaust manifolds can affect the way the engine runs. Even a stock engine. In a swap its always best to have someone look at it whether you send them logs or have it looked at in person.

 

Ideally the fuel trims "should" keep everything happy but messing with the MAF airflow can mess with things.

 

I completely forgot the 706 was the "crappy" heads that cracked.
but I thought it was only when they were removed??

Either way I will check it before the engine goes in the truck.

literally just a 3.5" PVC tube with a silicone 90* and 45* with the MAF mounted at the cone filter.
IMO the intake I have is a restriction since it's ID is only about 3-3.25"