Restoration & Engine Rebuild for a Supercharged MGB!

 

by

 Ray A. Wyberski

 

Manufactured by British Leyland U.K. Ltd. on 13 May 1977!

 Located in the United States Territory of American Samoa!

 

1st Place Overall Winner (Best of Show)

2006 American Samoa Inaugural Auto Show!

   We are providing this web-site of our Restoration and Engine

Rebuild with Technical Data acquired to MGB Enthusiasts that may

have a desire to modify or Supercharge their MGB.

 

All information provided below is exactly the way our MGB is today with

 engine modifications that work with the Supercharger!

 

   Our MGB Restoration Project had the following Goals!

***Keep our 4 cylinder 1798cc engine making modifications to compliment

the installation of a Moss Supercharger with emphasis placed on low and middle

range torque/power for increased street performance.

***Improve the appearance of our MGB by making body modifications that will

enhance our MGB with a more modern look.

***Change old parts with modern parts to enhance reliability, drivability and

dependability of our MGB.

***Attention to Detail...Take your time and do it right... The best tuned

engines are ones that have careful planning and the correct combination of

subtle modifications.

 

Time to get Started with the Restoration!

    For some reason we liked the rubber bumper MGB's, but always wondered

how to make it look more modern looking. Since we were doing a ground up

restoration this would be the perfect time to make changes. Looking at the

early model MGB and MGRV8, we decided on the following changes that would

make our Rubber Bumper MGB more modern and appealing:

 

    Our ground up restoration started in May of 2005 by completely stripping

the car and taking it to a body/paint shop to perform body modifications before

sandblasting and painting. We never liked all the seams/beads on our MGB

located near the windshield, above the trunk, rocker panels, above the rear

bumper, and rear quarter panels. We had them all removed and body soldered.

The rear quarter panels were rounded out to match the early type rear tail light

assembly. The side molding strips were removed and holes welded. The two

jacking points underneath the rocker panels were also removed. The hole for the

antenna was covered up with sheet metal and welded. We liked the fluid flow

look of the early MGB without the side lamps and removed all 4 of them. We

decided the side mirrors needed a more sporty look like the MGRV8 and

installed 1992 Miata power side mirrors. The underside (Crack of Doom) was

reinforced to make it more capable of handling the weight of the new mirrors.

We now felt our MGB was more modern with a sporty look.

 

     With body modification completed it was time to sandblast the entire car.

Once sandblasted primer was sprayed immediately, and than the long job of

getting the car smooth all the way around. We wanted a show room quality

paint job and body preparation was the key. We decided on DuPont Chroma

Premier (Base and Clear Coat), with 5 coats of Gold paint, 3 coats of clear coat,

and finally to wet sand, buff and polish it out. Very professional job.

 

All New Parts!

With an empty body shell we decided to install all brand new parts

and any modern parts that we could find.

 

Modern Options added to our MGB!

 

Power Windows (Entire Window Mechanism),	Power Mirrors w/electric switch (1992 Miata)
Power Amplified Hidden Dash Antenna	Modern Circuit Fuse Block  (Blade Type)
Pioneer Premier DEH-P960MP Head Unit Motorized Dual Display	Rear Tubular Shock Conversion
Boston Acoustics Pro60 6.5 Component Speakers	Hood and Trunk Telescopic Gas Strut Lifts
Special Tuning Front Air Dam	Carter P60504 In-Line Fuel Pump
Moss Supercharger with SU HIF 44 Carburetor	Supercharger Heat Shield
5 Speed Ford Sierra T-9 Transmission with Close Ratio Gears	Hall Effect Sender Speedometer Cable
K & N RU-4410 Air Filter with Velocity Stack	Deluxe Biscuit Interior Carpet
VDO Gauges: Speedometer, Tachometer, Oil, Water,	Biscuit Molded Trunk Set
VDO Gauges: Fuel, Clock, Volt Meter, Vacuum/Boost	Cobalt Wires - NGK-6ES Spark Plugs
Peco Header (Jet Hot Coating)	Peco Big Bore 2" Exhaust System
High Flow Triple Chrome T-304 Stainless Steel Exhaust Tip	"SC" Supercharged Chrome Emblem
Mini-Lite Style Alloy wheels 15" x 5.5 w/195/65R15 tires	MGB V8 Brake pads with new Calipers
MGB Billet Pedal Covers: Clutch-Brake-Accelerator Pedals	"Roadster" Billet Door Sill Plates
"Roadster" Chrome & Black Emblem	Rosewood 6 piece Dash Trim Kit,
Long Lasting ABS Under Dash Liners and Rad-Lights	ABS Engine Air Scoop/Duct Panel
Stainless Steel Front & Rear License Plate Frames	Stainless Steel Front Grill
British Motor Heritage Vented/Baffled 13 Gallon Gas Tank	Permanently Mounted Battery Charger
Tripod Headlamps Halogen with Heavy Duty Relay Harness	96 amp GM/Delco CS-130 Alternator
14 " 10 Blade Spal Electric Cooling Fan/Adjustable Thermostat	High Torque Gear Reduction Starter
Original 41427 45D4 Distributor w/Custom Curve	Pertronix LU-143 Electronic Ignition (45D)
MSD-6A Electronic Ignition Control	Flamethrower II .6 Ohm Epoxy Coil
RV8 Moto-Lita 14" Eagle Leather Rim Steering Wheel	Black Leather Shift-boot
Mohair Black Convertible Top MGRV8 Style	Walnut & Chrome Shift Knob

