Qwik01

Who thinks that valve build up will be an issue in the new LT1 since it is direct injection? There will be nothing to keep the valves clean. Looks like an oil catch can will be a must.

BuddhaZ06

Hasn't been problems with the v6 cars.

JerriVette

Very interesting assessment on the carbon valve buildup ..

It is the combination of the new EGR system, the new box manifold, the reversed valves..the splayed (SP) valves...and the design of the heads themselves all work together to totally resolve that issue that is a concern for most direct injection vehicles.

That was a key factor in the proper development of this new GM V8...

Its an amazing engine.....

hig4s

While some manufactures have had this issue, most don't including GM in the Cadillac V6 DI engine..

It has to do with timing the valves so there is no back flush of fuel mix up past the intake valve.. How the timing to do this affects performance, and if those that change cams and time will then have a build up issue or not is still to be seen.

Latterlon

This is a huge problem on the B7 Audi RS4's. Do a google image search on it. Around 60K miles the heads have to be taken off and valves cleaned. It's apparently worth around 20hp on a dyno.

CPhelps

GM has used DI in their 4 cylinder engines since 2005 and the "HF" V6 cars since '08 and there haven't been any valve build up issues with those engines.

http://www.edmunds.com/autoobserver-...-adopters.html

Reading the section of this article "All Engines not designed equally", provides additional data that the GM engines do not seem to have this problem.

Qwik01

Good to hear. I was unaware of the v6's not having the issue. I know with my last car that had direct injection had a lot of build up even at 30k miles.

SCM_Crash

As far as I know the Ecotec motors don't have that issue.

MikeyTX

I think you're stressing unnecessarily.

Reciprocal

Over the coming years though I bet we'll be hearing plenty of conjecture about it, as enthusiasts seek explanations for dyno variations. Lexus, one of the manufacturers cited in the report for its carbon buildup woes in the is250 addressed the issue in their is-f and Ls series by combining port injection with direct injection while achieving e-lev status. I think it's inevitable that Corvette enthusiasts known for dyno'ing their cars will share this concern for as long as it remains a possibility.

CitationZ06@yahoo

I read some place that the bumps on the valve cover were air/oil separators that may help?

It looks like 8 bolts to pull the intake and hit the valves with some carb cleaner.