lawn tractor custom exhaust

Are you looking for the Lawn Tractor Custom Exhaust? Read through for aftermarket lawn mower mufflers. The article contains lawn mower exhaust silencer and lawn mower exhaust stack in the post.

You can build your own, homemade exhaust system for an old Briggs and Stratton lawnmower engine!

When taking my junk-picked 70s-era lawnmower apart, besides finding out that this motor was made the same year I was, I realized that the exhaust threads are a standard pitch 1/2 inch pipe thread!

aftermarket lawn mower mufflers

Lawn Tractor Custom Exhaust



The parts you will need are:
A short 1/2 inch nipple (short pipe, threaded on both ends)
A 1/2 inch x 1 inch hex bushing (female 1/2 inch on one end, male 1 inch on the other)
A 1 inch 90 degree elbow
A length of 1 inch pipe
A 1 inch cap
A drill and small drill bit(s)
Cutting oil for drilling (WD-40 or even motor oil will probably work)
(optional) Pieces of fiberglass tape or cloth for sound-deadening material.

PLEASE use black gas piping, NOT galvanized pipe. Galvanized pipe is coated inside and out in zinc. Zinc heated to very high temperatures can offgas and make you feel very sick. There is some debate as to whether zinc exposure leads to long term health effects, but I have gotten some stern warnings against welding zinc, so have used only black gas piping for this project.

You could also probably do this project with aluminum or threaded copper pipe, but for safety and affordability, I went with the steel. You probably wouldn’t want to use soldered copper, in case the solder were to melt and cause trouble.

Step 1: Remove Old Muffler

Remove Old Muffler

On these old engines, the muffler is easy enough to remove. Simply unscrew it from the engine block. (lefty loosey, and please do this when the muffler is cold!)

Step 2: Assemble the Manifold

Assemble the Manifold
Assemble the Manifold
Assemble the Manifold
Assemble the Manifold

The manifold (Part of the muffler that attaches to the engine block) is easy to make from a threaded nipple, a hex bushing and a 90 degree elbow.

Assemble these parts tightly. Depending on the final required orientation of the muffler, it may be necessary to attach some parts with a bit of fiberglass tape to allow more flexible positioning of the joints. Here, I used fiberglass cloth left over from a canoe pontoon project, but you could also use fiberglass drywall tape. You might not require the fiberglass at all. I didn’t use plumbers tape because I was concerned about the heat generated by the muffler burning the tape and causing a stink.

Step 3: Fabricate and Assemble the Muffler Body

Fabricate and Assemble the Muffler Body
Fabricate and Assemble the Muffler Body

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To make the muffler body, I used a 12 inch length of 1 inch diameter pipe, into which I drilled 5 3/16 inch holes. I discovered that two holes was not enough and 5 seemed to be OK. You can experiment with the number of holes if you like, and a 12 inch pipe is probably overkill.

Before and during drilling, I wet the steel with WD-40 (cutting oil may work better) to cool the drill bit so as not to wear it out. The metal is quite thick and I broke 2 drill bits by trying to rush things. Take your time and use plenty of oil.

After the holes are drilled, clean up the pipe to remove any metal particles and cut a short length of fiberglass tape. Roll it up and stuff it into the end of the tube. The fiberglass will serve to deaden the noise a little,but it may also come flying out of the exhaust holes when the engine is running. It helps to cut the fabric as little as possible so as not to create many loose threads.

Screw the pipe cap on tightly. You can remove the cap or disassemble the muffler entirely to repack or repair it in the future.

Step 4: Attach the Muffler

Attach the Muffler
Attach the Muffler

The original muffler has a stop on it to prevent you from over-tightening it and stripping the threads. Your new muffler will not have this safety feature, so be careful when threading the new unit into place. The engine block is aluminum and very soft in comparison to the steel pipe. Do not use a wrench to thread the pipe into the block – hand tight is plenty.

Once you are satisfied with the tightness and orientation of the manifold, screw the muffler body into it. You have a muffler!

You should now be ready to test the exhaust. Be careful when testing and running the engine!