 

Engine!

   With the exterior completed it was time to make an engine decision. Do we

install a V-6 / V-8 engine, or add a Moss Supercharger?

 

   We felt nothing would be more interesting than lifting the hood (bonnet) and

seeing an Original 4 cylinder 1798cc MGB engine with a Supercharger.

 

   Before any mechanical modifications were undertaken extensive research and

testing was conducted on cylinder heads, camshafts, valves, headers, exhaust

systems, and supercharging (Forced Induction). 

 

New Engine Rebuild Parts!

Payen Head and Lower Gasket Sets

ARP Performance Fasteners (Head-Rod Bolts-Main Cap Studs)

Tuftrided Rocker Shaft

Main Bearing Set

Oil Pump, Oil Pressure Relief Valve and Spring

Duplex Timing Chain, Crankshaft Gear, Camshaft Gear, Timing Chain Tensioner

16.2cc LC Hepolite Pistons with Rings and Pins

88G303 Steel Billet Camshaft

APT Lifter Set

Camshaft Bearings, Rear Main Seal, Rod Bearing Set, Thrust Wash Set

12H4736 Port & Polished Cylinder Head

 

Main Changes with our MGB Engine Rebuild!

 

Camshafts!

  The later 1975-1980 North American (NA) Rubber Bumper (RB) MGB's had

Camshaft #1156 installed. We replaced it with the earlier 1965-1974 Camshaft

#88G303 with duplex timing chain and camshaft sprocket. The 18G series and

early 18V engines used this camshaft.

 

  The duplex timing chain/sprocket was used on 1965-1971 MGB's, and the

single row timing chain/sprocket on 1972-1980 MGB's. The only difference in the

two sprockets is that the duplex sprocket is in fact 4 degrees retarded from the

single row camshaft sprocket.

 

  There are two easy ways to change the characteristics of your camshaft.

Advancing moves the power band down, more low-end torque. Retarding moves

the power band up a few hundred rpm, more high-end power. The second way is

to change the valve lash. Tightening the valve lash will increase top end power

while loosening will increase bottom end power. 

 

Advancing Cam Timing! Begins intake event sooner opens intake valve sooner Builds more low-end torque Decreases piston-to-intake-valve clearance Increases piston-to-exhaust-valve clearance Loosen Valve Lash! Increases Bottom End Power

Retarding Cam Timing! Delays intake event Opens intake valve later Builds more high-end power Increases piston-to-intake-valve clearance Decreases piston-to-exhaust-valve clearance Tighten Valve Lash! Increases Top End Power

 

   Why is cam timing so important? Because it affects engine performance. For

the engine to run its best, it needs accurate cam timing. As a rule for the MGB,

advancing cam timing from the original ground centerline ("Straight Up" 107.5°)

3 to 4 degrees helps low-speed torque and throttle response with little sacrifice

in higher rpm power. Retarding the cam improves performance at high rpm at

the expense of low speed torque which is not what you want in a stock or street

performance engine.

 

   We set our camshaft timing at 104° ATDC degrees because both the earlier

inlet and exhaust opening events will help the supercharger breathe more air

into and out of the engine which is recommended for increased low rpm and

torque. By opening the intake valve sooner and having a greater amount of

valve opening at TDC, the intake pressure can purge the residual exhaust from

the combustion chamber, thus providing better filling of the cylinders.

