Austin 7 aluminium cylinder head

This cylinder head was designed to overcome the low compression and breathing shortcomings of the standard cast iron heads. Two versions appeared a ‘Mark 1’ that used the Austin 7 pear shaped water outlet in the traditional place pointing forward as the one on the right. A ‘Mark 2’ version, as shown below to the left, had a specially cast water outlet based on a straightened water inlet branch. This had the advantage of being able to be used either way round, pointing forwards for a traditional type special with thermosyphon radiator or rearwards for a low special with a bulkhead mounted head tank, crossflow radiator and water pump. Click here to read more about crossflow systems.

Water branches

The Speedex head used a special water branch based on the standard Austin side branch. This was recast to allow the water to come straight up and out of the head rearwards towards a bulkhead mounted header tank. The branch shown on the head above (and the centre one in the other picture) is a Supaloy one—it comes straight up. The Speedex one comes up and bends slightly to the left, note the Speedex logo cast into it. The third is a standard side branch, a ribbed Reliant one in this case. SPEEDEX were the first with the reversed water branch. Raeburn’s used to advertise replacement Supaloy branches if you haven’t got one—many have lost their’s.

Austin 7 aluminium sump

The aluminium sump increases the oil capacity and through rigidity makes an oil tight joint easier to get. Like the ‘Nippy’ sump it is ribbed along the bottom but also up the front to increase cooling, an internal baffle makes the oil flow across the base to further improve cooling. This looks like a cosmetically changed ‘Dante’ item. The increased capacity is useful if you’re doing a long journey with a leaky engine but other than that it has a reputation for over cooling and not letting the oil get up to a working temperature. I have heard that some have filled in the webs with foam sealant to give the oil a fighting chance of warming up.

SPEEDEX aluminium wheels

These were perhaps the definitive SPEEDEX items to have on your car and were one of the first things advertised by the company when it started trading. If you buy a set and the special wheel nuts have been lost drop me an email, I’ve got a sample and can let you have a drawing to get a set made. These wheels like a number of other castings are copies of Dante parts. A few sets of Dante wheels were made before the company folded. You can tell the difference from the shape of the holes through the webs, Dante have round holes, SPEEDEX have curved segments as per these pictures. New wheels in the SPEEDEX style have also been remanufactured by Derek Jones (01905 767838) see the For Sale page. I’ve bought a set and can vouch for their quality.

Austin 7 aluminium tappet chest cover

The standard side cover has a reputation for oil leaks, perhaps unjustifiably being blamed for the almost inevitable leak from the block to crankcase joint. In response the specialist companies produced side covers that could have a good gasket fitted between two flat surfaces. The one shown at the top has an unusual ‘SPEEDEX’ script, I have never seen it used on another casting, has anybody any ideas over its origin or seen another one? The lower one is the more usual.

SPEEDEX Revcounter

SPEEDEX supplied their own revcounter optimistically graduated up to 7500 rpm! It has a very distinctive ‘SPEEDEX’ logo on the face and was unusual in that it rotated counter clockwise driven by a cable drive from the bottom of the distributor. The unusual rotation of the revcounter is necessary due to the direction the distributor turns. If you’re making a drive ensure the drilling of the dynamo is perfectly concentric with the distributor or it will chew up the cables. Thanks to Chris Oliver for the dynamo picture.

Water pumps

SPEEDEX’s have low crossflow radiators with a header tank and a Ford 10 ‘Export’ water pump. New ones are still available from Small Ford Spares, also the aluminium Aquaplane version if you’re feeling a bit richer or want to avoid the not inconsiderable weight of the cast iron Ford pump. A modern alternative is to use an electric water pump, see the section on cooling systems for more detail. The pump was driven by a steel or aluminium pulley on the cam shaft replacing the Austin flat belt pulley. These aluminium pulley’s tend to open out in the centre if they’ve been previously over tightened onto the camshaft taper, they really need a steel or brass centre.

Inlet manifolds

As all the tuning specialists SPEEDEX supplied a range of manifolds for the A7. Twin SU semi downdraught and sidedraught for both 1” and 1 1/8”were popular but they also did single side and downdraughts for SU’s and Zenith carbs. There were even twin manifolds for Amal carbs as per the bottom picture. With all these especially when combined with a tubular exhaust manifold, getting the manifold nuts on and secure can be hard. Try fitting tubes to the long studs. Don’t be tempted to fit Allen screws straight into the block, all the water will come out every time you remove them and they’ll leak in between times. If you have to have short studs just to get them in weld up some long nuts with two nuts joined by a few inches of 1/4” tube.

A neat installation with a sidedraught SU on a SPEEDEX manifold. Note how the mounting flange is horizontal taking the earlier type of SU or the standard side draught Zenith. Similar manifolds are available new from John Barlow. It’s a good way to get a decent carb under a narrow bonnet.