PRI 2015: Dart’s Billet LS Head Sneak Peek, Dart Seminar Overview

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When the opportunity arises to listen to Richard Maskin of Dart Heads and David Reher of Reher-Morrison Racing Engines discuss engine performance and product development, one is wise to listen. That’s why we made time last week at the PRI Show to attend their seminar, where a number of topics were covered — including the development of Dart’s brand-new billet LS head, which, unlike others on the market, is delivered complete with water jackets.

In previous discussions with Maskin, he’s impressed upon us that the LS engine may be the last of a dying breed — the final pushrod engine from a major OE manufacturer that’s still open to modification at the level that the current LS engine offers the enthusiast. From observing the evolution of Dart’s product line over the last several years, it appears that he’s betting on exactly that; the company offers a wide variety of LS-style performance engine blocks and cylinder heads targeted towards all ends of the marketplace.

The construction of the billet cylinder head was a main focus of the seminar, as the design of the head to include the water jackets for those applications where cooling is required was a major engineering feat for the Dart team.

Spy shots of the construction process on Dart's new water-jacketed billet LS head. (Left) The head as it appears after the initial machining processes on the CNC mill are complete, with the water jacket voids machined in. (Middle) The new plates welded up. (Right) The Dart billet LS cylinder head after final heat-treating and cleanup.

Starting with a monster chunk of aerospace-quality billet aluminum, the Dart engineering team located the major sections of the head — the intake and exhaust runners and combustion chambers, then carved out the bottom side of the cylinder head of as much material as possible without compromising strength. The area around the intake runners and combustion chambers along with the end sections where water jackets are present were all removed during the machining process to create the jackets themselves. Not only does this allow for the creation of the unique cylinder head, it also removes a great deal of weight that would typically be present in a billet component.

The billet head's rocker box has been designed to offer as much strength as possible for all-out performance with the LS platform. During the seminar, Reher said this is 'the ultimate' cylinder head in its class.

The billet head’s rocker box has been designed to offer as much strength as possible for all-out performance with the LS platform. During the seminar, Reher said this is ‘the ultimate’ cylinder head in its class.

Subsequently, Dart’s craftsmen welded up the areas using aerospace aluminum plate to seal up the newly-created water jackets, then the cylinder heads are final-machined into the state you see here.

“We had to cut through the deck, because it was the only way we could get in there,” says Maskin. “There is no core shift because it’s all machined. The plate is chamfered and welded, then the whole piece goes to heat-treat, and then it’s final-machined.”

None other than Race Flow Development's Curtis Boggs inspecting the new Dart billet LS head; we overheard Boggs say "This is a nice piece; I can work with this." That's a solid endorsement.

None other than Race Flow Development’s Curtis Boggs inspecting the new Dart billet LS head; we overheard Boggs say “This is a nice piece; I can work with this.” That’s a solid endorsement.

Seminar Discussion

A number of facets of engine theory and component design were touched on during the Maskin/Reher roundtable-style discussion.

When Dart initially made the LS Next block design, they encountered market resistance due to the fact that the skirt was removed from the bottom side of the block, it required a different oil pan, the oiling system was different, and there was no provision to attach an oil filter. Although the block solved the aftermarket’s issues with regards to performance capability, Dart heard the concerns and decided to make some changes to the LS Next design.

“You couldn’t do a lot of things with the LS engine that people wanted to do with them,” says Maskin. “Moroso came up with oil pan rail spacers for us, and then we had real spacers that you could put a dipstick in, and put the air conditioning and power steering on, but you still had to use an external oil filter with braided line.”

This drove the development of the brand-new skirted aluminum LS Next block. The block now offers these enhancements right from the Dart factory, as the skirt has returned, allowing for the use of many “standard” LS parts but retaining the previously-engineered priority main oiling system and other improvements.  The dipstick hole is also machined into the side of the block with the updated design, and the add-on pan rails are no longer necessary.

The new fully-skirted LS Next engine block, which will accept a stock-style oil pan and pickup design or an aftermarket dry-sump system.

The new fully-skirted LS Next engine block, which will accept a stock-style oil pan and pickup design or an aftermarket dry-sump system.

Now the ability exists to use a traditional-style oil pan and pickup like the kit offered by Holley. Dart also developed a standoff system from the main caps to permit the use of a windage tray, which is offered as a catalog piece to fit both the old and new block designs that don’t use half-inch main studs.

“We figure if you’re using half-inch studs, then you’re going to do a little better on the oiling system,” says Maskin.

Dart’s also prepared to shortly release an iron SHP version of their skirted LS block that will fulfill the needs of the SHP consumer — they were being finished up at the foundry but didn’t make it to Indianapolis in time for the show.

“This allows us as engine manufacturers to offer a package up to 1,000 horsepower with these new SHP blocks,” says Maskin.

One point in particular that Maskin discussed heavily was crankshaft counterweight design for the LS engine. For comparison, he showed the difference between the Gen I small-block casting and the LS Next casting; the Gen I has a measurement of 19.25-inches between from front main cap to rear cap, while the LS Next has 17.50-inches at the same dimension, a difference of 1.75-inch.

(Left) Here is the difference between the block dimensions. (Right) The LS engine has much smaller front and rear counterweights; Dart has engineered a billet crankshaft with center counterweights to solve this issue.

Why is this important? Because when developing products like crankshafts specifications need to be determined for where to put the counterweights on the crankshaft in the place where they will have the most efficient effect.

“Somewhere, we’re missing that much counterweight in the front and the rear of the block. Without center counterweighting, and without any front and rear counterweight, we have a problem,” says Maskin.

“That’s where our new fully-counterweighted billet crankshaft comes in. It comes in 4.000-inch stroke at this moment, with an LS1 or LS7 snout. This fills the gap between the cheaper cranks — which work to a decent, 800-900 horsepower level naturally-aspirated — and works in those power-adder engines that don’t need a Sonny Bryant or Winberg crank yet. David [Reher] brought a lot of this to my attention; he’s my eyes and ears in the field.”

When Richard Maskin speaks, people listen -- even David Reher.

When Richard Maskin speaks, people listen — even David Reher.

Reher discussed some of the shortcomings discovered in the field regarding the LS engine’s development from an engine builder’s perspective, and how they’ve been addressed in the line of products from Dart as a result of some of his input. Many other topics were touched on during the seminar — too many to cover here — but Dart will be releasing a full video of the seminar in the future.

One thing is for certain — if you’re at the PRI show next year and this seminar is offered, clear your schedule for the hour and find a seat in the gallery.

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About the author

Jason Reiss

Jason draws on over 15 years of experience in the automotive publishing industry, and collaborates with many of the industry's movers and shakers to create compelling technical articles and high-quality race coverage.
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