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The Dirt on Demolition Derby Engines

Fair food, warm summer nights and the roar of engines firing up can only mean one thing – it is demolition derby season. The days of going to the junkyard and picking up a beater, knocking the windows out, and heading down to the derby are long gone. Now are the days of 400+ horsepower engines, custom drivetrains, cradles, and reinforced cars with solid steel “pointy” bumpers.

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Fair food, warm summer nights and the roar of engines firing up can only mean one thing – it is demolition derby season. The days of going to the junkyard and picking up a beater, knocking the windows out, and heading down to the derby are long gone. Now are the days of 400+ horsepower engines, custom drivetrains, cradles, and reinforced cars with solid steel “pointy” bumpers. With large derbies and winning purses upwards of $30,000 per team popping up all over the country, it is easy to see why drivers and teams are willing to spend money on purpose-built engines that will get them the win.

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All the drivers who approached BRE wanted one thing – an engine that would run well while hot and not die on the track.

Baldwin Racing Engines (BRE) broke into the derby market around 2005 with something most people were not accustomed to, reliable derby engines making big power. At the time, there were already several known engine builders in the derby market such as Gard Speed Shop, Gropp Automotive Specialists, Colyer Performance, Redline Racing Engines, and Scott Zizelman. The general consensus was that rebuilding a factory style SBC with big tolerances was your best shot at getting an engine to run any length of time without water. 

Baldwin broke into the derby market in 2005 with reliable derby engines making big power.

BRE at the time, was heavily invested in circle track racing and drag racing when we were approached by several derby drivers in our area wanting us to build them engines to run in some of the larger derbies across the country. Over time we developed good relationships, and by having the engines close to home, we were able to tear them down regularly to see the fruits, or faults, of our labor. We were always trying to come up with new ideas just to get a few more minutes of run time with no water and outlast the next guy. 

Once business really took off, we realized all the drivers who approached us wanted one thing, an engine that would run well while hot and not die on the track.  

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The demolition derby market was, and still is, an extremely lucrative market when it comes to “getting in” and being accepted. Teams are very loyal to certain brands or builders and follow what they see work on the track more than anything. We have found that traveling to bigger shows to vend often gave drivers a chance to talk with us and ask questions, resulting in more sales and interest in our product. When we sent an engine to a new part of the country our phone would ring off the hook after that first run or win. People calling wanted to know what those drivers had, how much it cost and when they could have one in their car. Word of mouth is still very much a driving factor in demolition derby when it comes to who makes it and who does not.

Derby engines are subjected to more extremes than most engines involved in competition. We have shot engines with a laser thermometer coming off the track and seen temperatures upwards of 550–600 degrees F. It is extremely common for the cars to puncture the radiator within the first few minutes of a heat or feature, and the drivers are not going to stop or go easy on the engine. For the next 30 to 45 minutes, typically, that engine will see the rev limiter more times than you can count with no water circulating through it. On a stock engine, pistons will start to seize in the bores, valves will start to stick in the guides, oil becomes thin from extreme heat, valve seats start to drop out of heads, blown head gaskets can occur, and babbit camshaft bearings begin to melt.

The main goal of building a derby engine is to reduce or eliminate all known weaknesses or failure points that are heat related.

So you ask, what does it take to make an engine run for 30-45 minutes or an hour without a drop of water in it? The main goal is to reduce or eliminate all of the known weaknesses or failure points that are heat related. All blocks receive a full treatment in the machine shop, including a deck resurface, bore and hone, and a line hone. The clearances are, as you guessed, set looser than your average street or race engine would be. All heads receive a fresh valve job with a custom cutter we designed to help draw as much heat as possible away from the valve. Every housing and bearing is painstakingly measured during assembly to insure perfect bearing clearance. 

We also offer several custom machining options such as a roller cam bearing tunnel cut in-house or piston oiling jets to help pull heat out of the pistons and bores. Along with our custom machining options, we have started using thermal coatings on our high end builds and have seen a drastic reduction in wear and heat related issues. Being a race engine shop, we offer full engine dyno services as well, which have helped us in developing and refining our machining and building process. Not only do we use the dyno for research, we also utilize it for making sure engines leaving the shop are running the best they can.

At BRE we offer several different levels of SBC derby engines for our customers. With good usable SBC two-piece cores becoming increasingly harder to come by, we offer our “stage 1” as cores are available. Our entry level or “stage 1” engine features mostly stock parts set up with our machine work and tolerances. We use only certain factory casting heads that we found are less prone to cracking under extreme heat. These engines receive a standard rebuild with new cast pistons, rings, valve springs, bearings, gaskets, and a flat tappet cam and lifter set. While we are not particularly fond of retaining the flat tappet camshaft, especially in our derby engines, we offer it as a cost reducing option to keep our “stage 1” budget friendly.

