>> The World's Most Powerful MGB with an MGB Engine?

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Look at the attention to detail!	Differential
Empty Engine Compartment	This is how the car looked when it showed up
Scuffing on the piston skirts tells us the pistons were "sticking in the bores"	The interior of the engine block had previously been painted with glyptal
The camshaft hardness has failed. This after only 500 miles.	The cylinder head after only 500 miles.
You can see the "chatter" marks on the bottom of the lifters which indicates the hardness has already failed.	/The original engine disassembled, cleaned, inspected and ready to go to the machine shop.
The engine compartment less engine	The interior less all upholstery and dashboard

The World’s Most Powerful MGB
with an MGB Engine??

We were contacted by L.L. who inquired if we would be willing to finish reassembling his 1977 MGB. He had stripped out the interior, removed the drive train, dashboard, suspension, and wiring harness. L.L. had the body, interior, and underside beautifully painted. He had rebuilt and reinstalled the suspension and then brought the car to us. We installed a new main wiring harness, sourced used ancillary wiring harnesses that are not available new and made all the electrics function properly. Yes, it is possible even on a British car! We reassembled the console, the heater controls and ducting for the heater. We flushed and bled the brake and clutch hydraulic systems. We rebuilt the windshield frame (boy was that a project!) We contacted several glass shops but no one wanted to tackle that project. We found out why! We applied “Waxoyl” a waxy oily substance made by the British to prevent rust to all painted non-exterior surfaces.

Then, L.L. brought the engine in. The engine had only 500 miles on it since it was rebuilt 14 years ago.

Next, L.L. dropped the bomb! He was planning on supercharging the car and installing a 5-speed transmission. My response was when!? That started the discussion about drive train options.

I considered converting the car to a V8, which the factory did (only on the coupes known as an MGB GT V8) and decided it would be an excessively time consuming and expensive project. While a “bolt in conversion” there are a tremendous number of issues with this route. One is the exhaust manifolds. MG used some pretty restrictive ones. A common practice is to use headers and cut holes in the inner fender wells and run the piping through the wheel wells. As a general rule I do not like cutting up or modifying the structures of cars if I can help it. The intake system is another significant problem. The factory MGB GT V8’s used an intake manifold with 2 SU carburetors up against the firewall (a hard to find and not very “performance friendly option”). Since the “Buick-Rover V8” was originally purchased from GM in the early 60’s (and used in Rovers well into the 90’s). An intake manifold that uses an American 4 Barrel carburetor and fits under the hood is available, however an American 4 Barrel Carburetor wasn’t in the cards for this MGB. Another option was the fuel injection system and intake manifold from a TR-8 that was sold in California for 1 year only, if I remember my trivia correctly! Another difficult to source fleet of parts.

Lastly, The Rover fuel injection system and intake manifold can be made to fit under the hood by shortening the whole intake set-up. Again more of a project than I wanted to recommend.

On to Plan B, the supercharged engine!

Moss Motors sells a supercharger kit, as does a company in Australia. The two major differences are: The Australian kit uses an Opticon aka: Whipple, Sprintex, Lysholm commonly called a “twisted helix” design of supercharger. The Moss kit uses a Rootes supercharger commonly called a “screw type supercharger.” Without going too much in depth, my research from numerous sources yielded that the “twisted helix” design is much more mechanically efficient from the standpoint of energy used to create boost pressure, and is also more thermally efficient when compared to the “Rootes” type of supercharger to the amount of heat induced into the intake tract as a byproduct of compressing the air for supercharging.

All that said, if you are planning on running 8 PSI or less of boost pressure the additional complexities, cost and possible future serviceability issue of the “twisted helix” type of supercharger was not warranted.

At this point we had the supercharger kit picked out—on to the engine. As owners of Lotus Esprit (4 cylinder) turbos and Peugeot 505 gas turbos came to know- cast pistons will eventually fail. It was not a question of if, but when.

I discussed all this with L.L. and offered the following options: bolt the supercharger kit on to the existing “rebuilt” but old engine and see what happens. If it self-destructs we could then build a proper engine that was designed with supercharging in mind or we could put together an engine initially that was designed for performance and durability using modern tricks and techniques.
L.L. thought about these options and decided for us to partially disassemble the engine for initial inspection. It’s a good thing we did. We discovered some significant problems: all 4 pistons were scuffed on the skirts, the camshaft was already failing, 3 of the 4 pistons also had seized or stuck rings. Additionally, the crankshaft bearings were badly scored. This engine would probably not have lasted long in stock trim, much less in supercharged form!           

Preparing a proposal for a drivable, durable MGB engine with 100% more power, I came up with: running 8 PSI of boost on a stock MGB engine makes 120 ft. lbs. of torque at 2700 rpm and 90 hp at 5000 RPM. The original MGB GT V8 produced 190.5 ft. lbs. of torque at 3000 RPM and 137 HP (at sea level) with the stock dual SU carburetor set up.