 

Note: We tested cam timing at 110 degrees, 106 degrees, and 104 degrees. We felt the most

street performance from our Supercharged MGB when the cam was timed in at 104 degrees.

 

Camshaft Specifications!

 

MGB #88G303 Early Cam with Duplex Timing Chain and Sprocket!

Intake: 22 / 50     Exhaust: 57 / 15

Duration: 252°   Overlap: 37°   Intake: 104°   Exhaust: 111°   LSA: 107.5°

This camshaft was advanced at 3.5° BTDC

Worked extremely well with the Supercharger with a P&P Cylinder Head!

Above is our Camshaft Specifications at 104° ATDC!

MGB Camshaft #88G303 Cam Duration & Lift Specification for 18V Engines!

Intake: 20 / 52     Exhaust: 55 / 17

Duration: 252°   Overlap: 37°   Intake: 106°   Exhaust: 109°   LSA: 107.5°

18V engines, respectively. Four degrees advanced from 18G engines!

This camshaft was advanced at 1.5° BTDC

Early 18V Camshaft Specifications! Single Timing Chain & Sprocket! 

MGB Camshaft #88G303 Cam Duration & Lift Specifications for 18G Engines!

Intake: 16 / 56     Exhaust: 51 / 21

Duration: 252°   Overlap: 37°   Intake: 110°   Exhaust: 105°   LSA: 107.5°

18G engines, respectively. Four degrees retarded from early 18V engines!

This camshaft was retarded at 2.5° ATDC

18G Series Specifications! Duplex Timing Chain & Sprocket!

 

Transmission & Gear Ratio's!

 

Gear Ratio:  MGB - Ford T-9 - Ford T-9 Close Ratio	MGB  62-67	MGB  68-74	MGB  75-76	MGB   77-80	Ford T-9 Standard	Ford T-9 Close Ratio
1st Gear	3.64	3.44	3.03	3.33	3.65	3.36
2nd Gear	2.21	2.16	2.16	2.16	1.97	1.81
3rd Gear	1.37	1.38	1.38	1.38	1.37	1.26
4th Gear	1.00	1.00	1.00	1.00	1.00	1.00
5th Gear / OD		.82	.82	.82	.82	.825

   With a Supercharger we surely needed a better transmission and installed a

Ford Sierra Type 9 5 speed Transmission conversion kit. It is a robust gearbox

well capable of handling higher more torque than the standard gearbox, very

quiet and smooth, with a tight shifting gear radius.

 

   When it came to gear ratios we felt the T-9 Close Ratio Gears was a much

better choice. This gear ratio was actually used in 2.8L V6 engines as it's

Standard Gear Ratio. With a Higher Ratio Gear (Numerically Lower) means there

is less acceleration and will require more torque to accelerate. The Supercharger

adds this extra torque and accelerates quite well with the higher gear ratios. In

the chart below using a Higher Ratio gear increases the attainability of higher

speeds in 1st, 2nd and 3rd gear, giving greater top speed, lessens wear on the

engine, and improves fuel economy. With a 1.81 2nd gear ratio you can achieve

0-60 mph at 5700 rpm, well within the safe maximum rpm limit.

 

 

Approximate Speed/RPM Table

Tire Size: 195/65R15 Rims: 5.5"

Tire Diameter: 24.98 inches

MGB Bolt Pattern: 4 x 4.5 or 4 x 114.3mm!

Final Drive Ratio: 3.909

5 speed Ford Sierra Type 9 Transmission

(English Ford Sierra/Merkur XR4Ti T9 Transmission Kit)

The Chart below was made using a Speed Ratio Calculator:

Tire Size 195/65R15 -- 3.9 Axle Ratio -- 1st~5th Gear Ratio's --

Valve Float 6200 rpm w/Single Springs!

