I know I know, use the search, but I did that. Obviously the LQ9 has flat tops and the LQ4 is dish. However, I cannot see well enough into any of the spark plug holes to tell if the motor is an LQ9 or LQ4. The only thing I can see is that there is a number 0 stamped into the top of the piston as thought it was put there with a dot matrix printer. Now, the motor I'm told came out of a '04 GMC Denali which means it should be an LQ4 I know, but looking at the side of the cylinder head where they stamp the last 10 digits of the VIN in, I see the letter N, which I thought should mean it's an LQ9. Also I took the oil pan off and windage tray to peek inside the block to do a general once over to make sure everything is fine. I then come to find that this motor has Dimpled rods. Do dimpled connecting rods only come on LQ9's? Also, is there a way to identify from the bottom of the piston any casting marks or numbers that could tell me if it was a dish or flattop piston? I don't feel like yanking a head off to look but I need to know the compression of the motor so I can intelligently select a cam.

 

I think the only way you are going to know for sure is to pull the heads. From what I have seen if the engine was from an '04 then like you thought it should be an LQ4. If it was from a Denali manufactured in '04 for the 2005 model year however, it could be an LQ9.

 

didn't '04 and up all LQ4s and LQ9s had the same connecting rods? if so whatever you see stamped on the rod isn't going to help you determine what it is. might just need to pull the heads.

 

It's time for me to just buy a damned borescope isn't it?

 

get a bright flash light, and look down the spark plug hole . . . . .

 

GIMME THE VIN NUMBERS YOU HAVE

 

Man, thank GOD you said that Shannon! It should never be tghis difficult for someone to find out. Guys, here's a word of advice to always remember. You engine and transmissions RPO code will always be tagged to your vin. So when in doubt....ask someone to decode your VIN #

 

How does he have the VIN from the truck it came from? Do they really stamp it on the cylinder head? That's the first I've ever heard of it.


FWIW - My 6.0 said it came from a 2500 Silverado, but the paperwork that showed up with it save vin code N. I pulled the oil pan to look at the rods and was convinced that I had gotten an LQ9. Later when I finally took the motor apart, I found out that I had the dished pistons. The people who sell these motors don't always know what they are talking about.

 

Casting number on the block....tells all.

 

man if you can see a "0" on top of the piston you can surly tell if it is dished or or not? unless it is a really big number?