Big Block Options 2021

[slonomo]

I think it's good to stay on top of the Big Block options game, since it has been changing every year.

If you need to repower your cart, or want to repower, here are your current engine options, in no particular order.

Non Lifted Carts

1. Factory Rebuild or New
*best for quietest operation
*campground or golf course use
*longest lasting if done properly
*parts can be a bit expensive

2. Clone Engine
*this refers to the Honda GX390 engine and it's copies (or clones)
*Predator 420 13hp (Harbor Freight)
*Duromax 440 18hp (Home Depot, Amazon, online)
*Honda GX390 13hp (from Honda retailers)
*There are other engines, these are the most commonly used
*Good power increase over stock
*Louder than stock, but decently quiet when left unmodified
*Can be modified for more power
*Good aftermarket support
*Proven reliability in the Honda model for decades
*Clones are decently reliable

Lifted Carts
*this opens the door for more engine choices, almost unlimited, because the engine bay is made larger by lifting the cart

1. Factory Engine (see above)

2. Clone Engine (see above)

3. Briggs and Stratton Vanguard 479cc 16hp (various retailers/sources)
*Very quiet in stock form
*More power than stock
*High torque rating at lower rpm
*Pressurized oiling system
*Proven reliability for decades
*Can be rebuilt for a reasonable cost
*Good parts availability
*Can be modified for more power
*Good aftermarket support

4. Briggs and Stratton Vanguard 627cc 23hp (various retailers/sources)
*Moderately quiet in stock form, although louder than the 479cc
*Much more power than stock
*Extremely high torque rating at lower rpm
*Pressurized oiling system
*Proven reliability for decades
*Can be rebuilt for a reasonable cost
*Good parts availability
*Can be modified for more power
*Good aftermarket support
*Fairly tall and wide engine, can be tight for smaller carts

5. Predator 670 670cc 22hp (Harbor Freight)
*Moderately quiet in stock form, although louder than the 479cc
*Much more power than stock
*Extremely high torque rating at lower rpm
*Pressurized oiling system
*Reliability seems good
*Can be rebuilt for a reasonable cost
*Good parts availability
*Can be modified for more power
*Good aftermarket support
*Fairly tall and wide engine, can be tight for smaller carts
*Factory parts are near impossible to get, aftermarket is good option
*Lower cost alternative to Briggs engines

6. Honda GX630 688cc (various retailers/sources)
*Moderately quiet in stock form, although louder than the 479cc
*Much more power than stock
*Extremely high torque rating at lower rpm
*Pressurized oiling system
*Proven reliability for decades
*Can be rebuilt for a reasonable cost
*Good parts availability
*Not as friendly for modifications, most keep these stock
*Slightly smaller in dimension, good for tight fit applications

There are other engines, many in fact. These are just the most commonly used engines that have proven to be reliable enough to have developed a decent following.

Visit the "Site Sponsors" page and check with BGW's sponsoring companies for engines and engine swap parts. Some have complete kits available.

[slonomo]

There are some larger displacement engines available, but none that have a lengthy term of use in the aftermarket, so they are not listed here only for that reason.

I would not list any engine that hasn't had a reasonable track record for reliability and durability.

[slonomo]

Honda GX390

The GX390 is a 389cc OHV engine with 11.7 hp at 3600 rpm, and 19.5 lb ft of torque at 2500 rpm. It's a counter clockwise rotation, if looking at the PTO side. They come with a 1" crankshaft that will adapt to many primary clutches for golf carts. Since 2010 they have been equipped with a digital CDI ignition system. Max rpm on these engines in stock form is 3600 rpm, which is good enough for around 18-20 mph on most stock golf carts, very similar to stock speeds.

The idle speed is set at 1400 rpm from the factory, so shifting from neutral to forward or reverse might be a sticking point, with some grinding and hard engagement. To combat this, several manufacturers have introduced an "adjustable" carb replacement. While not perfectly ideal, the idle can be set to around 1100-1200 rpm, which will work with most golf carts. Some adjusting to the idle is likely needed with this engine.

Honda has been manufacturing small engines since the 1950's. The GX series engines have been in production and use since 1983. Millions of these engines have been used to repower generators, pressurewashers, lawn mowers, small equipment, and more. Decades of reliability are proven.

Many manufacturers have copied this design, which we call "Clones". Two popular and respected clones of the GX390 would be the Predator 420 and the Duromax 440. Both have shown to be viable engine replacements for small equipment. Some parts are interchangeable from one engine to another, but not all. You can find many members of BGW who have used different versions of this engine with good success. Some have even modified their engines for high performance use.

Attached is a copy of the Honda GX390 manual.

You can find more info on the Honda GX390 at https://en.honda-powerproducts.com/

Duromax engines website https://www.duromaxpower.com/collections/engines

Predator engines website
https://www.harborfreight.com/engine...s-engines.html

[slonomo]

Briggs and Stratton Vanguard 16

The 479cc engine is rated at 16 hp at 3600 rpm, and torque in the neighborhood of 24 lb ft at 2400 rpm. For a golf cart you would want the horizontal crankshaft in the 1" diameter to fit most golf cart clutches in the aftermarket.

