LQ4 or LQ9 how do I know?
LQ4 or LQ9 how do I know? Is there any way to identify them externally? The engine is from a 2004 denali. I have searched but haven't found any solid info. I already have it in a car but I'm curious. Also are 317 heads worth a port and valve job or should I find aftermarket?
No, the only way to tell is the RPO number or by looking at the piston design. LQ4's have a dish, 9's have a flat top. Another trick is to look for the flexplate spacer between the crank and flexplate. 4's will have it, 9's will not. 317's are good heads if you are fine with the compression ratio you have. 243's flow about the same as 317's stock for stock but have smaller chambers so you could bump the c/r up a bit with 243's.
I'm with ryanvv355. The only way I know how to do it is to look at the piston. But there should be some markings on the out side of the block that will let you know. teh 317 heads are the same design as the 243 (ls6/ls2) heads just with a larger cc.
If you do not have access to the Denali, can you at least get the VIN? You can probably call GM and give them the VIN and find out.
If you witnessed it being pulled out of the Denali it is a safe bet it is a 9. However, bear in mind, 9's are priced higher for that extra half compression point and claimed 20hp. So if I paid for a 9 I would like to know it was a 9. Being hard motors to differentiate between, it is not hard for a seller to advertise it as a 9 but be a 4.
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No, the only way to tell is the RPO number or by looking at the piston design. LQ4's have a dish, 9's have a flat top. Another trick is to look for the flexplate spacer between the crank and flexplate. 4's will have it, 9's will not. 317's are good heads if you are fine with the compression ratio you have. 243's flow about the same as 317's stock for stock but have smaller chambers so you could bump the c/r up a bit with 243's.
6.0 LQ 9's came in the 02+ Escalades and 03+ SS Silverado's and some special order 05-07 Classic Silverado's V-MAX, all with 8th digit vin: "N"
6.0 LQ 4'S came in 01+ Denali's, 00+ Truck variant's, and Vans, all with 8th digit vin: "U"
6.0 LQ 4'S came in 01+ Denali's, 00+ Truck variant's, and Vans, all with 8th digit vin: "U"
Ok so I saw the truck it was from and it has no spacer on the flexplate. So I could assume it's a lq9 but the only sure way I still think to tell is to see the piston. I think this is the only way. Thank you for the info from everyone.
It is very simple to tell. The way I have always done it to know without a doubt is pull a spark plug out and bring that cyl to tdc and shine a light in the
cylinder. If you cant see the top of the piston turn the crank a little then use a coat hanger with the end folded over (to make it dull) and feel across the top of the piston if it is flat all the way across it is an LQ9 if you feel it raise up near the edge of the piston its an LQ4. HTH Chris
Final thought: I have checked several motors this way. I have purchased two "lq9 engines" and paid a premium for them. I have found both of them to be lq4's with this method and sent them back. The guys at the yard are always like "woops" but theyre thinking FUCKK howd he know? If it was sold to you as an lq9 dont take any crap you've got a reciept that says you bought an lq9 so you deserve one. Dont let anyone tell you there isnt much difference. Theyre wrong. I pulled a couple apart and the rods are better, the wrist pins are full float, and the pistons are lighter as well as made of better material.
cylinder. If you cant see the top of the piston turn the crank a little then use a coat hanger with the end folded over (to make it dull) and feel across the top of the piston if it is flat all the way across it is an LQ9 if you feel it raise up near the edge of the piston its an LQ4. HTH Chris
Final thought: I have checked several motors this way. I have purchased two "lq9 engines" and paid a premium for them. I have found both of them to be lq4's with this method and sent them back. The guys at the yard are always like "woops" but theyre thinking FUCKK howd he know? If it was sold to you as an lq9 dont take any crap you've got a reciept that says you bought an lq9 so you deserve one. Dont let anyone tell you there isnt much difference. Theyre wrong. I pulled a couple apart and the rods are better, the wrist pins are full float, and the pistons are lighter as well as made of better material.
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This question has been asked so many times, and so many threads has been opened to ask that, including one from me months ago when I got my LQ9, he he.
I am not saying the question is dumb or anything like that, but these 6.0L truck engines are very popular among us (the budget builder), so IMO someone should make a sticky about how to difference them.
Sorry if I am missing that sticky.
And to help with the question, I took off the spark plugs, then with a slim long flat head screw driver I looked for the piston that were higher in the cylinder, then started to feel the piston surface or piston head or whatever (I´m not a tech). In my case I had the chance to try that with both an LQ4 and LQ9, and the difference is very obvious. So if you do that and do not feel the dish, you got a `9
I am not saying the question is dumb or anything like that, but these 6.0L truck engines are very popular among us (the budget builder), so IMO someone should make a sticky about how to difference them.
Sorry if I am missing that sticky.
And to help with the question, I took off the spark plugs, then with a slim long flat head screw driver I looked for the piston that were higher in the cylinder, then started to feel the piston surface or piston head or whatever (I´m not a tech). In my case I had the chance to try that with both an LQ4 and LQ9, and the difference is very obvious. So if you do that and do not feel the dish, you got a `9
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Joined: Oct 2007
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It is very simple to tell. The way I have always done it to know without a doubt is pull a spark plug out and bring that cyl to tdc and shine a light in the
cylinder. If you cant see the top of the piston turn the crank a little then use a coat hanger with the end folded over (to make it dull) and feel across the top of the piston if it is flat all the way across it is an LQ9 if you feel it raise up near the edge of the piston its an LQ4. HTH Chris
Final thought: I have checked several motors this way. I have purchased two "lq9 engines" and paid a premium for them. I have found both of them to be lq4's with this method and sent them back. The guys at the yard are always like "woops" but theyre thinking FUCKK howd he know? If it was sold to you as an lq9 dont take any crap you've got a reciept that says you bought an lq9 so you deserve one. Dont let anyone tell you there isnt much difference. Theyre wrong. I pulled a couple apart and the rods are better, the wrist pins are full float, and the pistons are lighter as well as made of better material.
