School me on a LQ motor swap

[Shibby50]

As the title states, I'd just like to learn a little bit about LQ swaps.
Are they completely interchangeable with lsx parts? As far as rotating assembly/heads/intake etc.?

And why go to one as opposed to a ls1/2/6? Just for block rigidity? If so, at what kind of numbers would it be worth it to switch to a LQ as opposed to re-using a ls aluminum block?

I see them used mostly on boosted applications, is it because of the cylinder walls or something? Better cooling or oiling maybe?

Just curious, as I've seen it done a million times and never really thought about it all.

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[Bob Kazamakis]

I would assume bigger cubes, cheaper price and a stouter block for boosting Are the reasons why

You can pick them up for pretty cheap compared to an ls2

 

[EmersonHart13]

Boost and strength go well together so that is the big reason, also cost as stated above they can be found for a good price.

 

[OffshoreDrilling]

its pretty much an iron block ls2, the heads use the same ports as the LS2/LS6 except they have a larger combustion chamber. They are the 317 casting heads if you have ever heard people talking about them. LS2/6 are 234s

 

[OffshoreDrilling]

stout block has nothing to do with it, its the price and availability that makes it so popular. If you get to the point that block strength is a concern on an ls2, you are at over 1000whp. You would likely be running an aftermarket block if you even though of building something with that much power.

 

[Bob Kazamakis]

What about the rotating assembly?

 

[OffshoreDrilling]

stock crank is just as stout. 1000 crank hp is about the limit id say

 

[Bob Kazamakis]

Pistons? Are they forged?

 

[Yaj Yak]

is an lq4 block > ls6 block?

 

[skeezer]

88lbs heavier

 

[Yaj Yak]

but extra displacement correct?

 

[EmersonHart13]

LS2 and LQ4 and LQ9 are all 6.0

 

[Yaj Yak]

ya sorry i was talking ls6 before.

 

[EmersonHart13]

Generation III

LQ4 (VIN U)
The Vortec 6000, or LQ4, is a V8 truck engine. Displacement is 6.0 L (~366 cu in) from 101.6 mm bore and 92 mm stroke. It is an iron/aluminum (2000 model year engines had cast iron heads) design and produces 300 horsepower (220 kW) to 325 horsepower (242 kW) and 360 lb·ft (488 N·m) to 370 lb·ft (502 N·m). LQ4s are built in Romulus, Michigan and Silao, Mexico.
LQ4 applications:

• Chevrolet Express/GMC Savana
• Chevrolet Silverado 2500 Pickup, 3500 Pickup, Crew Cab, and Chassis Cab/GMC Sierra 2500 HD Pickup and Crew Cab, C3, Denali, and 3500 Pickup and Chassis Cab, 1500HD Crew Cab
• Chevrolet Suburban/GMC Yukon XL Denali
• Hummer H2 SUT
• GMC Yukon Denali

LQ9 (VIN N)
The Vortec HO 6000 or VortecMAX is a special high-output version of the Vortec 6000 V8 truck engine originally designed for Cadillac. This engine was introduced in other truck lines as VortecMAX for 2006. It features high-compression (10:1) flat-top pistons for an extra 10 hp (7.5 kW) and 10 ft·lbf (14 N·m), bringing output to 345 hp (257 kW) and 380 ft·lbf (515 N·m). LQ9s are built only in Romulus, Michigan. GM also listed it as based on LS architecture.[24]
LQ9 Applications:

• 2002-2006 Cadillac Escalade
• 2002-2006 Cadillac Escalade EXT
• 2003-2006 Cadillac Escalade ESV
• 2003-2007 Chevrolet Silverado SS
• 2004-2005 Chevrolet Silverado and GMC Sierra Vortec HO Edition Only [Badging on truck](B4V)
• 2006-2007 Classic Chevrolet Silverado and GMC Sierra VortecMAX Option

 

[OffshoreDrilling]

Pistons? Are they forged?

nope, cast.

