Generation IV Internal Engine - LS7 Internal questions




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jnebraska
01-01-2012, 07:40 PM
Happy New Year all,

Long story that I'll keep short, I just picked up a LS7 long block for cheap....with a 1 bent rod. I've occasionally seen used factory rods for sale on eBay. There's nothing there now.

Not trying to keep this on the cheap... what would any of you recommend for a complete rotating assembly to replace the stock pieces? What shop/builder would you trust on the East Coast, Virginia's, Georgia and Carolina's area to install the assembly?

Intentions for this engine are to run it carburated, street/strip possibly with a small shot of speed gas. Thanks in advance for the help.
V/R
Joel


redbird555
01-01-2012, 08:06 PM
well ls7 rods are titanium so not only are they really light but incredibly strong. I'd much rather have a complete set of those over a set of forged ones. why not just call gm or scoggin dickey and get a replacement rod? it would be much cheaper than a new assembly and ls7 rods have been known to take well over 600hp

WS6sleeper
01-01-2012, 08:13 PM
Titanium? wow I never knew that. Why do most guys go forged then? (when going boost)


DietCoke
01-01-2012, 11:02 PM
well ls7 rods are titanium so not only are they really light but incredibly strong. I'd much rather have a complete set of those over a set of forged ones. why not just call gm or scoggin dickey and get a replacement rod? it would be much cheaper than a new assembly and ls7 rods have been known to take well over 600hp


Ls7 ti rods are barely worth their weight in scrap, much less in any sort of purpose-built engine. First thing that should be yanked out, they're junk.

jnebraska
01-02-2012, 01:13 PM
Ls7 ti rods are barely worth their weight in scrap, much less in any sort of purpose-built engine. First thing that should be yanked out, they're junk.

Back to my original note...if the stock stuff is junk, WHAT WORKS???? and who can be trusted to do the work on East Coast?

What makes the stock titanium rods junk? As far as I can see, their C to C length is different then aftermarket rods being offered.

JC

jnebraska
01-02-2012, 09:55 PM
Was hoping somebody would chime in from/for Virginia Speed. Anyone?

May have to stop by their shop the next time I'm up at Damneck?
JC

Whistler
01-03-2012, 10:22 AM
Exactly. The length is shorter than other LS rods due to GM not wanting as short a compression height typical with 4" strokes in these engines.
So you'll need new pistons to go with the rods you'll be buying.

There are many choices out there.. I've had great luck both With Compstar, Manley and K1 on the budget end of things.

Back to my original note...if the stock stuff is junk, WHAT WORKS???? and who can be trusted to do the work on East Coast?

What makes the stock titanium rods junk? As far as I can see, their C to C length is different then aftermarket rods being offered.

JC

redbird555
01-03-2012, 12:26 PM
Ls7 ti rods are barely worth their weight in scrap, much less in any sort of purpose-built engine. First thing that should be yanked out, they're junk.
not saying your wrong but can you post up some links to where people have had issues. I have seen multiple builds of them supporting well over 600hp and the stock redline on an ls7 in 7k so idk that I would call them junk. if the op isnt planning on going to 1000 hp and building a race motor i think i'd keep the titanium lightweight rods and save a bit of money. if the motor is going to the sky hp limits and 8000 rpms then i might look to upgrade just my .02

jnebraska
01-03-2012, 10:01 PM
not saying your wrong but can you post up some links to where people have had issues. I have seen multiple builds of them supporting well over 600hp and the stock redline on an ls7 in 7k so idk that I would call them junk. if the op isnt planning on going to 1000 hp and building a race motor i think i'd keep the titanium lightweight rods and save a bit of money. if the motor is going to the sky hp limits and 8000 rpms then i might look to upgrade just my .02

