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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.
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. In general, the earliest cars used valves with a singl...
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” without modifications, when fitted to a cylinder head that has standard or near standard valve spring heights. However, where possible...
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).
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
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.
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.
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.