Boring out LS1

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Oct 19, 2024 | 06:30 PM

#21

helga203

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Quote:

Originally Posted by jamed30

Yeah I understand that I just couldn’t find what was the culprit when I had it apart before I took it over to the machine shop. Just seemed odd I guess oil pressure was fine also.

I hear you. Cant sleep tell you find the smoking gun.

Oct 20, 2024 | 03:21 AM

#22

RonSSNova

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From: Portland OR

Yeah, that bearing looks like some kind of grit went through it.
How’s the crank look? And the rest of the bearings?

Good choice just honing .005”.

Oct 20, 2024 | 12:35 PM

#23

jamed30

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Quote:

Originally Posted by RonSSNova

Yeah, that bearing looks like some kind of grit went through it.
How’s the crank look? And the rest of the bearings?

Good choice just honing .005”.

Rod bearings looked fine but #4 had some "chips" coming off of it but never spun. All the mains looked fine & crank looked good too. Ran my finger on the crank where the thrust bearing goes and felt smooth with zero blemishes & sides looked fine as well. They're going to see if the crank is out of whack though but they seem to think something wasn't cleaned good enough and just slowly ate my bearings. I always had some crap on my metal plug changing the oil when I got it rebuilt after busting a ringland 3 years ago.

Oct 20, 2024 | 09:07 PM

#24

93Polo

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From: Guinness Its whats for B'fast JAWGA

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Not cleaning the parts or attached oil coolers, oil lines etc coould get debris in the engine.

You maybe fine with polishing the crank, near berings and maybe a fresh hone on the cylinders.

Oct 27, 2024 | 10:53 PM

#25

Mc556

Burning Brakes

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As has been said you can’t go .20 over on a LS 1
The liners are thin and can’t be bored out they can only be honed.

Oct 28, 2024 | 12:02 PM

#26

helga203

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Quote:

Originally Posted by 93Polo

Not cleaning the parts or attached oil coolers, oil lines etc coould get debris in the engine.

You maybe fine with polishing the crank, near berings and maybe a fresh hone on the cylinders.

You got it, looks like there was some kind of debri
left on crank or bearing and when cranked down damaged the bearing.

Oct 29, 2024 | 08:16 AM

#27

cdee63

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From: In the woods

2024 C5of the Year Finalist - Unmodified

I have been researching this as well. As mentioned one cannot bore out the LS1 very much. It is my understanding the absolute max overbore would be 3.905" with 3.903" being the most common size. I am also pretty sure there are no parts interchangeable between old and new small blocks. IIRC lifters and con rod bearings were interchangeable but not sure about that.

Oct 29, 2024 | 09:15 AM

#28

Gordy M

Melting Slicks

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From: Northville, MI

Have you check the lifters, they are been know to break down and cause bearing and crank damage.

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Oct 29, 2024 | 10:11 AM

#29

93Polo

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From: Guinness Its whats for B'fast JAWGA

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Quote:

Originally Posted by cdee63

Some blocks can go 3.910. 3.907 is pretty common. You may want to have the block sonic checked especially an earlier block. I'd check with a machinist who regularly works with aluminum LS blocks.

https://ls1tech.com/forums/generatio...ls1-block.html

Oct 29, 2024 | 10:22 AM

#30

Supercharged111

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From: Da U.P.

The newer updated blocks can take more of a bore than the early blocks, but neither will take a .020" overbore. That said, reman places do it every day. But I'd never run one.

Oct 29, 2024 | 10:27 AM

#31

93Polo

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From: Guinness Its whats for B'fast JAWGA

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Quote:

Originally Posted by helga203

You got it, looks like there was some kind of debri
left on crank or bearing and when cranked down damaged the bearing.

A friend worked for an engine builder locally who built LS motors for the ASA series. He did a basic hone, with new rings and bearings on the side for another friend. We went over to his house for the final cleaning and assembly. A wide selection of brushes was used and then blown out with air. Prep is critical.

Racers also need to replace or ultrasonic clean lines and oil coolers if they send debris into the oil circuit.

Oct 31, 2024 | 08:41 AM

#32

cdee63

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From: In the woods

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Quote:

Originally Posted by 93Polo

If it is a sleeved block wouldn't the sleeve itself be the limiting factor as far as bore diameter vs the block?

Oct 31, 2024 | 09:34 AM

#33

93Polo

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From: Guinness Its whats for B'fast JAWGA

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I understood they could check the thickness of the sleeve.

Oct 31, 2024 | 01:06 PM

#34

cdee63

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I understand that and it is my point. It was mentioned it is the block that dictates the bore size, it is not. It is the sleeve.

Oct 31, 2024 | 03:31 PM

#35

93Polo

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From: Guinness Its whats for B'fast JAWGA

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I think you misunderstood the point of my post, inside the "LS1" blocks there are multiple versions identified by casting number with varying sleeve thickness and accepted max bore.

Further even inside the same casting number, the sleeve thickness can vary. People have taken the 97/98 blocks out further than what was the published max without issue which isn't to say all blocks or sleeves inside the block can.

Oct 31, 2024 | 06:38 PM

#36

cdee63

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From: In the woods

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^^ Why I ask questions. This detail I did not know, that there were different sleeves used in the LS1 block, makes sense. Thanks for the clarification. I imagine most cite 3.905" as a max that is safe in all variations of sleeves.

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