1) The new muffler is much heavier than the old muffler, and may cause stress damage to the engine block if it is not installed and supported properly.
2) The fiberglass tape may come out of the exhaust holes – be aware of this and on alert in case the engine decides to suck up a strand.
3) The muffler gets VERY hot, VERY fast. Do not EVER touch a muffler after running the engine for more than a few seconds.
4) Please do NOT use galvanized pipe. Only use black gas piping. Galvanized pipe is coated in zinc and when exposed to extreme heat, it could offgas and make you feel very sick. My original attempt was with galvanized pipe, and I got a bit light headed after the muffler heated up for the first time. Also never weld galvanized metal for the same reason.

Please be careful. This project involves extreme temperatures, hot gasses and fast moving parts. Do not rush things and be always aware of where your hands and feet are in relation to the mechanisms.

Step 5: Fit and Finish

Fit and Finish
Fit and Finish

The final steps are up to you.
The muffler may need extra support, which could be accomplished with cleverly placed bolts, hose clamps or pipe support straps. Use your head and think of where the forces are going to be transferred.

Dress up your exhaust tube and add a margin of safety with an exhaust tip or cover.

Don’t be afraid to experiment with the amount of packing material, number, size and placement of holes, etc. This muffler is completely customizable.

I originally designed a much smaller muffler with larger diameter pipe, but when I moved to the black gas pipe, the larger pipe diameters were not available.

lawn mower exhaust stack

Types of Crate Engines

REBUILT/REMANUFACTURED

Rebuilt or remanufactured engines are among the most widely available and affordable choices. All these terms mean is that the third-party seller took an existing engine with a good core and went through to ensure it’s back to factory specifications. Speaking of factory specifications, if you’re just looking for a direct replacement, this is probably the type of offering that’s available to you. It’s just as good as an engine that’s brand new.

MANUFACTURER-DIRECT ENGINES 

The manufacturer of a vehicle may offer direct replacement crate engines for your car. For the most part, this is something that’s limited to performance or specialty engines, though. These engines are brand new, as though they were assembled to go with a car coming fresh off the assembly line. Because of this, you can generally expect the price point to be quite a bit higher than remanufactured engines. 

PERFORMANCE-BUILT

Crate engines that are already worked over are also widely available. These engines can feature a list of custom parts such as pistons, rotating assemblies, camshafts, intake manifolds, and forced induction systems to meet a specific performance goal. As you can expect, these engines are often a lot more expensive than the previous types of crate engines that we visited. That said, they can be either brand new directly through the manufacturer or remanufactured by a third-party supplier. 

RACE-READY 

Sometimes sanctioning bodies get involved and enforce a long list of rules for what parts engines used in certain events can or cannot use. Race car owners can either build an engine to match a specific list of rules or buy a crate engine approved by the sanctioning bodies for events. This is typical for something like circle-track racing. And yes, the tech inspectors might even go as far as looking at the engine internals on race day to ensure that the pistons and rotating assembly meet their standards, especially if it’s custom-built.

Top Brands

GM PERFORMANCE PARTS

Based out of Green Bay, Wis., GM Performance Parts builds and designs a number of products for vehicles. The company focuses on manufacturing transmissions, drivetrains, accessories, and both big-block and small-block crate engines. One of its most popular engines is the Genuine GM 350i / 5.7L Gen 0 Engine.

GENERAL MOTORS

Formed in 1908, General Motors is one of the most popular and well-known names in the world of motorsports. The company’s central location is in Detroit, Mich., and it makes a number of vehicle accessories and parts, including the Chevrolet Performance 6.2L LS3 Engine Crate GM.

EDELBROCK 

A company that has roots that go as deep as 1938 needs little introduction, especially when the founder has had as much of an influence on automotive culture as Vic Edelbrock did. This titan of a company works out of Torrance, Calif., and pumps out anything you’ll need to hop an engine up, even if it means replacing the engine with something like the Edelbrock Performer RPM 410 Crate Engine.

FORD RACING 

Despite Ford’s legendary triumphs in the world of racing that extend as far as LeMans, the Ford Racing division wasn’t introduced until 2014. Naturally, the headquarters is found in Dearborn, Mich., just outside of the Motor City. They produce pretty much anything you’d need to hop up your Ford, including the monstrous Ford Performance Parts M6007-572DR 572 Big Block Crate Engine.

