Curtis Jacobson's 1971 MGB GT with Buick 215 V8
Owner: Curtis Jacobson
Forum UserName: Moderator
City: Portland, Oregon
Model: 1971 MGB GT
Conversion by: owner
Bonnie's Story
This 1971 MGB GT was worn out, wrecked, and left derelict by the mid 1980s. My buddy Donnie Moyer
discovered it on an old farm, tucked behind Dulles airport in Northern Virginia. Donnie and I had
been talking about building a racecar. We were college freshmen: clueless and poor. But this
little MGB GT could be had for one dollar if we could convince its owner that we'd give it a good
home. (We also had to fix his wife's Oldsmobile; that only took a moment.) He had turned down
offers from people who wanted his MG for parts. We promised we'd put it back on the road.
That's what he wanted to hear.
We went to work with baling wire and duct tape, second hand tires, discarded road signs, alligator
clips and chewing gum. We managed to get the original MGB engine to run; we even put one or two
thousand miles on the old girl. She burned a whole lot of oil! At about that time, we christened our
cute little MGB GT "Bonnie". Why that name? Suffice it to say that she's always had a distinctive
"bonnet" - that's British for "hood" - and incidentally she's now wearing her fourth one. Anyhow,
just when we thought we had her carburetors sorted out, Bonnie threw a connecting rod. We had
to park her while we finished college, but we continued to think she might make a good racecar
someday. Largely ignorant of SCCA class restrictions, our daydreams included American V8 engines.
We learned that Buick's "215" aluminum V8 is the most important production engine in the history
of motorsport. It's the only American V8 to ever win a proper Grand Prix. These little aluminum
V8s powered Jack Brabham to victory in the 1966 Formula One World Championship! Buick's 215 is also
the production engine that ended the Offenhauser engine company's long monopoly at the Indy 500.
In 1962 Dan Gurney drove a Buick 215 in his "Rookie of the Year" appearance, paving the brickyard
for Ford production V8 entries in 1963. (From 1964 onward the Ford V8's that powered successful
Lotus racecars were designed exclusively for racing.) Countless other cool racecars have used the
215, or later Rover variants.
A stock Buick 215 delivers twice the power and torque of an MGB 4-banger, yet weighs fully forty
pounds less. And it's a V8!
Very shortly after the connecting rod flew, I found a running 1963 Buick Special for $150 in a
"Penny Trader" newspaper. A heart to transplant! I bought it, but it had to wait 'til after graduation.
After college, I settled in North Carolina and Bonnie moved into the parking lot of my apartment building.
I rebuilt the Buick engine in my living room. In another Penny Trader I found a complete set of Buick
manual transmission parts. Amazingly, I got them for $150 too. With help from two Volvo Truck colleagues,
Ashley Dudding and Rob Henson, I installed the engine in 1990. The hardest part was fabricating custom
sand-bent tri-Y headers. In 1991, Bonnie was complete enough to pass North Carolina's required safety
inspection. She was still pretty rough looking, but she was drivable.
Since then, Bonnie and I have road-tripped through 46 of the United States (so far), and into Canada.
We've enjoyed occasional track days and autocrosses too. Mostly during winters, I've made countless
modifications and upgrades. Willing to try innovative design and fabrication approaches. Always on a
shoestring budget. Favoring junkyard parts over aftermarket. Avoiding trends, trademarks, and excess.
Letting Bonnie evolve into the fierce little racecar she's always wanted to be.
The 1963 Buick 215 aluminum V8 has been updated with custom sequential electronic
fuel injection and a custom crank-fired eight-coil ignition system.
How It Was Done
| Engine: |
stock Buick 215 engine block, crankshaft, connecting rods, valve gear, valve covers, oil pan,
timing gears, etc.
Silvolite 8.8:1, 0.030" oversize pistons.
Kenne-Bell camshaft (model 1XA, 0.462" lift, 260 degree duration, 110 degree lobe center).
Buick V6 timing cover.
Buick V6 "metric" oil pump.
AC Delco PF47 oil filter.
MegaSquirt MS3-Pro engine control module.
Rover 14CUX intake manifold and fuel rail.
Lucas fuel injectors and fuel pressure regulator.
Chevrolet throttle body and MAP sensor.
Walbro GSS250 (190 liter per hour) fuel pump with Honda Civic (45-degree angled) prefilter.
Chevrolet "LS2-truck" ignition coils.
Champion "Truck" spark plugs (part# 4404).
Custom motor mounts, utilizing Barry Controls 22000 series isolators.
Custom cowl induction intake with Ford Probe oiled gauze panel air filter.
ISO7840 fuel filler hose.
Original Buick cylinder heads were replaced in May 2009 with Rover 4.0L heads (circa 1996-2003). These late model heads have smaller combustion chambers (~28cc vs. ~37cc). Shaved 0.010" and with composite head gaskets, they raised the engine's static compression ratio to ~10.1:1. The Rover 4.0L heads also have larger valves (1.570" inlet vs. 1.5", 1.350" exhaust vs. 1.312") and significantly larger ports. For compatibility with the relatively high-lift camshaft, it was necessary to reduce the height of the valve guides. Stock valvesprings were checked for coil bind, and found to be okay. All head work was performed by Abacus Racing. At installation, lifter preload was set to 0.040" by making and installing custom pedestal shims. |
 The engine was rebuilt and installed in 1991. Engine block and internal components have remained unchanged since then, while nearly everything else in this photo has been upgraded. |
|
| Cooling: |
- AFCO dual-pass aluminum radiator, part number "80107N", reworked with 1.5" ports and a vent bung,
installed with all of core above the plane of the radiator shelf. Core measures 12" x 17.75" = 213 square inches.
