Building the Ultimate Dirt Modified Race Engine: Insider Secrets Revealed!

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foreign [Music] [Music] 400 RPM on a push rod small block God Bless America [Music] hey this is Jeff Honeycutt with the horsepower monster got a fun one for you we have traveled up to beautiful Medford Minnesota for stone Racing Engines where Jamie Stone is building a throw down dirt modified race engine to support the racing Community it's going to be a great build yeah so this is what we're building the engine for now if you're not familiar these are dirt modified race cars and they are an absolute blast these cars are sanctioned by the United States modified touring series or the usmts as most Racers know it and these are the a mods which is the top of the Heat they boast over 600 horsepower the chassis are lightweight and handle incredibly well and because the US MTS has done a really good job of keeping costs down for the racers the tracks are absolutely busting at the seams with these cars creating side-by-side racing action and fantastic fun incidentally the usmts is going into its 25th season of racing this year and stone is celebrating his 25th year as an engine builder so they decided to work together and give back to the racers by building and giving away a race spec a mod engine here I let Jamie give some more of the background on this build hey this is Jamie Stone of stone racing engines in Medford Minnesota uh just uh putting together a 415 cubic inch usmts us-ra modified engine for a touring series that goes throughout the country uh it's uh got parts from all the vendors that we use throughout the series and I've had great luck with our shop we uh We've primarily focus on usmts usra a modifieds we also do some Luke soil we're all Outlaw late models we've dabbled into some of the drag racing truck pulling as well and a little bit of the Lower Class B mod Street stocks as well on the local local racing community so let's get started usmts rules require a cast iron block So Jamie says the obvious choice is a World products Motown 2 block compared to a stock Chevrolet block the World products Motown 2 has many advantages besides being cast and machined in the USA from super high strength iron World products Engineers also redesigned the oiling system so that the critical main bearings are fed first and then the camshaft and lifters also here you can see the lifter gallery that runs down the center of the lifter Valley so that both Banks of lifters are fed at the same time and at equal pressure the block has already been machined with four inch 125 000 cylinder bores although the casting can handle up to four inches 200 thousands reliably and from the underside you can see how the block is notched to accept crankshafts with as much as four inches of stroke this will be a high revving race engine however so the stroke is going to be limited to three inches 875 thousands Jamie has already done the hard work of Blueprinting the engine so all the important stuff like checking the bearing clearances were done before we arrived so all Jamie has to do is reinstall the clevite 8 series main bearings apply a little assembly lube and the crank is ready to be dropped into place this is a Cali's cop star forging with standard size Mains and raw journals as I already mentioned the stroke is three inches 875 thousandths for the giveaway engine Cali's went with a standard weight 48 pound crank but Jamie says he often uses a lightning crank for his builds with good success one really nice upgrade for the Motown 2 block is the use of Steel main caps instead of nodular iron for added strength normally on four bolt main caps the outer bolts are smaller but here they're all the same size oh and here all the Fasteners both bolts and studs are high tensile strength pieces from ARP to absolutely minimize any chances of a failure plus world's design uses four Fasteners on all five main caps not just the center three like usual Jamie Torx both the inner studs and the outer bolts all to 7 70 foot pounds to mount up the crankshaft we've got a set of Steel forged connecting rods which are also from Cali's these h-beam rods are six inches from Center to center with a 928 thousandths wrist pin and actually these are Cali's extreme version of the compstar connecting rods which are designed to be as light as possible while still maintaining optimal strength you can see the extra Machining along the beam of the rod to help cut out a few additional ounces these rods weigh in at just 644 grams attached to the connecting rods are custom slugs from je Pistons Jamie works with je for these Pistons to come up with the right dome and piston relief combo to maximize the combustion ratio while also maintaining a high speed flame front and these are custom to this build because we'll be using steel valves on Jamie's titanium valve builds he likes to have a hundred thousandths of an inch of clearance for the exhaust valves but because he doesn't know who will win the engine and how particular they will be with the maintenance this time they went with steel valves steel valves are heavier than titanium obviously so the valve reliefs are a bit deeper to create about 140 thousandths clearance anyhow once everything is dialed in this engine will have a little over 14 to 1 compression ratio and burn 116 octane race fuel to help make room for big valves and minimize shrouding going