The Hunger

The Popular Hot Rodding Engine Masters Challenge is an open forum, meaning anyone who's got the guts to enter could. The doors closed on entry at the end of March, which means potential engine builders had from the time we announced the contest (in December '01) until April 1st to get involved.

The very first entry sheet we received was from Tom Nelson of Nelson Racing Engines. We met Tom at the PRI Show in Indianapolis where we announced the contest. He was enthusiastic about it from the moment we began discussing it with him. We weren't surprised to receive his application, but we still had not heard too much about the young L.A.-area engine builder.

We thought it would be cool to profile his efforts. First, because he was very organized and had a very good idea what he was shooting for, and second, because his "racing" engine shop actually specializes in hot street engines designed to run on pump gas. Immediately, we felt this would make for a great story, as a young, relatively unknown builder was prepared to take on the pros. This is a guy who started building performance powerplants out of his grandmothers garage, and did so for almost two years before moving into his own shop. Now, after six years in business and with a team of trusted partners, he wants to make a bold statement.

His research into street-flavored combinations could only help, and Nelson told us he'd recently completed a customer engine that was painfully similar to what we were after. We think he's got a good shot at the prize money, and sharing his buildup ideas should give readers a good idea what to expect in the contest and also some education in the intricacies of streetable superiority.

The best part about this plan is how Tom wants to offer the Engine Masters Challenge design small-blocks as crate engines to customers. "I'm developing a budget package here, and I should be able to get an affordable version together for anyone that wants one. I'm keeping the budget between 10-15 grand, and even if I don't win this contest, I doubt there will be any less-expensive engines readily available to the public finishing with more power than mine."

That sounds like a dare, Tom. We hope all the other engine builders read this and respond in kind.

Tom chose to build a Chevy-based engine, but the theories and dimensions he's working with are universal to powerplants of this nature. Let's take a look over his shoulder as the combination comes together. Although none of the dimensions are iron-clad (Tom will still do plenty of fine-tuning once the engine is running), we got a good taste of what Nelson Racing Engines is serving up.

Nelson's entry into the Challenge begins as a new non-Bow Tie "ZZ-style" Chevy block. This design has the one-piece rear main seal and is designed for hydraulic rollers. The first thing Tom did was measure the line bore. He then finished the line hone to his own standards with an oil pump boss in place and torqued to spec.

We've mentioned how this boss makes a measurable difference in the rear main bearing clearance in past buildups, and Nelson wholeheartedly agrees. "If you don't believe it, measure it yourself. It makes a difference, and the main bearing clearances are too critical not to take this into consideration. If your machinist doesn't do this, find another machinist." He chose .0028 inch for a final clearance dimension; no more, no less.

Tom then decks his blocks using a BHJ tool. The tool (mounted on the BlockMaster and supporting the block) is designed to make precise block deck finishing a snap.

Setup time is minimal with this tool, and the accuracy is precise. This will be a "zero-deck" block, meaning the piston is perfectly level with the top of the bore at TDC.

Tom finish-hones all of his blocks to suit specific needs. For the Engine Masters Challenge powerplant, he'll run 220-, 280-, and 400-grit stones in succession, lessening the pressure with each stone change. The final cross-hatch angle will be between 20-30 degrees. The final finish will be provided by a plateau hone, which looks like a big bottle brush. The final bore size will be 4.005 inches.

Nelson will fill the block with a Cola crankshaft. This forged 4340 steel unit is designed to be lightweight (32 pounds) and strong, with carefully-contoured knife-edged aerodynamic counterweights. The stroke is 3.625-inch, which (when combined with the 4.005-inch bore) delivers 365 cubes--just under our 366.0ci size limit.

The connecting rods are from Eagle and these "Talon" rods measure in at 5.9 inches center-to-center (top). The pin diameter is .865 (compared to the standard 5.7 rod and its .927-inch pin on the bottom), while the big end is 1.771 inches in diameter. Isn't that an oddball size? Yes, unless you're familiar with Mitsubishi bearings.

Tom swears by them in performance small-blocks. Nelson's choice rod is lighter, longer, and plenty strong for street use on pump gas. We placed the smaller rod on top of the larger so the dramatic size differences could be clearly seen.

Tom's pistons are from Wiseco and are built to his specs. The 300-gram units will use horizontal gas ports (not machined yet) to push the top ring into the cylinder wall and seal completely. The deck is .170-inch thick and has a high top ring (only .140-inch from the piston top) to maximize compression effectiveness. This will also allow Tom to keep .150 inch between the top and second rings, giving a generous air gap between them to help stabilize the rings.

Note the coatings on this piston top and skirt. The gold-colored coating on top is a thermal barrier, while the black coating on the sides is a poly-moly lubricant film to minimize friction. Swain Tech Coatings does all Nelson's work, and these aren't the pistons headed into the "Challenge" engine, but the coatings will be identical.