Crate Engine Pricing

  • $2,000 to $3,000: Remanufactured/refurbished engines typically fall in this range. It’s likely that the engines in this range require parts like the induction system and sensors for assembly.
  • $3,000 to $1,0000: Complete engines and performance options can appear in this price range. For the most part, these are either high-performance factory offerings or custom assemblies.
  • $10,000 to $20,000: High-performance factory engines and serious performance crate engines populate this price range. Performance and build-quality increase with the price.
  • $20,000 and up: Exceptionally powerful engines are almost exclusive to this price range. Fuel injection, superior rotating assemblies, and even superchargers are typical for these crate engines.

Key Features

COMPATIBILITY

Crate engine compatibility is something that has many meanings. For many, it might just mean ensuring the motor is a direct match for the application. For others, it can mean making sure that it’ll work with the parts they need for an engine swap. It can even suggest that the engine matches rules set forth by a particular event in some cases. In any situation, you need to do your homework to ensure that the engine reaches the criteria you need it to. 

POWER OUTPUT

The amount of power that an engine puts out is something to pay close attention to. It’s easy to simply look at peak power, but you want to consider when it makes that power and how. Compression ratio, displacement, and power curves all tell you how that engine behaves. How and when it makes power ultimately tells you what kind of driving it’s good for. 

USE OF APPROPRIATE PARTS

We can say that you want to make sure quality parts are used in the crate engine. However, that paints a broad stroke that doesn’t explain what you’re looking for. If it’s a factory-spec engine, “quality parts” is typically a descriptor telling you the engine uses factory equipment. That is fine for a direct-replacement engine, but those components may be risky for use on performance engines. If you’re looking for an engine that boosts performance, make sure to look at the types of pistons, connecting rods, and crankshaft used to ensure it’ll handle the power it produces. 

INCLUSION OF PARTS YOU NEED

You’ll see that some engines don’t come with the induction system, sensors, and other parts necessary to their function. In the case that you can scrap these parts from your old engine, that’s not a big deal. If you don’t have an old engine to pull pieces from, you might want to consider a different crate engine. Sure, the long-block does make up for a significant portion of the expenses associated with engine building, but the small “nickel and dime” parts can quickly add up to a big price tag. 

Other Considerations

  • Warranty Coverage. Just because a warranty is listed under “other considerations” doesn’t mean it’s not important. Crate engines often come with a warranty to protect the owners from any defects. Considering you can spend a massive amount of money on the engine, it is worth checking out the warranty to ensure your investment is protected.

MORE ON AUTOMOTIVE PARTS & TOOLSBest Engine Air Filters: Keep Your Engine Free Of Contaminants

Best Crate Engines Reviews & Recommendations 2021

BEST OVERALLChevrolet Performance 6.2L LS3 Engine Crate GM

Chevrolet Performance 6.2L LS3 Engine Crate GM

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Yep. We’re starting our list of crate engines with an LS. Don’t worry — there’s a lot to unpack here as it’s not just another LS. This is an LS3 6.2-liter engine that’s been suited up to perform. It’s turning a nodular crank that’s attached to hyper eutectic pistons via powdered connecting rods. While that is a pretty much factory rotating assembly, it’s capable of spinning out an impressive 525 horsepower at 6200 RPM and 486 pound-feet of torque at 5200 RPM. Most of that power output is due to an appropriate valvetrain, which just goes to show that you don’t need much to bring these engines to life. 

As for those screaming, “just go to the junkyard,” we hear you. This price tag is quite a bit more than someone can use to turn out even more power with a used LS engine. However, the fact that this is a 500+ horsepower engine with a warranty makes it worth the consideration.BEST VALUEGenuine GM 350i / 5.7L Gen 0 Engine

Genuine GM 350i / 5.7L Gen 0 Engine

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Ever since the LS took the world by storm, everyone forgot about the “Mouse.” The Chevy 350 was once thought to be one of the most versatile engines in the world as it made its way into seemingly everything. That said, there comes a time when you need a basic 350 to keep your rig moving. That’s precisely what we’ve got here. It’s no monster performer, nor is it going to take your older Chevy car or truck into a whole new world of speed. That said, it’s every bit as reliable and compatible with any aftermarket parts that you could expect the classic 350 to be. 