 

Ford T-9 Close Ratio	1st 3.36	2nd 1.81	3rd 1.26	4th 1.00	5th 0.825	Ford T-9 Standard	1st 3.65	2nd 1.97	3rd 1.37	4th 1.00	5th 0.82
0        rpm	0	0	0	0	0	0        rpm	0	0	0	0	0
500    rpm	3	5	8	10	12	500    rpm	3	5	7	10	12
1000  rpm	6	11	15	19	23	1000  rpm	5	10	14	19	23
1500  rpm	8	16	23	29	35	1500  rpm	8	14	21	29	35
2000  rpm	11	21	30	38	46	2000  rpm	10	19	28	38	46
2500  rpm	14	26	38	48	58	2500  rpm	13	24	35	48	58
3000  rpm	17	32	45	57	70	3000  rpm	16	29	42	57	70
3500  rpm	20	37	53	67	81	3500  rpm	18	34	49	67	81
4000  rpm	23	42	60	77	93	4000  rpm	21	39	56	76	93
4500  rpm	25	47	68	86	104	4500  rpm	23	43	62	86	104
5000  rpm	28	53	75	95	116	5000  rpm	26	48	69	95	116
5500 Redline RPM	31	58	83	105	128	5500  rpm	29	53	76	105	128
5700 0-60 mph	32	60	86	108	------
6000 Safe Max RPM	34	63	91	114	------	6000  rpm	31	58	83	114	-----
6200 Valve Float	35	65	94	118	------	6200  rpm	32	60	86	118	-----

Note: Our G-tech results confirmed that the T-9 Close Ratio RPM/MPH

measurements is exactly what our MGB achieved, very accurate! 

O-60 mph was exactly at 5700 rpm in 2nd Gear!!!

MGB Ford Sierra T-9 Five Speed Conversion Kit!

Technical Data Ford T-9 5 Speed

The 5 speed Ford Sierra propeller shaft is manufactured to specification:

Torque rating (Short Duration): 570Nm Maximum (422 lb.f.ft)

RPM rating of propeller: 7000 rpm Maximum

This corresponds to an engine speed of 5740 rpm in 5th gear (ratio .82:1)

or an engine speed of 7000 rpm in 4th gear. (ratio 1:1)

Length: 30 1/2"  Speedo Output: 18"-24"  Center of lever opening: 28 3/4"

Underside mounting point: 21"  Weight: 86 pounds

Oil: Castrol SAE 75w90 Full-Synthetic Oil

Note: Ford specified Standard oil grade SAE 75w90 Semi-Synthetic gear oil for 5 speed gear boxes

while it proved faultless for cold engagement there was some tendency to baulk at high rpm when

the gearbox was hot. Using Castrol SAE 75w90 Full-Synthetic has proven an admirable performer for

normal and higher rpm's use and found shifting very easy when the transmission is hot.

Note: We used a VDO Speedometer Gauge. A Hall Effect Sensor (above photo) must be attached to

the speedometer cable in order for the gauge to work properly. We sent our cable that came with

the 5 speed to Speedometer Service Company who cut the cable and installed the Hall Effect

Sensor to the end of the cable. Total length of the cable after completion was 18 inches.

 

Cylinder Heads!

  The 18V RB MGB had cylinder heads fitted with smaller inlet valves back to the

1.5625 inch (39.8mm) diameter of the early 18G series 1962-1971. From 1972-

1974 the 18V inlet valves were enlarged to 1.625 inch (41.3mm). With bigger

inlet valves it would be reasonable to expect more power but this turns out not

to be the case. Both the smaller valve 18G engines and the big valve 18V

engines produced the same horsepower and torque! The larger 1.62 valves

provided more high end power while the smaller 1.56 valves provided more low

and middle range torque and power.

 

Cylinder Head Porting and Horsepower!

   There are many opinions on which cylinder head is better and in reality any

cylinder head can be ported to work with a supercharger, it all depends what

you want for engine performance. We wanted a cylinder head that would

compliment the Supercharger and our driving habits by having low and middle

range torque and power, this is where we spend most of our time driving.

 

   A Port and Polished (P&P) cylinder head with 3 angle valves/seats will usually

gain anywhere from 10-15 HP with a Supercharger. An additional benefit of

porting is it clearly reduces detonation, which allows you to run either more

ignition advance, boost, or both. You should notice a reduction in boost, and

this is normal. You are essentially making the same horsepower with lower

boost because the cylinder head is flowing better, added performance.

 

We installed the 12H4736 Cylinder Head !

   The MGB engine used four basic cylinder head designs. The fourth version of

the cylinder head was a slightly modified version of the 12H4736 cylinder head

first introduced on the Austin Marina and used on the UK/European market RB

MGB (74½-80) as Original Equipment. 

