Ethanol fuel damage to carb, fuel lines, and tank
high- Typically appears
- Any — present from first fill with E10+ fuel
- Estimated repair
- $400 – $2,000
1926 Buick
Master SixRoadster
242 CI I6 · Roadster
The 1926 Buick Master Six Roadster is a pre-Depression-era American luxury open tourer built on Buick's larger Series 50/60 chassis. Powered by a 242 cubic-inch overhead-valve inline-six — unusually advanced for its day — it offered a smooth, quiet ride that set Buick apart from competitors still running flathead fours. The Roadster body style seated two to three passengers in an open cockpit with a fold-down top, making it a stylish choice for warm-weather motoring. Nearly 100 years old, surviving examples are now collector and show vehicles, not daily drivers. Mechanical parts are largely unobtainium from retail channels; owners depend on specialty suppliers, marque clubs (the Buick Club of America), and machine shops willing to fabricate. The drivetrain is fully mechanical — no electronics, no OBD ports, no fuel injection — so modern scan tools are irrelevant to this car. Owning one is a labor of love and historical stewardship. Expect to invest in professional restoration work, period-correct parts sourcing, and ongoing preservation against the elements. This is not a car you drive to work; it is a car you take to a show on a sunny Sunday and store carefully the rest of the time.
Reliability
3/5
Verified data
Engine
242 CI OHV I6
Drivetrain
RWD
Fuel
Gasoline
MPG
12 city / 18 hwy / 14 combined
Seats
2
Doors
2
Body
Convertible
MSRP
$1,595
Overview
AI-curatedThe 1926 Buick Master Six Roadster is a pre-Depression-era American luxury open tourer built on Buick's larger Series 50/60 chassis. Powered by a 242 cubic-inch overhead-valve inline-six — unusually advanced for its day — it offered a smooth, quiet ride that set Buick apart from competitors still running flathead fours. The Roadster body style seated two to three passengers in an open cockpit with a fold-down top, making it a stylish choice for warm-weather motoring. Nearly 100 years old, surviving examples are now collector and show vehicles, not daily drivers. Mechanical parts are largely unobtainium from retail channels; owners depend on specialty suppliers, marque clubs (the Buick Club of America), and machine shops willing to fabricate. The drivetrain is fully mechanical — no electronics, no OBD ports, no fuel injection — so modern scan tools are irrelevant to this car. Owning one is a labor of love and historical stewardship. Expect to invest in professional restoration work, period-correct parts sourcing, and ongoing preservation against the elements. This is not a car you drive to work; it is a car you take to a show on a sunny Sunday and store carefully the rest of the time.
Known for
- Advanced OHV inline-six engine for its era — smoother than most 1920s competitors
- Quality coachwork and Buick's reputation for durability among pre-war American makes
- Open roadster body style with fold-down fabric top
- Mechanical simplicity: no electronics, purely mechanical fuel and ignition systems
Best for
- Dedicated pre-war car collectors and restorers
- Buick marque enthusiasts and Buick Club of America members
- Show-car participants and vintage car events
- Owners with access to a machine shop and specialized pre-war parts suppliers
Watch for
- Parts scarcity — virtually nothing is available off the shelf
- Wood-framed body components that rot, warp, or lose structural integrity
- Asbestos-containing gaskets and brake lining materials common in this era
- Ethanol in modern pump gasoline attacks original fuel system materials
- Total lack of modern safety equipment: no seatbelts, crumple zones, or airbags
Common issues by mileage
6 knownWooden body frame rot or structural failure
high- Typically appears
- Any — age-related regardless of use
- Estimated repair
- $2,000 – $15,000
Brake system degradation (mechanical 4-wheel brakes, no hydraulics)
high- Typically appears
- Any — age and storage related
- Estimated repair
- $500 – $3,000
Fabric convertible top deterioration
high- Typically appears
- Any — UV and age-related
- Estimated repair
- $800 – $3,500
Valve and piston ring wear requiring engine rebuild
medium- Typically appears
- Any surviving example
- Estimated repair
- $3,000 – $10,000
Electrical system failure (6-volt positive-ground wiring)
medium- Typically appears
- Any — age-related insulation cracking
- Estimated repair
- $300 – $2,500
Maintenance schedule
- 1 Every fill-up Use non-ethanol (ethanol-free) gasoline exclusively
Ethanol degrades the original rubber fuel lines, cork gaskets, and pot-metal carburetor components found on all pre-war Buicks. Non-ethanol fuel is available at select stations in the Lake Geneva area and is essential for this car.
- 2 Every season or before any driving Inspect and adjust mechanical brakes at all four corners
The Master Six uses mechanical linkage-actuated brakes — no hydraulics. Cable and rod stretch, and brake lining wear is uneven. Brake failure on this system is a real safety risk.
- 3 Every season Change engine oil with a non-detergent straight-weight oil (SAE 30 or 40)
Modern detergent oils can dislodge accumulated sludge in old engines and clog oil passages. Non-detergent oil is correct for flat-tappet pre-war engines without full-pressure oiling to all components.
- 4 Every season Inspect and re-pack all grease nipples (Zerk fittings) on front suspension, steering, and driveline
1920s chassis have numerous lubrication points that require manual greasing. Neglecting them leads to rapid wear of bronze bushings and kingpins, which are difficult to source.