cylinder. If you cant see the top of the piston turn the crank a little then use a coat hanger with the end folded over (to make it dull) and feel across the top of the piston if it is flat all the way across it is an LQ9 if you feel it raise up near the edge of the piston its an LQ4. HTH Chris
Final thought: I have checked several motors this way. I have purchased two "lq9 engines" and paid a premium for them. I have found both of them to be lq4's with this method and sent them back. The guys at the yard are always like "woops" but theyre thinking FUCKK howd he know? If it was sold to you as an lq9 dont take any crap you've got a reciept that says you bought an lq9 so you deserve one. Dont let anyone tell you there isnt much difference. Theyre wrong. I pulled a couple apart and the rods are better, the wrist pins are full float, and the pistons are lighter as well as made of better material.
Way to go.
I bought as a 9. I pd $1600.00 for a complete engine trans. acc. harness ex. man. y pipe a pedal for dbw. I'm not worried about it a whole lot as far as getting taken. I'm more concerned about compression for future mods. Thank you everybody for info. There should be an engine I.D. sticky simply to state check piston tops for a 4 or a 9 and that is that. imo.
Feel free to have it stickied. I have posted that info a few times but it keeps getting lost. IMO that is the only way to know for sure. Vehicles have so many running changes and configurations you just cannot trust external cues to be 100% sure. Chris
I bought as a 9. I pd $1600.00 for a complete engine trans. acc. harness ex. man. y pipe a pedal for dbw. I'm not worried about it a whole lot as far as getting taken. I'm more concerned about compression for future mods. Thank you everybody for info. There should be an engine I.D. sticky simply to state check piston tops for a 4 or a 9 and that is that. imo.
Get me the VIN Derivative and I will give you the info
FYI: 99-06 Trucks, Vans & SUV
4.3L, VIN X or W(03+) (8th digit)
6.0L, VIN U (8th digit), (LQ4) Trucks, Vans and Denali
6.0L, VIN N (8th digit) (LQ9) Escalades & SS Silverado
4.8L, VIN V (8th digit)
5.3L, VIN T (8th digit, opt LM7)
5.3L, VIN Z (8th digit, opt L59)
5.3L, VIN B (8th digit, opt L33 05+ HO aluminum and iron block with 243/799 heads)
FYI: 07+ Trucks
classic body style, 6.0L, VIN U (8th digit, opt LQ4), natural gas and gasoline
classic body style, 6.0L, VIN N (8th digit, opt LQ9)
classic body style, 4.8L (VIN V, 8th digit, opt LR4)
classic body style, 5.3L, VIN T (8th digit, opt LM7)
classic body style, 5.3L, VIN Z (8th digit, opt L59)
classic body style, 5.3L, VIN B (8th digit, opt L33)
classic body style, 4.3L (VIN X, 8th digit, opt LU3)
new body style, 5.3L, (VIN 0, 8th digit, opt LMG)
new body style, 5.3L, (VIN J, 8th digit, opt LY5)
new body style, 5.3L, (VIN 3, 8th digit, opt LC9)
new body style, 5.3L, (VIN M, 8th digit, opt LH6)
new body style, 6.0L, (VIN Y, 8th digit, opt L76)
new body style, 4.3L, (VIN X, 8th digit, opt LU3)
new body style, 4.8L, (VIN C, 8th digit, opt LY2)
FYI:5.3L: 2003-4 GMC Truck Envoy XL, 2003-4 Isuzu Ascender , 2003-4 Chevy TrailBlazer EXT (all with VIN "P", 8th digit) & 05-06 (all with VIN "M", 8th digit)
4.3L, VIN X or W(03+) (8th digit)
6.0L, VIN U (8th digit), (LQ4) Trucks, Vans and Denali
6.0L, VIN N (8th digit) (LQ9) Escalades & SS Silverado
4.8L, VIN V (8th digit)
5.3L, VIN T (8th digit, opt LM7)
5.3L, VIN Z (8th digit, opt L59)
5.3L, VIN B (8th digit, opt L33 05+ HO aluminum and iron block with 243/799 heads)
FYI: 07+ Trucks
classic body style, 6.0L, VIN U (8th digit, opt LQ4), natural gas and gasoline
classic body style, 6.0L, VIN N (8th digit, opt LQ9)
classic body style, 4.8L (VIN V, 8th digit, opt LR4)
classic body style, 5.3L, VIN T (8th digit, opt LM7)
classic body style, 5.3L, VIN Z (8th digit, opt L59)
classic body style, 5.3L, VIN B (8th digit, opt L33)
classic body style, 4.3L (VIN X, 8th digit, opt LU3)
new body style, 5.3L, (VIN 0, 8th digit, opt LMG)
new body style, 5.3L, (VIN J, 8th digit, opt LY5)
new body style, 5.3L, (VIN 3, 8th digit, opt LC9)
new body style, 5.3L, (VIN M, 8th digit, opt LH6)
new body style, 6.0L, (VIN Y, 8th digit, opt L76)
new body style, 4.3L, (VIN X, 8th digit, opt LU3)
new body style, 4.8L, (VIN C, 8th digit, opt LY2)
FYI:5.3L: 2003-4 GMC Truck Envoy XL, 2003-4 Isuzu Ascender , 2003-4 Chevy TrailBlazer EXT (all with VIN "P", 8th digit) & 05-06 (all with VIN "M", 8th digit)
Last edited by BORN2FLY; May 11, 2009 at 09:26 PM.
