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Cylinder Head
Created: March 23, 2017
Any aluminum head will have advantages in lighter weight and better cooling due to aluminum being able to shed heat better than iron.
Classic Mini Cooper rockers, push rods and more
Created: December 21, 2015
When you are trying to build a motor to get the ultimate of performance you often optimize the life expectancy of the entire assembly. One such area centers around the rocker assembly. In general the rockers are part of the process that translates the lobe of the rotating camshaft to the vertical deflection needed to open the valves on the cylinder head.
Do I need to do a Valve Job?
Created: April 25, 2014
Most motors will go at least 80,000 miles before "needing a valve job"! But what are the signs? How do I determine if I really need it? Do I do it myself or pay a local machine shop.
Valve Stem seals
Created: January 15, 2014
Valve stem seals
Valve Stem Keepers
Created: October 10, 2011
Call them cotters, collets or keepers, these little items are often overlooked during a head rebuild. If yours are worn and need to be replaced, make sure you order the right ones. Minis used three different versions over the years.
Cylinder head - What can easily be achieved
Created: February 03, 2011
The engine build I recently covered in previous Mini Magazine issues developed into a bit of an ongoing 'project'. During a discourse with the editorial staff at Mini Mag, it was decided the build feature presented an ideal opportunity to demonstrate just exactly what such an engine build is capable of in days where it's generally believed you have to have an all-singing, all-dancing 1380cc engine to have an enjoyable road burner - leaving those with very limited budgets a little depressed.
C-AEA526 DUAL VALVE SPRING FITTING INSTRUCTIONS
Created: March 16, 2005
This valve spring set has been developed to fit standard sized top caps, and cope with high rpm and high valve lifts without crushing of up to 0.570”
Cylinder head - Combustion chamber shape
Created: February 09, 2004
This addendum to the Cylinder Head section was fueled mainly by pictures of combustion chamber shapes and folk's excitement at what they could possibly do for them. It is also prompted by the 'new isn't always great' teaching. So what's in these varying and dramatically different chamber shapes?
Cylinder head - Min Tec head range
Created: October 27, 2003
Detailed description of the numerous cylinder heads as built by Mini-Tec
Engine - Small-bore engine, 12G940 head fitting
Created: July 24, 2003
There is no specific large-bore (1275cc-based) head casting number that will fit the 998 engine any easier than any other. They all have the same problems - generally requiring exhaust valve relief cut-outs machined into the block and re-alignment of the front water gallery transfer ports. However, I would avoid using heads with valves bigger than 35.7mm on the intake since these are too big for most 998 engines unless they are absolutely full-race spec where top end power at high rpm is all that is required.
C-STR1057 Group A Turbo head gasket
Created: December 12, 2002
This gasket was originally developed by Howley Racing way back in the mid eighties for what was then part of the factory Rover Group racing effort - the Group A Metro Turbo
Rocker gear - General compendium
Created: August 28, 2002
Whether you’re building a solid road performer or fire-breathing monster, the main goal is to improve air/fuel flow into the engine. The more you can get in, the more power you can get out. Cheapest chunk of power improvement comes from sorting the asthmatic manifolding and exhaust by applying a stage one kit. Then what?
Cylinder Heads - About Min Tec heads
Created: May 25, 2002
Cylinder Heads - About Min Tec heads. '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 minimize drag. Four-angle valve seats in head.
CYLINDER HEAD - Torque-down and head gasket problems
Created: July 11, 2001
First a brief word on head gaskets. If it is not a genuine Rover or Payen gasket, don’t use it.
CYLINDER HEAD - Suitability basics
Created: May 01, 2001
Whatever else owners do to their Minis by way of interior/exterior modifications or none at all, a very large proportion desire and search for an increase in engine performance.
Valve Guides - Materials and Usage
Created: April 13, 2001
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.
C-AEA527 DUAL VALVE SPRINGS FITTING INSTRUCTIONS
Created: April 13, 2001
This valve spring set has been developed to fit standard sized top caps, and cope with racing rpm and high valve lifts without crushing of up to 0.570” without modifications, when fitted to a cylinder head that has standard or near standard valve spring heights.
MSE4 - Post 1992 unleaded stage 2 (Road Rocket) large-bore head
Created: October 23, 2000
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. 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).
MSE6 - POST 1992 unleaded stage 2 (Road Rocket) large-bore head
Created: October 23, 2000
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. Three-angle valve seats in head. Super-quality MG Metro valves modified to increase airflow.
MSE3 - PRE 1992 unleaded Stage 2 (Road Rocket) large-bore head
Created: October 20, 2000
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. 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).
Austin MIni CYLINDER HEAD - Valves; shapes, materials,& finishes.
Created: October 19, 2000
Many moons ago, the standard performance valve shape was the then-ubiquitous 'penny-on-a-stick' profile. For the very good and simple reason it minimised airflow obstruction by having the least amount of material in the way. Very plausible, and a design that many have stayed with to this day
Rocker Gear
Created: January 30, 2000
The new generation of short period, high lift cams have been developed to give the best results in large bore engines when used in conjunction with 1.5 ratio, hi-lift rockers. For the small bore range, the stock 1.3 ratio is optimum. In certain instances ratios of 1.7 to 1 are of benefit - but is really only applicable to fully developed race engines.
Stage 2, Budget big bore head
Created: January 30, 2000
Modified to give maximum performance gain for cost. Combustion chambers, inlet and exhaust ports extensively reworked. Stone-ground finish in ports promotes ultimate atomisation.
Competition head stud and nut kit
Created: January 30, 2000
This kit has been produced by Mini Spares to reduce head gasket problems on performance orientated engines, especially those utilising large over bore sizes. Standard type head studs and nuts are mass produced which unfortunately compromises the specification of the end product. Worst affected are the threaded portions which create problems during torque-down; thread deformation, stud distortion and possible stretch, off-square seating of the nut to head and so on.
High lift rocker assembly, C-AHT436
Created: January 30, 2000
Ensure that posts, spacers and rockers are evenly distributed along the length of the shaft to allow smooth pivoting. On no account must the valve springs be allowed to become coil-bound as this will place undue stress on the rocker and could lead to failure.
Cylinder Heads Identification, Austin, Midget, Sprite, Morris
Created: January 30, 2000
Everybody has their own opinion on this subject. The most experienced people will tell you that the best way to maintain your engine performance is to accept the fact that valve jobs need to be done 2 or 3 times more often than rings and bearings! And this data base was concluded when leaded gas was the norm! Now that unleaded is all you can get, valve jobs are needed even more often! The purpose of a valve job is two fold; first the valve seats. The impurities in the air and gas often get trapped between the valve and the seat in the head; under worst conditions stopping the valve from closing, but more commonly being smashed enough to allow just a little seepage of hot gases.
Competition Cylinder Heads
Created: January 30, 2000
A selected range of modified cylinder heads are available to suit a wide variety of applications. All port and chamber modifications are carried out by experts to current state of the art specifications. Therefore, actual specifications may alter slightly as gas flow and port velocity efficiency improvements are developed. Where large bore heads are used on small bore engines (i.e. 12G940 casting on 948/1098cc block), it is necessary to check full lift of exhaust valve, and pocket the block as necessary.
Offset rocker bushes, C-AEG644
Created: January 29, 2000
Using these bushes it is possible to achieve an increase in valve lift of upto 0.030". They must be pressed into the rocker with the thick section pointing forwards, ie. toward the rocker pad. It is advisable to use bearing-fit compound (Loctite) to ensure the bush does not rotate in use, taking up ‘wear’ in old rockers. Once fitted, they need to be reamed out to 9/16", for best easy slide fit on the intended shaft.