What’s the drawback? Considering this is the most affordable option on the list, you’d think we’d leave the price alone. But for nearly $3,000, you should expect a little more than the predicted 195 horsepower. Not only that, but there’s no induction system, which means you’ll be spending another couple hundred bucks to get it running.HONORABLE MENTIONFord FRDM6007-A52XS XS Aluminator Coyote 5.2L Crate Engine

Ford FRDM6007-A52XS XS Aluminator Coyote 5.2L Crate Engine

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This offering from Ford is a good example of the level of performance that’s available to you when you opt for a crate engine. Rather than having to sit down and figure out how to not only rebuild an engine, but make it more powerful, you simply pick the part number that gives you nearly 600 horsepower. This mighty Coyote 5.2-liter comes to your doorstep ready to make 580 horsepower at 7,800 RPM and 445 pound-feet of torque at 4,500 RPM. And don’t worry, the forged rotating assembly is more than capable of taking whatever you throw at it.

Of course, the drawback to this engine is that it costs nearly as much as a new car. We can groan about it all day long, but the reality of buying a crate engine often means you’re in for a considerable expense. Which is exactly why many opt to build rather than buy.BEST UPGRADEFord Performance Parts M6007-572DR 572 Big Block Crate Engine

Ford Performance Parts M6007-572DR 572 Big Block Crate Engine

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Crate engines are known for supplying copious amounts of power and cutting down the amount of homework that builders need to do. That said, this 572 cubic-inch, or 9.4-liter, big block is a prime example of the kind of power that you can have delivered to your doorstep. This monster can wind up to put out an impressive 655 horsepower at 5500 RPM and an insane 710 pound-feet of torque at 4500 RPM. That’s more than enough to get any car or truck moving fast enough to rattle anyone’s cage. That said, the hydraulic-roller camshaft and beefy rotating assembly are more than capable of keeping things safe and manageable.

Of course, it’s no light expense. This is yet another engine assembly that costs nearly as much as an entire car. But, again, that’s something to expect when you want that kind of power.HONORABLE MENTIONEdelbrock Performer RPM 410 Crate Engine

Edelbrock Performer RPM 410 Crate Engine

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Something like this really makes Ford and Mopar guys hate Chevy nuts. Why? Because it puts out a considerable 410 horsepower and 408 pound-feet of torque with a 9.5:1 compression ratio. So, not only is it producing 1.17 horsepower per cubic inch, but it’s doing it on pump gas. That may be possible for any engine with the right build, but the cost is about what you’ll invest in parts for those other platforms to get the job done — never mind machining and assembly. This thing even comes with the carburetor, water pump, and harmonic balancer. That makes it pretty much a true drop-in option.

There really aren’t too any drawbacks to this model. No, it’s not the most powerful option, but it really doesn’t need to be. About the only thing to complain about is the impossible standard this type of crate engine produces for folks outside of the GM world to look for.HONORABLE MENTIONFord Performance Parts M6007-M50C 2018-2019 Coyote 5.0L Crate Engine

Ford Performance Parts M6007-M50C 2018-2019 Coyote 5.0L Crate Engine

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Ford’s Coyote engines are notoriously expensive. As you can see from some of the options on the market, you can spend a serious amount of money to obtain one of these platforms. This particular engine is pretty much on the low side in terms of dollar value, making it a far more favorable option for many. That said, it’s a factory-spec 2018-2019 5.0-liter Coyote. That might seem a little lackluster, but remember that these engines are rather impressive in their natural configuration. It’s a great option for someone who needs to replace the worn engine they’re working with, or someone looking to Coyote swap whatever they’re working on.

The price is high, but it is what it is. It is high for a direct-replacement engine, but these Coyotes aren’t exactly the most affordable option from the get-go. You might be able to save money if you’re lucky enough to cop one from the scrap yard. But Ford nuts are hot on it, so your chances of doing so are slim unless you’re Johnny on the Spot.HONORABLE MENTIONPROFessional Powertrain DDH8 Chrysler 5.7L Hemi Engine

PROFessional Powertrain DDH8 Chrysler 5.7L Hemi Engine

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We admit that Mopar isn’t seeing much love throughout this entire piece, so it’s only appropriate to squeeze in an example. In this case, we’re looking at a remanufactured 5.7-liter Gen 3 Hemi. It’s a remanufactured bit, which gives us peace of mind knowing that a good engine wasn’t melted down and turned into a set of skillets. All joking aside, this is a great option for folks needing a replacement engine for their 04-08 V8 Mopar commuter that’s seen its day. It includes everything from the block and rotating assembly to the cylinder heads and valvetrain, effectively cutting down the number of parts you need to pull together to get your rig running again.