(Stock core was 10.5" x 17.5" = 183.75 square inches.) - Dayco hoses (top: #70635 1970-79 Camaro and Monte Carlo. bottom: #71013 1969-06 Ford Mustang.) - Transparent remote header tank (1985-93 VW part# 171121407E) installed on firewall. - Twin 8.5" Honda Civic electric A/C condenser fans, pushing, with low-clearance fan rings. - Custom carbon fiber recirculation shield. - Stainless steel mesh bug screen. |
| Exhaust: |
- Custom sand bent Tri-Y headers. - Dual Thrush Turbo mufflers (11" long, 2" inlet, 2" outlet). - Evil Energy stainless steel, 2.0 inch, V-band clamps. |
| Transmission: |
- 1992-model Borg Warner T5 "World Class" 5-speed manual. - Gear ratios: 1st 2.95, 2nd 1.94, 3rd 1.34, 4th 1.00, and 5th 0.73. - Custom transmission mount, utilizing Barry Controls 22000 series isolators. - Buick 215 bellhousing. - D&D Fabrications steel flywheel. - 10.4" Camaro clutch and diaphragm pressure plate. - Stock MGB master cylinder. Externally mounted Girling slave cylinder. |
| Front Suspension: |
- Gutted Armstrong lever-type shock absorbers serve as upper control arms and shock mounts. - GAZ adjustable coilover shock absorbers. - SuperPro polyurethane replacement shock absorber bushings, upper and lower. - Eibach 6", 2.25" diameter, 525#/inch springs. - MG Limited (Killer Beez Racing) dropped spindles, with steering arms modified specifically for my car. - Stock lower wishbone arms, lightened. Spring pans from a Moss coilover front suspension kit, lightened. - Polyurethane wishbone bushings. - ADDCO 7/8" front anti-sway bar on polyurethane mounts. |
| Rear Suspension: |
- Custom 3-link of my own design.
- All three links utilize Ballistic Fabrications forged chromoly 2" rod ends with 1/2" bore balls and 3/4-16 shank threads, part#s BJ-678-11 & BJ-678-12. These rod ends have hardened 416 stainless balls supported by Nylatron GS races. (From 2025 onward, Ballistic has used polyurethane races.) The rod ends support up to 33 degrees of misalignment, and are adjustable to eliminate play. - Top link is a Speedway 1" OD swedged steel tube, part#: 91034234-13. 438mm center-to-center, installed upward 4.5 degrees from body at static ride height (loaded). Lower links are Speedway 1" OD swedged steel tube, part#: 91034234-15. 500mm center-to-center, installed level at static ride height (loaded). The lower links are parallel, mounted 865mm apart, and are 73mm below axle centerline. - Panhard rod is a Speedway 7/8" OD swedged steel tube, part# 91034258-29.5, with QA1 PCM-series 5/8-18 shank Heim joints. 800mm center-to-center, installed level at loaded static ride height (loaded) and 75mm below axle centerline. - Ridetech HQ 6.3" stroke mono-tube, gas-pressurized coilover shock absorbers with forged and anodized aluminum bodies, 1.834" pistons, 5/8" shafts, and 24-position rebound adjustment knobs mounted at the top of 2" stud mounts. They weigh 3.43# each. Previous telescoping shocks weighed 2.83# each. Custom titanium lower shock mount bushes, turned by my friend Ryan Thomas. - Eibach 14", 2.5" diameter, 150#/in, coil springs weigh 3.73# each. Previous springs weighed ~22# each. Delrin coil spring washers. |
| Rear End: |
- 1984-5 Mazda RX7 GSL-SE axle. (Purchased used for $500.) - Housing narrowed and brake/suspension brackets TIG welded on by Spriso Motorsports. (28.7# including brackets.) - Axle shafts narrowed by Dutchman Motorsports. (13.1# each, including bearings, retainers, & conversion to 1/2" lugs.) - Mazda Miata NA third member housing, lightened ~1.9# via removal of power plant frame attachment features. (46.4# fully assembled with new gears, differential, bearings, etc.) - Mazda Miata 3.636:1 ring and pinion set part number MA02-27-110, as used on Australian market 1994-2005 Miatas with automatic transmission option. (Purchased new for $575.) - Ring and pinion REM finished by Performance Engineering & Manufacturing LLC. - Mazda Miata NA type-1 Torsen limited slip differential. - SKF pinion outer seal part# 12751. - Mazda crush sleeve part# M035-27-171. - Inner pinion bearing and spacer transferred to new pinion. - SKF differential bearings part# 32008X pressed on. - Timken wheel bearings, part# 511017. - Timken wheel bearing seals part# 710320. - Valvoline full synthetic 75W-90 gear oil. - Ford threaded steel breather vent. - Mazda Miata NA propshaft flange, lightened via removal of vibration dampener. - Powertrain Industries propshaft yoke part# 2602-37$42-->. - Dana 1310 series to 7260 series (OSR to ISR) conversion u-joint, part# 5-788X (to mate to the same propshaft I previously used with a Ford 8.8). |
| Brakes: |
- New MGB master cylinder. Wilwood 2psi residual pressure valves.
