C-AJJ4037 BRONZE VALVE GUIDES - FITTING INSTRUCTIONS
Current performance levels achieved from the A series using modern cam designs combined with high ratio rockers have produce a demand for longer lasting valve train components. The valve guide is no exception and to meet this demand more modern materiel specifications have been employed. Over the past five or six years many materials have been used to try and attain the desired criteria, many of which are so hard that the valve stems are wearing out instead.
Cylinder Head - Unleaded Fuel Use
The specter of 'unleaded fuel only' - instigated in UK on January 1st 1999 and seemingly from decades ago across the rest of the world - seems to be forcing more and more folk into frightened, panic orientated action. And Mini owners are featuring heavily in this.
See bottom for useful part numbers.
The situation not at all being helped by all sorts of conflicting information from 'leaned' sources, such as lead levels in humans has declined greatly since 1935 - despite the rapidly expanding ownership of petrol-burning vehicles. And benzene and toluene used in unleaded fuels are cancerous.
Still, the powers that be are relentlessly forcing through the 'no heavy metals in fuel' bills, not being at all put off by such trivia. Not surprising bearing in mind the complete debacle on the catalytic converter front - the type decided on for world wide and universal use was developed and tested in California!
Cylinder Head - Unleaded Fuel Use
The specter of 'unleaded fuel only' - instigated in UK on January 1st 1999 and seemingly from decades ago across the rest of the world - seems to be forcing more and more folk into frightened, panic orientated action. And Mini owners are featuring heavily in this.
See bottom for useful part numbers.
The situation not at all being helped by all sorts of conflicting information from 'leaned' sources, such as lead levels in humans has declined greatly since 1935 - despite the rapidly expanding ownership of petrol-burning vehicles. And benzene and toluene used in unleaded fuels are cancerous.
Still, the powers that be are relentlessly forcing through the 'no heavy metals in fuel' bills, not being at all put off by such trivia. Not surprising bearing in mind the complete debacle on the catalytic converter front - the type decided on for world wide and universal use was developed and tested in California!
Valve Guides - Materials and Useage
Material choices for guides are down to two distinct types - cast iron and bronze. Yes, cast iron. NOT steel as described in many adverts and by vendors.
Never have been, never will be. These are as fitted to the various A-series cylinder heads as standard in all applications. Cast iron is used because it is a very dissimilar metal from any used in valve manufacture - important to eliminate galling that causes seizure of the valves in the guides - is softer, yet resilient enough to wear well. Bronze, on the other hand, is a very general description as there are a variety of 'bronzes' used by various folk. In days gone by, the bronze base type used was 'PB1' (also known as 'Navy Bronze') - a phosphor-bronze alloy that was very orange in colour, and very soft, used primarily in race engines. Unfortunately they wore out very quickly. Silicone-brass content bronze is probably the most popular now - often with a high aluminium or manganese content - is very yellow/gold in colour.
MSE4 - Post 1992
Modified to give maximum performance gain for cost. Combustion chambers, inlet and exhaust ports extensively re-worked. Stone-ground finish in ports promotes ultimate fuel atomisation.
MSE4 - POST 1992 unleaded stage 2 (Road Rocket) large-bore head
Part No Applications: MSE4, C-AEG544, C-AEG106, TAM2069, C-AJJ4037, C-AEA526, ADU4905
Inlet Valves: 35.6mm(1.401") dia. Tuftrided EN214N s/steel P/No. C-AEG544
Exhaust Valves: 29.5mm(1.161") dia. Tuftrided EN214N s/steel P/No. C-AEG106
Exhaust seats: Latest type Beryllium-based for lead-free fuel P/No. TAM2069
Valve Guides: Magnesium bronze P/No. C-AEA526
Valve Springs: Nominal 180lb. Max actually valve lift 0.500" P/No. C-AJJ4037
Stem Seals: Latest 'top-hat' design with tensioner springs (inlets) P/No. ADU4905
Chamber Volume: Nominal 20cc
Three-angle valve seats in head. Cooper S size valves with current maximum flow profiles and Tuftrided for durability/longevity when used with unleaded fuel (hence 'black' finish).