You can build the strongest engine possible and it will still need to be freshened up periodically. How long an engine needs before freshens is anyone’s guess when it comes to derby engines, since you cannot count laps or passes under ideal conditions.

The “stage 2” is by far our most popular selling and winningest engine. We offer this engine in 355 cid and 377/383 cid combinations depending on what the customer desires. This setup starts off with a good 350 cid core block or a new GM casting 350. We typically use a cast aftermarket rotating assembly in our “stage 2” engines from companies such as SCAT or Eagle products. All balance work is performed in-house on our CWT balancer to ensure that everything is within our tolerances. For cylinder heads, we will typically go with a cast iron set of Dart or World Products heads and finish machine them in-house. 

All of our “stage 2” engines come equipped with solid roller lifters and custom camshaft setups. We use solid lifters as opposed to hydraulic ones to avoid losing control of the valve train as the oil thins out and pressure decreases due to heat. MLS head gaskets are used, which are clamped down with ARP head studs. ARP studs are commonplace on these engines to help increase the clamping force and avoid blown head gaskets. 

Due to many customers running a cradle on their engine, which is a large, steel containment unit used to protect the engine, we are often limited to running a factory style oil pan. The factory oil pan influences our decision to steer away from high volume pumps as we have seen several pans sucked dry from sustained, high rpm runs. These engines are topped off with a good, dual plane intake, MSD RTR distributor and a Holley 4412 carburetor.

The Nitro Elite series engines are built to be the strongest and most powerful engine on the track at any time. Boasting 625-800 horsepower in sizes ranging from 355 cid to 427 cid, the Elite series is the highest quality derby engine we offer. We start with a Dart SHP or Little M block to gain strength, bore size and a priority main oiling system. Piston cooling jets and thermal coatings are used in the engine to help control heat. Elites come standard with roller camshaft bearings to eliminate the chance of cam bearing failure. A Callies 4340 crankshaft is used to make sure the bottom end has a strong base. Forged CP-Carrillo pistons are fitted to either Callies or CP rods. We use Total Seal rings on our Elite builds to ensure the rings can stand up to the abuse and keep going. COMP Cams provides the thump with a custom ground camshaft and a set of solid roller lifters. 

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As with the stage 2, we use cast iron Dart heads in conjunction with ARP head studs and MLS gaskets. COMP Cams pushrods and rocker arms are fitted to the heads using 7/16˝ hardware. For the Elite series, we either use a large, dual plane intake or small, single plane intake. And, rather than only using a 4412 two-barrel carburetor on the Elite, we recommend a Willy’s Carburetor and Dyno Shop four-barrel as an upgrade to make as much power as we can.

You can build the strongest engine possible and it will still need to be freshened up periodically. How long an engine needs before freshens is anyone’s guess when it comes to derby engines, since you cannot count laps or passes under ideal conditions. Some of the things we consider are how hot has it been, how long it ran at extremely high temperatures, and what kind of maintenance schedule the driver follows. 

Some drivers choose to wait until the engine has had a complete failure before bringing an engine back in; while others are more proactive and have a regular maintenance and freshen schedule they religiously follow. More often than not, a derby engine we built only requires a standard freshen up, consisting of a fresh hone, rings, bearings, a valve job, and new gaskets. 

While we do everything we can to ensure the inside of the engine is durable, you can’t always guarantee that things won’t happen. One of the most common issues we see are blocks that have externally cracked or have had the motor mount holes broken out of them from impact. While you can try to repair these issues and limp an engine along, it is more cost effective in the long run to reblock the whole engine and get the driver back out and winning.

Anyone in motorsports can tell you that engine trends will continue to ebb, flow and evolve over time. During the time we have been involved in derbies, we have noticed the trend go from stock-style builds to trying to make as much power as you can make. However, recently the trend has been leaning toward going to less power to increase run times and fuel efficiency. With many features taking longer than ever and getting up into the two and three hour marks, many people are concerned about making sure they have enough fuel to make it the whole feature. With that being said, there are still big horsepower engines out there, but now many drivers have multiple cars with different drivetrain combinations they can tailor to the rules and conditions of a particular event.

The future of demolition derby is a very bright one. With shows all across the U.S. and Canada, the opportunity to participate as well as spectate is becoming available to a larger audience. Many drivers are taking the step to run on a national level and travel the country to chase big payouts. More shows in new places means people who have never seen a demolition derby now have the chance. We urge you, if you or your friends have never attended a demolition derby, it is worth your while!

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