# Briggs vanguard conversions

Discussion in 'Firewall Forward / Props / Fuel system' started by Hephaestus, May 12, 2019.

1. May 16, 2019 at 4:43 AM

### Vigilant1

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This B&S video has some graphics on a V-Twin lubrication system (they don't say which one). Don't expect to learn a lot. It's a PR video, not a true technical one. It looks like the pressure lube goes to both crankshaft bearings and the heads in the vertical shaft engine shown. It's not clear how the camshaft or wrist pins get oil.

I'm assuming there are some complete technical manuals for these engines somewhere. My local library has only the most basic material, and the B&S manuals online are primarily very rudimentary manuals for owners (how to check the oil, etc) or parts manuals with exploded diagrams.

2. May 16, 2019 at 5:42 AM

### mcrae0104

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Arcticle. I see what you did there.

Look, this carb ice thing is beside the point of this thread, but contrary to your what you stated earlier, extreme cold weather is in fact not as conducive to carb icing as the conditions one is likely to find in Rolla during any given day of the year.

3. May 16, 2019 at 9:11 AM

### pictsidhe

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I've done a lot of small engine repair myself and the No1 issue I see is water in the fuel from poor gas storage in unsealed cans, No2 is running them dry of oil. Mostly user error...
I've seen Briggs with oil pump and filter that only lube the top bearing and ones that lube both.
Very few home porting jobs on engines are any good. It is not as easy to make an improvement as the 'experts' on YouTube claim. Small engine ports are not very good and will be very difficult to improve without filling them first.

I haven't been inside a Vanguard yet.

4. May 16, 2019 at 11:17 AM

### BBerson

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The bearings are designed for a particular load. If exceeded, failure may occur. I have a blown Briggs that the mower shop gave me that was overevved in mower racing. It has a hole in the case. I imagine hot oil blew out. The mower racer probably thought the rod through the case was funny.
What does a typical pilot want?
I don't want to exceed the factory redline or BMEP output in airplanes I fly.

5. May 16, 2019 at 1:02 PM

### Basil

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I agree. The reason to use a Briggs is to get a cheap reliable engine of moderate power. The 810cc Briggs in the SD1 has no performance mods. Only changes are lightened flywheel, removal of fan and changes to oil pick up to convert it to horizontal shaft. Removal of fan and aircraft exhaust system yields modest power increase over standard engine. Vertical shaft is used as it is lighter than horizontal shaft.

6. May 16, 2019 at 1:19 PM

### Vigilant1

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Basil, thanks for chiming in. BBerson reported that the 810cc engine on the SD-1 has the flywheel keyway slightly shifted to advance the ignition timing and improve power a little (somewhat increasingirisk of detonation, so use good fuel). They also appear to have improved carb capacity, which may be worth a bit of power. It would be interesting to know why they use the B&S Lawn and Turf Professional series as their starting point rather than the B&S Vanguard. The Professional series sells for a lower price, and if it is adequate (or functionally equivalent ) then that would be good to know. My impression was that the used the vertical shaft 810cc engine because no horizontal shaft version is made.

7. May 16, 2019 at 1:43 PM

### BBerson

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I don't actually know if the SD-1 modify the flywheel key. I meant that's a possible modification that some do.
Looks like they don't use the flywheel at all. Thanks.

Last edited: May 16, 2019 at 1:57 PM
8. May 16, 2019 at 1:43 PM

### Basil

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The 810cc vertical shaft was used because it is lighter than most similar engines. The SD1 needs a firewall forward installation of less than 40kg. The previous engine used was a Kohler buy it was 3hp less and several kg more weight . Don't know why it is lighter but it is.

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9. May 16, 2019 at 3:39 PM

### Armilite

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My point was it can happen in many different Temperatures then People think with the different Climates everyone Flys in the World. You have Moisture in the Air, you have Moisture in the Fuel, especially with Ethanol in most Pump Gas today. It's the least understood Engine Failure, account it melts soon after an Accident or Engine Out Landing. Like the Article said, it could be 100F outside, but if the Humidity is High it can be 30F in the Carb Venturi which can lead to Carb Ice. EFI Throttle Bodies don't have a Venturi so are less likely to have Carb Icing problems. If you look at the Accident Database there is a lot of Unknown Causes of Airplane Accidents, a percentage of them Accidents is probably from Carb Ice which soon disappears after the Accident.

10. May 16, 2019 at 5:09 PM

### blane.c

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11. May 16, 2019 at 5:19 PM

### pictsidhe

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Huh?