MSE4 - Post 1992
Modified to give maximum performance gain for cost. Combustion chambers, inlet and exhaust ports extensively re-worked. Stone-ground finish in ports promotes ultimate fuel atomisation.
MSE4 - POST 1992 unleaded stage 2 (Road Rocket) large-bore head
Part No Applications: MSE4, C-AEG544, C-AEG106, TAM2069, C-AJJ4037, C-AEA526, ADU4905
Inlet Valves: 35.6mm(1.401") dia. Tuftrided EN214N s/steel P/No. C-AEG544
Exhaust Valves: 29.5mm(1.161") dia. Tuftrided EN214N s/steel P/No. C-AEG106
Exhaust seats: Latest type Beryllium-based for lead-free fuel P/No. TAM2069
Valve Guides: Magnesium bronze P/No. C-AEA526
Valve Springs: Nominal 180lb. Max actually valve lift 0.500" P/No. C-AJJ4037
Stem Seals: Latest 'top-hat' design with tensioner springs (inlets) P/No. ADU4905
Chamber Volume: Nominal 20cc
Three-angle valve seats in head. Cooper S size valves with current maximum flow profiles and Tuftrided for durability/longevity when used with unleaded fuel (hence 'black' finish).
MSE3 -Pre 1992
Modified to give maximum performance gain for cost. Combustion chambers, inlet and exhaust ports extensively re-worked. Stone-ground finish in ports promotes ultimate fuel atomisation.
MSE3 - PRE 1992 unleaded Stage 2 (Road Rocket) large-bore head
Part No Applications: MSE3, C-AEG544, C-AEG106, TAM2069, C-AJJ4037, C-AEA526, ADU4905
Inlet Valves 35.6mm(1.401") dia. Tuftrided EN214N s/steel P/No. C-AEG544
Exhaust Valves 29.5mm(1.161") dia. Tuftrided EN214N s/steel P/No. C-AEG106
Exhaust seats Latest type Beryllium-based for lead-free fuel P/No. TAM2069
Valve Guides Magnesium bronze P/No. C-AJJ4037
Valve Springs Nominal 180lb. Max actually valve lift 0.500" P/No. C-AEA526
Stem Seals Latest 'top-hat' design with tensioner springs (inlets) P/No. ADU4905
Chamber Volume Nominal 20cc
Cylinder Head - Unleaded fuel use
The specter of 'unleaded fuel only' - instigated in UK on January 1st 1999 and seemingly from decades ago across the rest of the world - seems to be forcing more and more folk into frightened, panic orientated action. And Mini owners are featuring heavily in this.
Cylinder Head - Unleaded fuel use
The specter of 'unleaded fuel only' - instigated in UK on January 1st 1999 and seemingly from decades ago across the rest of the world - seems to be forcing more and more folk into frightened, panic orientated action. And Mini owners are featuring heavily in this.
Engine - 998 tuning, further options
Following on from the easily bolted on performance enhancing components out-lined in the stage one section, we need to consider where to go to get more power output.
Terminology: MSC/MM - Mini Spares Centre/Mini Mania BBU - Big Bore Unit (refers to all 1275cc-based units) SBU - Small Bore Unit (refers to all sub-1275cc units, here the 998) BHP - Brake Horse Power CR - Compression Ratio
To improve engine out-put, you need to increase the engine's 'breathing' ability. The stage one kit deals with all the easily bolted-on external parts, and represents the best increase for investment. From here on in the power increases will cost commensurately more money. Power production of any engine, once the 'breathing apparatus' (induction/exhaust system) has been dealt with to cause no restriction ...
Valve guides - Materials and usage
Material choices for guides are down to two distinct types - cast iron and bronze. Yes, cast iron. NOT steel as described in many adverts and by vendors.
Never have been, never will be. These are as fitted to the various A-series cylinder heads as standard in all applications. Cast iron is used because it is a very dissimilar metal from any used in valve manufacture - important to eliminate galling that causes seizure of the valves in the guides - is softer, yet resilient enough to wear well. Bronze, on the other hand, is a very general description as there are a variety of 'bronzes' used by various folk. In days gone by, the bronze base type used was 'PB1' (also known as 'Navy Bronze') - a phosphor-bronze alloy that was very orange in colour, and very soft, used primarily in race engines.
