Truck Motor (LQX) questions
04-02-2009, 11:28 PM
#1
Truck Motor (LQX) questions I have built 3 engines for "other" marques. But the options have always been limited, and I followed set standards using only a handful of custom parts here and there. Its in the German car area - where all of my experience rests.
But I bought a 2000 Suburban 6L. I love the truck.
I thought it would be fun to build (using some terminology I learned from searching on LS1tech for several days) a 408.
So I was thinking of the best option to build one budget-minded but not dirt cheap would be to buy a running LQ4 or better yet, LQ9, which I understand to have the aluminum heads? - And take what I need and leave the rest.
It seems like a simple 408 would be a 6L LQ block of 2000-2006 or so, and a strong 4 inch stroke crank, and some 6.125 rods. But the pistons are still an unknown. I see no reason to go hog wild on the heads - porting or chamber shaping-wise - I mean it IS a truck, and the way the 4L80E shifts, I would want ALL the power between 2000-5000rpm.
What DO NOT know about is stuff like what length changes may or would be needed on the push rods if I were to change the cam and/or rockers to something more robust. Lifter tick really, really bothers me, so I would probably upgrade most of the valve train so this would be a 100k motor.
Would it be simpler to get some sort of kit from summit or Jegs?
The pistons for the 408 - Is there anything specific on the rod/piston combination I should know about when putting a 408 together other than that I would need a dish that would work with the "317" heads?
The reason I was thinking about buying a running engine is that all the small stuff is there - pickup, oil pan, coils, intake, throttle body - and I think it would really add up the $$ quick to go the other way - GMPP virgin block, new heads, etc. I have always had better luck with seasoned metal anyway when reconditioned properly. Even at 1600 for a moderate usage LQ9, thats 800 for the block, 300 for the heads, it includes all the parts I would need to hunt and peck for.
One other issue is that I understand from reading here that the LW4 that is currently in my truck has a thicker crank flange that attaches to the flex plate for the automatic. I would need to change that out to a thicker flex plate so I could use something like a Callies Compstar or Eagle (is Eagle still crap? I was told long ago that it was) stroker crank in this engine and mate it properly to the 4L80E.
I would assume I would go for forged, as I may wish to run boost later after I beef up the Automatic.
Any comments and advice are greatly appreciated.
But I bought a 2000 Suburban 6L. I love the truck.
I thought it would be fun to build (using some terminology I learned from searching on LS1tech for several days) a 408.
So I was thinking of the best option to build one budget-minded but not dirt cheap would be to buy a running LQ4 or better yet, LQ9, which I understand to have the aluminum heads? - And take what I need and leave the rest.
It seems like a simple 408 would be a 6L LQ block of 2000-2006 or so, and a strong 4 inch stroke crank, and some 6.125 rods. But the pistons are still an unknown. I see no reason to go hog wild on the heads - porting or chamber shaping-wise - I mean it IS a truck, and the way the 4L80E shifts, I would want ALL the power between 2000-5000rpm.
What DO NOT know about is stuff like what length changes may or would be needed on the push rods if I were to change the cam and/or rockers to something more robust. Lifter tick really, really bothers me, so I would probably upgrade most of the valve train so this would be a 100k motor.
Would it be simpler to get some sort of kit from summit or Jegs?
The pistons for the 408 - Is there anything specific on the rod/piston combination I should know about when putting a 408 together other than that I would need a dish that would work with the "317" heads?
The reason I was thinking about buying a running engine is that all the small stuff is there - pickup, oil pan, coils, intake, throttle body - and I think it would really add up the $$ quick to go the other way - GMPP virgin block, new heads, etc. I have always had better luck with seasoned metal anyway when reconditioned properly. Even at 1600 for a moderate usage LQ9, thats 800 for the block, 300 for the heads, it includes all the parts I would need to hunt and peck for.
One other issue is that I understand from reading here that the LW4 that is currently in my truck has a thicker crank flange that attaches to the flex plate for the automatic. I would need to change that out to a thicker flex plate so I could use something like a Callies Compstar or Eagle (is Eagle still crap? I was told long ago that it was) stroker crank in this engine and mate it properly to the 4L80E.
I would assume I would go for forged, as I may wish to run boost later after I beef up the Automatic.
Any comments and advice are greatly appreciated.
