Awesome post. Spin's editorial and humor bring the funny.

Thanks for putting this up.

Very cool.

 

Guy- Great write-up. What did you use to remove the carbon buildup?

 

Some were lighter than others. Gumout and a rag for the easy ones. A scotch bright pad for the more stubborn carbon spots.

 

Scotch bright is not a good thing inside a engine. It shouldn't be used for anything that isn't getting completely torn down and wash. I would change the oil and don't worry about it at this point. But don't conutine to use it for this operation.

Other then that

Randy

 

Spin, that was a great write-up of an excellent project. Your writing style is easy to read, and completely informative. I will drive up from Miami for the book signing at your local Barnes & Noble when you gather everything up into one volume !!!

 

Just curious what is wrong with Scotch bright? I couldn't see/feel anything coming off the pad and it was wiped/vacuumed to clean it up. I didn't want to sand or scrape on the pistons so it seamed like a good alternative. The oil was changed later too.

 

spin!

 

Great write up Spin - back in my old Dragster days we used to make those cutters out of old oversized valves with a collar on the stem to control our depth and run it with a drill. Pretty cool you can do the cutting by hand with a good cutter.

 

That is actually not a bad idea!!

 

Hey thing #2!!! Whats up buddy, gonna make it down this time around?? Got your very own sombrero waitin for you!

 

I'm not sure when it was installed but the car didnt have an oil return to the intake. It was fitted with Jeramy Formato's two hose deal with no catch can. The real test would be to pull off a head in 2k miles.

 

In 30 years I have never seen an engine have an issue with this nor have I come accross a single person that said to not remove carbon from a piston. Any surface would have a smoother RA with the softest pad and the surface smoothness was the only thing I was told is the issue. Is it safe to assume you are worried about contaminants?

Carbon on pistons is very bad. It causes hot spots. The machine shop I go to and the engine builders I was around all told me the issue with cleaning pistons started and ended with the surface smoothness. Sandpaper in the 440-600 leaves a surface that would actually collect carbon faster than an new piston and it was my understanding that this was the only reason you dont do that to a piston. A buffed surface would resist carbon build-up and its why head porters use a polished surface in an exhaust runner.

Since the surface is smoother than before, I would need to hear a tech reason as to why the piston shouldnt be cleaned other than a perpetuated rumor mill answer. I am not saying your answer is such but it is heresay until the source and reason are divulged because I doubt any mechanic would say to leave the carbon in place as that IS the devil.

Not everyone is disassembling and engine to remove carbon 95% wont on a H/C install where there is no engine damage and the carbon is definitely comming off no matter what. Obviously leaving it is not an option.

What do you use to remove it? Since it can be assumed that you do H/C installs, I would be weary of advertising here that you dont remove carbon so there is an answer to how you get it off. A scotchbright pad will leave a smoother RA to the surface than stock and short of coating a piston for carbon and heat immunity its a distant second with a stock carbon filled surface being a 4th place way to redo an engine's top end.

This is a good topic for debate and research. Anyone feel free to research it. I do not consider it to be off topic since its part of the psiton surface prep for flycutting. My quick run of the internet prodiced the most common method being a wire brush which would never be done by me. Scotchbright pads come in various textures and can leave a much smoother surface without scarring anything. I wasnt involved in this clean-up as they were clean when I got there. I wuldnt have stopped him with scotchbright pads.

Lastly, I dont care what a poll of tuners would produce. What a guy does to his customers engines is irrelevant and there are lots of people that are forum tuners that do some things I consider really bad like install parts without a TQ wrench thinking thier experience makes it ok to guess at a bolt's tightnesss. I use a TQ wrench on everything. Having had a tuner mis-torque bolts that hold by differential on my car and having it come loose and kill a transmission along with the diff, I question any tuner's proceedure for any operation. I work on every car as if its my own.

Edit: Local machine shops (2), Westons and S/K, both said to use scotchbright.

 

Awesome time here too.

The next step is gears and tires.

The mileage on many cars goes up especially if optimum compression is used. This engine had a compression bump. Other benefits to the higher compression are that it smooths out lope and driveability issues. It also serves to increase low end TQ quite a bit plus a bit to the peaks of HP and TQ. Throttle response is my favorite benefit with the throttle being very sensitive. I think its very needed on a head with a 260cc intake runner.

 

Hey wassup!!??

 

I dont like killing birds.

Louis at LG had quite a hand in the prep of this write-up. Originally he was going to send me the fly-cutter to try out some cams he had for me. In discussion of his cam projects he noted that this type of clearancing would be central to using any real cam with the LS3 heads even on the 2008+ corvette. He wanted me to do this write-up as part of the agreement for him to supply the tools and cams for some R&D.

Louis was quick to point out that one should be weary of cams that are installed in this motor without flycutting where L92/LS3 heads are used. The Cam only approach to the LS3 is inviting but how do you check the intake side clearance? Once the cam is in the lifter isnt pumped up to resist the spring tension. You cant check without removing heads. Personally I think heads have to come off for all cam installs except where cam specs are verified (cams do get ground wrong) and its a know fact that small cams of 224 and down fit fine. As I said, one tuner verified another tuner's huge cam to have only .034 clearance on the intake side which is about a 1/3 of what is needed.

As a note of warning to the LS3 crowd: Your intake valve is a hollowstem thats is welded in 2 places to the stem (head and tip). It has much less weld area than the normal L92 solid version and is never a replacement for a stainless one piece. Piston contact will break the valve head off and destroy the lower end. Huge cam only installs without fly-cutting is a bad idea especially if the cam is a limit size. I can install a 234+ cam and get 500rwhp out of one too but I wont use it without flycutting. If a tuner tells you I am wrong, they are lying. Tell them to post that view online and not in a private phone call.

The heavier weight valves have no issue as long as you use a good spring. I wound out my engine to 7k and had no valve float. If it were a higher revving engine, I would have Manley make up a titanium set and spend the extra 800 bucks.

 

In all fairness to Jeremy Formato Its not known how many miles were on that engine before he installed the atmospheric two line vent. I have
one on mine w no issues. It doesnt seem practical to pull the heads say after 2000 miles or so just to see the tops of the pistons. I guess
only time will tell on this one as ls2 owners start switching to ls3 heads.

 

Already in the works..... Not to let the cat out of the bag, but there are website and book ideas in the works, just working out the trademark, copyright and legal issues.

Think information, consultation, streaming video, virtual simulation (wouldn't it be WAY COOL for say Dennis in NJ do a virtual run against Ponchorello in TX from their living rooms while we all watch????)...you get the idea.

 

I can't wait to see that chit!

 

Spin,

Great write-up! Just another reason why you are my HERO!

Thanks,
Glenn

 

Trying to get sometime off, Guy will fill me in on the dates, I want to see Maggie breathe some fire!!!

Big Stick coming.....

True, but I don't know that it is a prudent idea to have unfiltered, open hose lines hanging out of the bottom of the engine bay, but that's a topic for another thread.