I have been researching the 05 lq4 bottom end. I have not found some answers to my questions.

1. Is the crank forged?

2. Is the rods in a 05 lq4 strong enough for 450 to 500 horse?

3. Is the lq4 dished pistons cast or hyoer? It appears they are cast.

4. Can a stock bottom end take a 150 shot of juice?

 

1 No it is not forged

2 Yes plenty

3 dished cast

4 No problem

 

Thanks for the good information.

 

4. as long as your tuner is worth a crap...

 

Made a mistake here. The motor is a 01 not a 05. Does this change the answers?

 

05 has the internals of an LQ9...full floating rods vs pressed but under 10:1(dished). The 05 pan is also stronger than previous years but not as important on an iron block. There are some differences in the early (oo-01) crankshafts and iron heads but not sure of specifics. Ditto on the tune from above....maybe someone can confirm the 01 differences

 

As has been stated, the '05 and up have the heavier rods with floating pins and the pistons had coated skirts in the later models as well to help with the CSK noises people have always complained about. Other than that, they were essentially the same. The LQ4 as most already know is rated at 9.4:1 and it's the '99 and '00 models that had the long crank. The long crank models are easy to tell apart from the newer ones at a glance unless someones has changed the heads, due to them having iron heads.
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Difference in crank length.
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4.8L Rods on the left, Standard non-bushed rods in the middle & Bushed LQ9 rods on the right. You cans see how much heavier built the the bushed rods are.
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Gen III pistons starting from the left: 4.8L, standard 5.3L, 5.7, and LQ9 6.0L. The pistons for the LQ4 will have tops like the standard 5.3L. In this photo you can see the coating that was applied to the later model pistons.

 

Thanks for the great information.

 

Do ALL LQ9's have these rods that are on the right?

109615jpg_000000054522.jpg?t=1260125938

 

Yes, the casting number for the LQ9 rods as identified on the side of the cap should be 123/145. The casting number for the 4.8L is 121BW & the 5.3L, 5.7L and the standard LQ4 6.0L used casting number 143. Typical weight of LQ9 rods are around 645 grams, while the standard rods typically weight around 609 grams.