Briggs has manufactured small engines since the early 1900's. In the early 1950's they introduced their lightweight aluminum block small engines. Since the 1990's the Vanguard engines have been used regularly in racing applications, including the legendary "Bandolero" race car in 1998. See link https://www.briggsracing.com/about/racing-history

Vanguard engines have been proven reliable and have been widely used. Parts availability is excellent and aftermarket support is also excellent. These engines have also been modified heavily for more power over the years with good success.

One thing to note here is that the Vtwin engines are much taller than the OE engines and GX390/clone engines. The lift kits of most golf carts allow more room in the engine compartment, which typically allows the use of a Vtwin engine such as the Vanguard. Another thing, most of these engines don't come with mufflers because they are used in many different applications, so plan on buying a muffler.

Some reasons to choose this engine: The 16hp Vanguard is one of the more compact versions of the available vtwin engines making it a very popular choice. Another reason this engine is popular is the sound/noise from the engine is less compared to the larger displacement engines. Finally, the idle quality and speed of these engines is ideal for a golf cart, since the carb is adjustable, has an idle circuit, and is possible to idle at or below 1000 rpm for easy shifting.

More info on these engines can be found at:
https://www.briggsandstratton.com/na...l-engines.html

Briggs and Stratton Bankruptcy

Yes, this year, Briggs has filed for Chapter 11 bankruptcy protection and has sold the company to KPS Capital Partners for $550 million. KPS plans on continuing to operate Briggs and Stratton products with some restructuring and new partnerships. The following articles outline the issue.

https://www.bloomberg.com/news/artic...for-bankruptcy

https://www.foxbusiness.com/markets/...asset-sale-kps

[slonomo]

Briggs Vanguard 18 and 23

All the same advantages apply to these engines as with the 16 version above.

Keep in mind....Both of these engines are larger in displacement and physical size compared to the 16 version. Both are rated higher in horsepower and torque. Both are heavier. Both will use more fuel, especially if the engine is equipped with the 2 barrel carb. The upside here is BIG POWER over stock and lots of grass shredding fun. So if power, torque, and speed are your goals, go for the gusto with the 18 or 23.

Please note that two of the forum sponsors currently sell kits for and/or with these two engine options. Please visit the sponsors and check out their kits!

[slonomo]

Predator 670

This engine is gaining popularity recently. We have seen several companies making speed parts for them. Check with our sponsors to see if they are offering any kits with this engine in mind.

Since it's newer to the market, not as much reliability and durability info is available. The 670 is rumored to be a good powerplant with plenty of power, with 670cc of displacement. On a good note, the 670 does come with a muffler so you won't have to purchase one separately, like with some of the Briggs Vanguards.

Some of the members here have used them with good reports, although I have read about a few problems as well. Do a search here and read the threads about it to make your determination if it's for you.

Details and specs can be seen here
https://www.harborfreight.com/22-hp-...epa-61614.html

[slonomo]

Honda GX630

This Vtwin engine is 688cc and has 20.8 hp at 3600 rpm and 35.6 lb ft of torque at 2400 rpm. Compression ratio is 9.3:1. It features a digital CDI ignition with variable timing and built in rev limiter.

Specs and info can be seen here
https://engines.honda.com/models/mod...ontal#Features

One downside I can see with this engine is the rev limiter. I believe for those who want to go fast, the rev limiter is not something you can bypass because it's built into the CDI ignition. The rev limiter is good for those who want to maintain their speed and keep the engine operating within it's parameters. Also to note, there are not many performance parts available for this engine, at least not like the Vanguard and the Predator.

That these engines have proven to be a fantastic powerplant with years and year of reliability and durability reports. They are priced comparably to the Briggs Vanguard engines. These engines are also BIG but with that come big power and torque. Keep the size in mind with using them in your cart.

[TheNewGuy]

Sticky

[slonomo]

Originally Posted by TheNewGuy

Sticky

Thanks Ron! Hopefully this thread will help some members with big block info.

[slonomo]

Engine Mounting

One of the bigger challenges with a big block swap is mounting the new engine. There are engine mounts available for many of the newer models, but some older less common ones seem to be left out. Bolt in engine mounts are not cheap, but save lots of time and eliminates the need to fabricate. The engine mounts in the kits are usually adjustable to some degree. Some companies make entire installation kits with all the parts you need and directions.

If a kit is not an option, the solution is to fabricate your own. I have seen anything from fully welded works of art to mounts made with scrap steel and even wood. Anything that holds the engine straight and level and has good strength should do, but really, this mount has a lot of load on it from the torque of the engine and the cvt system, so it should be made well.

The basic idea is to have a flat steel plate, minimum 3/16", or even aluminum in 1/4". The engines typically have 4 mounting holes on the bottom, so the plate should have matching holes to accommodate. The better mounts have slotted holes so you can slide the engine forward and backwards to get your drive belt tight. The best mounts also have some side to side adjustability.

Some home built mounting plates simply bolt to the original engine mounting plate, some need more fabrication and welding to get the mount fitted. Either way, one of the more important design elements is that the engine sits level front to back and side to side. The engine sitting level helps with oil flow and distribution inside the crankcase. Getting this wrong could starve your engine of oil and cause major damage. Care should be taken when building the engine plate.

These photos are some examples.