Lost oil pressure
 

Well, it's been a good 189,000 mile run with my tired Lq4. Something is going on and my oil pressure has gradually decreased to almost nothing at an idle now. I've changed oil, viscosities, filters and sensors but its toast.

Its probably an oil pickup tube gasket but since I've been fighting oil leaks and wanting a little more umph I've decided to get a new long block for it.

I have access to a brand new GM LQ9 long block which is rated at 450hp. I'll be switching heads (it comes with square port intake) to a set of LS6 cathedral port heads. These heads have a slightly smaller chamber so it will up the compression to 10.9 to 11.0 to 1. Its a got a factory LS6 type cam which might not be perfect for a truck but its a lopey cam that will be easy to tune and requires no converter change. I would expect about 425hp when all said and done. It's definitely going to test the latest transmission I had built.

I'm deciding on installing it myself or having my transmission guy do it for me. Wish me luck.

Tim

That sounds awesome. LQ9 is the way to go. Why the heck didn't GM put the LQ9's in our H2's to begin with?
Please keep us updated, and oh yeah, how about some pics.

Why are there so many versions of the iPhone? :rolleyes: Droid life!:cool:
The LQ9 Introduced in 2006, the LQ9 was referred to as the Vortec HO 6000 or VortecMAX. It was a high-output version of the LQ4. The LQ9 was equipped with flat-top pistons and floating wrist pin rods. The flat-top pistons allowed for an increase in compression, and the engine produced slightly more power than the LQ4 -- plus-10 horsepower and plus-10 foot-pounds of torque.

This is the base of what I started with: https://www.chevrolet.com/performanc...nes/ls-364-450
I wanted to keep the cathedral port heads so I swapped the square ports that the engine came with with some fresh 243 heads. They have a 5 angle valve job, mild porting and a set of GM blue springs. These heads will also bump the compression up to near 11to1.

The cam that it came with is a LS6 cam, which is not really what the Hummer needs, so I'm waiting on a BTR stage 2 truck cam to arrive later today. This cam will have a killer lope at idle and power will come in early at around 1400 rpm. Specs are 218/218 .553/.553 111+0. Sound clip here:
To top it off I have a TBSS intake with 50lb injectors and a 90mm gold blade throttle body off a LS7 Corvette.

I'm debating a baby stall converter but haven't made my mind up yet. It would be fun that's for sure.

I'm trying to learn my way thru HPTuners so I can get a good start up tune. The truck was tuned before but I don't know if that tune will work with this engine. I'm guessing this new engine will be in the 420-450 hp range without having to spin it too hard.

IN progress pics below. I'm not working on it too hard. I won't have all the parts in until the middle of next week.

Tim
https://cimg4.ibsrv.net/gimg/www.hum...343a966604.jpg
https://cimg5.ibsrv.net/gimg/www.hum...dfb4f8d703.jpg
https://cimg6.ibsrv.net/gimg/www.hum...77ee737b4.jpeg
https://cimg8.ibsrv.net/gimg/www.hum...90cdc049b2.jpg
https://cimg9.ibsrv.net/gimg/www.hum...ebcde5f9d.jpeg

That is going to be BA when you get it done. I also dig your FLTR, I have an orange one.

Fantastic. What a nice project you have going.

My 07 has 108,000 miles on it, but I'm really heading in the same direction as you, if not I'll go with a supercharger set-up on my factory motor.

Decisions, decisions. Great Pics!

Ya it should be a fun ride for sure.
The RGS is waiting a fat front tire kit and some pro audio, I need more time.
Tim

I'd be so very tempted to go with some later rectangle port heads just to make it easier to through on an LSA supercharger. Those come far cheaper than a full on new kit from magnuson.

Either way it will be a nice big boost over stock.

they sell cathedral port to rectangle port adapters. my friend just used the setup on his chevell with the lq4 bottom end and the Cadillac super charger

Boost District has the adapters and the cathedral ports are better lower end that square ports. It should be going in tomorrow but I'm waiting on a tube before I fire it up.

Tim