Thanks Redbird and Whistler. Both gave sound advice. I'm not opposed to putting a new piston in the engine either since it could see some gas. Since I'd be darn happy to be in the 600HP range, maybe the stock rods will live form me. It's not an "all out/in" engine, I think they'll be fine if I can find a replacement rod. The local machine shop has said they can straighten the bad rod....not going to trust that. Would not mind finding extra CI's with a stroker kit if I can find a good shop to trust. Can I make 600HP w/stock heads?
Joel C

flash911
01-04-2012, 06:51 PM
not saying your wrong but can you post up some links to where people have had issues. I have seen multiple builds of them supporting well over 600hp and the stock redline on an ls7 in 7k so idk that I would call them junk. if the op isnt planning on going to 1000 hp and building a race motor i think i'd keep the titanium lightweight rods and save a bit of money. if the motor is going to the sky hp limits and 8000 rpms then i might look to upgrade just my .02

There's a bad mofo, Ron Schwartz on Pro-touring.com that runs an LS7 in an early mustang on the road course. Earlier this year he broke a valve, stressed the piston and broke a Ti rod which busted a hole in the block. Yard sale, I'm telling you.

My rookie .02...Ti are lightweight, great for street cars and can hold 600 HP. If you're gonna beat on it be prepared to rebuild. Me, I put Crower billets in my LS7...:drive:

alcohol altered
01-05-2012, 05:47 PM
GM makes a stage 3 cam designed for the LS7 that makes 600 HP at the flywheel. Im building and LS7 and going with the stage 3 cam. It's a bit pricey @ a little over $400 but it sounds NASTY.

COPO9560
01-05-2012, 07:42 PM
If you have a bent rod, check the block very closely. LS7 sleeves are kind of thin and whatever bent the rod could have also damaged the sleeve.

Lots of sponsors on here that can sell you a complete balanced rotating assembly. If you only need one rod and everything else checks out OK, that would be your least expensive option coupled with a new cam and valve springs.

jnebraska
01-05-2012, 10:38 PM
That's the first I'd heard about the sleeves being thin. I will have that checked....looking at Virginia Speed more and more.
JC

S10xGN
01-06-2012, 09:03 PM
That's the first I'd heard about the sleeves being thin. I will have that checked....looking at Virginia Speed more and more.
JC

I've not heard anything about the sleeve "thickness", you can look at Darton's site and see the difference in the metallurgy between their sleeves and the factory sleeves. The alloy used is much weaker in factory sleeves...

jnebraska
01-06-2012, 09:19 PM
GM makes a stage 3 cam designed for the LS7 that makes 600 HP at the flywheel. Im building and LS7 and going with the stage 3 cam. It's a bit pricey @ a little over $400 but it sounds NASTY.

Thanks Altered...I'll look into that as I plan on a cam and spring change. I need to get the rotating assy right first!
JC

Pumba
01-07-2012, 01:29 PM
Back to my original note...if the stock stuff is junk, WHAT WORKS???? and who can be trusted to do the work on East Coast?

What makes the stock titanium rods junk? As far as I can see, their C to C length is different then aftermarket rods being offered.

JC


The best thing to do with stock LS7 rods is to send them to KATECH and have them install a one-piece bushing in the small end and their H11 bolts. This is a standard upgrade that KATECH does.

Next, I would recommend that you order a set of 4.130-inch MAHLE pistons. Part number LS7181130F03. These pistons are designed to work with the Titanium rods. They will yield approximately 11.4:1 compression ratio with 70 CC LS7 heads.

After that, I would have your rotating assembly internally balanced and put an ATI damper on the front of the motor. Part number 918620.

Good luck with your new motor.

-

jnebraska
01-08-2012, 10:30 PM
The best thing to do with stock LS7 rods is to send them to KATECH and have them install a one-piece bushing in the small end and their H11 bolts. This is a standard upgrade that KATECH does.

Next, I would recommend that you order a set of 4.130-inch MAHLE pistons. Part number LS7181130F03. These pistons are designed to work with the Titanium rods. They will yield approximately 11.4:1 compression ratio with 70 CC LS7 heads.

After that, I would have your rotating assembly internally balanced and put an ATI damper on the front of the motor. Part number 918620.

Good luck with your new motor.

-


Thanks Pumba....Do you feel that compression ratio is still safe with Pump Gas Premium?
Joel C