Hello gentleman. My compression check turned up some bad stuff last night and it turns out I have to pull the Stock Ls7 out of my 2008 Z06 because I have Low compression on number 1 cylinder (150). The engine runs fine, just uses some oil. The car has 90k on it and the only engine mods thus far is a Borla Catback.

I am looking to spend around 8 grand on parts to rebuild this thing. Most of the work I will complete myself to save on cash. I am thinking about having TPIS do the complete short block for me. They are a 4 hour drive and have a very good LS build reputation. I was quoted 2700 from them. Thats all the machine work, new rod bolts and forged pistons of my choice and complete assembly.

My other choice is to trust a local machine shop to hone the block .005 and assemble the short block here in my shop. If I took this route I would need some advice. I have rebuilt lots of SBC engines but never a LS engine. Not a whole lot has changed between the two, But there are some things that concern me about the LS7 block. From what I understand .005 to .010 is the most you want to take out of the bore. My engine runs fine so Im sure the bores are ok. I am not 100% sure on zero decking the LS7 block. Is it something I should have done? How about line honing when using ARP main studs.

For the 8 grand limit I have I think I should beable to get some tasteful mods to keep the car naturally aspirated and still make some good HP. My plans are Forged pistons, cam, WCCH stg2 heads, Lt headers/X pipe and a CAI. There is a huge selection of cams out there. My goal is to have a well street mannered, baaad sounding ls7 that makes some nice power through out the whole power band. If you guys have some videos of what your car sounds like with your cam choice, please post it.

I would appreciate it if you guys could share your LS7 engine build advice and recommendations with me. This is my first LS build and I want it done right the first time. I also want to get the biggest bang for my buck ofcourse.

Thanks in advance gentleman!

 

No suggestions guys?

 

Don't laugh, but I went on Amazon and bought 5 books on building LS motors. It tells you what interchanges, what works with what, etc.

I use to travel 150K air miles a year, so I would read one on each trip.....

 

I wouldn't laugh at that! knowledge is power and reading is a very good way to obtain knowledge.

 

I'm not keen on honing .005. I'd suggest getting the short block as you suggested and go ahead and bore it .020 just to get it true. Get the rings and pistons to match and make sure they balance the rotating assembly

Given what you have said so far, I think 2700 for a short block is a good start. Especially if they are going to bore it and check line bore etc.

replace the oil cooler. You can rarely get them properly clean again. Pull the sump tank, disassemble and clean it well along with oil lines

 

The engine wasnt blown up. It runs fine, its just wore out and has above the 10% limit between cylinders on compression and uses a little oil.

I imagine the stock bore is fine. I dont have it out for inspection yet.

 

90,000 miles, they'll be oval'd out and just enough scaring that 005 wont get it cleaned up as good as a new rebuild should be. are you considering running the same pistons? Consider the wear on the cylinders. It will be at least that same amount again on the pistons. Unless your findings fool me, I would reconsider your choices. When you check your pistons, check them at the bottom of the skirts. I would be surprised if you find the clearance between the cylinder at its widest location and the piston at the bottom of the skirt to be near .010 then .005 hone and your into piston skirt slap range and still out of round.
jmho

I don't know what the factory spec for clearance on the ls7 is. The above info is based on most of my other builds. .002 to .004 is a typical rebuild clearance and .008 is wear limit as a general rule.
Not being a smart A**, just trying to provide you with my best opinion. Please let us know what you find out when you pull the heads

 

Ok will do. I appreciate the advice. I do plan on going back with forged pistons.

 

So what did you end up doing?