 

[Yaj Yak]

can lq4 bottom ends handle boost?

 

[OffshoreDrilling]

from the factory most of the ls motors have pretty high compression. 9lbs seems to be the most you can run on a safe tune up. Of course there are always exceptions, but Id say thats generally the consensus. Most turbo/sc kits are set up to run 6-7lbs from the aftermarket on stock bottom ends.

 

[Smokinhot]

LQ4 = Dished pistons and is an excellent boost motor..... what i'm installing,but putting 243's on to boost Comp to compensate for the dished pistons
LQ9 = Flat Top pistons so higher compression (10:1 or 10.5:1)

Both have 317 casting heads w/72cc chambers so they are persfect for boost

Most of the guys swap in the LQ motors in their trucks b/c of the durability to handle the power and they are found rather cheap.

Cast iron > Aluminum

Yes to all LS parts being interchangeable, and the rotating assemblies are basically identical. But you doent hear about spun rods bearings in them as much as you do in LS motors.

 

[Junk86]

LQ4 = Dished pistons and is an excellent boost motor..... what i'm installing,but putting 243's on to boost Comp to compensate for the dished pistons
LQ9 = Flat Top pistons so higher compression (10:1 or 10.5:1)

Both have 317 casting heads w/72cc chambers so they are persfect for boost

Most of the guys swap in the LQ motors in their trucks b/c of the durability to handle the power and they are found rather cheap.

Cast iron > Aluminum

Yes to all LS parts being interchangeable, and the rotating assemblies are basically identical. But you doent hear about spun rods bearings in them as much as you do in LS motors.

I would NEVER run a 243 on a boosted app if your shooting for anything over 15 pounds of boost. The decks are not that thick and move around a lot causing the motor to push water and eventually end in gasket failure. Thats why most people use 317's on a a decent boosted car, not mention the drop in compression they offer..but yet again...the decks still are not optimal for a high boost race application. For that I would go with a decent All Pro or such.

BUT......I do know some stock block cars with home ported 317's that are way over 1000 HP on E85 with turbo's....they just push a little water every once in awhile.

 

[THEHKP7M13]

...Yes to all LS parts being interchangeable, and the rotating assemblies are basically identical. But you doent hear about spun rods bearings in them as much as you do in LS motors.

Because you don't have buttheads drag racing them and putting a bunch of speed parts and tuning on Savanna vans and the sort now do you?

 

[Eagle]

Good thread guys!

 

[HILROD]

All LQ4's are the lowers compression 6.0 stock. The blocks are way stronger, and hold head gaskets better. The iron block weighs 77 pounds more than an LS1. The acc. are also slightly heavier. The iron blocks can be bored over and honed instead of re-sleeved. Get some good rods and pistons and go to town.

 

[Smokinhot]

I would NEVER run a 243 on a boosted app if your shooting for anything over 15 pounds of boost. The decks are not that thick and move around a lot causing the motor to push water and eventually end in gasket failure. Thats why most people use 317's on a a decent boosted car, not mention the drop in compression they offer..but yet again...the decks still are not optimal for a high boost race application. For that I would go with a decent All Pro or such.

BUT......I do know some stock block cars with home ported 317's that are way over 1000 HP on E85 with turbo's....they just push a little water every once in awhile.

I'm wanting the higher comp b/c i plan on putting a little cam in it down the road. If its ever boosted the heads will be changed back to 317's or better

Because you don't have buttheads drag racing them and putting a bunch of speed parts and tuning on Savanna vans and the sort now do you?

oh they get raced thats not my intention

 

[KagA152]

in the 99-00 motors, the crank is a little longer, so if you want to use a th350/400 youre good, if you want to use a 4l60/t56 you would have to change cranks. but the heads sucked in those years anyways, so probably best to stay away.

as for how much boost a stock one can take, maybe well find out next year but it seems like most people either start forged, or blow up because of a fueling problem