- Front: Wilwood Dynalite calipers. Wilwood 11.75" vented rotors and adapter hats. Wilwood BP-20 brake pads. Braided stainless steel reinforced brake hoses. - Rear: Mazda Miata 1994-2002 calipers (Power Stop part#'s L1377A & L1378A. 6.1 pounds each.) Volvo S40/V4 2000-2004 rotors (Volvo part# 30872940, 7.4 pounds each.) Ceramic disc brake pads (Akebono part# ACT636). Mazda CX-5 2013-2017 caliper-to-axle brake hoses (Mazda part# K01143810). Mazda brake hose retainer clips (Mazda part# W023-43-635A). Mercedes 2005-2014 axle-to-chassis brake hoses (Mercedes part# 221-420-09-4). - Stock MGB parking brake lever. Mazda Miata 1994-2002 parking brake cables. |
| Wheels/Tires: |
- VTO "Lemans" 4-spoke 15"x6" wheels (22mm offset fronts = 13.8# each. 3mm offset rears = 14.8# each).
- Continental Extreme Contact tires, size 205/50R15. - ARP 100-7730 front wheel studs with 0.509 knurl and 1.950 overall length. (These are necessary to get adequate lugnut thread engagement when using VTO wheels. Stock MGB studs only extend 1.0" from the hub. VTO seats are spaced ~0.68" from the hub surface, leaving ~0.32" thread engagement. Note: to use the ARP studs on MGB hubs you must first grind or turn down their head diameter.) - McGard 64000 lug nuts (1/2"x20 by 1.5", cone seat). |
 Spring 2016: Autometer Speedometer model 2489 and Tachometer model 2499. |
|
| Instruments: |
Speedometer - Autometer "Traditional Chrome" model 2489 (0-160mph).
Air/fuel ratio - AEM, electronic. Used with a Bosch UEGO wideband oxygen sensor. Tachometer - Autometer "Traditional Chrome" model 2499 (0-8000rpm). Fuel level - Stewart Warner "Track Force", electrical. Oil pressure - Stewart Warner "Track Force", mechanical. Water temp - Stewart Warner "Track Force", electrical. |
| Electrical: |
- Nippondenso 55A alternator from a Chevy Swift. (Suzuki 31400-86210, Nippondenso 100211-4150.) - TS Imported Automotive mini starter (8.0#). - Braille B2015 AGM battery (14.0#. 1067 pulse cranking amps. 21Ah. Right side positive.) - FIA-approved battery disconnect. (Shunts alternator to ground before disconnecting battery.) - 6-gage battery cables fabricated to order by BatteryCables.com. - Volvo Truck sealed bulkhead pass-thru. All new custom wiring featuring crosslinked polyethylene insulation (instead of PVC) and primarily Metri-Pac connectors. Where possible, wiring has been moved inside the cabin instead of running under the car. Fuses and four relays are mounted inside the dashboard to stay cleaner, drier, and cooler than the engine bay (and closer to the battery.) |
| Lighting: |
- Wipac "Quadoptic" (made in England) H4 halogen headlamps.
- VW Jetta front turn signals (part# 165953155). - Hyundai Excel side marker lamps (part#'s 92306-21551 front and 92308-21551 rear). - LED taillamps (see below). - Toyota license plate lamps (as used on 84-87 Corolla and MR2, plus 89-92 Geo Prizm). - Chevy S10 rearview mirror with integral map lights (see below). |
| Body: |
- PPG Deltron 2000 basecoat/clearcoat in 1995 Jaguar "Brooklands Green" (code "HFB" = 46968) with Sebring
stripe in 1995 Ford "Polar White" (code "YD" = 91196). - Custom carbon fiber bonnet (over Nomex honeycomb core) by Dave Craddock at Preform Resources. - Custom removable polycarbonate rear quarter windows on steel box-tube frames secured with three Dzus quarter-turn fasteners per window. - Grille, external badges, side trim, rain gutters and bumper overriders deleted. - Late model MGB mirrors painted body color (instead of satin black). - Late model MGB windshield wiper arms (because they're satin black instead of silver). - Xenon "Ureflex" air dam. |
| Interior: |
- Home-made aluminum dashboard with early-model MGB padded eyebrow. - Custom steering column (longer, lower, and lighter than stock) with Garlock flanged Teflon bushings. - Racetech anatomical, suede, dished, 330mm steering wheel on Allstar Performance quick-release hub. - Original MGB seats, reupholstered. Bottom cushion trimmed 1.25" in height. Custom support webbing. - Schroth Rallye Cross ASM 2" safety harnesses with bolt-in lap belts and wrapped shoulder belts. - Six point roll cage. (Stitched/seam-welded body seams in the engine compartment too.) - Custom upholstered, two-piece, removable, fiberglass drivetrain tunnel cover. - Custom upholstered aluminum door cards and custom taller/lighter fiberglass armrest caps. - 1972 MGB door pull handles. - Custom built-in toolbox in cargo area. |
| Comments: |
I've had Bonnie over 40 years, and I installed her Buick engine over 35 years ago.
I could have stopped there, but she's a continuing project by nature and intent.
I've driven much more powerful and refined MGB V8 conversions but she feels, sounds, and behaves more like a racecar than the rest.
Being a GT, plus having a full rollcage, she's far more rigid. Rigidity is great because it translates into confidence.
The fuel injection installation dramatically improved performance, drivability, and idle quality.
It was an especially big deal when I lived in Colorado and took lots of road trips because it tunes itself for elevation and weather.
The most recent updates are a lightweight rear axle and custom 3-link rear suspension. These have dramatically improved ride quality and handling.
Now almost 300 pounds lighter than when she left the factory, she feels more nimble and alert than ever.
This effect is doubled by her new, shorter gearing which makes her much more fun to drive at lower speeds.
(My old Ford 8.8 axle was stupid heavy, and its way-too-tall 3.27:1 ratio only made sense for highways. Don't make those mistakes.)
I try to leverage what I've learned from a career with the world's two leading commercial truck manufacturers.
I hope you can sense my OEM sensibilities in the photos below. Reliability is important, and Bonnie is reliable.