04-03-2009, 12:08 AM
#2
The LQ4 and LQ9 both come with aluminum heads with the exception of the 99 model. The LQ9 has flat top pistons with a stronger connecting rod and the LQ4 has dished pistons(Some LQ4's also got the better rods). But since your talking about building a 408 the stock internals don't matter.
If you are concerned with valvetrain noise then I suggest staying away from the aggressive ramp cams. A Comp XE series with the lower lift and less aggressive ramp rates is much quieter. Pushrod length should be measured after all of your upgrades have been installed for optimum results.
There are plenty of sponsors here that sell pre-packaged 408 rotating assemblies. That would be the best route to take to insure the rods and pistons are a match for your bore and desired stroke. Lots of folks here have had good luck with the Eagle products, so I wouldn't be concerned with the quality.
The later model 6.0L's use a spacer between the crank and flexplate instead of the thicker crank flange. So all you need is the spacer to mate the new engine to your existing tranny.
As far as going forged or not... I don't think anyone makes a cast crank for LSX engines.
If you are concerned with valvetrain noise then I suggest staying away from the aggressive ramp cams. A Comp XE series with the lower lift and less aggressive ramp rates is much quieter. Pushrod length should be measured after all of your upgrades have been installed for optimum results.
There are plenty of sponsors here that sell pre-packaged 408 rotating assemblies. That would be the best route to take to insure the rods and pistons are a match for your bore and desired stroke. Lots of folks here have had good luck with the Eagle products, so I wouldn't be concerned with the quality.
The later model 6.0L's use a spacer between the crank and flexplate instead of the thicker crank flange. So all you need is the spacer to mate the new engine to your existing tranny.
As far as going forged or not... I don't think anyone makes a cast crank for LSX engines.
04-03-2009, 03:08 AM
#3
Launching!
Join Date: Feb 2004
Posts: 260
Likes: 0
Received 0 Likes
on
0 Posts
What sort of power are you after?
The 6.0L engines are capable of giving good power with the stock block. They just need the valvetrain up-graded (better springs and pushrods mainly) along with a decent cam and tune.
The 6.0L engines are capable of giving good power with the stock block. They just need the valvetrain up-graded (better springs and pushrods mainly) along with a decent cam and tune.
04-03-2009, 10:56 AM
#5
The LQ4 and LQ9 both come with aluminum heads with the exception of the 99 model. The LQ9 has flat top pistons with a stronger connecting rod and the LQ4 has dished pistons(Some LQ4's also got the better rods). But since your talking about building a 408 the stock internals don't matter.
If you are concerned with valvetrain noise then I suggest staying away from the aggressive ramp cams. A Comp XE series with the lower lift and less aggressive ramp rates is much quieter. Pushrod length should be measured after all of your upgrades have been installed for optimum results.
There are plenty of sponsors here that sell pre-packaged 408 rotating assemblies. That would be the best route to take to insure the rods and pistons are a match for your bore and desired stroke. Lots of folks here have had good luck with the Eagle products, so I wouldn't be concerned with the quality.
Thanks
04-03-2009, 10:58 AM
#6
Valve springs and pushrods. Okay. Cams are all over the place, as I have seen. Power - well, at least a solid 1hp/ per cubic inch at least. Hopefully more. Solid mid range torque and off the line power. I think the 4L80E in the truck mostly shifts at about 5800 rpm.
04-03-2009, 11:04 AM
#7
Trending Topics
04-03-2009, 11:49 AM
#8
The only other issue I know of is GM had a thicker rear flange up to a certain year on the crankshaft. I have a 2002 and it came with a removable adapter that is needed for the 4L80E. A car flexplate is needed if a 4L60e is used. The extended rear flange may cause some issues but I am not sure. The truck forum may be your best bet.
04-03-2009, 03:36 PM
#9
T
The later model 6.0L's use a spacer between the crank and flexplate instead of the thicker crank flange. So all you need is the spacer to mate the new engine to your existing tranny.
As far as going forged or not... I don't think anyone makes a cast crank for LSX engines.
The later model 6.0L's use a spacer between the crank and flexplate instead of the thicker crank flange. So all you need is the spacer to mate the new engine to your existing tranny.
As far as going forged or not... I don't think anyone makes a cast crank for LSX engines.
The only other issue I know of is GM had a thicker rear flange up to a certain year on the crankshaft. I have a 2002 and it came with a removable adapter that is needed for the 4L80E. A car flexplate is needed if a 4L60e is used. The extended rear flange may cause some issues but I am not sure. The truck forum may be your best bet.