To ensure durability along with good drivability my recommendations included: balancing all reciprocating and rotating components, “blue-printing” which means adjusting all internal engine clearances to nominal (middle of the factory) specifications, replacing all critical hardware (cylinder head, connecting rod and flywheel) with aircraft quality fasteners, larger stainless steel intake and exhaust valves, double instead of single valve springs, a custom ground camshaft especially suited for use with a supercharger, roller rocker arms with a slightly higher lift ratio for more efficient cylinder filling (read more power, since an engine is just an air pump and getting more air in and out is the goal), the pistons will be JE high silicon content forged aluminum pistons--which will be coated on the crowns with an aluminized ceramic that distributes heat more evenly and helps to eliminate hot spots which could possibly lead to a catastrophic meltdown.

The piston skirts will be coated with a molybdenum disulfide compound which helps eliminate scuffing and friction. The cylinder head will be gas flowed, the combustion chamber, exhaust valves and stems, and the intake valve heads will be coated with a thermal barrier that will improve engine efficiency because the heat of combustion will be directed back into the engine rather than “leaking” into the cooling system. The intake ports and the intake valve stems will be coated with a Teflon derivative for more efficient induction flow.

The transmission will utilize a Datsun 280Z 5-speed, which will “bolt in” (more on that later). The shifter will be in the original location, and removing the transmission for clutch service will be a cinch-unlike the factory 4-speed or overdrive transmission.

While we are waiting for the first test drive we have a lot more work to do! Today, it’s off to the interior shop to have the interior put back in. The internal engine parts are at the machine shop. Boatloads of parts are on order.

The MG is back from the trim shop. The interior is gorgeous, as you can see.

The 5 speed transmission, crossmember, flywheel, rear engine plate (which being made from aluminum saves 50% in weight) and clutch all arrived for our inspection.

The cylinder head was shipped and has arrived back from the coating shop.
Brandon, from Kleeman USA stopped by and was chatting with us about the project. He said, “Why not fuel inject it?” When I recovered my composure I replied “Hmmm… that’s an interesting thought. Siamesed ports??” If you are interested in this unique problem please go to www.starchak.ca/efi/siamese.htm.

I discussed with L.L. the possibility of fuel injecting the MGB. He asked “What would the benefits be?” I answered ”The car would start, run, and idle properly at all times. There would be no need for a choke. We would be able to vary boost pressure and always have the correct air/fuel ratio. It would be just like a modern car! The only downside would be the time and expense involved.” L.L. responded enthusiastically, “Let’s do it!”

I discussed the functionality of the Moss supercharging kit with Paul of Sports Car Craftsmen in Denver who has installed more of Moss’s MGB supercharger kits than anyone else that I know. He said the kits have a real problem running rich under boost and lean on transition from cruise. I researched keeping the supercharger wet (with injectors in front of the supercharger) and found a single injector would be too small and would require an additional injector or injectors downstream of the supercharger. We then called PSE Supercharger, a well known rebuilder of superchargers. They said that the Rootes type of supercharger is not designed to be run wet (having fuel pass through it). So our choice became clear, 2 injectors downstream of the supercharger. Designing a fuel rail, adding sensors for engine RPM and TDC, coolant and air temperatures, throttle position, plumbing a fuel return line, installing a high pressure fuel pump and regulator along with a throttle body and idle speed motor only touched on the challenges we faced!

Fortunately, we have access to a very talented machinist, Paul Rust, who owns Rocky Mountain High Wheels which constructs modern “high wheel bicycles.” Watching Paul ride one is an experience every bicycle enthusiast should have. I am an avid mountain bike rider but I declined Paul’s very generous offer of a test ride. I’m pretty good at falling off my bike and not getting hurt, But falling off from 4 feet up scares me-but I digress.

Between Paul and our shop and large amounts of research, we came up with what I think is the simplest yet most elegant solutions to all the problems we faced.

On to the engine!

While researching the throttle plate, we found a 2 inch throttle plate will support 200HP. The Moss kit comes with a 44mm carburetor (almost 1 ¾ inch) which according to Dave at APT has a pressure drop of almost 2 inches of mercury which indicates a loss of power on the stock Moss set up. A larger throttle plate would give more power but alas there is no room for the 2 inch carburetor under the hood with the current Moss kit configuration and MG hood
height limitation.

Since we are fuel injecting the engine we had the luxury of using the 2 inch throttle plate which bolted right up to the Moss supercharger inlet. The throttle body is made by TWM Induction. We then “mocked-up” a throttle linkage arm with related throttle cable bracketry.