She hasn't been towed or trailered since the engine swap. She brings me joy every single time I drive her.
My main plan for the future is to drive her more, but I'll make lots more updates too.
|
As measured on August 22, 2026 this MGB GT V8 weighed 2016 pounds "wet" (i.e. full tank of fuel).
That's 294 pounds less than when she left the factory and 411 less than "factory" MGB GT V8s.
Corner weights 501 (LF), 536 (RF), 499 (LR), 480 (RR). Distribution: 51.4% front to 48.6% rear.
Trend: at BritishV8 2013 she weighed-in at 2150 pounds, and at BritishV8 2008 she weighed 2180.
2026 Updates: Lightweight Axle, 3-Link Rear Suspension, Etc.
Narrowed 1985 Mazda RX7 GSL-SE rear axle assembled with 1994 Miata 3rd member, Torsen
Type-1 limited slip differential and 3.636:1 gear ratio. Weight w/o brakes = 101 pounds.
With affordable Mazda Miata iron calipers (6.1# each) and Volvo S40 brake rotors (7.4# each), the
axle weighs 128.3#. A Ford 8" with long unavailable Currie aluminum carrier and pricey Wilwood
aluminum calipers weighs about 7# more. My old Ford 8.8 with drum brakes weighed 41.3# more.
Besides being lighter, the new rear system performs much better and is far more tunable. I can
easily change ride height, spring rates, shock damping, and I have more brake pad options.
It's smoother, more balanced and precise, quicker in all situations, and it stops better.
The suspension's upper link is angled upward from body to axle to achieve some anti-squat effect.
Lower links are dead-level when seats are occupied (which I simulated with stacks of barbell plates)
to prevent roll-steer. I chose to set the Panhard rod dead level, although for symmetrical weight
transfer I learned the axle end should theoretically be slightly lower than the body end.
Lower links and Panhard rod are approximately 75mm below axle centerline. I put the Panhard rod as
low as feasible because its placement defines the rear suspension's roll center, both statically and
dynamically. In his book Chassis Engineering, Herb Adams explained "A lower roll center at the
rear makes a car handle more consistently, so I recommend mounting the bar as low as possible."
In his book Nuts, Bolts, Fasteners, and Plumbing Handbook Carroll Smith wrote "A floating bushing
installed in a double shear lug will both ensure a proper fit and minimize crash damage to the lug."
He credited fellow racecar designer Gary Anderson with this innovation. I used floating bushings for
Panhard rod and lower shock mounts because I think it's an elegant detail. (See close-ups below.)
Coilovers are forward of axle to facilitate my preferred Panhard rod placement. Inboard mounting with
towers enabled relatively long shocks and springs. Long (14") springs contribute to a low natural
frequency for the suspension and thus better ride. 6.3" Ridetech HQ shocks have large pistons and
shafts plus forged aluminum bodies to provide durability and cool operation. Their mono-tube,
gas-pressurized design and their valving provide quick response and thus better handling.
Some design and fabrication details reflect workarounds due to working on a carport, without a lift.
(Example: extensive use of plug-welds from the cabin side when installing suspension mounts.)
All three trailing links have Ballistic Fabrications forged chromoly 2" rod ends with 1/2" bore balls.
Their hardened 416 stainless balls are supported by adjustable Nylatron GS races. They're stupid
heavy but I trust they will provide precise location for many years whilst damping noise somewhat.
The Panhard rod however has conventional QA1 PCM-series 5/8-18 shank Heim joints at both ends.
I adapted the propshaft previously used for my Ford axle with a Powertrain Industries yoke and a Spicer
1310-series conversion u-joint. With car loaded: crankshaft angles down 3.0 degrees, propshaft 4.1, and
pinion 4.9. So, the first operating angle is 1.1 and the second is 0.8. Spicer says operating angles
should be at least 1/2 degree but less than 3 degrees, and within 1 degree of each other.
Mazda Miata parking brake cables have weather seals and an internal spring mechanism to help
retract pads after lever release. Tips: stainless steel control cables are best cut to length with
a cutoff wheel. Then, I recommend dipping their ends in silver solder to prevent fraying.
Shock absorber 24-position rebound adjustment knobs are conveniently accessible, inside the cabin.
Schroth "Rallye Cross" ASM 2-inch safety harnesses with bolt-in lap belts and wrapped shoulder belts.
ASM stands for Anti Sub-Marining, a feature that prevents sliding under the lap belt during a crash.
Safer than previous vintage Simpson 3-inch latch-and-link belts, more comfortable, and lighter too.
VTO Lemans 15x6 +22 wheels weigh 13.8 pounds, versus 15.0 for the Panasports they replaced.
They have steel seats for lug nuts to bear against, but stock MG front hub studs are short!
Since 0.32" of thread engagement is inadequate, I installed ARP# 100-7730 (1.95" long) studs.
Continental Extreme Contact tires, size 205/50R15.
Here's another picture with the new wheels.
2023-2025: Rear Axle and Suspension Build Photos
After stripping down my 1984-5 Mazda RX7 GSL-SE axle and tack-welding suspension brackets to it,
I took it to my friend Michael Spreadbury of Spriso Motorsports to be narrowed.
Michael has narrowed about 80 GSL-SE axles, mostly for use in Datsun sportscars. GSL-SE axles
come standard with heavy duty axle shafts (with 4x4.5" lug pattern), disc brakes with
vented rotors and integral parking brakes, limited slip differentials, mounts for a 4-link
rear suspension, a Watts linkage, and an axle-mounted anti-sway bar.
Michael has the jig, lathe, TIG welder, and experience to narrow these efficiently with confidence.