into the cylinders Jamie maximizes the Piston diameter and shortens up the stroke these Pistons as I mentioned are four inches 125 thousandths in diameter so combined with the three inch 875 000 stroke that'll make the final displacement 415 cubic inches anyway after dropping the Pistons in the bores Jamie Torx the ARP Rod bolts the 75 foot-pounds which equates to between five and six thousandths of an inch of Rod bolt stretch so that's the rotating assembly and now it's time to move on to the cylinder heads and valve trains [Music] [Applause] [Music] engine builder Jamie Stone stabs in the roller camshaft Jamie worked with urson on this Cam and together they came up with this it's a 4-7 swap cam with a grind featuring 260 degrees of duration for the intakes and 268 for the exhausts both at fifty thousandths tap it lift the intake Center Line is set at 106 degrees and there's 450 thousandths of an inch of lobe lift for the intakes and 430 thousandths for the exhaust Jamie says he normally installs the camshaft with the timing Advance at agree or two to help the engine really accelerate hard coming out of the turns but using the cam timing as a tuning tool is certainly one of his options on down the line to help the engine match the driver and the car so an adjustable Tire timing set is a must here because adjusting the cam timing is an option down the road Jamie uses a Billet timing cover from cloy's with a removable panel that makes getting to the timing chain of a snap it also has an integrated adjustable cam button to set the camshaft in place here he works a little bit of oil into the berries before installation and then once the timing cover is bolted up setting the camshaft in play is as simple as running the button in or out with an allen wrench the rotating assembly is internally balanced so we'll be using a neutral balance harmonic damper from PBM this is their SS series of bonded dampers with steel for both The Hub and the inertia ring allowing enough Mass to dampen vibrations because still keeping the damper on a small diameter for quick acceleration and if you're wondering no I don't know where you can get this really cool hydraulic damper install tool Jamie's using he says a friend fabricated it for him and he's not making them anymore I know because I asked if I could get one for myself still pretty cool though the damper by the way is also SFI certified so it'll be allowed at any Racetrack and has laser etched timing marks all the way around which are pretty large and should be easy to see when trying to set the timing on your race car in a dark pit area and then the Billet timing pointer which is also from PBM helps ensure accurate ignition timing readings and won't ever bend on you like those flimsy stamped steel pieces with the timing cover installed Jamie can lay down the oil pan gasket we've already installed the mailing wet sump oil pump and the Kevco pickup the oil pan is a fully fabricated unit from Kevco with a windage tray and a large kick out to help reduce windage Jamie recommends Champion racing oil in 20 w50 weight now that may seem a little bit thick for you at first but Jamie says after lots of testing he's found the higher weight oil offers better protection even in the harsh environments of racing and in the event the engine runs hot on the dyno they'll run it with nine quarts but Racers will often add an extra quart for a total of 10 just for Extra Protection from high g-forces uncovering the pickup on the racetrack but you don't want to overdo it Jamie says he's run oil level tests and found that with 12 quarts on the dyno the engine will lose 40 horsepower for lifters we're using a set of solid rollers from Comp Cams they're standard Chevrolet small block diameter at 842 thousandths of an inch but they're 300 thousandths taller so that the tie bars will clear the tops of the lifter boxes Jamie has custom thinner multi-layer steel head gaskets made from kemetic with a compressed thickness of 36 thousands that's just four thousandths of an inch thinner than a standard MLS gasket but Jamie says he's found it helps tighten up the quench area for better burn of the combustion charge and now we're finally ready to get to the cylinder heads the usmts racing series allows a lot of leeway when it comes to the bottom end of the engine but when it comes to the heads the only ones allowed are these brodex spec heads the rule book says engine builders aren't allowed to cut weld or polish either the ports or the combustion chamber but you are allowed to Deck the heads so to get as much out of these heads as it can Jamie is angle milled the decks and managed to cut the 68 CC combustion Chambers down to around 61 CC's still engine builders are pretty limited here too when it comes to angle Milling because you aren't allowed to change the valve angle more than one degree although engine builders aren't allowed to touch the combustion Chambers they come from brodix already CNC cut and they're pretty nice for this build Jamie is using steel valves with lightweight titanium retainers which are all sourced from PBM the intakes are sized at two inches 55 thousandths while the exhausts are an inch 600 thousands now rules require a minimal valve spring diameter of 5 16 of an inch but in this case these are 11 30 seconds just to help move more heat from the exhaust valves and into the head where it can be carried away by the coolant in the water jackets also