The professional mower guys get around 1000hrs from a stock Vanguard. Work it harder, you either need better parts, or expect a shorter life. The Briggs have aluminium conrods. They have a very definite fatigue life. The majority of the load on them is the gas load, so increasing torque much will noticeably reduce their life. Yes, there are billet rods, but I do not know the original alloy so it is hard to predict how much more life the billet rods will give. 7075 will age at temperatures not much above the boiling point of water, so may not be quite as good as you expect.
Anyone know the standard rod alloy?
FWIW, all 5 broken rods that I've seen in stock engines were in engines with a much too short dipstick...

As for running these at higher than rated power or torque for hundreds of hours, we really are venturing into the unknown. The racers don't run them at high power for very long. My own project will have a legal cap to the hp in cruise of below stock, the extra power is for takeoff and playing around. That will be fairly small portion of the hours it will do.

The 810 vanguard is a fairly new engine, that is likely why it is not used in the conversions yet. I believe it is based on the old 810.

12. May 16, 2019 at 5:31 PM

### Armilite

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These Roller Ball Bearings used on the Honda/Briggs/Clones is the same as used on most 2 Strokes. IF, you looked up these Bearing Spec's you will find if used at Max 6500rpm what Rotax's, Hirths, Simonini, etc., and other's use, they have a 1500hr Life. You have (4) Types of Crank Ball Bearings, (3) with Steel Balls with either a Plastic Retainer(Worst), Steel Retainer(Better but can Rust) and 3rd with a Nylon Retainer(Best). Then you have the New Hybrid Ceramic Ball Bearings, that need less Oil, Run Cooler, last 3 times of a conventional Ball Bearing. But they Cost a lot more.

Since we're talking Honda/Briggs/Clone Type Engines in this thread, what is their Failure Points? We can't Fix Stupid People, but we can Fix or Upgrade these Engines to make them better, it only takes $and Time! For Detonation: 1. Run Higher Octane Gas for what CR you use. Stock 8.0-8.2cr can run 87, but if it's 2-3 weeks Old that 87 can drop 2-3 Points in Octane. Most Airports only carry 100LL so that is what the Engine should be designed to run. For Heat: 1. Use Full Synthetic Oil. Most Racers use Mobil 1(7000 mile Oil). I would use Mobile 1 Gold(15,000 mile OIl). 2. Use Higher Octane, Airports usually only carry 100LL anyway. 3. Use the Ceramic Coatings on Piston Tops, Combustion Chambers & Valves, Exhaust Ports, Exhaust, Heat Shields, etc. 4. They also have Heat Wraps for Exhaust. 5. Needle Bearing Rockers have less Friction, so less Heat. 6. Moly Coated Pistons generate less Friction on Cylinder Walls. 7. Ceramic Bearings makes less Heat in Engine and Gear/Belt Drives. 8. Use Stainless Valves vs Stock Valves. For Durability: 1. Billet Rod 2. Billet Flywheel (Saves Weight and is Stronger) 3. Billet Lifters 4. HD Chrome Moly Push Rods 5. HD Valve Locks & Keepers 6. Billet Cam 7. Use the Best Bearings 8. Use a Big Oil Cooler 9. Use Forged Pistons 10. HD Needle Bearing Rocker Arms 11. Higher lb Valve Springs even if using Stock 3600rpm 12. Debur/Polish all Engine Parts of Casting Flash, Enlarge/Polish any Oiling Holes 13. Use Coatings for all Internal Parts 14. Use Heat Shields on Exhaust 15. Balance the Engine Assembly 16. Use Max 5500rpm (What a Rotax 912 80hp is Rated at) 17. Use Good Octane Gas 91+ For making more HP: 1. Take out the Governor usually set for (3800-4000rpm) and Install Hi Rev Kit 2. Turn Higher rpm up to 5500rpm Max 3. Use a Bigger Carb or better EFI 4. Use Bigger Lift CAM with Long Duration 5. Use Bigger Intake & Exhaust Valves 6. Use a K&N Type Air Filter 7. Use a Tuned Header Exhaust 8. Use a Higher 9.0 to 11.5cr Max, most Stock Engines use 8.0 to 8.3cr for 87 Octane. 9. Port & Polish the Heads to Flow more Air 10. Balance the Engine Assembly 11. Some of the ignitions have a Governor Coil, so Replace with None Governor Coil 12. Big Bore for more CC 13. Add a Turbo. While Turbos sound Cool, I don't think they're worth the Extra Cost, extra R&D needed, extra Weight. You have Singles now up to (96mm x 86.5mm) 626.3cc and can be Bored to 100mm. (100mm x 86.5mm) 679.6cc. These Van Guard V Twins with Carbs, Small Block Versions 479cc 16hp-18hp, 570cc 18hp, 627cc 21-23hp, and the Big Block Version 896cc 25hp-33hp, and 993 33hp. With their EFI versions, they say, Up to 25% Fuel Savings. They list today a 40.0 Gross HP* EFI - 993cc Marine using 8.5cr. https://www.vanguardengines.com/na/...-shaft/vanguard-400-gross-hp-efi--marine.html Does Say: Performance Muffler Designed for increased air flow. Video says Performance Cam. I don't see what Rpm they use. 13. May 16, 2019 at 5:34 PM ### BBerson ### BBerson #### Well-Known Member Joined: Dec 16, 2007 Messages: 10,963 Likes Received: 1,960 Location: Port Townsend WA 14. May 16, 2019 at 5:44 PM ### Armilite ### Armilite #### Well-Known Member Joined: Sep 6, 2011 Messages: 2,872 Likes Received: 218 Location: AMES, IA USA ====================================================================== Honda/Briggs/Clones (20+ Brands) most use just a Cast Aluminum Rod, but some Higher End brands do use Forged Aluminum Rods. Billet Rods are better than Forged Rods and usually Cost more. Most of these Billet Rods and Flywheels used in Honda/Briggs/Clone Race Engines are made by ARC. https://www.arcracing.com/6212-arc-billet-rod-4-225-x-1-x-490-flathead-stroker/ Product Description Billet Rod ARC Enduro Series CNC Machined from aircraft grade 7075 T-651 aluminum. Our 1" Stroker Rods are designed to handle the rigors of todays high horsepower Junior Dragster and open Kart Engines. These Rods are designed for aftermarket flathead blocks with extra cam clearance. They also utilize our splayed bolt design for extra clearance and advanced oiling features for superior lubrication. Rod includes bearings and high strength ARP bolts. Call us to help you choose the best rod for your particular application. 6622 ARC Billet Flywheel, Honda GX340/GX390$250.00