Trial installation of upper bracket, ready to be welded to both rollcage and body sheetmetal.
My lower link brackets are 5-piece assemblies below the floor, plus doubling plates above.
Why didn't I just use original MG leafspring mounts, plus braces forward underneath the seats?
Too much of that space was claimed by my exhaust system years ago.
For all three trailing link brackets, I used plug-welds from inside the cabin plus stitch welds from below.
(This photo was taken before the stitch welds.)
My car's mufflers have been tucked up under the seats since about 1990, and I like them there.
I did however take a weekend to freshen up the system, adding V-band clamps for easier service
Thrush Turbos remain my favorite mufflers, by the way.
Panhard rod bracket, preassembled and ready for attachment to the MGB's body.
This view of the Panhard rod bracket from the opposite side shows its tab-and-slot
fabrication details. Note also how it mates to the Heim joint with a floating bushing,
enabling the bolt to be torqued to spec without pinching the bracket ears together.
Where the faces of steel parts are welded together, I used weld-thru primer. However,
I removed the primer where I knew I'd be striking arcs to prevent weld splatter. I don't
think it's a great primer for paint, so I removed overspray after completing welds.
(Not shown: another doubling/reinforcing panel underneath the floor.)
This is a cardstock model of the bracket I designed for mounting coilover absorbers. I used
this model to determine what offset for the stud mount would maximize clearance around
the springs. After finalizing the design, I uploaded 2D CAD files to Send-Cut-Send's website.
They laser-cut and bent my steel parts, and delivered within 2 weeks.
With each successive fabrication, I took more effective advantage of tab and slot features for
component part self-alignment. Metals stretch when folded, so I had to learn how to calculate
bend allowance. (This photo was taken minutes after my package from Send-Cut-Send arrived.
Later, I lengthened one slot with a file to eliminate the gap you see at bottom-left corner.)
The coilover brackets required TIG-welding instead of MIG-welding to prevent
distortion, so I called on Michael Spreadbury (Spriso Motorsports) again. To ensure
the parts are vapor proof, we followed-up with braze around the top-plate slots.
I conceived these "foundations" as a way to spread out the force my coilovers exert on the body.
Coilover shock absorber mounting brackets, viewed from below.
Coilover shock absorber mounting brackets, viewed from above. All the plug-welding was
complete, but there was still some welding to do around the edges of the parts.
(Foreground: Clark & Clark Specialty Products battery compartment / storage bin.)
Final welds and paint. In lieu of traditional rubber mounts, Ridetech stud-mount coilovers
swivel on 2-piece nylon ball mounts within aluminum sockets, sandwiching a 3/16" plate.
I purchased a brand-new Mazda 3.636:1 ring and pinion set (part# MA02-27-110).
Made for Australian market auto-transmission Miatas, Mazda didn't offer this ratio in USA.
Ring and pinion were sent to Performance Engineering & Manufacturing for REM finishing.
Mazda Miata NA Type-1 Torsen limited slip differentials perform better than clutch-type
limited slip differentials, including even the one my RX-7 GSL-SE axle came with.
I followed Jesse Prather's instructions to the letter when I set-up my differential.
This photo shows proper gear engagement on the drive side. Next photo shows the coast side.
Jesse revealed a couple tricks: one of them is that you never need to mess with shims
to set-up Miata ring and pinion sets if you observe that their housing and pinion spacers
are matched pairs! (Just don't get the spacers from two different third members mixed up.)
This is the reason I chose to use the Miata carrier in lieu of the RX-7 carrier.
Manual transmission Miatas come with vibration dampeners installed on their prop-shaft flanges.
I removed and discarded the ~1.75# vibration dampener. It's unsprung, rotating dead weight,
and a potential cause of vibration if its rubber component fails.
1994 Mazda Miata third member weighs 46.4#, complete with new gears, differential, bearings, etc.
(Note: I lightened the carrier ~1.9# via removal of Power Plant Frame attachment features.)
Dutchman Motorsports narrowed my axle shafts. They now weigh 13.1# each, including bearings,
retainers, & lugs.
The narrowed GSL-SE axle housing weighs just 28.7#, including all my heavy-duty suspension brackets
Note also: Ford threaded steel breather vent in lieu of Mazda's plug-in plastic vent.
Driver side lower link / coilover bracket.
Passenger side lower link / coilover bracket also supports the Panhard bar.
Both lower link brackets also include features for supporting brake hoses.
Mounting brackets designed to suit Miata calipers.
If you're interested in building your own multi-link rear suspension for MGB, here are more examples:
Ken Biermann's,
Steve Carrick's,
Ivan Collins',
Martyn Harvey's,
Dan Masters', and
Terry Schulte's.
August 2023: Battery and Starter Weight Reductions
Braille B2015 AGM battery (1067 pulse cranking amps. 21Ah. Right side positive.)
This battery weighs 14.0#, whereas the lead-acid battery it replaced weighed 29.0#.
The battery is installed in the passenger-side footwell, behind a simple stainless steel cover.
The new bracketry, hold-down, and cover are 5.6# lighter than what they replaced.
FIA-approved battery disconnect switch with removable key.
(Separate contacts disconnect the alternator before the battery.)
Volvo Truck sealed bulkhead pass-thru. The total weight of pass-thru and cables is 1.0#,
versus 2.2# for the previous cable solution.
TS Imported Automotive mini starter weighs 8.0#, versus 21.8# for my old Delco-Remy starter.
Total battery and starter weight reduction: 35.8 pounds.
Lightweight aluminum storage bin cover, upholstered to match door trim panels as described below.
(Chrome-bumper MGBs came with a heavier, painted-steel version for the twin battery compartments.)