Being a long block, the lack of an induction system, a timing cover, and sensors means there’s still a fair bit of work ahead of its new owner. You’ll either need to pull what you can from your old engine or buy all new parts that could tally up to a considerable expense. We should also note that this is the truck Hemi, meaning Challenger and Charger owners would likely want to consider a different option.HONORABLE MENTIONGenuine GM (12568758) 5.7L Gen1 Truck Engine

Genuine GM (12568758) 5.7L Gen1 Truck Engine

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Use this engine to replace a tired, worn engine. The engine allows you to start with this economical production motor, then you can add your choice of power-adding accessories.

It’s a 5.7 liter, 350 cubic inch engine that fits in 1987-1995 light GM trucks (under 8,500 pounds), but you can adjust it for use in many other small-block applications. It uses a late-style, one-piece rear main seal and the motor’s cylinder heads have center-style cover hold downs. Other details include a machined fuel pump (no hole for the fuel-pump push rod, though) and a gear-driven oil pump assembly. The motor develops 210 horsepower at 4,000 RPMs. Torque is 300 foot pounds at 2,800 RPMs. It has a cast-iron block, one-piece rear seal, two-bolt main caps, and a one-piece nodular crankshaft. Compression ratio is 9.4 to1.

Note that this engine cannot be used in marine applications.

Tips

  • Don’t rule out short blocks. You might not find a crate engine that suits your needs, but that doesn’t mean you’re out of luck. You can purchase a high-performance short block to fit heads and a valve train that’ll meet your demands.
  • Don’t go with more than you need. It’s tempting to invest in a more powerful engine. Keep in mind that more power is more wear and tear. The factory transmission and drivetrain might not be able to keep up with the power you’re introducing, leading to significant headaches and more expenses. 
  • There’s still plenty of work ahead of you. Crate engines don’t install themselves, and you’ll need plenty of time to “drop one in.” Not only does that mean that you’ll need the tools for the job, but enough time to do it right. Always remember that things never go the way they’re supposed to. Calculate that into the time you set aside to work on your car. 
  • Be conscientious of who you’re giving your money to. There are a shocking amount of suppliers offering crate engines. Be aware that not all are as respectable as they make it seem. Take the time to research the suppliers and find one that you know you can trust. 
  • Consider your machine shop. Just because an old motor is worn down doesn’t mean it’s junk. Your local machine shop can likely breathe new life into an engine by honing the cylinders, rebuilding the heads, and so on. It’s always a good idea to support local businesses, and the machine shop can even build an engine custom to your demands.

FAQs

Q: HOW DO I DETERMINE WHAT CRATE ENGINE IS BEST?

It depends on the style of driving you do and the car you are fitting it into. If the vehicle is your daily driver, then consider matching the replacement engine as close to your original one as possible. If you plan on racing, choose one with more power and torque.

Q: HOW DO I INSTALL A REPLACEMENT CRATE ENGINE?

That is a tricky question to answer. Ultimately, it depends on your particular case. In any situation, however, it’s not as simple as just removing the old engine and dropping the new one in place. You will need to carry over any accessories or parts from the old engine that are essential to getting it running. In short, you’ll need to do your homework to find out what’s necessary for your particular setup and the engine you’re using.

Q: DO I NEED TO REPLACE EVERYTHING CONNECTED TO THE ENGINE?

That depends. If you’re just experiencing mechanical issues, there’s no reason that you couldn’t use the accessories and sensors attached to your old engine unless they’re junk. It’s best to evaluate each of the components you’re considering carrying over to ensure they’re suitable for use.

Final Thoughts

Again, our top pick goes to the Chevrolet Performance 6.2L LS3 Engine Crate GM, and our choice for Best Value is the Genuine GM 350i / 5.7L Gen 0 Engine. We get that we’re talking about crate engines, though, so these engines might not even work for your application.

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