Blown 5.3, Looking for 6.0, which ones fit?

[mattt]

I may have got lucky... I found a guy who has an LQ9 he tore down. He is selling me the heads for $100 and says he has the bottom end / short block for $550. He will even drop it off at my house.

I'm going to go to his house on Saturday and take a look at the block. It's got the oil pan, heads, and intake off.

He mentioned the block was acting up / needs new bearings. He said he didn't believe he spun any bearings. However, was tearing it down to rebuild.

I'm a little worried about the cam bearings. Any way I can check those while it's torn down? How do you check them? Will the cam wiggle or anything? Anything else I should check?

Pictures of the motor:

I did a quick search and found this thread with pictures of a cam with one of the inner bearings stuck to it. https://www.yellowbullet.com/threads/cam-bearing-came-out-when-removing-cam-6-0l-ls.2626433/


If you spend some time and search the web for Chevy LS Cam Bearing Failure, you will come up with lots of threads and pics to guide you.

To really check the block right, the cam has to be out. The cam bearing bores in the block should not have any ridge or scarring. I have a picture somewhere that shows a block with a cam bearing bore, hole with a fat ridge worn into it from bearing spin.

One thing you can tell right off in the picture you posted; This engine has been opened up and toy'd with at some point. Head studs are not factory. The factory uses TTY head bolts. I'd ask for further info on what he means by "the block was acting up." Sounds a bit off.

 

[Matthew Jeschke]

I did a quick search and found this thread with pictures of a cam with one of the inner bearings stuck to it. https://www.yellowbullet.com/threads/cam-bearing-came-out-when-removing-cam-6-0l-ls.2626433/


If you spend some time and search the web for Chevy LS Cam Bearing Failure, you will come up with lots of threads and pics to guide you.

To really check the block right, the cam has to be out. The cam bearing bores in the block should not have any ridge or scarring. I have a picture somewhere that shows a block with a cam bearing bore, hole with a fat ridge worn into it from bearing spin.

One thing you can tell right off in the picture you posted; This engine has been opened up and toy'd with at some point. Head studs are not factory. The factory uses TTY head bolts. I'd ask for further info on what he means by "the block was acting up." Sounds a bit off.

For sure, partly why I want to buy heads tomorrow and ask him more questions. He said I can meet him at his work to buy the heads. I have a flat metal and feeler gauges to check surface of heads. hopefully they aren't cracked or anything. He wanted 100$ for them which is super cheap.

I will ask him more questions then... then he said saturday to come by his house, he will be off work and check out the engine.

I noticed the studs as well... gr8 advice on the cam. I may ask he pull the cam out.

I also bought a bore gauge hopefully it will reach all the journals in the block to check their roundness and size for the cam. plan to check the engine... would be nice of he let me tear it down there and measure everything up.

Sent from my SM-A505U using Tapatalk

 

[mattt]

For sure, partly why I want to buy heads tomorrow and ask him more questions. He said I can meet him at his work to buy the heads. I have a flat metal and feeler gauges to check surface of heads. hopefully they aren't cracked or anything. He wanted 100$ for them which is super cheap.

I will ask him more questions then... then he said saturday to come by his house, he will be off work and check out the engine.

I noticed the studs as well... gr8 advice on the cam. I may ask he pull the cam out.

I also bought a bore gauge hopefully it will reach all the journals in the block to check their roundness and size for the cam. plan to check the engine... would be nice of he let me tear it down there and measure everything up.

Sent from my SM-A505U using Tapatalk

317 heads which is what all 6.0s come with are pretty cheap these days. So many people remove them and swap to a 243/799 head for a compression bump on a factory 6.0. If you're after even higher compression, then the 862/706 heads from a 5.3 are the next best bet. The lq4 and lq9 both use the same cylinder head, casting 317, which have a pretty large combustion chamber. Since the heads are off already, I'd have them gone thru(including a surface cut), checked and cleaned up prior to reinstallation.

 

[Matthew Jeschke]

I snagged a book, "How to rebuild GM LS Series engines"

I hope it has all the machine shop specs / dimensions. Torque specs are nice too. But I want a list of bore sizes, tolerances, etc.

Especially before I go look at the block. Curious where might I find the bore specs and tolerances otherwise?

Sent from my SM-A505U using Tapatalk

 

[Tonyrodz]

I snagged a book, "How to rebuild GM LS Series engines"

I hope it has all the machine shop specs / dimensions. Torque specs are nice too. But I want a list of bore sizes, tolerances, etc.

Especially before I go look at the block. Curious where might I find the bore specs and tolerances otherwise?

Sent from my SM-A505U using Tapatalk

I think @mikeyss might know where you could find them. Iirc he was a GM tech at one time.

 

[mikeyss]

I think @mikeyss might know where you could find them. Iirc he was a GM tech at one time.

Most if the specs came from gm direct. I know alldata is another good place for specs. What sort of specs are you looking for?

 

[Tonyrodz]

Most if the specs came from gm direct. I know alldata is another good place for specs. What sort of specs are you looking for?

I snagged a book, "How to rebuild GM LS Series engines"

I hope it has all the machine shop specs / dimensions. Torque specs are nice too. But I want a list of bore sizes, tolerances, etc.

Especially before I go look at the block. Curious where might I find the bore specs and tolerances otherwise?

Sent from my SM-A505U using Tapatalk

 

[Matthew Jeschke]

I have all data can find lots of specs justbbn not the cam bearing specs? Probably I am missing them. Is really tricky to find stuff on All data :/

Sent from my SM-A505U using Tapatalk

 

[mattt]

https://help.summitracing.com/app/a...5/~/i-know-my-vin.-which-ls-engine-do-i-have?

Click the RPO code for each individual engine and it gives specific info on that particular engine. If you want to see the 1st design and 2nd design cam bearing bore dimensions, click on LQ9 for example and it has the bore sizes there.

The few that I have seen, you don't need to measure precisely to see if the cam bores are toasted. It is very obvious to the naked eye. One I saw had a ridge of about .080" worn in the block where the cam bearing was installed from the cam bearing spinning. The other link I posted had a picture of a cam with the cam bearing toasted and stuck to the cam itself. That is what I'd be looking for, first and foremost.

 

[iamdub]

Richard Holdener did a 799 vs 706 comparison on a 6.0 with a comp 459 cam. 706s are up 12 tq and 799s have 9 hp above like 4500 so I'd take the tq over the hp in a heavy tahoe.

You will pay more for an lq9 because of the mystery factor, it's just a 6.0 with different parts. If you are doing a true rebuild you're putting whatever parts you want in it anyway dont pay extra for just a rpo designation.

I agree to both!