valve relief pistons in a lq4? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

GMC70c20 · 10-22-2012, 03:59 AM

I bought a lq4 a couple years ago and am finally getting around to getting it built. The enigne came out of a 2006 van and according to the casting number on the block it is a 2005. It is a gen III block because the knock sensore are in what would be the lifter valley and the cps is in the back of the engine. I thought that the lq4s all had dished pistons with no valve reliefs but this one has one for the intake valve. What is going on here?

68GMCCustom · 10-22-2012, 09:55 AM

Is it a standard bore?
Posted via Mobile Device

BR3W CITY · 10-22-2012, 12:00 PM

thats the "newer" style lq4 pistons, although last I saw them was an '07. Its actually for the exhaust valve, and there are 2 because it can be used either direction, only one relief serves a function. They were designed for the VVT engines, but went into non-vvt trucks as soon as the part number changed.

GMC70c20 · 10-23-2012, 02:31 AM

so would these pistons have the floating wrist pins?

BR3W CITY · 10-23-2012, 11:49 AM

god knows what the general put in there

technically they didn't start putting the floating pins into lq4's until 2005, so I'd think Yes, but I have no idea how to prove it.

10-22-2012, 03:59 AM	#1
GMC70c20 Registered User Join Date: Feb 2003 Location: Iowa Posts: 974	valve relief pistons in a lq4? I bought a lq4 a couple years ago and am finally getting around to getting it built. The enigne came out of a 2006 van and according to the casting number on the block it is a 2005. It is a gen III block because the knock sensore are in what would be the lifter valley and the cps is in the back of the engine. I thought that the lq4s all had dished pistons with no valve reliefs but this one has one for the intake valve. What is going on here? Attached Images __________________ 1970 c20 converted to c10 sleeper 1979 c20 the wood hauler 1991 honda civic daily driver spray and pray baby

10-22-2012, 09:55 AM	#2
68GMCCustom Truck and auto performance nut Join Date: Feb 2007 Location: McKinney,Texas Posts: 3,848	Re: valve relief pistons in a lq4? Is it a standard bore? Posted via Mobile Device __________________ Kurt - '68 GMC short step - NIB '09 LY6 6.0L crate motor w/mods, NIB '12 crate 4L85e w/billet 3k stall Circle D, 3.73 posi 12 bolt, DynaTech f-swap headers, 3/4 drop, handling mods, etc. - my toy '72 Chevy LWB C-10 Highlander - 350/350 ps/pb/tilt/ac - not original but close '06 Chevy TrailBlazerSS - LS2/4L70e - little black hot rod SUV - my DD '18 Kia Sorento - wife's econo-driver '95 Chevy S10 - reg cab shortbed, LS, 4.3, auto... my '68's powertrain and chassis build -links broken A surprise phase - carb to efi -links broken

10-22-2012, 12:00 PM	#3
BR3W CITY meowMEOWmeowMEOW Join Date: Sep 2009 Location: MKE WI Posts: 7,128	Re: valve relief pistons in a lq4? thats the "newer" style lq4 pistons, although last I saw them was an '07. Its actually for the exhaust valve, and there are 2 because it can be used either direction, only one relief serves a function. They were designed for the VVT engines, but went into non-vvt trucks as soon as the part number changed. __________________ *'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING* MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD

10-23-2012, 02:31 AM	#4
GMC70c20 Registered User Join Date: Feb 2003 Location: Iowa Posts: 974	Re: valve relief pistons in a lq4? so would these pistons have the floating wrist pins? __________________ 1970 c20 converted to c10 sleeper 1979 c20 the wood hauler 1991 honda civic daily driver spray and pray baby

10-23-2012, 11:49 AM	#5
BR3W CITY meowMEOWmeowMEOW Join Date: Sep 2009 Location: MKE WI Posts: 7,128	Re: valve relief pistons in a lq4? god knows what the general put in there technically they didn't start putting the floating pins into lq4's until 2005, so I'd think Yes, but I have no idea how to prove it. __________________ *'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING* MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD



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