Tuning a 1622cc Engine

This was written by Neil Cairns.  While this section mainly deals with taking a Farina Saloon 1622cc engine to MGA spec, much of this applies to 1489cc vehicles as well.  For Americans not familiar with Austins, we will refer the MGA 1600 Mk2 version as just MGA, and the engine found in all Farinas, as A60, the Austin version of the Farina line. You will need a workshop manual in addition to this information.

Although you get considerable power from an 1800cc engine, there are quite a few people who do not want to take that course to more power.  Why not just improve the 1489 or 1622cc engine already fitted ?  The A60, Series 6 Morris Oxford, and the Wolseley 16/60 all produce a tiny 61 bhp, and the Mk4 MG and Riley 4/72 manage 68 bhp, all with a torque of about 89-90 lb/ft.

The MGA 1600 Mk2, made from 1961-1962, (and only 8,719 were made,) used the SAME 1622cc engine at the A60, but in MGA form produced 93 bhp and 95 lb/ft of torque.  If you fit the relevant bits that this MGA used, to your Magnette or A60, you too can have quite a powerful motor.  Best of all you don't even need to take the engine out!  What you do is build your present A60 engine to MGA specification.

Right from the start, lets get some things very clear, 1) you will not have a smooth saloon car engine any more, 2) your insurance will go up (in UK, depends on state in US), 3) your engines condition must be good, and 4) you are going to have to do a lot of spanner work.  Your A60 engine has some very important limitations, the same the MGA 1600 Mk2 had.   These limitations were the reason the 1800 engine was developed.  

Diagram1 shows the reciprocating and rotating bits of your B-series.  The cam followers are of the 'barrel' type, and the con-rod has a pinch bolt on the little-end, (gudgeon pin.)  See diagram 2 for this bolt, it makes the con-rod rather weak, and limits the power/revs.  These arrangements were also in the three-main bearing MGB engine, (18G & 18GA).

Your A60 produces maximum power at 4,500 rpm.  The MGA did so at 5,500 rpm.  Your A60 was designed to last donkey years, while sportscars get quite regular rebuilds.  The MGA had disc front brakes, and you have drums.  I hope I make my point.

What do you need to do?

Obtain an 1800 cylinderhead from an MGB or Marina.  Recondition it if it needs it or realize this is a good time to go lead-free.  The 1800 has huge valves, and better ports than out A60.  See diagram 3 and note how close the edge of the inlet valve is to the cylinder bore.  On the 1800 the inlet valve will hit the block.  You need to grind out a tiny "scallop" to clear it.  The combustion chambers of the 1800 head are shallower, (though both the A60 and the 1800 have volume of 43cc,) AND you are going to need to fit a camshaft with more lift.  See diagram 4.

With your head off, remove your grill, radiator, and sump.  (The sump can be removed in-situ if you put 1" blocks of wood under the engine mounts on the cross member, to lift it.)  Now take off the timing chain cover, and the manifolds and side tappet chest covers.  Remove the pushrods and the cam followers.  Remove the oil pump and the distributor and its jack-shaft.  (See your workshop manual.)  Now pull out the camshaft from the front once you have taken off its chain, CAREFULLY.

Buy an MGB camshaft, it is identical to the MGA one, (less tacho drive,) with the MGA 1600 Mk2 timing and lift.  Also buy, or beg, a set of 1800 18V onwards bucket cam followers and the necessary longer push rods.  The barrel followers are shown in diagram 3 and the 1800 bucket followers in diagram 6.  These bucket followers are the same ones fitted to the 1275cc A-Series, they are much lighter than the old type, and hence allow higher revs and less loss of power.

With lots of oil on it, fit the camshaft into your block.  Ensure the timing is correct, see diagram 7.  Fit the pulleys and make sure the oil thrower is fitted the right way round.  Diagram 8.  Fit the oil pump, but make sure it is in good condition.  Now buy an MGB oil pressure relief valve spring, and swap it with your old one.  Diagram 9.  Your oil pressure will now be around 70-75psi.  Fit a new oil filter.

Now you can keep your old pistons, with their 8.3 to 1 compression ratio, or buy and fit MGA 1600 Mk2 pistons with their 8.9 to 1 compression ratio. To use your old ones will be FAR cheaper and you will lose 3-5 bhp only.  Fit the sump with a nice new gasket. Fit the timing chain cover, with a new gasket and seal. Fit the distributor with MGB springs on the weights for the advance curve, (again not essential, but it helps pulling power.)

Now, having fitted the head with NO gasket, but pushrods and followers in, and wound the engine over carefully on the handle to see if the valves clear the block, (put plasticene on the valve edge to make a mark) taking it off again to check for marks....you can now fit it properly, with a 1800 head gasket. Remember to put in the new bucket followers, and the longer push rods. Torque down the head.You can use your old rockers, BUT if you used a Marina cylinder head, make sure the oil drilling in the head lines up with that in the rocker piller The Marina one is further forward, and you may have to beg borrow, or buy a Marina puller with the extra lug on it.  (When you buy the head, take the current rockers, then there will be no problem.) See diagram 10. Diagram 11 shows the Marina head, with the awful log manifold. You need to buy a MGA Long Centre Branch, (LCB) exhaust manifold. It will need a sleeve to connect it to your old system as they are both the same size. Removing the rear expansion box helps power, and noise! ! An MGB LCB will fit, but NOT the standard MGB system. Fit the two side covers BEFORE the manifolds.

The inlet manifold needs to be the standard 'B' series twin carb, version, fitted with either MGA, or MGB, or Riley 1.5, or MG ZA or ZB, twin SU carburetters, if you can find any. Riley and M.G. Farina already use twin carbs. Those fitted to the Marina 1.8TC are perfectly OK, (diagram No12,) but what ever you fit, you will need a pair of K&N pancake air filters, with stub-stacks. The MGB rich needle is an ideal starting point to fit,a number 6. N9Y plugs are ideal, as is an 88 degree thermostat, and a 7psi radiator cap.

Now, with the ignition tuning set at about 5 degree BTDC static, and a cable throttle control made up as per the Marina 1800, fill the sump with oil, the radiator with water, and start it up: Once you have sorted out the odd faults, and get the car onto the road, providing you have followed the instructions, your engine should be making about 85 to 90bhp. It will be a bit rough at idle, so tickover has to be higher at 850 rpm. Yes, the car will quite fly along, use the revs.

But.................you really need to get the radiator fitted with a four-core matrix, as the A60 three core will not be capable of cooling the engine efficiently at high speed.  Or fit an oil cooler.  As with the 1800, you need radial ply tyres, and disc brakes if you are rich. A nice alloy rocker cover finishes it all off.

Where do you get the bits....

Well, a whole MGA 1600 Mk2 engine can be had on 01954 231318, as can an MGA/MGB LCB exhaust manifold, twincarb manifolds, new twin carbs, K&N filters, and MGB camshaft. Ring a few other M.G. specialists, as prices can vary to your advantage. A cylinder head can be had from M.G. magazine spares adverts,(M.G. Enthusiast Magazine at Smiths,) or scrapyards.