C-AHT88 STAGE THREE SPEC SMALL BORE CYLINDER HEAD
Modified to give maximum performance gain for cost. Exhaust seats Latest spec inserts for lead free fuel Modified to give maximum performance gain for cost. Combustion chambers, inlet and exhaust ports extensively reworked. Stone-ground finish in ports promotes ultimate fuel atomisation.
MSE3 - PRE 1992 UNLEADED STAGE 2 (ROAD ROCKET) LARGE-BORE HEAD.
Modified to give maximum performance gain for cost.
Combustion chambers, inlet and exhaust ports extensively re-worked. Smoothed finish in ports - not mirror-finish polished to minimise drag. Multi-angle valve seats in head.
MSE4 - POST 1992 UNLEADED STAGE 2 (ROAD ROCKET) LARGE-BORE HEAD.
Modified to give maximum performance gain for cost.
Combustion chambers, inlet and exhaust ports extensively re-worked. Smoothed finish in ports - not mirror-finish polished to minimise drag. Multi-angle valve seats in head.Cooper S size valves with current maximum flow profiles and Tuftrided for durability/longevity when used with unleaded fuel (hence 'black' finish).
MSE5 - PRE 1992 UNLEADED STAGE 2 (ROAD ROCKET) LARGE-BORE HEAD.
Combustion chambers, inlet and exhaust ports extensively re-worked. Smoothed finish in ports - not mirror-finish polished to minimise drag. Multi-angle valve seats in head. Cooper S size valves with current maximum flow profiles and Tuftrided for durability/longevity when used with unleaded fuel (hence 'black' finish). Combustion chamber volume used to give slight static compression ratio increase over standard. Head mods employed greatly increase volumetric efficiency
MSE7 - TPi UNLEADED STAGE 3 (ROAD ROCKET) LARGE-BORE HEAD.
Modified to give maximum performance gain for cost. Combustion chambers, inlet and exhaust ports extensively re-worked. Smoothed finish in ports - not mirror-finish polished to minimise drag. Multi-angle valve seats in head. Cooper S size valves with current maximum flow profiles and Tuftrided for durability/longevity when used with unleaded fuel (hence 'black' finish). Combustion chamber volume used to maintain standard static compression ratio because head mods employed greatly increase volumetric efficiency, boosting actual running (dynamic) compression ratio.
MSE9 - PRE 1992 UNLEADED STAGE 2 (ROAD ROCKET) LARGE-BORE HEAD,
Modified to give maximum performance gain for cost. Combustion chambers, inlet and exhaust ports extensively re-worked. Smoothed finish in ports - not mirror-finish polished to minimise drag. Multi-angle valve seats in head. Cooper S size valves with current maximum flow profiles and Tuftrided for durability/longevity when used with unleaded fuel (hence 'black' finish). Combustion chamber volume used to give slight static compression ratio increase over standard. Head mods employed greatly increase volumetric efficiency, boosting actual running (dynamic) compression ratio.
Historical Article - Nov 1992 - A Guiding Hand - Do not adjust your seat too muc...
A question frequently asked by customers buying new valve guides is what size the guide should be reamed to once fitted. The answer initially is easy, 9/32” (.812”). However, nothing in life is simple.
Correct sizing of the guide is very important. Not only does the guide support the valve, but also helps dissipate heat from the valve – especially important for the exhaust valve. This particular point is even more critical now that hi-grade fuels are no longer available, worsened by many people converting to lead-free fuel.
Historical Article - Nov 1992 - A Guiding Hand - Do not adjust your seat too muc...
A question frequently asked by customers buying new valve guides is what size the guide should be reamed to once fitted. The answer initially is easy, 9/32” (.812”). However, nothing in life is simple.
Correct sizing of the guide is very important. Not only does the guide support the valve, but also helps dissipate heat from the valve – especially important for the exhaust valve. This particular point is even more critical now that hi-grade fuels are no longer available, worsened by many people converting to lead-free fuel.
|