 

   This cylinder head was also used as a replacement cylinder for the CAM1106

on the US RB MGB (74½-80). They are essentially the same as the CAM1106

with slight modifications. It was referred to as the "lead-free" cylinder head

and was induction hardened to withstand higher combustion temperatures of

lead-free fuel. The process involved 1% tin being added to the molten iron

before casting, additional depth was used which was machined off before the

induction hardening process was applied to the valve seat area, all valve seats.

This was a complex process and applied only to the US market cylinder heads.

It used 1.5625" inlet valves and 1.343" exhaust with a more efficient "Open"

Kidney-Shaped combustion chambers featuring a larger squish area as well as

reduced promontory between the valves, a chamber height of .375" with a

volume of 39cc, (UK 43cc). The rear rocker shaft pedestal had an offset oil feed

in order to accommodate the redesigned cooling passages that assisted in

preventing overheating of the rear cylinder. These larger coolant ports also

provided a greater service area to assist in dealing with higher combustion

temperatures that resulted in efforts to reduce emissions. It has air injection

ports and a water choke outlet at the rear of the cylinder head. The main

difference compared to the CAM-1106 was a slightly more improved intake port

design and the outer shaping of the head was revised giving a much smoother

appearance. The Patent Number 565394 located by the thermostat housing was

removed and marked inside the cylinder head. We felt this cylinder had that

little extra and when ported would provide us with low and middle range torque

& power for increased street performance that we wanted.

 

Work done to our 12H4736 Cylinder Head!

* Cleaned and glass-bead blasted!

* Magnafluxed & Pressure Tested!

* Ported & Polished with 3 angle Valves and Seats!

* Manganese-Bronze Inlet & Exhaust guides!

* Guides Reamed and Honed!

* Hardened, Lead-Free Exhaust Seat Inserts!

* New 1.56" inlet valves & 1.343" Stellite exhaust valves!

* Removed Air Injector Tubes!

* Air Injection Plugs: 7/16"-20-3/4" Bolts Cut Off Flush!

* Deck surface milled .020" true!

* New Single Springs installed!

* Fel-Pro SS70373 Valve Stem Seals  (71-74 Chevrolet)

* New Inlet Manifold Studs with Brass Nuts!

* High Performance Manifold Gasket!

* Gloss Black Color!

 

Cylinder Head Depth Height!

   Our cylinder head was milled .020" with a depth height of 3.105" (3 7/64")

from the original 3.125" (3 8/64") depth height. (Cylinder Head Thickness)

   

Deck Height!

   Deck Height with standard pistons measured at .030" using the top of the

piston where the dish goes up and flattens out. 

 

Payen Head  Gasket  .035"   Compressed !

  We purchased a Payen Head Gasket set CK665 and measured it brand new.

The steel bore rings measured 1.2mm or .04724", and the black resin area

measured 1.1mm or .043307". During our rebuild we did measure this gasket

compressed at .9 mm or .03543".

 

Payen Head Gasket comes in different sets!

CK663, CK664 and CK665 all uses the AK660 head gasket.

 

Combustion Chambers!

    Our combustion chambers measured in at 36.8cc's average per 4 chambers.

 

Compression Ratio!

 With the information listed above we could now check our Compression Ratio.

Cranking compression check reveals:

 #1=150, #2=150, #3=150, #4=149

(Standard compression ratio is 130 for 8.0:1)

 

Single Springs!

   We decided that Single Springs were sufficient for our cylinder head. They

are suitable for cams up to 400 thou valve lift, allowing 6200 rpm before valve

float/crash. Double springs are helpful at higher rpm's, but on the street they

just add drag and wear to the camshaft.

 

Valve Clearances!

   Normal Book Valve Clearance is .015 Cold for the early 18G Series with 1.56"

inlet valves. Commonly used is Inlet & Exhaust .015" Hot valve lash setting.

 

*** Mr. Peter Burguess informed me of a engine tweak he uses. Set the inlet

tappets at .012" Hot, keeping the exhaust valves at .015" Hot, and set the

spark plug gap to .035". This gives an even distribution of BHP throughout the

rev range. Also, because camshafts are not perfectly phased follow the tappet

clearance as you rotate the engine and set the clearance to the loosest position

as this helps achieve the BHP in your engine.

 

   Valve Clearance makes a small difference to valve timing and overlap. They

affect the opening and closing speeds of the valves. If the lash is too loose,

you will not get the full benefit of the opening and closing ramp profile of the

cam lobe. This means the valve will tend to slam open and shut more than if

the valve lash were tighter. This can cause poor closing conditions where the

valve bounces off the seat which can happen at any rpm, but usually happens at

higher rpm's. If the valve lash is to tight it will hold the exhaust valve off the

seat causing the valves to get hot and possibly increasing the chances of

detonation.

