Ls7 build

Reply Subscribe

Thread Tools

Search this Thread

Jan 28, 2017 | 06:05 PM

badazz81z28

Thread Starter

Racer

Joined: Mar 2012

Posts: 295

Likes: 13

Ls7 build

Does anyone know if replacement LS7 blocks come ready to assemble? If a buddy gave me all the internals to an ls7, can it just assemble it?

Jan 28, 2017 | 08:02 PM

rkj427

Race Director

Joined: Apr 2014

Posts: 15,064

Likes: 4,748

From: Washington Township Michigan

2025 C8 Stingray of the Year Finalist - Unmodified

2024 Corvette of the Year Finalist - Unmodified

2023 C6 of the Year Winner - Unmodified

2020 C6 of the Year Finalist - Unmodified

2019 C6 of Year Finalist (appearance mods)

Blocks typically have cam bearings installed and main caps bolted in place. Rest is usually transferred over or replaced during build.

Jan 28, 2017 | 09:34 PM

Brandon619

Le Mans Master

Joined: Dec 2003

Posts: 5,047

Likes: 252

From: San Diego

Quote:

Originally Posted by rkj427

Blocks typically have cam bearings installed and main caps bolted in place. Rest is usually transferred over or replaced during build.

I agree with rkj427, personally I would not throw old LS7 rotating assembly in a new LS7 or used LS7 block for that matter. The LS7 crank is stout but I would do some forged pistons and nice connecting rods.

Jan 28, 2017 | 11:28 PM

badazz81z28

Thread Starter

Racer

Joined: Mar 2012

Posts: 295

Likes: 13

^^whys that?

Jan 29, 2017 | 12:21 AM

southspeed

Burning Brakes

Joined: May 2004

Posts: 768

Likes: 30

From: Olive Branch MS

I would put a set of replacement forged pistons in it but I wouldn't give up the ti rods. That way you can boost it or spray down the road without much worry.

Jan 29, 2017 | 10:03 AM

badazz81z28

Thread Starter

Racer

Joined: Mar 2012

Posts: 295

Likes: 13

Quote:

Originally Posted by southspeed

I would put a set of replacement forged pistons in it but I wouldn't give up the ti rods. That way you can boost it or spray down the road without much worry.

Would I have to rebalance everything?

Any other inputs on putting the parts in a new block?

Jan 29, 2017 | 12:58 PM

Brandon619

Le Mans Master

Joined: Dec 2003

Posts: 5,047

Likes: 252

From: San Diego

Quote:

Originally Posted by badazz81z28

^^whys that?

Why, because when you put the time, money and effort towards a build I would want it to be fresh. Yes would I use the existing LS7 crank, have that micro polished and balanced. I'm not sure if I would use the factory TI rods depends on budget and I would definitely use some light weight forged pistons. Contact any reputable engine builder and tell them your plans and I'm willing to bet 98% of them would advise on new rods and pistons. Again this is my opinion and I have some experience on building a motor, not great experience but I've spec'd a motor before.

Jan 29, 2017 | 10:55 PM

subfloor@centurytrans

Supporting Vendor

Joined: Feb 2011

Posts: 3,520

Likes: 880

2024 C6 of the Year Finalist - Modified

2020 Corvette of the Year Finalist (track prepared)

2019 C6 of Year Winner (track prepared)

Quote:

Originally Posted by badazz81z28

Does anyone know if replacement LS7 blocks come ready to assemble? If a buddy gave me all the internals to an ls7, can it just assemble it?

The correct answer is - sort of.

Here's exactly what I've done a several times starting off with a new block and used internals:

- buy new stock piston rings, new main and rod bearings as well as new main and rod bolts
- have the rotating assembly measured and checked out because even something coming from a running motor can occasionally have issues
- if the rotating assembly parts all came from the same engine then you could probably get away with not having it balanced, but if even one piston or rod came from somewhere else I'd recommend it
- buy and install a new rear main seal as well as the one for the front timing cover
- start bolting everything together