The top rings are from Total Seal, and are gapless diamond-lapped versions measuring in at .043-inch thickness. Tom plans to run minimal groove clearance (.001-inch) to maximize the sealing potential. The second ring is a traditional (gapped) ring, and is a low-tension design. The oil ring set is also a low-tension design (8 pounds) that works great with Nelson's bore finishing techniques. This has resulted in no oil control issues and can work with the simple crankcase evacuation system to make crankcase vacuum, saving the hassle of adding a vacuum pump on the street.

Tom turned us on to this trick he says is a must-do. He uses powdered "Quick Seat" dry film lubricant in his bores. No other lubricant is used in the bore, and the film is applied to the dry, clean surface. He claims this Total Seal product, while expensive, can be used conservatively and delivers excellent results. Ring seal is ultra-critical in performance engines, especially for a dyno entry like this. We've not used this product before, but after hearing Tom rave about it, we'll have to try it in the future.

While the camshaft dimensions will be researched on the dyno (Tom says he'll probably test about seven different profiles), there's little doubt who will manufacture it! Nelson is a believer in Crane components, and he applauds our consistent preaching about using the same manufacturer for all valvetrain weapons. "You've got to use parts designed to work together, and sticking to the same manufacturer is the best way to accomplish this. Working exclusively with one supplier saves time and headaches down the road, and Crane's stuff has always proven to be great equipment for street engines." The cam design will be an inverse radius hydraulic roller, but that's all we can tell you about it now.

Connecting the crank to the cam is a job destined for this Jesel beltdrive unit. Proven in competition, the Jesel part (PN SPD38650) replaces the timing cover and runs dry.

The slotted holes on the cam gear allow for quick and easy camshaft timing adjustments, clearly defined by these graduated reference marks on the gear. Choosing a beltdrive also eliminates harmonics issues between the crankshaft and the camshaft.

When Tom had to choose a lubricant, he was glad to see Red Line Oil had signed up for contingency. He chooses Red Line for all his engines, and uses Red Line assembly lube, too. While he's not sure what grade of synthetic he'll have in the crankcase on dyno day, he assures us it will be a Red Line product.

Nelson's cylinder head of choice is one we expect to make a good showing in the Challenge--Pro Action heads will top the block.

Their 23-degree raised-runner design is a great part out of the box, but Nelson will have Richard Reyman of West Coast Cylinder Heads (818-705-5454) work his over before they go to Swain Tech to have the ports and chambers coated.

Nelson does plenty of flow research in his own shop on his own bench. He likes tailoring the port size and shape to each individual application. He uses a probe inside the port to determine where the air is moving fast and where it's moving slow. As he says: "The probe measures inches of water being pulled, and when I probe into a port, I'm looking for the highest water depression. This is normally a busy area that could use some help. The width of the short-side radius (in the corners), along with the port roof, is where I do most of my work."

"I'm shooting for around 360 cfm of flow with excellent port velocity at around .600-inch lift at the valve. This should provide a really good power curve, with solid average power numbers to win the Challenge. Peak power should occur right at 6,500 rpm, which means I'll leave no "wasted" power on the table after 6,500. By using a big port, a short cam, and tight lobes, this should be a real contender.

The intake manifold will begin life as an Offenhauser low profile single four-barrel cross ram, PN 5893 (base), with a single four-barrel top (PN 5901). It will be modified to work in concert with the Pro Action heads, and should provide the fat torque curve necessary to win this contest. Tom has great faith in this design.

Feeding fuel to the engine is no meek task. Tom has experienced great success in working with Troy Patterson of TMP Carbs. Troy's custom-built Holley-based carb designs are all built specifically for each customer. In this case, they'll be using a relatively large carb (1,100 cfm from a 4150 body) outfitted with Weber metering plates. They use emulsion tubes to meter fuel, and many tuners prefer them.

The Weber parts have been available for awhile, and allow for fine-tuning of the fuel curve without the need to drain and remove the float bowls. They also space out the fuel bowls further from the carb body, making the entire carb larger. If you'd like to upgrade to plates like this, make sure you've got clearance around your carb first.

A key to making the large carb work on the small-displacement engine without bogging is the secondary linkage. Those familiar with Holleys will notice the huge linkage for the secondaries--TMP makes this in-house. By delaying the opening of the secondary plates (through custom linkage cams and custom-engineered secondary linkage elements), the engine is able to accept the additional air and fuel being fed to it. Without the custom parts, this carb would open too quickly and cause a stumble. By fine-tuning the carb in this manner, Nelson hopes to take advantage of the large cfm capacity of the TMP design.

Tom chose Milodon parts to control oil on the bottom end, including a PN 32250 diamond-screen windage tray and crank scraper. Air filters (14x3-inch round elements), headers, and mufflers will be required on the dyno for the Challenge pulls. Nelson has chosen a K&N filter element (and oil filter), and he's close to choosing Hooker Headers. Tom is still looking over muffler choices for a good "straight-through" design. While we weren't able to describe every tiny element of this particular entry, we hope you've gotten a good idea what to expect from the Engine Masters Challenge. The design and parts choices for this engine may be very similar or radically different from other entrants, and future Engine Masters Challenge buildups we're following will reveal some of the competition.