Parked alongside the Willamette river, near my home in Portland Oregon's St Johns neighborhood.
Portland's expansive Forest Park and spectacular St Johns bridge may be seen in the distance.
June 2014: Upholstered Door Panels
When I installed the roll cage, I got the front hoop too close to the passenger-side window crank.
Moving the cage wasn't practical, so I decided to clock the window winder bracket rearward.
With the window crank in a non-standard location, a standard MGB door card wouldn't fit anymore.
No worries! I preferred to make my own upholstered door cards and caps anyhow. I molded the
door caps out of fiberglass. I made them taller than stock to be more comfortable as armrests.
Of course they're lighter weight than stock too. I made door cards out of flat aluminum panels.
Two-needle hand stitching through pre-drilled holes. Like the transmission tunnel cover (above),
door panels and caps were covered with landau pad and then premium automotive grade vinyl.
Stitching across the door panels was aligned to match rollcage tubes.
Stock 1972-only MGB door pulls were substituted for the earlier style.
April 2014: Upholstered Transmission Tunnel
From shifter to firewall, the steel transmission tunnel was fabricated in 1990. Since then, it had
only been covered with paint. I had a lot of time to think about covering it. Goals: total weight
under a pound, easy to keep clean, and removable without tools. I decided to hand-stitch Morbern
"Allsport" 4-way stretch vinyl over 1/8" landau pad on a lightweight 2-piece fiberglass shell.
In this photo, the rearward fiberglass part was newly made. The forward part had been made the day
before. Both were constructed of two layers of glass fabric and regular polyester resin. First, I
taped 1/16" craft foam to the steel tunnel to even out its irregular shape. I covered the foam with
aluminum foil faced duct tape, and then applied mold release to the tape. (Quick. Easy. Cheap.)
I applied a very modest amount of Evercoat "Lite Weight" body filler to the fiberglass to fill in
some of the hollows. Then I laid-out and drilled a pattern of over 1000 5/32" diameter stitch holes
on 5/16" spacing. After that, I used Weldwood HHR (high heat rated) contact cement to secure
sandable/sculpable, 1/8" thick, closed-cell cross-linked polyolefin landau pad over the fiberglass.
Contact cement holds the vinyl tightly in place, and hundreds of of strategically placed stitches make
sure. I used waxed nylon thread from Tandy Leather and a two needle saddle stitch technique. (Both
needles pass through every hole, one from the back and the other from the front.) The two covers
fit tightly with no fasteners, except ones that secure a stainless panel next to the throttle pedal.
May 2014: Easy LED Taillamps
Commercial trucks use light emitting diodes for rearward lighting. Compared to LED bulbs that mount
in standard bulb bases I believe they're far superior, so I installed sealed truck taillamps as shown.
They illuminate in all three modes: stop, turn, and park. I left incandescent brake and tail lamps
for redundancy. Result: much more effective and reliable service for less than $30 total.
This schematic shows how to use four diodes to isolate the lamp functions. One diode keeps the
incandescent brake lamp from blinking with the LED turn signals. Another keeps front and rear lamps
from affecting each other. My friend Fred Key suggested adding two more diodes to keep the rear turn
signals blinking even when brake lights are applied. This all works with an ordinary flasher module.
This photo shows how nicely my LED taillamps light up. (Additional photos appear here.)
Winter 2012/2013: Electronic Fuel Injection
Here, a bespoke fuel injection system was coming together! The basic plan was to combine a
Rover manifold and injectors, a custom cowl-induction plenum, a GM throttle body, and a
custom built/programmed MegaSquirt (speed-density) control system.
6061-T6 aluminum (16-gage) has the right properties for a wraparound plenum wall. However,
to form it with modest force you must first anneal the bend region. Draw a line on the surface
with a Sharpie, and then use a propane torch to heat the surface until the line disappears.
(I had to repeat the annealing process several times as I worked my way around each bend.)
December 2012: a Rover fuel rail has been extensively modified, then electroless nickel plated.
The plenum wall has been welded up. I also fabricated a new air cleaner housing.
This photo shows attachment of a PCV and MAP sensor port block to the bottom of my plenum.
The guys at Peterson Fluid Systems in Denver certainly do beautiful TIG welding, don't they?
They're fun people to work with too. (Photo by Mike Morten for BritishV8.)
Top: Rover intake manifold thermostat bypass has been relocated to suit Buick style timing cover.
The volume of each intake tract, measured from valve seat to trumpet top, has been
carefully cc'd and equalized. Note that the trumpets for cylinders #1 and #7 were
shortened significantly compared to the trumpets for cylinders #2 and #8.
Plenum wall trimmed down (at an angle) and capped with a lid.
Note racing stripe offset to one side, to echo my car's paint scheme.
My very good friend Scott McRoberts was incredibly helpful with this project.
I heartily recommend his family business: McRoberts Machine of Longmont Colorado.
The throttle linkage is rather elaborate, but it proved to work well.
I sent it and some other parts out to be electroless nickel plated.
I'd planned to use a Hyundai crank sensor because they're widely available and have a nice
form factor. After mounting the Hyundai sensor on my engine, I thought to verify its signal
output. Instead of producing a 0 to 5 volt waveform, the output toggled between 5 and 8 volts.
So... this is a second generation Hall effect sensor on a second generation bracket.
This is a "36-1" trigger wheel: it has 36 teeth positions on ten degree centers and one
missing tooth to provide a reference for indexing. I mounted the trigger wheel between
balancer and crank pulley on the six existing bolts. (Buick's six-hole pattern is unusual.
Most of the pre-drilled aftermarket trigger wheels are set up for four or eight bolts.)
