Texas Speed & Performance LT1 Engine Tear Down!
 

We have been busy yesterday and today tearing down one of our 6.2L LT1's! We have one on the dyno engine stand, ready to be bolted into place. We have another that we have torn down to a bare block. We have been taking various measurements as we tear it down, and we are already working on some prototype camshafts to test on the dyno. As you will see in some of the new pictures, the factory pistons have a dome on the intake side. So, it is going to further restrict the piston-to-valve clearance for larger camshafts. VVT cannot be disabled, but AFM can. You honestly would not want to disable VVT anyways because it gives you the best of both worlds! You can advance a cam in the lower RPM's for better low-end power and retard the cam in the upper RPM's for better top-end power. We have seen excellent results with our VVT line of cams for the L99 2010+ Camaro SS, so we expect the same great results! Some random things we have noticed: no gaskets used for the front cover, oil pan, or rear cover; complete new oil pump design; the fuel pump is mechanically driven via a lifter that rides on a separate lobe on the rear of the camshaft; crank and rods are very similar to the LSA design; factory coated bearings. The list can go on and on! We will continue to update as we continue to test and measure. We have a set of pistons getting ready to go into production for a 416 CID LT1 stroker, so once our testing is complete on the stock engine we will begin testing the stroker version.

Click on the link below to check out some of the updated pictures!

http://s851.photobucket.com/user/Tex...0Engine%20Pics

Enjoy! :cheers:

Awesome!!!
So I take it pistons are a must as well for a build then?

get er done!

Pistons will not be a requirement for heads/cam. The stock pistons will simply be a limiting factor as to how much duration you can run. The VVT will be able to help some with this, but lots more to come on that front once we start testing different cams on our engine dyno. Aftermarket pistons will allow you to run larger cams because they will have an intake valve relief. The factory pistons only have a valve relief on the exhaust side.

Can´t wait to see results.
I am just under the impression, that if you want the most from your LT1 you´ll need to eliminate DOD and according to your post - pistons.
But I´ll patiently wait and see what the limits are going to be :)

We will design packages with customers retaining the stock pistons because this is what the vast majority of customers will most likely do. We will also develop cams for the stroker setup when piston-to-valve clearance is not a restriction. It's similar to the LS3 engines. They were more limited on p-to-v clearance vs. the LS1, LS6, and LS2 engines due to the large intake valve of the LS3 cylinder heads. I certainly would not rule out a heads/cam package while retaining the factory pistons. Not only will it be cheaper because you won't have to tear into the short-block, it will also still produce excellent power. The direct injection is certainly a new aspect for GM's sports car market, but it will also provide the aftermarket with a lot more possibilities. Case in point, look at the factory 11.5:1 compression ratio! There are some Ferrari engines with direct injection with 13:1 CR, so it definitely opens up some additional possibilities for more power on pump gas! Lots of great possibilities and testing on the horizon!

Trevor - can you tell if the stock pistons and connecting rods are forged?

Sounds exiting. How about the heads? Will you use the same DI and add PI? The high performance C7 will probably use the pump and injectors you will require. The Photobucket pictures load directly into my account.
I see Alfa has a VVT with a wide lobe cam that has a progressive grind with a twist. The cam moves back and forth hydraulically. Look forward to the next report.

Awesome pics and info, thanks!

Am I seeing gasket-maker where the oil pan gasket used to be? When you said no more gaskets for the pan and front/rear covers I was thinking they came up with some new way to seal it. Gasket maker sucks.

http://i851.photobucket.com/albums/a...psb1d47bd9.jpg
http://i851.photobucket.com/albums/a...psd122a589.jpg

Ugh... this means you'll have to scrape and clean and re-apply just right when working on these things.

No, neither are forged. The rods are still a "cracked" design with 6.098" length. The only LS-based engine to leave the factory with forged pistons is the LS9 that is found in the 2009+ ZR1. Even the 6.2L supercharged LSA engine found in the 2009+ CTS-V has hypereutectic pistons and non-forged internals. The crankshaft in the LT1 appears to be identical to the LSA crankshaft. They use an 8-bolt flange on the back, and the balancer is keyed from the factory.

Let me know if anyone has any other questions!

Yes, unfortunately they're using gasket maker to seal the covers. I'm sure it's part of cost-cutting, but it will certainly add a little time to the reassembly.

Can't wait!

By gasket maker you mean RTV I assume?
Way superior to gaskets and how often do you clean that stuff? Once every... Never.

Man, I wish there was a separate section in the forum to house this fantastic tech threads so I didn't have to dig through all the BS threads any more...

Why in the world would they cut costs there? One of the nicest thing about working on LS motors is the high-quality reusable gaskets :willy:

Send a PM to the mods. Would be GREAT to have that sub-forum like for the C6 :thumbs:

I agree it's time to have a tech section.

MARKETING OPPORTUNITY!!! Develop them $$$

Not sure if that'd work. The covers and bolt alignment need to be spec'd for the compressed gasket thickness. RTV will compress more than the gaskets used on the C5/C6.

I just can't imagine GM doing this... sure initial assembly it'll work fine, but working on the cars will be a PITA.

I just got done assembling a new LS6. Oil pan alignment is critical. You have to install it and measure and sometimes tap with a hammer to get it where it needs to be. Using RTV makes this a mess and if you have to pull it back apart you have to spend all that time cleaning it up all over again and work extra hard not to get chunks of stuff in the motor.

I'll stop mucking up this thread, but I'm just very surprised to see this.

Trevor,

Can you post a photo of the head showing the rocker arms, and you explain the unusual shape of the valve covers, with the recesses for the coil packs? Also, what is the red cap for in the valve cover?
Thanks for posting the other photos.