- 5 Every season Test and service the 6-volt battery and charging system
The 6-volt positive-ground electrical system is unique compared to all modern vehicles. Use a 6-volt battery (not a converted 12-volt system unless already professionally retrofitted) and verify the generator output.
- 6 Every 2–3 years or as needed Inspect and treat all wood body framing
The body frame uses structural wood that absorbs moisture and rots. Annual inspection and treatment with a penetrating wood preservative, plus correct storage, dramatically extends body life.
- 7 Before and after storage Drain or stabilize fuel and fog the cylinders with oil
Ethanol-free fuel still degrades over winter. Add fuel stabilizer or drain the carb and tank before storage. Fogging the cylinders prevents rust on bare cast-iron bore walls during long layups.
- 8 Annually Have a pre-war specialist inspect ignition points, condenser, and timing
The distributor uses mechanical points that pit and wear. A worn condenser causes misfires and hard starts. These are still available as new-old-stock or reproduction parts through Buick Club of America suppliers.
Always defer to the manufacturer's service manual for warranty-mandated intervals.
Cost of ownership
Annual maintenance
$500 – $5,000
Fuel
Non-ethanol premium recommended; typical show/fair-weather use means very low annual fuel volume, but non-ethanol fuel commands a small premium per gallon. Fuel cost is essentially negligible compared to maintenance.
Insurance
Agreed-value collector car insurance is strongly recommended and is typically inexpensive — often $200–$600/year for a show vehicle with mileage restrictions. Standard auto insurance is inappropriate for a vehicle of this value and use profile.
Annual costs vary wildly based on restoration status. A fully restored, show-quality car in stable condition may cost only a few hundred dollars per year in consumables and storage. A car needing work can easily demand $5,000–$30,000+ in a single restoration season. Budget for surprises — parts fabrication, machine shop time, and upholstery work are the biggest line items. Join the Buick Club of America; their technical advisors and parts network are the single most cost-effective resource available.
Seasonal care
Lake Geneva, WI Winter
- Store indoors, ideally in a climate-controlled or at minimum dry, unheated garage — never outside. Wisconsin road salt will destroy the undercarriage and body in a single season.
- Do NOT drive this car on Wisconsin winter roads under any circumstances. Salt brine is catastrophic for exposed cast iron, steel chassis, and wood body components.
- Before storage, drain the cooling system completely — the correct antifreeze for this era (if any) and the cast-iron block make freeze cracking a real risk. Consult a pre-war specialist on coolant choice.
- Fog the cylinders with oil, drain or stabilize the carburetor and fuel tank, and disconnect the 6-volt battery or use a low-current maintainer rated for 6-volt positive-ground systems.
- Place the car on jack stands to take the weight off the tires, which flat-spot easily during long storage.
- Cover with a breathable car cover — not plastic — to prevent moisture condensation on the bodywork and interior.
Summer
- Check tire condition and pressure before each outing — original-style bias-ply tires age and crack regardless of tread depth; replace any tire showing sidewall cracking.
- Monitor coolant temperature closely; the non-pressurized cooling system boils at 212°F and has very little headroom on a hot day in traffic. Avoid idling in summer heat.
- Check that the fabric convertible top's bows and hardware are secure before driving — UV degradation makes old top fabric brittle and prone to tearing at speed.
- Carry a basic tool kit, spare points, condenser, and belts on any drive. Roadside assistance for a 1926 vehicle is essentially nonexistent.
- After summer outings, wipe down all chrome and exposed metal to remove any contaminants before storage.
Comparable vehicles
1926 Cadillac
Series 314
Direct luxury-market competitor in 1926; V8-powered and more expensive, but in the same pre-war American collector tier. Parts and expertise communities overlap.
No catalog match1926 Chrysler
Series 70
Chrysler's 1926 six-cylinder was a close rival to the Master Six in price, performance, and market positioning. Comparable restoration challenges and collector community.
No catalog match1926 Packard
Single Six
Packard's entry-level six occupied overlapping price territory with the Master Six. Strong marque club support and similar pre-war restoration considerations.
No catalog match1927 LaSalle
Series 303
GM's near-luxury companion to Cadillac, introduced 1927 — positioned just above the Master Six and sharing some GM design DNA. Comparable collector market and restoration complexity.
No catalog matchIf you're shopping for one
Red flags
- Seller cannot provide documentation of engine, body, or VIN authenticity
- Signs of fresh paint covering rust or body filler on steel panels or wood-framed areas
- Engine knocking, smoking, or coolant in oil — pre-war rebuilds are expensive and slow
- Any evidence of flooding or prolonged outdoor storage (floor pan rust-through, stained upholstery, rotted wood)
- Non-original drivetrain substitutions without disclosure — dramatically affects collector value
- Asbestos brake linings still in place — a health hazard requiring professional abatement before any brake work
What to inspect
- Wood body frame integrity — probe with an awl at all joints, sills, and door pillars for soft or punky wood
- Engine compression on all six cylinders before purchase — low compression means a costly rebuild
- Brake rod and cable condition, adjustment, and lining thickness on all four wheels
- Authenticity of major components — many cars have been fitted with incorrect engines, transmissions, or body panels over 100 years
- 6-volt electrical system integrity — check for amateur 12-volt conversions done poorly
- Fuel system for ethanol damage: cracked lines, pitted carb body, contaminated tank
- Title and documentation history — ownership records and restoration receipts significantly affect value