 

Adjusting Valve Clearances!

   You can adjust your valves by adjusting 2 valves at one time by cranking the

engine to move the valves. Simply leave the spark plugs in, take the plug wire

off the coil. Disconnect the White & Brown wire from the ignition relay and by

attaching a wire to it, slightly touch the bottom live fuse in the fuse box or any

power source that is live momentarily. The slight engine crank will move the

valves each time and you can adjust your valve clearance.

 

(Fully Open) means Valve is Down or Depressed! Than You Can Adjust Valves!

Adjust Valves 1 & 3 when 8 & 6 are Fully Open

Adjust Valves 5 & 2 when 4 & 7 are Fully Open

Adjust Valves 8 & 6 when 1 & 3 are Fully Open

Adjust Valves 7 & 4 when 2 & 5 are Fully Open

Valves: Exhaust & Intake!

#1 Exhaust, #2 Intake, #3 Intake, #4 Exhaust, #5 Exhaust, #6 Intake, #7 Intake, #8 Exhaust

 

   You can also adjust each individual valve separately using the "Rule of Nine".

 

Rule of Nine!

Add the 2 Valves and they Equal 9!

Adjust Valve #1 when Valve #8 is Fully Open!

Adjust Valve #3 when Valve #6 is Fully Open!

Adjust Valve #5 when Valve #4 is Fully Open!

Adjust Valve #2 when Valve #7 is Fully Open!

Adjust Valve #8 when Valve #1 is Fully Open!

Adjust Valve #6 when Valve #3 is Fully Open!

Adjust Valve #4 when Valve #5 is Fully Open!

Adjust Valve #7 when Valve #2 is Fully Open!

 

Fine Tuning Valve Lash!

   You can use both methods listed above to find the valves you want to adjust

but you must rotate the engine to find the point where each valve has the

widest clearance and than adjust it. Takes a little more time, but you will have

a very fine tuned engine.

 

The Right Curve!

   Next was getting the right distributor and curve to have the timing spot on.

We all know timing is everything and you can actually lose 3-5 horsepower or

more if your timing is off a couple degrees. We had an Original Lucas 45D 41427

"E" distributor that was rebuilt with a custom curve. Superchargers like a lot of

initial advance up-front, and we extended the curve to 32° @ 3000 rpm. This

custom curve worked extremely well helping that "Seat of Your Pants" feeling.

Above is our Custom "Supercharger" Distributor 41427 "E" 45D4  1384

 

Engine - 18G, GA, GB, GD, GG

Lucas Distributor -45D4- 41427 "E"

This Distributor is used to Exchange or Replace:

Lucas #'s  40897 - 41155 - 41220 - 41288 - 41290 - 41264 - 41339

High Compression (HC) 1962-1971 Original Specifications Curve Data!

Original Curve		Degrees	RPM
Dwell		51+-5
Static		+10
Strobe		Idle Setting        +14	600
Centrifugal		+4	600
		6	700
		9	900
		15	1600
		20	2200
Vacuum  -  Ported    5-13-10° Starts 5 hg in    Max 13 hg in    10°distributor (20°crank)

Below is our Custom Curve Specification Sheet we used with the Supercharger!

Custom "Supercharger" Curve		Degrees			RPM
Dwell		51+-5
Static		+10
Strobe		Idle Setting        +20			950
Centrifugal		5	600	8	800
		+10	950	11	1000
		13	1200	14	1400
		15	1600	16	1800
		17	2000	18	2200
		20	2400	21	2600
		21.5	2800	22	3000
Vacuum  -  Manifold    5-13-10° Starts 5 hg in    Max 13 hg in    10°distributor (20°crank) 22° Mechanical Advance  +10° Static Timing  = 32° Total Advance

Notice this custom curve is basically "All In by 2600 Rpm" and only going up 1° to 3000rpm. 

(Ray's curve is about perfect for most SC cars. Carl H.)

 

Note: The Standard Spark Plugs are NGK-BPR7ES. These colder plugs caused plug fouling and a

slight hesitation. We installed one step hotter NGK-BPR6ES Stock Plugs (Equivalent to Champion

RN9YC), this eliminated the hesitation and provided a Normal Plug Appearance with a light tan

insulator nose.