Next, we worked on converting the chassis fuel plumbing for fuel injection. We used a Mercedes-Benz fuel pump and filter, complete with bracketry mounted on the proper anti-vibration (“lord mounts”) for quiet operation. We installed the return line in the fuel filter neck by purchasing the necessary “bits” from Moss. As they had already fabricated the parts, we didn’t need to. We chose to bend and install the hard lines under the car rather than use a rubber hose to promote a safer job and more factory appearance.

Next, Jason fabricated the throttle body to air intake horn plumbing. We ended up using an air horn (or velocity stack) from a BMW air filter assembly.

All readily available fuel rails are designed to have the injectors in the same plane. But this is not possible with the Moss inlet manifold and confines of the MGB engine compartment.

After much head scratching we came up with an elegant solution. Paul of Rocky Mountain High Wheels did a beautiful job of taking our ideas and making them a reality (thanks Paul!) he also cleaned up the throttle body to give it a more finished look.
We chose to bead blast, scotch Brite ™ and clear coat all the aluminum and bare metal parts under the hood (including all our fabricated intake plumbing).

On to the actual engine assembly. We used Calico coated engine bearings and upon initial assembly we found too much rotational friction (the crankshaft required too much effort to rotate in the engine block). So, out came the crankshaft, we measured the I.D. of the bearings (with the bearing caps torqued down) and the O.D. of the crankshaft journals—all were perfectly within specifications. But we determined that the block bores were not “looking at each other.” So, we removed the crankshaft and bearings, and shipped the block back to the machinist for
align honing.

Mark hand ground the piston rings for the proper end gap (.012). It is the double and triple checking of all these little details that makes or breaks a project like this.

Next, Mark installed the camshaft after bolting on the cam thrust plate (a brand new one) but the camshaft would not rotate. We discovered the new thrust plate was not flat. Once again Paul at Rocky Mountain High Wheels came to the rescue and made it flat, and ground it to the proper thickness to have the proper end float. While we were at it, we had the proper thickness shim made to properly align the timing chain.

Then we bead blasted and painted all the engine ancillary bracketry. While doing that we discovered the left motor mount stand was cracked, so we welded it. The through bolts for the supercharger bracket interfered with the motor mount stand, so we modified the stand to clear the through bolt for the supercharger bracket.

We checked the exhaust valve to cylinder block recess for clearance. We found it to be .027 and the minimum spec is .060-.070. Hopefully, the third time will be a charm. Again, we disassembled the engine and shipped it back to the machine shop.
This time everything was right within specifications. We timed the camshaft using APT’s vernier cam timing kit. We discovered the radius of the ball on the bottom of the pushrods to be incorrect and the length was also wrong. We had custom made pushrods shipped to us from Smith Brothers. I learned more about pushrods then I ever thought there was to know! We used a Cometic ™ multi-layer steel (commonly known as MLS) head gasket. The beauty of these gaskets are, they don’t need to be retorqued and they seal better. The downside to them, is the cylinder block and head surfaces need to be mirror smooth. This type of gasket is what all modern engines use.

We designed, fabricated, and installed the crankshaft position sensor.

The engine management computer and wiring were the next to install. The ECU was installed in the passengers footwell behind and below the glovebox. All the wiring was routed and after testing we sourced the appropriate blue vinyl electrical tape to match the original MGB wiring loom color and material.

Mark did the final engine assembly with the supercharger, and installed an intake air temperature sensor in the intake manifold. We installed the alternator, water pump pulleys, and shimmed them for proper belt alignment. Next, we tried to install the new aluminum rear engine plate for the Datsun 240Z 5 speed transmission conversion. The bolts around the rear main seal on the engine plate contacted the flywheel. The holes in the rear plate had to be counter sunk for clearance. The starter had no clearance to the ring gear, so we had to enlarge the starter opening in the rear engine plate by .030in. The transmission crossmember needed some fiddling to function correctly and to get the driveshaft geometry right. The sum of the angles of the differential pinion and the transmission output shaft flange should be 180 degrees. The transmission tailshaft was too high and had to be lowered 1 inch. We also had to re-drill the crossmember to center the transmission in the tunnel—it was too far to the left. The drive pin for the angle adaptor for the speedometer cable would not fit in the transmission. We had to drill out the drive pinion so it would accept the drive pin. We built an adjustable push rod for the slave cylinder out of a MGB valve cover bolt and jam nut, now the “bolt in kit” fit and worked well. Just for grins we weighed both rear engine plates. The aluminum one weighed 9lbs. while the original steel one weighed 17 lbs. As Colin Chapman (the founder of Lotus) said, “to go faster add lightness.”
Mark assembled the engine and transmission and installed the driveline in the car. It took 3 shims on the left motor mount to level the driveline (gotta love those Brits!) We discovered that our throttle body would not clear the brake booster, so we turned it 180 degrees (upside down) and redid the plumbing and throttle cable as required.

