Valve Reliefs For a 6L LQ9
12-07-2015, 05:53 PM
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Valve Reliefs For a 6L LQ9 Hey Guys im wondering where you guys find your information on valve clearance. Im rebuilding an LQ9 and plan on doing some L92 heads a bigger cam and a fast intake. Its time to order my Con rods and pistons for my short block. I chatted online with a guy from comp cams basically asking him for a ball park base line for the max lift i could expect out of a medium to aggressive lift street cam with a big lopey idle. Before the guy disconnected me from the chat line all he could tell me was the cam was the last thing to buy in an engine build.
I understand that, but i dont want to build the engine and shoot myself in the foot by not buying valve reliefs or big enough valve reliefs. If someone could steer me in the right direction that would be great. I probably need to try and plan this whole thing out better but being my first build im new to this stuff so bear with me!
I understand that, but i dont want to build the engine and shoot myself in the foot by not buying valve reliefs or big enough valve reliefs. If someone could steer me in the right direction that would be great. I probably need to try and plan this whole thing out better but being my first build im new to this stuff so bear with me!
12-07-2015, 06:13 PM
#2
If you are buying aftermarket forged piston, most come with ample valve reliefs for all but the most extreme applications. Just make sure that when you order your pistons for your LQ9, that you choose pistons with LS3 style valve reliefs. Many pistons are designed to work with both cathedral and rectangle port heads, but best to check to avoid problems and extra work later.
Next, forget about Comp Cams tech. It is pot luck on who you might get on the phone there. When you are ready to get your cam, call Kip @ Cam Motion, Martin Smallwood or Geoff Skinner at EPS. They are knowledgeable, accessible and will get you a superior quality camshaft.
While this may surprise you, lift is not the primary consideration in valve clearance. It is valve timing. So, your duration and lobe centers will be what is important. As I said though, with aftermarket forged pistons, you will likely have ample clearance.
Next, forget about Comp Cams tech. It is pot luck on who you might get on the phone there. When you are ready to get your cam, call Kip @ Cam Motion, Martin Smallwood or Geoff Skinner at EPS. They are knowledgeable, accessible and will get you a superior quality camshaft.
While this may surprise you, lift is not the primary consideration in valve clearance. It is valve timing. So, your duration and lobe centers will be what is important. As I said though, with aftermarket forged pistons, you will likely have ample clearance.