The trigger wheel shifted my crank pulley out of alignment, so I made a spacer for the
water pump pulley and a new outboard bracket (and spacer) for the alternator.
Here's a snapshot of the MS3-Pro engine computer. Initially, I only used it to control
electronic fuel injection. It's much more powerful than that! MS3-Pro computors will
support electronic ignition and they're handy for all sorts of data logging too.
Although designed to be easily removable for service or upgrades, this instrument panel
served without modification from 1991 until 2013. Originally, a fuse panel was mounted
on the back side of the panel. As part of the EFI installation, I decided to add several
relays and make the long-overdue upgrade from glass fuses to blade fuses.
This new fuse and relay center will be mounted on the firewall next to the MS3-Pro ECM.
Incidentally, the two relays and two fuses at right are highly recommended features of
the MegaSquirt installation. Fuel pumps and injectors produce a lot of "noise" which
could potentially compromise the ability of the control module to "hear" various sensors.
Part of this fuseblock was assembled by American Autowire (and marketed as a "Comp-9" kit).
I bought it at auction because I recognized they'd used DillBlox modular components. Thus,
it was easy for me to add a two-#10-power-stud block and also a two-relay-two-fuse block.
I also re-wired one of the previously existing relays to control my radiator cooling fans.
An intake air temperature (IAT) sensor is installed between the new fuse/relay center
and the MS3-Pro controller. Cables to the switch/gauge panel will pull out about eight
inches further. It attaches with three Metri-Pack connectors. The oil pressure gauge
is mechanical, and in this view you can see the hose that connects to it.
In-tank fuel pumps offer major advantages: fuel cools them and also muffles their noise.
However, a stock MGB fuel tank measures just six and half inches tall. I decided to
mount a Walbro GSS250 (190 liter per hour) fuel pump at a 45 degree angle.
A Honda Civic (1992-on) prefilter facilitated the installation.
Fuel sloshing within the tank could easily cause the filter to come loose from the fuel pump,
so some sort of baffle is highly desirable. I fabricated a "false sump" type baffle from
materials in my recycling bin: an old solvent can and scraps of half inch box tubing.
A new fuel outlet was fabricated from an AN-6 male weld-in fitting and a scrap of 5/16" stainless
steel tubing. Electrical passthrough connections were created by stacking PTFE washers of two
different outside diameters. The MGB's original fuel pickup remains in place, but will now
be used as a return line directly to the false sump.
The higher pressure fuel supply line is PTFE (Teflon) lined with stainless steel braid
and a black outer sheathing so it's easy to keep clean plus less destructive to chassis
paint along its routing. Fragola straight AN-6 fittings are used at the fuel filter.
Fragola sixty-degree swivel fittings are used at the fuel rail and fuel tank.
Fuel injector and sensor wiring is clipped to a formed and nickel plated steel rod
assembly, and then covered in nylon convoluted tubing of various sizes.
Throttle position sensor (TPS) and Idle Air Control (IAC) stepper motor valve
connections on the side of the throttle body assembly.
Winter 2013/2014: Electronic Ignition
By this point the EFI system was running very well in batch-fire mode and I'd put a couple thousand
miles on it, but there was more to do. Addition of a cam position sensor would facilitate upgrading
to sequential injection and implementing electronic ignition. (Cam position sensors have a simple
job to do: differentiate exhaust strokes from compression strokes.) This photo shows an early 2000s
Ford Taurus/Windstar V6 cam position sensor (top and right) that I purchased and took apart. At left
is a section of old Buick 350 distributor. I copied its dimensions and used its drive gear for the
new custom part in the center. My good friend Scott McRoberts did the machine work.
The Ford shaft was cut in diameter and length. We milled flats onto its end to drive a Buick oil
pump. Note how it has a "half moon wheel" at the top instead of one with one or more narrow
teeth. The sensor at right came with it; it's a VR (variable reluctance) 2-wire sensor. I prefer
to instead use the Hall effect 3-wire sensor at left. This particular Airtex Wells sensor (part#
5S1283) is an improved version of a Hall effect sensor Ford used in the 1990s. It features an
over-molded magnet instead of one that can shake loose. The functional advantage of a Hall
effect sensor in combination with a half moon wheel is quicker starts. MS3-Pro can "poll" cam
position when the crank sensor detects a missing tooth and immediately sync ignition timing.
Here's the mount I invented to hold eight Chevy LS2 Truck ignition coils.
These coils are bad boys - possibly the most powerful coils ever installed by a major OEM.
A neoprene gasket provides a modest measure of vibration isolation.
This bracket spans between the cylinder heads and a boss on the timing cover.
(The coil pack connects to it three places too.)
I reworked a pair of Chevrolet coil harnesses into one new harness. Now all eight
trigger leads come through one eight-way Metri-Pack connector, and a second three
way connector provides power and ground connections. (One ground is connected to
the engine. A second ground lead connects to the MegaSquirt MS3-Pro computer.)
The top cover snaps back on neatly and tightly.
Aurora custom spark plug wires and Made-4-You Products "Smoothie Stac-Pak" separators.
MS3-Pro will reportedly drive any modern tachometer. My tach wasn't modern, so I pieced
together an adapter from a gutted relay, a transistor, and a resistor. This photo shows
the finished part potted inside a 35mm film canister and some spare components. (The
adapter worked fine, but I upgraded to a new tach in 2016, making this redundant.)
October 2014: Refined Engine Tune
This is an "AFR Table" for my Buick/Rover V8 engine. Obviously the x-axis is engine speed.
The table's y-axis is "Fuel Load %", which is derived from the MAP sensor's measurements.
