I called up there yesterday and here is what they found. Two weeks ago he sent some wav files off to a guy who looks at the data to determine what the issue is. The data showed that there could possibly be an issue with the lobe on the cam shaft. Well...he took the truck apart yesterday and said the cam shaft is worn on Cyl 3. It appears to him that at somepoint some a small piece of dirt might have gotten into the roller causing extra wear on the cam shaft lobe. That or the roller just wore out. Today he was going to look into it in a bit more detail and make sure that is the last issue he can think of while he's in there. A new camshaft it will be and prayers that I'll have it back this week and it will be fixed.

Thanks to everyone for all of the help and updates. As of today it appears it was a combination of two leaky exhaust valves and a worn lobe on a camshaft. Once I get it back I'll make a final post so that people can refer to all of the great information in this thread in the future.

 

If your engine is that badly worn, you would definitely be better off with a rebuilt crate engine. ‘Cause who knows what other problems are lurking undetected on a H2 that was not maintained. With not that many miles on her. Someone dumped her for a reason.

Or do it right, and send the engine out to a professional engine rebuild shop. These H2 are are seriously underpowered compared to SUVs and pickup trucks made today, and you could use that extra 100HP and peace of mind knowing it was done right. They will not go over 70mph on the steepest highway grades over mountain passes. Every new vehicle can. If you care. I do. Unless you can not afford it.

Spend your money wisely if you plan on keeping her for a while.

 

not everyone can afford a crate engine. he will probably be fine if thats all it is. cam and lifters. hopefully he does not reuse the old lifters and gets a fresh set. might want to have him check oil pressure as well as the oil pickup tube o-ring hardens and is notorious for going bad and killing pressure which can lead to a wiped cam and lifters plus engine bearings.

 

There are a number of camshaft available for the LQ9 that will allow it to make additional hp and increase the torque as well. True that these are not what GM would call green cams but they will make a difference in performance, add a decent tune if you wish and you will notice the difference between a standard LQ9 and one that is cammed.

Here is an article if you are interested: https://www.motortrend.com/how-to/ne...-low-end-loss/

Hot setup for an 07. Good luck in whatever direction you go in.
Dan

 

But its an LQ4, which I am sure there are cams for it also. Rebuilt Heads, new cam and hopefully all lifters and timing chain. Oil pump also at that point or Nah? Should be pretty good motor for a while. hope the mechanic cuts you a good deal for diagnosing it as valves from the git go.

 

Actually, it’s a LQ9, The H2 started to use the early model Escalade engine in 07, it featured higher compression and VVT. It features flat top pistons vs the dished used in the older LQ4. Both are great engines and will benefit with a cam upgrade. Considering the situation a new cam and set of lifters with a fresh valve job will really wake things up as long as the bottom end is in good shape.

 

The LQ9 was never put into the hummer H2 from the factory and VVT did not show up until the L92 (6.2) in 08

Neal

 

Neal, you are right, hats off to you, back when I had my 06 looking for more performance I was told by a GM Service writer that the H2 in 07 used a LQ9 at the end of the 07 model year production run.

Looks like that was wrong and now that you sparked my interest And looking into it further I cannot find any info on the web supporting the LQ9 usage. I imagine, if Hummer put the LQ9 in the 07 H2 it would be in some article somewhere stating that.

Either way there are some great camshafts on the web for the LQ4 that really wake them up, my friend recently installed one in his Silverado 2500HD LQ4, I was amazed with the difference and he said it really tows his travel trailer much better.

Cheers!

 

I do agree the LQ9 would have been a better choice for an OEM engine for the H2 and don't know why GM didn't do it.

Upgrades for the LQ4 are plentiful and its a solid engine for them,

put one in a 99 short bed with a small Lunati cam and head work along with some tuning with great results,

Neal

 

As it turns out it's not the cam or the rod....it's quickly looking like a new engine is going to have to go into the H2. What can I expect to pay for a brand new engine?