Cylinder head - Min Tec head range

 

I'm often asked about the range of cylinder heads I do for Mini Spares/Mini Mania, so here's the low-down…

 

Although the following range of heads accommodate specific fitments - like pre-1992 where by-pass hoses and heater take-offs on the clutch end of the head are used and post-1992 where neither of these exist, and on SPi (single point injection) heads where they don't usually have a threaded hole for the temperature sender - in reality it is easy to convert almost any of them to fit any other engine since holes are easily blocked off - or by-pass hoses not used, water pumps blanked off and drilled thermostats fitted (see articles on cooling/engine transplants). A list of which is what and what to do to each to convert is at the end of this article.

 

For more in-depth descriptions of the head specs, see article 'Cylinder head - About Min Tec Heads' - basically the valve sizes used have been decided on after extensive and in-depth flow testing/dyno testing. The sizes used provide the best balance of airflow and gas speed for their typical uses to give optimum all-round performance. Typically the large-bore heads have consistently proven to provide sufficient induction flow to produce up to 118 crankshaft bhp (quality fast road 1380, single 1.75" HIF SU, MSC inlet manifold, MD286 cam). Finished specifications will change/evolve as and when anything new/better is discovered.

 

 

 

C-AHT88      Small-bore 'stage 3' spec head. 1.218"(30.93mm) inlet & 1.043"(26.5mm)

                   exhaust valves in EN214N stainless steel, manganese-bronze valve guides, A+

                   spec stem seals, 180lb (nominal) double valve springs, nominal 23.5cc chambers.

                   Suitable for all fast road small-bore engines and lead-free fuel use. Has by-pass

                   hose and heater valve take-offs.

 

C-AHT133   'Budget' large-bore 'stage 3' spec head. Modified, standard MG Metro spec

                 1.406"(35.7mm) inlet & 1.151"(29.2mm) exhaust valves, cast iron valve  

                 guides, A+ spec stem seals, 180lb (nominal) double valve springs, nominal 24.5cc

                 chambers. Suitable especially for fast road large-bore engines of 1380cc type

                 capacity where extra chamber capacity is required to keep compression ratio

                 sensible and lead-free fuel use up to 6,500rpm continual peak rpm limit. Has by-

                 pass hose and heater valve take-offs for pre-1992 engine types. Near zero flow-

                 loss from modified standard valves when compared to race-spec valves.

 

C-AHT135   'Budget' large-bore 'stage 3' spec head. Modified, standard MG Metro spec

                 1.406"(35.7mm) inlet & 1.151"(29.2mm) exhaust valves, cast iron valve 

                 guides, A+ spec stem seals, 180lb (nominal) double valve springs, nominal 21.0cc

                 chambers. Suitable for fast road large-bore engines and lead-free fuel use up to

                 6,500rpm continual peak rpm limit. Has by-pass hose and heater valve take-offs for

                 pre-1992 engine types. Near zero flow-loss from modified standard valves when

                 compared to race-spec valves.

 

C-AHT136   TPi 'Budget' large-bore 'stage 3' spec head. Modified, standard MG Metro spec

                 1.406"(35.7mm) inlet & 1.151"(29.2mm) exhaust valves, cast iron valve 

                 guides, A+ spec stem seals, 180lb (nominal) double valve springs, nominal 21.0cc

                 chambers. Suitable for fast road engines and lead-free fuel use up to 6,500rpm

                 continual peak rpm limit. Near zero flow-loss from modified standard valves when

                 compared to race-spec valves.

 

MSE3         Large-bore 'stage 3' spec head. Race-spec stainless steel 1.406"(35.7mm) inlet &

                1.161"(29.5mm) exhaust valves, manganese-bronze guides, A+ spec stem seals,

                180lb (nominal) double valve springs, nominal 21.0cc chambers. Suitable for fast

                road/occasional hill-climb/sprint/auto-test engines and lead-free fuel use. Has by-

                pass hose and heater valve take-offs for pre-1992 engine types.