notice how high the valves sit in the chambers these seats aren't sunk into the heads at all now this is a nice touch and helps both increase compression ratio and airflow into and out of the heads the moment the valves crack open there is a flow path for air to follow the way that brodex makes it easy for a US MTS Tech officials to check and make sure that the ports haven't been opened up for more flow is by actually casting the word spec in every port as you can see here for the intakes it's in the floor of the port but in the exhaust it's in the roof because those are the areas most affected by any changes if the tech man checks inside the porch and sees that the word spec has been defaced in any way at all the engine is declared illegal and the team is thrown out simple as that Jamie installs the heads and secures them with a set of ARP head bolts torque the 70 pounds while he's doing that here's a look at the iski valve springs and PBM titanium retainers the Springs are set up so that at maximum valve lift they are approximately a hundred thousandths of an inch away from coilbine that's just to help reduce damaging harmonics the spring pressures are approximately 290 pounds on the seat and 780 open that's enough to help this engine live happily at the rules mandated 8 400 RPM Redline now that's just for the 415 cubic inch Motors the usmts actually allows a higher 8700 RPM rev chip for smaller 372 cubic inch race engines which Jamie also builds and while I mentioned that this engine will go 1500 laps between rebuilds the Springs will need to be swapped out for new ones at 750 laps mainly because the risk of a broken valve spring on the racetrack can result in a very expensive broken valve and grenaded engine finally we're ready to finish off the valve train Jamie installs and aligns the push rod guide plates and then drops in the eight inch long push rods [Music] the Rockers are lightweight aluminum units from urson we're using 1.6 ratio rockers for the intakes to help get a little more area under the curve and stock 1.5 ratio rockers for the exhaust that will make the gross valve lift one inch eighty thousandths for the intakes and 968 thousandths for the exhaust Jamie and his father Roger set the Lash on the valves for both the intakes and the exhaust at 14 thousandths of an inch cold they'll actually get them close to the Target at 18 thousandths hot latch setting and we'll double check that on the dyno once the engine gets warm and that buttons up the valve train on our 415 cubic inch dirt modified race engine now remember the big curveball with a build like this is the brodex spec heads that the usmts requires as a method for limiting costs to the racers the idea is there's no reason to spend big bucks on other components if the ports And the cylinder heads are going to be the choke point no matter what and that's mostly valid but in order to build a winning Engine with these restrictions Wiley engine builders like Jamie Stone must be able to build around the cylinder heads for example using a cam with more lift and duration will give more time for a flow limited intake Port like these spec heads have to move more air and fuel into the combustion Chambers it's also important to match the induction to the heads here Jamie and his dad Roger glue down the intake gaskets so they can't move and partially block the intake ports when the intake is bolted down then a nice bead of silicone is applied to the China walls and we're ready to roll the rule book leaves the choice of intake manifold largely open but after much testing Jamie says edelbrock's super Victor delivers the best results with this combination but he also says you have to avoid the temptation to grab a grinder and just hog out the runners for better flow Instead This intake package agrees with the smaller intake Runners the way the intake comes out of the box to help keep the velocity of the air and fuel entering the intake ports nice and high in these shots you can also see the hoses Jamie has already installed from the rear of the intake to the coolant Outlet up front now this is a simple way to help remove coolant from both the front and rear of the engine at the same time and help eliminate hot spots as we mentioned earlier these race engines are run at the absolute Red Line lap after lap and protecting against overheating is Paramount these hoses connect to a Billet aluminum thermostat Riser at the water crossover made by Weir's machine now this especially makes for a super sanitary Plumbing setup up front engine accessory steel horsepower that could go to the rear wheels so there's really nothing being spun off the crank pulley other than the water pump there's no power steering so no pump is needed there plus the races are short enough that an alternator is rarely needed anyhow this setup is made by Jones Racing Products and includes the water pump stock size pulleys can spin the water pump way too fast on a race track at racing speeds and that not only Burns horsepower but it can also cause cavitation this kit is designed with both the crank and the water pump pulleys specifically size for typical racing RPMs so that the water pump isn't spun any faster than necessary Kevco the same company that provided the racing oil pan also fabricates these high clearance aluminum valve covers that AN fitting you see at the front is for the Breather an MSD Pro Billet distributor will be used to Route the spark