Lewis Raymond Miles

Tomorrow morning I am going to be checking out a Lc9 engine that came out of a Yukon. According to this guys mechanic, and I quote "2008 5.3 with fuel active management. #4 cylinder has a low compression by 30 psi lower. Causing rough idle. Flat cam on #4?" I am not a mechanic and I cant answer any technical Questions. if you are interested you can contact me"

Any ways do plan on rebuilding the engine, but is there anything I should be watching out for?

LLLosingit

iTrader: (4)

I would confirm the flat cam lobe, It should be easy enough to have them show you by turning over the engine by hand while watching the rocker arm on that lobe or by pulling the valley cover and looking at it. Since you plan on a rebuild a flat cam is not an issue, The metal from the cam is usually pretty fine and although it does damage bearings it usually doesn't damage cylinder walls. Just make sure the block gets a good cleaning before reassembly because the metal will be spread throughout the oil passages.

Lewis Raymond Miles

Thanks for the reply, that makes sense. I will pull the valve cover and take a look at it. I also plan on deleting the DOD system and upgrade the cam. Any advise on to what cams work? Sorry for the noobish questions, I have built rotary engines and other 4 and 6 cylinders but the LSX gives me headaches with all the "could works"

lil john

How to Rebuild GM LS - Engines by: Christopher Werner would really help if your doing it yourself.
On the cam get in touch with someone like Tick Performance, Texas Speed, Pat G. or any reputable Ls cam maker as cam choice is not to be over looked with stock springs:-)

Sales2@Texas-speed

iTrader: (5)

I agree that I would want confirmation that it's an issue with a flat cam lobe. We can certainly help you out with a new cam! We stock a variety of grinds that range from stock-like idle to an aggressive lope. We can also help you out if you are interested in sending your cylinder heads to us for porting! Lots of options to make more power! Feel free to give us a call at 512-863-0900, and any of our salesmen will be glad to discuss your options with you!

Lewis Raymond Miles

I went ahead and bought the engine, it was a pretty good deal regardless, I just had to take a shot at it. It looks pretty good so far but I haven't had a chance to remove valve covers and oil pan since it's frigging cold and snowing.

Any ways the next step is to figure out what cam/ valvetrain I can use. I have been doing some reading and to be honest my head is pounding.

What would you guys suggest?
Delete DOD and VVT and run a LS based camshaft?
Delete DOD, keep VVT and run an upgraded VVT cam?

Bear in mind that this engine will end up in a 2800lb car, a Mazda Rx7 to be specific so power is way more than I could wish for and the cam swap is only to add reliability and a little performance.

Oh, the heads are #243 which I read are good.