SAM Racing May Try Variable Cam Timing in Engine Masters

SAM Racing crew members thrash on the dyno in preparation for the Amsoil Engine Masters in October.

With the Ford Modular motors no longer a threat, the 436ci LS engine entered by the School of Automotive Machinists, or SAM Racing, is poised to return as champion of the Amsoil Engine Masters competition. The team placed fourth behind three of the Ford 4-valve engines last year – which was the first time overhead-cam engines were allowed. But now the rules say only pushrod engines can compete, and SAM Racing has made a few interesting changes to its engine, including the use of variable cam timing — a move that could support more performance and race LS engines adapting that factory technology.

“We haven’t got it done yet,” cautions Judson Massingill. “We’re working with Holley and we think we got it figured out.”

The refreshed engine was fired up and broken in last weekend with encouraging results.

“There was a dip between 3,500 and 4,000 rpm,” reports Massingill. “It was better than last year from 4,500 to 6,000, then a dip from 6,000 to 6,300.”

The engine based on a LSX block and features a Bryant crankshaft, Scat rods, Diamond pistons and ARP hardware.

The team made only three pulls before checking the oil filter and measuring leakdown.

“We usually pick up about 15 horsepower across the board when we take out the petroleum break-in oil and switch to synthetic,” notes Massingill, who led SAM Racing to victory in 2012 with a Chevy SB2 engine.

Massingill says the first dip is often common, and experimenting with different header extensions has usually solved the problem.

“We need to get as good as we can without the variable cam timing,” explains Massingill. “We don’t want the cam timing to take the tip out. We want to take the dip out and then the variable cam timing pick up everything.”

Will it work?

Whether or not the stock LS variable cam adjustment mechanism will work is still a mystery.

Last year’s LS engine that was campaigned by SAM Racing.

“We know it works with stock spring pressures,” says Massingill. “But we can’t run stock springs with the cam we’re running. We won’t know for sure until we put it on the dyno and tell it move.”

The team is actually running softer springs on the CID-built heads than last year, as a slightly less aggressive cam was ground by Comp Cams.

“But the springs are stronger than what we know will work with variable cam timing,” says Massingill. In addition to overcoming the spring pressures, other unknown factors related to variable cam timing include operating the mechanism with thin racing oil or the need to increase operating oil pressure.

Judson Massingill, far right, and the SAM Racing team at last year’s Engine Masters competition.

“We can’t change the pressure right now,” adds Massingill. “If it doesn’t work, we’ll have to look at that.”

The factory cam phaser has a range of about 40 degrees to address not only power curves but also issues of emissions and fuel economy. SAM Racing designed a limiter to take advantage of only 8-10 degrees change. They also adapted a larger reluctor wheel that is more accurate than stock, giving the Holley  Dominator ECU more precise information to control the cam advance and retard.

Last year’s winner was Jon Kaase Racing engines with a Ford Modular engine that sported unique 16-tube headers.

New pistons needed

“As an example, we’ll have it around a 97 intake centerline at 3,000 rpm, then back it up to 105 or so at 6,500 rpm,” explains Massingill, noting that the new cam is slightly softer than last year’s with a shorter duration numbers. The ability to move it around prompted a change in the reciprocating assembly. “It’s basically the same engine as last year but we put in a new set of pistons with deeper valve notches to make sure there’s enough piston-to-valve clearance.”

Another effort to broaden the torque curve involves a long-runner intake to replace the traditional high-rise racing intake used last year. Currently two companies are working with SAM Racing to test intakes with runners in the 9-to-13-inch range.

SAM Racing won the 2012 Engine Masters with a 402ci SB2 engine that made 853 horsepower.

Engine Master rules states that all intakes must be commercially available, so interest in that product could build around the competition.

The engine is based on a Chevy Performance LSX block and sports a Bryant crankshaft, Scat 6.0-inch connecting rods, Diamond pistons, Total Seal and Mahle rings, Clevite bearings, Fel-Pro and Cometic gaskets, Innovator’s West damper and ARP fasteners. Lubrication is provided by a Schumann pump, Stef’s oil pan and Amsoil SW20 oil. The valve train includes Bullet lifters, Smith Bros. pushrods, Jesel rocker arms and Ferrea valves. MSD provides the spark, and SAM Racing built the headers. Other suppliers include Champion spark plugs, Meziere water pump, ProForm valve covers and Earl’s plumbing.

So far 36 teams have entered the 2014 contest that will be staged Oct 6-10 on the dynos at the University of Northwestern Ohio. The top five teams from the first round of competition will advance into Friday’s final. Engines are awarded points based on the horsepower and torque averages divided by the displacement. Points can also be deducted for rules infractions. The competition was started by Popular Hot Rodding, but that magazine recently folded and is now under the umbrella of Hot Rod. Last year’s winner was Jon Kaase Racing Engines.

About the author

Mike Magda

Mike Magda is a veteran automotive writer with credits in publications such as Racecar Engineering, Hot Rod, Engine Technology International, Motor Trend, Automobile, Automotive Testing Technology and Professional Motorsport World.
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