A Conversation with Charlie Stewart

Info provided by Charlie Stewart told by Calvin of the Nivlac57 youtube channel

So sort of a funny story. I was telling a friend that works at our local speed shop about how hard it is to find information on the Vortec 4200s. Obviously they are being used for very high performance stuff in the Competition Eliminator world, but the information is not being shared. He was surprised by this and unbeknownst to me he went on a mission to find me some information. So he starts web searching. He finds a post from someone who sounds like they know what they are talking about. and notices a racing number in their profile picture. He recognized the racing number as so-and-so's number. So he gave so-and-so a call. Yep, it was him. So my friend puts me in contact with so-and-so, and he talks my ear off and then gives me Kevin Self's personal number and Charlie Stewart's number. 

Kevin Self? I know that name. They did the 1300 hp drag week Nova Wagon. So I figured I would try to call them first. No answer. Try again later... No answer. Leave a message. No response. Ok. This is a dead end... So I decided let's try Charlie Stewart. Picks up immediately. We talk for about an hour. Then he calls me back later unprompted to share more. Fantastic guy. His remarks were the guys at Self Racing were very hard to get a hold of unless you are paying them money. They also are very secretive about information they are willing to share. He had sent them custom ground cams and they didn't want to tell him what combination of cams that he sent them worked the best. Charlie had no issue sharing what he knew with me though.

Here is a summary of our conversation:

As many of you may know, the Competition Eliminator guys are making 650 crank hp and spinning 4200s to 10,200 RPM. Therefore, if anyone knows how to make them last, they do.

On the Crankshaft, he recommended to not grind the rod journals any smaller than 2.200 (Big Block Chevy), because they crankshaft loses a lot of strength when doing this. He has had the most success with getting custom Big Block Chevy Rods and grinding the crank. He has run both the 02-05 12 counterweight crankshaft and the later 06+ 8 counterweight crankshaft. His comments were the 8 counterweight crank did not seem to last as long, but he admitted that he didn't have strong evidence to back that up. He has run 3.800", 3.900", 4.000", and 4.125" stroke engines. He commented that the shorter stroke would be better, but You are limited by what you can do obviously with the stock crankshaft.

On the block he recommended use of a 06+ block. He said that under high cylinder pressure, the top of the sleeve will crack on the early engines. He has run a max bore of 3.700", but he strongly advised keeping the bore stock. The sleeves are not super thick and there is not much to be gained there.

He said, the hardest part is the oiling system. When they were running an engine on the engine dyno, he said they kept running into oil starvation issues during the pulls. So he decided to give the engine plenty of sump to pull from, in the form of a 5 gallon bucket full of oil. He said that the engine sucked the entire 5 gallon bucket dry during a pull before it started to return oil. What they found out was that because they had removed the factory main girdle to install one that tied into the oil pan rail, they were having oil return issues. The factory main girdle as they found out acts as a crank scraper and helps return oil to the pan. Therefore, he recommends retaining the factory main girdle. For high output applications (like his), he definitely recommended some sort of reinforcement. The factory main girdle is not enough. They were beginning to see accelerated main bearing wear when they tried that. He said that dry dump was not 100% necessary. He ran an external pump with  wet sump for a while.

On the head, he highly recommended going to solid lifters if you plan to rev past 7500. He recommended setting lash to 0.004"-0.008" cold. With a turbo, he said that it may take more lash, perhaps as loose as 0.014". He said that he never had issues with the cam followers, and when I mentioned the Ecotec followers, he said he never had an issue, and wouldn't bother. He also said that he has run as much as 550 lift with 268 intake duration, and 272 exhaust duration, but that really isn't required on a 4 valve head. On his particular application, revving to 10200 RPM, he recommended very little overlap and locking out the VVT. He recommended and Intake centerline of 110-113 degrees, and an exhaust centerline of 105 degrees. He recommended a valve spring with a seat pressure of 205 lbs. He also mentioned that Bullet Cams may still make cams for people.

For bearing clearances he recommended 0.0035-0.00375" on the rods, and 0.0025" on mains.

He sent me pictures of how to make your own adjustable sprocket.