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DIY Classic Mini Cylinder Head Articles
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BMC A-Series Valve train - Setting valve clearances (lash)
(Engine)
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The A-series engine cam followers were originally designed to use 0.010-in clearance between the cam follower and standard cams to allow for heat expansion of the parts and ensure the valves would close properly. On sportier and race profile cams this went up to 0.012-in to cater for the higher running temperatures and far higher rpm capability/use. Because we set the clearance at the valve, we need to allow for the rocker ratio. To do this a little simple math is involved; taking the standard 0.010" cam to follower clearance we need to multiply this by the standard rocker ratio originally quoted as 1.25-1, although in actual installation this is more like 1.22-1. So, 0.010-in x rocker ratio 1.25 gives 0.0125" at the valve.
As a concession to the slightly reduced installed...
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Classic Mini Cooper rockers, push rods and more
(Engine)
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Classic Mini Cooper rockers, push rods and more!
Shop Rocker Assemblies & ComponentsShop PushrodsWhen you are trying to build a motor to get the ultimate of performance you often will also 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...
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Rocker gear - General compendium
(Engine)
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Rocker gear - General compendium
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?
Considering the &lsq...
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Rocker Gear
(Engine)
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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.
12G12211.3-1 ratio "Cast" rocker. Reproduced ...
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Classic Mini Cooper Valves covers - page 32
(Classic Mini Catalog)
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Find a Part No. in the catalog below. - Type or copy/paste it into the search box to find it on the website. If you would like to view this information in our complete 84 page color catalog- Click here This browser does not have a PDF reader installed. Please download the PDF file to view it: /Mini%20Mania%20Catalog.Valve%20Covers.32.pdf...
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High lift rocker assembly, C-AHT436
(Engine Drivetrain Exhaust)
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SPECIFICATION: Material is drop forged EN16 with the valve pad face hardened to 52.5-55 on the Rockwell C scale. RATIO: Rocker ratio is 1.5 as opposed to 1.25 of the standard rocker.
TAPPET CLEARANCE SHOULD BE 3 THOU MORE THAN STANDARD. ON REALLY HIGH LIFT CAMSHAFTS AN EXTRA 2 THOU AGAIN MIGHT BE BENEFICIAL.
Ensure that posts, spacers and rockers are evenly distributed along the length of th...
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Offset rocker bushes, C-AEG644
(Engine Drivetrain Exhaust)
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FITTING INSTRUCTIONS
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 ...
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C-AEA527 DUAL VALVE SPRINGS FITTING INSTRUCTIONS
(Engine Drivetrain Exhaust)
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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. However, where possible, it is always advantageous to correct and match the valve spring heights (measured from the spring seat in ...
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C-STR1057 Group A Turbo head gasket
(Engine Drivetrain Exhaust)
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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. The engines developed by Howley Racing were giving 220+bhp and 185lb ft running 16.4psi boost - quite a chunk of power in a car little bigger than a Mini! Despite 10" wide sticky slicks, the engine chirped the tyres in...
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C-AEA526 DUAL VALVE SPRING FITTING INSTRUCTIONS
(Engine Drivetrain Exhaust)
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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, it is always advantageous to correct and match the valve spring heights (measured from the spring ...
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Cylinder Heads - About Min Tec heads
(Engine Drivetrain Exhaust)
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Cylinder Heads - About Min Tec heads.
Terminology -
VFM - Value For Money
CR - Compression Ratio
VE - Volumetric Efficiency
'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. Four-angle valve seats in head. Cooper S size valves w...
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Stage 2, Budget big bore head
(Engine Drivetrain Exhaust)
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STAGE TWO SPEC. BUDGET LARGE BORE CYLINDER HEADAEG592 Inlet valve : 35.7mm (1.401") diameter, standard ‘S’ spec. material CAM4601 Exhaust valve : 29.3mm (1.156”) diameter, latest lead free spec. material 12G1963 Guides : OE specification cast iron, bullet nosed C-AEA526 Valve springsNominal 180lb progressive rate dual spring. Max valve lift 0.500"ADU4905 Stem seals : Latest &lsqu...
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Cylinder head - Identification by casting number
(Calver's Corner)
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Number
Inlet dia.
Exhaust dia.
Nominal cc
Standard fitment
2A628
1.0625"/26.99
1.00"/25.4
24.5
850, 998 Mini & 948 Sprite
2A629
1.0625"/26.99
1.00"/25.4
24.5
948, A35 & Morris Minor
12A1456
1.0625"/26.99
1.00"/25.4
24.5
850, 998 Mini & 948 Sprite
12G202
1.156"/29.36
1.00"/25.4
26.1
997 Cooper, Austin 1100 Mk
CAM4180
1.0625"/26...
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Head Work
(Restoration)
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Head Work
November 28, 2012
The engine bay is empty, and the cylinder
head is sitting on our bench
The top head is not original to a 1275
Cooper S, but the bottom head is
Once you start changing stuff, where does it stop? Our Mini came with a head, though it wasn’t bolted to the engine. Or anything, for that matter. In fact, it wasn’t even near the car...
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Mini Cooper Specials
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13H5872
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C-AHT54
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GUG705560GM
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REV14
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DAH10037
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17H8600
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22G2083
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7H7250
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MAMBA-NUT-.625
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AHA6423
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22G2595
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DAM3022
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DDJ10002
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MSSB1109
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37H3833
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AUC4900
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AUC1316
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ALA7231
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2A54
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CAM150
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12G1268
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17H2646
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SV2017C
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DAM2377
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AUD4251
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