We wired the crank sensor, coolant temperature sensor, and throttle position sensors (how novel for an MGB!) We welded in an oxygen sensor bung and wired the oxygen sensor as well. We installed a “big bore” stainless steel exhaust system.

We ordered and installed a suspension lowering kit from Moss. It puts the ride height in between a European spec MGB V8 and American spec “rubber bumper” B. So it gets a little more ground clearance and the ride height
looks perfect.

We obtained and installed a set of Panasport alloy wheels 15”x 6”. Frank custom made and installed the emblems in the wheel hubs. We installed an oil cooler and thermostat. Jason fabricated a lower grille, the air inlet plumbing along with an air filter shroud and bracket. Several folks at the British Car Conclave asked us if the air inlet was a “kit?”

We now found that the Lucas distributor with electric ignition would not interface with the autronic engine management system. We installed an Audi distributor pick-up and trigger. We can only hope that this bit of German technology will go a long way in this British machine. The next step was to install a Bosch ignition amplifier (again, the hope was it will “raise the bar” for the British electrics!)

Now the moment we all have been waiting for. We put the fuel in it, installed a battery and turned the key. It started right up. We ran the engine for 20+ minutes at 2000RPM to break in the camshaft and lifters.

Next, we adjusted the base idle setting for the motor. Imagine that—an MGB that has a constant idle speed—is that cool or what? We had trouble deciding between the original expansion tank or a more modern looking aluminum tank. L.L.’s son, B.L. decided to use the aluminum one—in it went.

After initial set up and tuning (thanks to Burt at Kleeman) we determined that the boost pressure was too low partially because of our Colorado altitude and partially because the engine we built was “too volumetrically efficient. In other words, the supercharger has less to “push against” and therefore makes less boost. We called Ed at PSE Superchargers and found out what the recommended maximum supercharger speed was, so we had a new crank pulley made that was 6.75” in diameter. The original one supplied with the kit was 5”. We determined at 6000RPM the supercharger would be turning at 15,000RPM (it’s recommended maximum RPM).

Next, we located a period correct boost gauge. We first installed it where the clock went. That got voted down, so we installed it where the cigarette lighter originally was.

Burt from Kleeman called about to the dynamometer and said, “I have good news and bad news. We are now making 150 foot lbs. of torque, at the rear wheels, altitude corrected, but the clutch is slipping.”

Back at our shop, Mark pulled out the transmission and we began the hunt for a clutch that would work. We obtained an MGB “competition” pressure plate and measured the torque required to make it slip. The idea for doing this came from Jonathan Burnette, “the French car guru,” who shipped us a Datsun Z car input shaft which we welded a nut to and measured the torque (with a torque wrench) it took to make it slip. Even shimming the pressure plate (by .090) the best results we could obtain were 148 foot lbs. of torque. Dave at APT said, “They just don’t make good clutches for MGB’s anymore.”
Of course, no other MGB (that I’m aware of) has made this much torque.

We obtained a Datsun Z flywheel from the recycler and tested a stock Z car clutch and it yielded at 160 foot lbs. of torque. If we needed more pressure plate they had 4 more upgrades on the shelf. We drilled the MGB flywheel for the Datsun pressure plate.
As the Brits would say “we offered up” the redrilled flywheel along with the Datsun Z clutch and 5 speed transmission back into the MGB. A test drive revealed no clutch slippage—Yay!

Frank and Jason designed the 1800i graphic for the front fender, we had decals made and Jason installed them. Back to the dyno. At 180 foot lbs. of torque, we determined the “big bore” exhaust system was not big enough. Burt fabricated a stainless steel exhaust system 2 ¼” diameter. With more dyno time, we ended up with 200 foot lbs. of torque and 165 HP. A stock 1977 MGB we ran on the same dyno (altitude corrected) at the rear wheels previously had 85 foot lbs. of torque and 48 horsepower.
After some test driving we ended up adding a relay for the cooling fans, so all the current for the motors doesn’t go through the temperature sending unit. The fans operate with the key off, to limit high under hood temperatures “known as hot soak”, after the car is turned off.

Finally, we decided on, and Burt programmed in to the engine management system several safety protocols, which included reducing the boost when:

• Coolant temperature exceeds ___°F
• Engine intake air temperature exceeds ___°F
• Boost pressure exceeds ___ °F.

B.L just got back from driving the MGB and said, “wow!” Now, we just need for dad to give it the final ok. The wonderful thing about this car is that B.L. drove this car when he was in high school.

This car truly has ended up being the world’s most powerful MGB with an MGB engine. What an honor it has been to give this car such an amazing transformaion.

Respectfully Submitteed,
Mark R. Weiner
President, Concours Cars