 

MSE4        Large-bore 'stage 3' spec head. Race-spec stainless steel 1.406"(35.7mm) inlet &

                1.161"(29.5mm) exhaust valves, manganese-bronze guides, A+ spec stem seals,

                180lb (nominal) double valve springs, nominal 21.0cc chambers. Suitable for fast

                road/occasional hill-climb/sprint/auto-test engines and lead-free fuel use. Has NO

                by-pass hose and heater valve take-offs for post-1992 non-injection engine types.

 

MSE5        Large-bore 'stage 3' spec head. Race-spec stainless steel 1.406"(35.7mm) inlet &

                1.22"(31.00mm) exhaust valves, manganese-bronze guides, A+ spec stem seals,

                180lb (nominal) double valve springs, nominal 21.0cc chambers. Suitable for fast

                road/occasional hill-climb/sprint/auto-test engines and lead-free fuel use. Has by-

                pass hose and heater valve take-offs for pre-1992 engine types.

 

MSE6        'Budget' large-bore 'stage 3' spec head. Modified, reconditioned standard MG

                Metro spec 1.406"(35.7mm) inlet & 1.151"(29.2mm) exhaust valves, cast iron

                valve guides, A+ spec stem seals, 140lb (nominal) single valve springs, nominal

                21.0cc  chambers. Suitable for fast road large-bore engines and lead-free fuel use

                up to 6,500rpm continual peak rpm limit. Also limited valve lift use (max 0.420"

                valve lift). Has NO by-pass hose or heater valve take-offs for post-1992 cars

                including single point injection. Near zero flow-loss from modified standard valves

                when compared to race-spec valves. Can be up-rated for more valve lift by simply

                fitting C-AEA526 double valve springs.

 

MSE7        MPi  large-bore 'stage 3' spec head. Race-spec stainless steel 1.406"(35.7mm)

                inlet & 1.161"(29.5mm) exhaust valves, manganese-bronze guides, A+ spec stem

                seals, 180lb (nominal) double valve springs, nominal 21.0cc chambers. Suitable for

                fast road/occasional hill-climb/sprint/auto-test engines and lead-free fuel use. Has

                NO  by-pass hose and heater valve take-offs for post-1997 twin point injection

                engine types (alternator bracket bolted to head).

 

MSE9       Large-bore 'stage 3' spec head. Race-spec stainless steel 1.406"(35.7mm) inlet &

                1.161"(29.5mm) exhaust valves, manganese-bronze guides, A+ spec stem seals,

                180lb (nominal) double valve springs, nominal 24.5cc chambers. Suitable especially

                for fast road large-bore engines of 1380cc type capacity where extra chamber

                capacity is required to keep compression ratio sensible and lead-free fuel use Has

                by-pass hose and heater valve take-offs for pre-1992 engine types.

 

 

To change pre-1992 head to post-1992 fitment (except TPi) -

Fit heater take-off blanking plate (p/no. 2A180) and gasket (p/no. 88G221) and fit by-pass hose blanking cap (p/no. CAM4126) or remove by-pass hose adaptor and fit blanking plug (p/no. 88G619). For single point injection only - blank water temp gauge sender unit hole off with 5/8"UNF threaded plug (p/no. 5/8UNF).

 

To change post-1992 head (including TPi variants) to pre-1992 fitment -

Drill 9/16"/14.5mm hole through counter-bored heater take-off hole (1/4UNF heater tap retaining stud holes are already in place) or remove blanking plate if fitted. For by-pass hose, either drill/tap 5/8" UNS (16TPi) port in required place and fit by-pass hose adaptor p/no. 12A2075, or drill/tap 5/8"UNF and fit adaptor p/no. 12H1405, or blank water pump port off with blanking cap p/no. CAM 4126 and either drill 6 1/8"/3mm holes around thermostat periphery or fit blanking sleeve (really not good for road use - recommend thermostat is fitted). For water temp gauge sender unit either drill/tap port out to 5/8"UNF thread or remove 5/8"UNF socket headed grub screw if fitted.

 

Anything beyond this - i.e. for specific applications like full race and so on, contact me direct.