 

MSD-6A  Ignition Control!  

   MSD-6A features a capacitive discharge ignition design. The majority of stock

ignition systems are inductive ignitions, the coil must store and step up the

voltage to maximum strength in between each firing. At higher rpm, since there

is less time to charge the coil to full capacity, the voltage falls short of reaching

maximum energy which results in a loss of power or top end miss.

 

   The MSD-6A ignition features a capacitor which is quickly charged (within one

millisecond) with 460-480 volts and stores it until the ignition is triggered. With

the Captive Discharge design, the voltage sent to the coil is always at full

power even at high rpm. 

 

   The MSD-6A produces full power multiple sparks (3 sparks) for each firing of a

plug. The number of multiple sparks that occur decreases as rpm increases,

however the spark series always last for 20° of crankshaft rotation. Above 3,000

rpm there is simply not enough "time" to fire the spark plug more than once, so

there is only one powerful spark.

 

   The MSD 6A unit installs between the distributor and the coil. The input to

the MSD is isolated electronically from the distributor output, whether that be

points or electronic, so there is virtually no load on the distributor, regardless of

the output voltage of the coil and depending on the coil you use.

 

   We used the super low resistance 0.6 ohm Pertronix Flamethrower II 45,000

volt Epoxy 0.6 ohm coil mounted upright. Originally engineered for use with the

Ignitor II electronic ignition it works extremely well with the MSD-6A. 

 

   The MSD is a great performance upgrade that can be added to MGB's. Benefits

such as easy starting, steady smooth idle, reduced plug fouling, and increased

fuel economy can be expected. The MSD-6A produces a sequence of powerful

multiple sparks for every firing of the spark plug ensuring complete combustion

of the fuel mixture resulting in improved performance and power.

 

   Our MGB has a VDO tachometer and we can state that there is "No" need for

the MSD tachometer adapter 8910. The MSD-6A with a Pertronix Ignitor LU-143

(45D4 Distributor) and Flamethrower II coil works flawlessly and we highly

recommend this setup.

 

Manifold Vacuum!

   We changed ported vacuum to Manifold Vacuum. Manifold vacuum means the

port will be drawing vacuum below the throttle blades. A good running MGB

engine should have a measured vacuum at idle between 18-20 in/hg. This will

give you a lot of advance at idle, but as load increases (vacuum drops) you will

take timing away. This is excellent for fast burning fuels offered today as well

as having better idle quality.

 

  Ported vacuum means the port is drawing vacuum "above" the throttle blades

in the carburetor. This means that as RPM increases, vacuum increases and in

turn, vacuum advance increases.

 

Our Vacuum is 20 in/hg at 950 RPM Idle!

 

180 Degree Thermostat!

   We wanted to know what really is the best operating temperature for our

MGB with a Supercharger. A thermostat has one simple function and that is to

stop engine coolant from flowing below a certain temperature, and to allow it to

flow at or above a certain temperature.

 

   MGB original standard thermostat was 180°F (82°C), with alternative

thermostats rated at 165°F (74°C) for hot climates, and 190°F (88°C) for cold

climates. Soon after 1964 the 165°F became standard to increase oil pressure

and decrease oil temperature under normal working conditions. The 180°F

thermostat was re-introduced as the "Standard Thermostat" in March 1969 and

remained to the end of production. We assume the engineers new best.

  

   So what will a 180°F thermostat do? The law of physics states, cooler air is

denser than warmer air. Horsepower increases as the amount of air and fuel

burned increases, cooler air makes more power. A cooler running engine

improves performance by increasing the mass air flow rate of intake air by

reducing the engine's tendency to detonate. By keeping the pistons, cylinder

head, cylinder walls, cooler, helps to reduce or eliminate hot spots, which could

prematurely ignite the fuel causing pinging and detonation. The correct water

temperature is required for the cylinders to achieve a minimum specific

temperature in order to allow fully homogenized Air/Fuel mixture to combust

efficiently. What is the minimum number? "180 Degrees". Another added benefit

is the sooner the engine reaches 180° the sooner you burn off contaminates.

 

   If you want the optimum coolant temperature for increased engine longevity,

supercharger efficiency, and performance, use a 180° thermostat. Temperatures

at 180°-190° have the same engine wear as an engine at 200°+.

 

Exhaust System!

