{"id":6606,"date":"2014-07-02T11:33:11","date_gmt":"2014-07-02T18:33:11","guid":{"rendered":"http:\/\/www.racingjunk.com\/news\/?p=6606"},"modified":"2016-11-30T15:23:59","modified_gmt":"2016-11-30T23:23:59","slug":"drag-race-101-building-an-ls-bracket-motor-from-scratch-part-ii","status":"publish","type":"post","link":"https:\/\/www.racingjunk.com\/news\/drag-race-101-building-an-ls-bracket-motor-from-scratch-part-ii\/","title":{"rendered":"[Drag Race 101] Building an LS Bracket Motor from Scratch Part II"},"content":{"rendered":"

\"Parts<\/p>\n

Part II: Picking the Power Parts for the Bottom End<\/strong><\/p>\n

In the last segment of our hypothetical LS motor build, we picked the parts for the top end. This time we have to \u201ccontain\u201d the carnage with the bottom end of the motor. Now, we\u2019ve referred to the bottom end as a place that isn\u2019t as responsible for power production when compared to the top. That still holds true, but you can still make extra power (sometimes a bunch of it) downstairs with wise component selection. Besides, picking the right parts sure does help when it comes to reliability.<\/p>\n

One of those places, believe it or not is the cylinder block. Case-in-point is Dart Machinery\u2019s LS Next cylinder block. The LS Next block is a significant departure from the norm in the bottom end of the LS engine. By eliminating the \u201cY-block\u201d layout and incorporating conventional style main caps along with conventional oil pans, Dart addressed the various issues that came from the LS motor\u2019s separated crankcase bays. Windage is greatly reduced. The result is increased power and improved lubrication.<\/p>\n

This LS Next block has main webs that are significantly stronger due to the elimination of the bay-to-bay breathing windows. Eliminating the windows allowed the cylinder barrels to be extended 0.3750-inch deeper into the crankcase. This makes for superior piston support at the bottom of the stroke. Conventional style 4-bolt steel main caps are used. The full deck design measures 0.625-inches with six head bolts per cylinder. Dart also increased the head-bolt size to 7\/16-inch. The head boltholes are blind, meaning that they don’t extend into the water jackets. Dart\u2019s priority main oiling system ensures high rpm reliability and includes a provision for oil restrictors in the lifter valley. Maximum bore is 4.220\u201d for iron blocks (which we\u2019re using) and 4.165\u201d for aluminum blocks, or you can get an optional Darton M.I.D. sleeve kit allowing up to 4.220\u201d bore on the aluminum block. \u2028\u2028For our hypothetical build, we\u2019ll take the engine to 4.1275-inches in bore, which in turn leaves plenty of room for rebuilds down the road. FYI, the blocks come 0.010-inch undersize in the bore size, which allows for honing and piston fit. And by the way, aside from some select bottom end bits (oil pan, etc.) and the larger head bolts\/studs, most stock and aftermarket LS components can be utilized. Dart\u2019s part number for the big bore iron block is 31837211.<\/p>\n

For the crank and rods, we\u2019d go straight to Molnar Technologies and order a 4.00-inch stroke LS Crank (part number 346-4000LB6F-610). These 4340 forged crankshafts are heat treated to increase tensile strength, shot-peened to increase fatigue life, nitrided for wear resistance and 100% mag particle inspected to insure against cracks. The critical sizes on the crank are held to extreme tolerances too. Bottom line here is, this is a stout piece you can count on.<\/p>\n

We\u2019ll include a 6.125-inch long H-Beam rod from Molnar Technologies. Their lightweight rod (part number CH6125NLB-LS8-A) weighs in at 602 grams. They\u2019re manufactured from 4340 billet material, heat treated to increase tensile strength and are shot peened to increase fatigue life. All rods have a wear resistant bronze bushing for long wrist pin life and feature ARP2000 series fasteners. All Molnar Technologies connecting rods are finished in Michigan. Sizes are held +\/- -.0001-inch (yes, that\u2019s taking it to the extreme). The truth is, Tom Molnar knows cranks and rods. It shows in his products.<\/p>\n

Pistons, pins and rods for our paper build are out of the CP Bullet catalog. Pistons are CP part number BLS1114-0025. The pistons have a bore of 0.1275-inches and are designed for use with our 4.00-inch stroke crank and 6.125-inch long (center to center) connecting rods. They have a compression height of 1.181-inches. The pistons are flat tops with 4.6 cc\u2019s of valve notch(es). They\u2019re setup for 1.5 X1.5X3.0-mm rings (which we\u2019ll source from CP) and the wrist pin is a 0.927 X 2.250-inch job (supplied by CP). Finally, the pistons are manufactured from 2618 alloy.<\/p>\n

Given the different bottom end layout of the Dart LS Next block, a different oil pan is required. Moroso has the application covered with a very slick aluminum pan complete with billet aluminum spacer rails and a complete fastener set (part number for the pan is 20144). The pan fits most vintage Camaro-Chevelle-Nova and G-body chassis. Moroso also offers a high flow wet sump pump for this engine (part number 22120) along with a special pickup (part number 24144).<\/p>\n

So far so good. Next up we\u2019ll need some additional hardware to make the motor run. ARP offers a complete array of hardware for the LS (including Dart\u2019s LS Next block). We\u2019ll use ARP parts exclusively in our hypothetical build. We\u2019ll also need a timing chain package and Cloye\u2019s Billet Single Roller is perfect. Part number 9-3672TX9Z is a three-bolt, single roller (extreme duty \u201cZ\u201d chain) based upon a set of billet gears. It\u2019s adjustable (nine keyways) and includes a chain damper. A damper (harmonic balancer) is also required. We\u2019d use an ATI # SK286S setup for a wet sump motor. This particular damper is designed for use with a serpentine belt.<\/p>\n

The final big accessory we need (not counting water pump and drives which are pretty much car specific) is the ignition. These engines are distributorless (eight coil jobs). We\u2019d use a Chevrolet Performance LSX ignition controller for a crank with a 58X reluctor wheel. The internal software allows for custom vacuum advance curves, timing curves, a programmable rev limit, and so on. To round it out, we\u2019d need a set of coil packs. Chevy\u2019s #19257878 fit the bill perfectly. Besides, they\u2019re designed specifically for this application.<\/p>\n

That\u2019s pretty much a wrap on the bottom end of our engine. Next time around, we\u2019ll fire up our hypothetical dyno (dyno simulation software) and see how the beast runs. You might be surprised! Meanwhile, check out the accompanying photos for more info:<\/p>\n

 <\/p>\n