The table's cells (i.e. the z-axis) show the target air/fuel ratios I had as of 2014. (Note: as
of 2016, my tune has been updated to "stoich" (14.7:1) at idle speeds and it's also leaner
in the cruise region. Result: a smoother/slower idle and better fuel economy.)
This is the exact same AFR Table, except converted into a "topographic map" view.
This is a Volumetric Efficiency table, tuned for the characteristics of my engine
including for example its fuel injection system, camshaft grind, cylinder heads, etc.
The VE table is really critical for engine operation because its z-axis is the main
determinant for how long fuel injectors are pulsed for each combustion event.
If you're familiar with mechanical and vacuum advance mechanisms on distributors,
you'll have no trouble comprehending this table: x equals engine speed, y equals
manifold vacuum, and the z axis shows ignition advance (in degrees before TDC).
April 2013: Wilwood Dynalite Brake Calipers and 11.75" Vented Rotors
Wilwood Dynalite four-pot forged aluminum brake calipers and 11.75" vented rotors,
sourced from Bill Guzman at Classic Conversions Engineering.
May 2012: Coilover Front Suspension with Dropped Spindles
Gutted and milled out Armstrong lever shock absorbers have been combined with GAZ single
adjustable coilover shock absorbers from Moss Europe and Eibach 525 pound/inch springs.
Lower spring pans from Moss Motors have been drilled out to reduce their weight. MG Limited
(a.k.a. Killer Beez Racing) dropped spindles lower the car one inch, and do so without
shifting the suspension's roll center lower. Most importantly of all, MG Limited modified
my steering arms to minimize bump steer associated with the lowered ride height.
April 2012: My First Home-Made Carbon Fiber Part
This custom carbon fiber and epoxy recirc shield touches the bottom of the bonnet all
the way across, preventing any airflow from bypassing the radiator. This part only
weighes about five ounces! It'd be even lighter if I had tools for vacuum bagging.
Foreground: the new carbon part, freshly removed from the mold (and trimmed on a bandsaw.)
Background, bottom to top: a quick-and-dirty fiberglass/polyester prototype, an MDF "plug",
and the fiberglass mold made by draping over the plug. Obviously I could have made the
recirc shield out of aluminum or whatever, but learning new fabrication techniques is fun.
Winter 2011: Custom Carbon Fiber Bonnet
In 2011, my good friend Dave Craddock of Preform Resources built this custom carbon fiber bonnet.
The new bonnet weighs less than five pounds! That's over twenty pounds less than a steel one.
I reckon Bonnie probably has the lightest weight bonnet of any MGB in the entire world.
These photos were snapped just hours after I received it. Hood pins have subsequently been installed
to hold down the front. Hidden aluminum tabs hold down the back; they slide into slots cut into the
MG's steel bodyshell above the original hinge positions.
The large "RV8 style" bulge in the bonnet provides room for a new induction system (see below).
"When you got it, flaunt it!" - It would be a pity not to show off a little of the carbon fabric.
Instead of regular glued-on reinforcements with provisions for hinges and latches, this hood
"skin" has only a honeycomb core to provide its stiffness. To avoid crushing the core when
installing OMP aluminum hood pins (part# EB/492/A), I crafted aluminum reinforcements.
Somebody Asked For Close-up Photos of my Oil Filter Installation
A Buick V6 "metric" oil pump facilitated doing away with the previous remote oil filter.
I formed a shallow recess with a few blows of a ballpeen hammer.
AC Delco PF47 (and similar) oil filters fit nicely.
Vinyl hose and compression fitting for the oil pressure gauge.
Miscellaneous/Older Photos
One of the custom motor mounts. Buick V6 "metric" oil pump, which angles the filter forward.
Note: Pete at Mantell Motorsport blasted & powder-coated all the black parts shown here.
A compact Nippondenso alternator and an external clutch slave cylinder, both on custom brackets.
The seven accessory mounting bosses on Rover 4.0L heads are placed differently than the two bosses
on original Buick 215 heads. Upgrading heads necessitated significant alternator bracket modifications.
Also, two bosses had to be cut off to clear the driver side bulkhead. A more surprising difference:
exhaust port spacing is slightly different between Buick and Rover heads. Just different enough
that I had to enlarge the mounting holes in my precision-crafted headers!
The radiator is directly above the anti-sway bar, not out in front.
The Buick V8 engine is mounted further rearward than usual too.
AFCO "Scirocco" dual-pass aluminum racing radiator (part number 80107N).
Twin Honda Civic electric cooling fans.
Homemade sand-bent Tri-Y headers with slip joints at the collectors for easy installation. The
theory of this design is that proper pairing can improve exhaust scavenging. For the Buick's
firing sequence, cylinders are paired as follows: 1 & 5, 3 & 7, 2 & 4, and 6 & 8.
(Note the modified MGB radiator, which was used for about seventeen years.)
Custom mount for a Girling slave cylinder, and shortened throw-out fork.
Left: Chevy S10 rear view mirror with integral map lights. Right: 12V power socket & binder posts.
Lightweight polycarbonate quarter windows are secured in place with Dzus quarter-turn
fasteners (three per window), and they're easily removable for ventilation.
Righthand photo also shows one of many supplemental cage-to-body brackets.
Six-point roll cage made from 1.75" seamless (DOM) mild steel tubing, w/ 0.090" wall thickness.
Note horizontal tubes under the dashboard, at shoulder-strap height, and low, behind the seats.
This photo also shows the built-in tool chest, with lid held down by Dzus quarter-turn fasteners.
Many more glamorous photos of Bonnie may be found here:
Moss Motors' 2014 Motoring Challenge!
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