lamboworld

I figured that I would start a fresh thread about my rebuild project that I plan to do in Oct or Nov. I am currently around 600whp N/A and about 725whp on Nitrous. I want to be able to turn up my Nitrous shot to around 300 in 1/2 mile events so I have decided to have my LS7 rebuilt. I only have 8,500 miles on my 2011 Z06, so it probably isn't necessary at this point, but I figured that it is better to do it before I break something.

Here are my plans:
Reuse TI Rods and resize rod to accept ARP 2000 Rod Bolts.
Reuse OEM Crank - Polish and Chamfer.
Bore/Hone block with torque plates, square deck surfaces, line hone mains, debur block.
Custom Wiseco pistons to keep compression at 11.5 with coated skirts
Balance and Assemble Short Block
ARP Main studs
King XP Main Bearings
King Rod Bearings
Durabond HP cam Bearings

I will probably switch my OEM balancer to a IW balancer and switch my lifters to GM High Speed lifters. I plan to reuse my oil pump, and rockers.

My heads were rebuilt by AI last year and I am using ARP bolts for my heads. They only have about 4,000 miles on them, so they should be good to go.

1. Am I missing anything?
2. What oil should I use to break-in my engine and what is the break-in procedure.
3. I know that I could resleeve and switch the rod bushings, but I have decided against it.

Am I missing anything?


I plan to keep this car for a while and I am hoping to get a lot of miles with this rebuild.

AzDave47

Others will pipe in but around 800 HP the cylinder liners need to be replaced with thicker, stronger liners. Maybe the 300 shot will be OK without them.

User Omega

LMR and LME both have put these cars over 900whp on nitrous with stock liners. On that much nitrous you will beat the stock rod bushings to death pretty quick. If you stick with a 200 you they will last longer but ultimately that will likely be your weakest link if it is properly tuned and set up. 1/2 mile of nitrous is very hard on things.

gameover4

id say if your in this deep, worth to spend the extra money and build motor to hold up to the events you will be putting it in

lamboworld

Maybe I am missing something, but I haven't seen one report with a failed LS7 rod other than Jason from Katech saying this. I spoke to LME about the rod bushing and they saw no need to change them.

I am also not sure why Nitrous at 850 to 900whp would be harder on the engine than a turbo LS7 at 850 or 900whp. The good thing with Nitrous is that is it only used for small intervals of time and it is supplemented with lots of fuel and timing pulled to reduce detonation.

Michael_D

Do yourself a favor and speak directly to Erik Koenig. You're getting bad advise.

https://www.corvetteforum.com/forums...roduction.html

lamboworld

Michael_D. I guess that an additional $800 to ensure that the bushing doesn't fail is a small price to pay.

User Omega

I have never heard of a rod failure either. I am only speaking to the bushing. The car was on a 300 shot for quite a few passes before the issue was discovered.

Having been down this road and talked to several companies I would hope that I am not giving you bad advice but hey, at the end of the day I do not do this for a living. I do it for fun and can only go off of what I've seen and been told.

That being said, I think you should follow Micheal's advice and pick a company and trust them to tell you what should and should not be done. I have an LMR forged 440 setup in my car.

Michael_D

I was not only referring to rod work.... What's the point of pulling and going through the engine for the reasons you have stated, and not doing it the way it should be done?

lamboworld

I am starting to question whether it is worth it to rebuild my LS7. Maybe I should just buy a shortblock from HPR and just sell my LS7 shortblock. My LS7 only has 8,500 miles on it.

Michael_D

Buying a purpose built short block is always an option worth considering. Especially after you get the bug to go faster. It's unlikely you will call it "fast enough" once you've got the bug. 300 hp shot now, 600 later......

You may have problems selling yours though. People shy away from buying a used engine that's been sprayed. I don't touch them, ever. Too much risk. I would not hit it with more than what you are now, if you intend to peddle it. 125 hit is pretty mellow, and not all that scary to a potential buyer. But if you up it, you will scare buyers away.

TXGS507

My C5Z only had a 414 Stroker w a 250 shot... I did 3 1/2 mi roll race events, multiple hwy pulls and over that time decided to go w some different heads... glad I did, you could see where the head was starting to lift from the Nitrous.. I'd just keep an eye on it...

TXGS507

It was a sweet set up... I'll bet yours will be a blast!!!

newchevyman

Is there a reason you're using ARP head bolts instead of studs?

jayyyw

What do you mean by chamfer the crank? Knife-edge?

lamboworld

Chamfering the oil holes on the crank to allow for better oiling.

Michael_D

Probably journal oil supply holes.....

lamboworld

I am still debating on whether to do this or not.

The cost of starting with a new sleeved block vs rebuilding my existing LS7 isn't actually that much difference, especially if I sell my shortblock. The only real reason to rebuild the LS7 is to be able to reuse the Rods, but otherwise I see no advantage. However, no one has been able to answer how much does a lighter rotating assemble actually impact acceleration. Going from the TI rods to a steel rod adds about 200 grams for each rod and you probably reduce 20 grams per piston and maybe an aftermarket crank reduces weight, but I am not sure if that matters. I don't really want to give up the ability to rev this engine to 7000 quickly, so I would love for someone to chime in with the real impact of increasing rod weight.

I plan to keep this car for a while so I don't mind spending the money for some reliability and to be able to turn up the juice.

Michael_D

When you go from the Ti rod, to a heavier I or H beam steel rod, you will also need to add heavy metal (Mallory) to the crankshaft counterweights. Mallory is expensive. Keep that in the mix for cost adders. Most guys just eat the bullet and go with a different crank. And if you are going to do that, well then....might as well add stroke.....and while you are adding stroke, might as well make the cylinders bigger....and while doing that, might as well, might as well, might as well.....

A steel rod will not prevent the engine to rev up quickly or rob power at a level you'd probably notice......

The most endearing feature the lighter rod has, at least to me anyway, is reduced cylinder side wall thrust. This engine has a horrendous rod angle, to begin with, so adding unnecessary rod/piston weight only exacerbates issues associated with it.

lamboworld

Thanks for the explanation.

Long story short:
HPR 454 with forged crank, rods and pistons for about 7k
Rebuild LS7, reusing rods (bushed) and crank for about 5k

I suspect that I can probably sell my LS7 for more than the cost difference.

If I go with a 454 and reuse my LS7 heads will I notice much difference with how this engined revs vs. my LS7. If not, then I see no reason to rebuild my LS7.