GX390 Adjustable Hub Flywheel The ARC Billet Flywheels are CNC machined from 6061 T-6 Aluminum. It weighs 5.40 lbs. The main feature of this design is the steel crankshaft hub that allows for timing changes at 2° increments...

The Balance Shaft is 4-6lbs also and can also be eliminated.

Last edited: May 16, 2019 at 6:55 PM
15. May 16, 2019 at 6:33 PM

### pictsidhe

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I think think the flywheels for both the 627s and 810s are nudging 20lb. Deleting it is a lot of weight that can be saved if you are going DD. A redriven engine will likely need some flywheel retained unless you use a huge belt.

16. May 16, 2019 at 6:43 PM

### BBerson

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My Honda 670 is 65 pounds without the flywheel,alternator coil and starter. I think the flywheel was 15.

17. May 16, 2019 at 8:39 PM

### pictsidhe

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The starters aren't light, either. Perhaps hephaestus could weigh parts as he removes them?

18. May 16, 2019 at 8:54 PM

### Vigilant1

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I know they make lightweight flywheels with the starter ring gear. I wonder if a low-budget hillbilly builder of a direct-drive aero version who wanted to keep the starter ring and magnetron ignition coils could just use the stock flywheel and drill a lot of lightening holes.

19. May 16, 2019 at 9:03 PM

### blane.c

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It looks like some of the flywheel is fins so if you are going to remove the fan shroud they are useless? Some of the remaining weight is just there to support the fins so that could go with them?

Are you going to mount the propeller directly to the flywheel?

20. May 16, 2019 at 9:27 PM

### Vigilant1

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I think that's the B&S list price. These commercial series (i.e. non-Vanguard) 810cc engines can frequently be bought new for less that $800. Here are two places with good prices: Small Engine Warehouse: http://www.smallenginewarehouse.com..._fq:"Vertical"&sort=price asc&rows=20&start=0 Small Engine Warehouse has a web page with good search filters. They seem to be low on Vanguard 810cc engines right now, (or they aren't showing up for some reason), but a few weeks ago they had 'em starting at about$1200. The "Commercial Series" 810s sell for less than $900. Brand New Engines: https://www.brandnewengines.com/ Another source of inexpensive new engines. Expect to pay about$400 additional for one of these engines if it has the B&S EFI system. That's a closed-loop system, so any leaded fuel will eventually kill the sensor. I don't know what happens when the sensor fails--not a big deal on a lawnmower, a bigger deal for an airplane. IIRC, B&S does offer a dedicated open-loop system on their marine engines.

I still wonder about any difference between brand new engines with (per the spec pages) identical displacements, identical CRs, identical RPMs for rated HP (3600), but different model numbers, different prices, and different HP ratings. What is actually different? I doubt B&S makes a different cam for each of these engine models. So, if we are going to replace the carb and exhaust system anyway, would it make any sense to pay more for the higher HP version?
Example: Vanguard 810cc model 49V6: Rated HP: 24.
Vanguard 810cc model 49R9: Rated HP: 26
Vanguard 810cc model 49E8: Rated HP: 28 (this engine has EFI)