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Reducing wear and tear

Author: Dave Mann

Having rebuilt 3 Sevens which involved making good all the holes drilled in the body by previous owners I resist the temptation to undo my hard work. However I am not averse to carrying out modifications which reduce the wear and tear of our cars. Just like today's products they were built down to a price, however unlike today's products they can be repaired. The following are some of the modifications carried out to overcome the shortcomings of the original design:

1) Rear spring pin lubrication, as built the grease nipple is as much use as a chocolate fireguard, any grease pumped in goes around the pin in the gap between the two bushes and out the gap where the end of the main leaf is rolled to produce the eye for the bushes and pin without lubricating the pin and its bushes. See photo although my only spare spring has very little gap, there are a couple of solutions:

  1. The George Pratt method solder up the gap between the main leaf and its end.
  2. The John Foreman method ream the spring eye out to 3/4" and fit a steel bush to bring it back to size for the bushes, do not forget to drill the steel bush for the grease hole.

Rear spring

2) Radius arm ball mounting-so positioned to that all the road dirt thrown up by the front wheels is neatly channelled into it, oiling it merely washes the dirt into the joint. Both cups are drilled and tapped for a grease nipple pointing forward and a strip of rubber, with holes for the grease nipples is secured with a tie rap to keep the dirt out, well most if it, see photo.

Radius arm mounting

3) Air intake filter, my pet project, with the updraught 22FZB air intake positioned to induct all the dust thrown up by the front nearside wheel is guaranteed to accelerate engine wear. Austin's were aware of this and fitted filters to export cars. It took some time to come up with a viable design which uses an adaptor pipe incorporating a choke flap and a take off for a crankcase vent which also acts as a stop for the choke. The choke is fitted with the spring removed from the original choke and the adaptor pipe holds the original choke out of the way. The crankcase pressure was measured before modification at 5/8" water gauge (above atmospheric) at full throttle at 45 mph and 3/4" water gauge depression after. Inducting the mist from the crankcase provides some upper cylinder lubrication and when the blue smoke is noticeable from the exhaust I know it's time to clean the filter, which is quite often. (In case you are wondering we never, ever, ran an engine at work without a manometer to monitor crankcase pressure, more than a maximum of 1" water gauge at full power meant something serious was amiss.) Whilst the intake depression was 2" water gauge with and without filter. See photo, the clear plastic vent hose goes to an adaptor in one of the holes in the valve chest cover whilst the remaining holes are blanked off.

Air filter installation

4) Corrosion of cylinder block water passages, again all the engines we built at work were fitted with zinc sacrificial anodes, however these were big engines with loads of space to fit them the Seven engine has very little spare space for them. It wasn't till I was given the rusted remains of an RN saloon in 2005 did the answer present itself, the cylinder head was so badly corroded that one of the core plugs fell straight through its hole. So the hole tapped out 3/8" BSP and a plug tapped to take a zinc anode screwed in. With some information from Robert Foreman I'm working on a scheme to fit one or two to the cylinder block.

Non-original core plug and oil filter

5) Brake cross shaft lubrication, again applying the oil can to the ends of the bushes is not a good method of lubrication and probably washes a lot of dirt into the bearings. Again I must thank John and Robert Foreman for the following procedure, the shaft is drilled for grease holes at each journal with the smallest at the nearside and largest hole at the offside end and I can't remember the sizes. The bore of the shaft is thoroughly cleaned and the hole at the nearside end plugged with a plug fitted with a grease nipple.

6) 3 speed clutch thrust bearing pressure plate BJ 19 slots for toggle arms seem to wear at an alarming rate and I was always cutting new slots. This arrangement was identical to the 1950s AEC bus engine clutch, however this was considerably bigger with provision of a grease nipple for lubrication. I know because a mate of mine had a AEC bus and he didn't bother to grease the clutch operating gear which resulted in all 3 toggle arms breaking in Welshpool on an Easter Sunday eons ago. After fitting a 4 speed gearbox to one of our cars the solution became obvious. The 3 speed clutch cover plate was drilled for mousetrap springs, 4 speed toggle levers fitted and a 4 speed thrust bearing fitted with the bearing sprung back out of contact with the toggle levers.

7) Clutch thrust bearings, I have never liked the lubrication of this bearing with oil, scrabbling about under the dashboard with an oil can to find the oilway has blocked up and the oil doesn't get to the bearing or you overdo it and put oil in the clutch. So all new (used) thrust bearings are thoroughly cleaned, it's amazing just how much dirt can be removed from them, the oiler removed and replaced by a grease nipple. Grease is pumped in whilst rotating the bearing, just enough to lubricate the bearing and not to fill it.

8) Engine oil strainer, as a retired engine development engineer I'm well aware of the improvement in lubricating oils since our cars were built. Unfortunately with the rather crude oil strainer it is not really beneficial to take advantage of these developments. So one car has been fitted with a full flow oil filter and I'm wondering if this can be retro fitted to the other car without a total engine strip down. This was all done with the engine in the workshop and the filter position makes getting at the dipstick challeging.

9) Whilst the RN drag link didn't have grease nipples for the ball joints Austin's must have felt these were a requirement and fitted them to later models, so our cars have also acquired them.

10) The last seven that goes into the garage is pushed in being steered by moving the front wheels however whilst this worked well on two Sevens the steering on the third would lock in one direction, so it was off with the steering box for a refurbishment. I was never happy with grease lubrication because it tends to be wiped off the gears and the bottom thrust face and if you keep greasing it you will end up with grease on your trousers. So the refurb included making the box oil tight and lubricating with Castrol D140 and Molyslip, the result was well worth the effort so all my steering boxes had that treatment. The oil level is kept up to the bottom of the grease nipple hole, however one car decided to eject the oil onto my trousers, this is the one which was attacked by an errant BMW and had developed a tight spot in the position it was on impact so it was changed for a spare. I've inspected it and can't find any reason for the tight spot or oil ejection, so it remains in bits and will probably going to make razor blades.

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