Jaime doesn't worry about installing the distributor so that the engine is properly timed right now instead it's just stabbed into place so he can measure and cut the custom wire plugs it's got to come back out to Prime the oil pump later and will be installed correctly on the dyno by the way that black aluminum bar is the mount for the carburetor return spring the last thing you want on a race track is a carburetor stuck at wide open throttle so that kind of stuff is taken very seriously and the last thing to go on before we head to the engine Dyno is the Holley double pumper four barrel carburetor it's sitting on a one-inch open spacer to help improve signal to the venturi's now this carb is sized at 850 CFM but interestingly Jamie says he doesn't really worry about that he works with a specialized car builder and they will build a few different options with different Venturi sizes depending on the track and conditions Jamie says it isn't unusual for teams to travel with maybe five different carburetors and swap them out depending on weather track conditions and even the race car chassis setup now we're finally ready for the payoff it's Dino Time now if I haven't mentioned it already Jamie Stone is one of the most efficient engine builders I've ever been around of course I guess you'd have to be if you're going to keep up with all the racers demanding his engines out of his three-man engine shop anyhow since we've last seen him Jamie has gotten our 415 cubic inch a mod engine all hooked up in his super sanitary Dyno cell and even finished the break-in process this engine is built to the United States modified touring series rulebook specs so we'll be burning gasoline and not alcohol it is 116 octane to be exact which is necessary to keep the engine from detonating with its extreme 14 to 1 compression ratio those lines coming off of each of the exhaust header tubes or exhaust temperature sensors now most engine builders don't invest into the capability to monitor individual cylinder performance in real time but Jamie says he believes it's critical to be able to create the best race engines possible anyway let's get this thing fired up and make some pulls foreign engine combo dialed in but because we've made a few changes to his usual Parts package he's doing a timing sweep and starting with it a few degrees more than usual for this pull we've got it set at 30 degrees before top dead center with it fully Advanced so let's see what she's got all right [Music] [Music] on the dyno we pulled from 4 500 to 7100 RPM now on the racetrack this engine will see as much as 8400 RPM it turns out the dyno had some sort of a hiccup and the full runs we did after these didn't have the correct data but here you can see both the horsepower and the torque Peaks and we'll do a full 8 400 RPM run at the end of this Dyno so you can Revel in that glorious sound anyhow at 30 degrees timing this engine made peaks of 575 pound-feet of torque at 4 700 RPM and 596.2 horsepower at 6200 now that's good but Jamie knows this engine has more so we'll just make a quick timing change to 34 degrees before top dead center and let it rip again [Music] [Music] [Music] better as you can see this time we saw peaks of 575 foot-pounds of torque at 5100 and 5200 RPM and 609.3 horsepower at 6400. that's an improvement of 13.1 horsepower and while the peak torque stayed the same we actually did see improvements in torque across the pole so overall it's all good next up 36 degrees of timing Jamie said from the jump that 36 degrees would be the ideal ignition timing for this setup and he nailed it [Music] Peak torque ticked up a hair by two to 577 pound-feet and Peak horsepower also moved up slightly to 610.1 but it was the overall Improvement that we were looking for the averages throughout the run compared to 34 degrees of timing we're up 2.4 for torque and 2.7 for horsepower and that Jamie says is enough to win races in this class here's his take yeah just come out to dino here uh Jamie at Stone Racing Engines very happy with the results uh we this thing's configured off of some stuff we don't typically use on our our ultimate packages uh but this is a giveaway engine uh ran really really well uh very pleased with the results and how it's going to perform on Racetrack this will get the job done on any night in the right car oh high RPM run all the way up to the 8400 RPM Redline we weren't able to pull data from this run but it's still awesome just to listen to a V8 that an average guy can afford to purchase and race make a pull to these stratospheric levels and remember it should be able to do this for 1500 laps before needing a rebuild all right [Music] [Music] nice huh thanks again for watching and if you're an oval track racer please leave us a comment on how this engine compares to what you're running we'd love to read about it see you next time
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Channel: The Horsepower Monster
Views: 119,125
Rating: undefined out of 5
Keywords: Stoen Racing Engines, Jami Stoen, USMTS Dirt Modified engine, how to build racing engines, how to build race engines, Jeff Huneycutt, Horsepower Monster, race engine build, USMTS race engine build, spec cylinder heads, World Products, Erson, Edelbrock, Brodix, World Products Motown II
Id: LZ21JyKtUNc
Channel Id: undefined
Length: 27min 0sec (1620 seconds)
Published: Fri Aug 11 2023
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