   A good exhaust system will make a huge difference to the breathing of your

engine and especially with a Supercharger that is pushing more air in and out

of the engine. We used a Peco Header that was Jet Hot coated and matched up

with a Peco Big Bore (2") Free Flow Exhaust System. This system can add up to

5 extra horsepower and more with a Jet Hot header.   

Peco Complete Exhaust System!

 

Peco Header!

   Peco Headers made in the UK are simply the Best. The MGB is unique having

three exhaust ports. With this header each side port has it's own tube and the

center port being shared by two cylinders uses a Long Center Branch (LCB) tube

which is larger than the two side tubes. The Peco Header with 36" tube lengths

worked extremely well with the Supercharger. Engines producing more torque

and Red Line at 5,500 rpm's need a longer tube length of 36". Longer tubes pull

the torque down to a lower RPM range. Shorter tubes moves the power band up

into a higher rpm range. This is what is meant by the term "Tuned Length". The

tube length is "Tuned" to make the engine operate at a desired rpm range. This

header typically boost mid-range power by approximately 5 hp at the wheels.

 

Jet Hot Extreme Sterling!

   Jet Hot Extreme Sterling is very similar in appearance to Sterling but not quite

as bright. It will hold its shine 200ºF higher and can actually withstand temps

up to 1,700ºF. This amazing finish normally cuts down about 400ºF on the skin

temperature of pipes. This coating is great for supercharged or turbocharged 

applications. Extreme Sterling will normally boost power when applied to

headers for two reasons. First, the coating promotes denser, more potent

fuel/air charges by insulating the engine bay from exhaust heat. At the same

time, it accelerates the pulsed-vacuum effect on “Tuned” headers, resulting in

more effective scavenging of cylinders. The increased velocity of exhaust gases

produced by higher exit inertia not only clears each cylinder more quickly; it also

draws in the next fuel/air charge more efficiently.

 

   The optimum situation occurs with our four cylinder engine because of it's

firing cycle. Every 180 degree of crankshaft rotation there is one exhaust pulse

entering the collector. This is ideal timing because, as one pulse exits the

collector, the next exhaust valve is opening and the vacuum created in the

system pulls the exhaust from the cylinder. In this ideal 180 degree cycling the

collector outlet diameter only needs to be 20% larger than the primary tube

diameter. A good example is the Peco Header with 1 3/4" primary tubes going

into a 2" collector outlet diameter. The rule of thumb here is two tube sizes.  

This keeps the velocity fast to increase scavenging, especially at lower rpm's.  

 

Our Jet Hot Extreme Sterling Header!

 

Heat Shield!

   Heat robs horsepower, this means reducing the operating temperature of the

Supercharger unit is very important. This heat shield has a high tech aluminized

radiant barrier material to lower temperature, increases supercharger efficiency,

also isolates the air filter from the hot exhaust temperatures providing cooler

air around the air filter. It has a 12° drop at 60-70 mph driving temperature,

and a 30° drop in temperature after slowing down from freeway speeds using a

stock header, even more with a Jet Hot header.

 

Exhaust Tip!

   We wanted an exhaust tip that would fit right over the 2" Peco exhaust pipe

and found a 2" ID High Flow exhaust tip that fits perfectly with no welding or

screw mounting. We cut approximately 4" off the existing pipe, sprayed some

WD-40 and with a rubber hammer tapped it on making a very tight seal.

 

  The High Flow exhaust tip features a high quality stainless steel cone,

modified enlarged louvered openings which reduces back pressure while

providing Higher Flow for better performance. Once installed we immediately

noticed a very direct and smooth exhaust flow.

 

   We tried different tips in hopes of reducing the slightly loud Peco exhaust

note. Sometimes and especially with our MGB things happen for a reason and

with this tip the exhaust note was lowered to a Low Sporty Mellow sound. We

were very impressed with the overall performance and sound of these tips, and

they look great.

Hi Flow Louvered Exhaust Tip!

 

SU-HIF 44 Carburetor!

   The 1.75-inch SU HIF6/44 is the carburetor that comes with the Supercharger

and has been flow tested at 228 cfm for a power potential of 151 hp. Example:

The early Dual 1.5-inch SU carburetor each flow at 132 cfm, the pair at 264 cfm.

Lets look at the chart below to see how this works.

 

RPM	CFM Needed
1000	27.1
2000	54.1
3000	81.2
4000	108.2
5000	135.3
6000	162.3
7000	189.4
8000