Specialist Vehicle Restoration
5th April 2022
Unfortunately we must announce that the business is now closed; due to the passing of Bryan, following his long battle with Cancer.
Stock items may still be available by email request to email@example.com, but please be aware that we cannot guarantee response times to these enquiries.
We would like to take the opportunity to thank his many long standing customers for your custom and friendship over the years.
Practical Classics Guide continued
Not many of the SP250’s rivals could claim to have eight cylinders under the bonnet – and even fewer of those are now affordable. The V8 is a fabulous unit too, with astonishing flexibility and superb durability if properly maintained. While Daimler’s V8 saloon often suffered from worn engines after surprisingly low mileages, the SP250’s powerplant isn’t as stressed (as the car is much lighter), so it keeps going for far longer.
It’s quite normal for an SP250 engine to cover 250,000 miles between rebuilds, but allowing the unit’s coolant or anti-freeze levels to drop will have a dramatic effect on life expectancy. The unit features a cast iron block with alloy heads, so coolant that’s too dilute will lead to the cylinder heads breaking up internally and blocking up the whole cooling system – resulting in overheating and potentially causing the heads to warp. That’s why you need to check for emulsion on the underside of the oil filler cap, signalling that big bills are imminent. If the top end sounds tappety, it could be that the valve clearances need adjusting, but it’s more likely to be problems with the valve guides, which can move in the head.
Lumpy running may be down to the exhaust valves sticking, as they can get clogged up with carbon deposits; some Redex in the fuel tank normally sorts this. If it doesn’t, it’s time for a decoke. Most SP250 engines have an appetite for oil, with the earliest cars guzzling at the rate of 300-400 miles per pint. The B and C-spec cars are a bit better, but they’ll still get through a pint every 600 miles. Make sure there’s at least 15psi on the dial at tickover; expect to see 35-45psi at 40mph.
The gearbox struggles to cope with the V8’s torque, and if the car has been driven hard there’s a chance damage will have been done. Stripped gears are the usual result, with first being especially weak. If the gear has broken there will be lots of clicking; continuous whirring means the teeth have worn. Unusually for such a prestigious car, overdrive was never offered, even as an optional extra.
While the Daimler’s transmission is simple and easy to work on, it’s also fragile – a worn crown wheel and pinion assembly is likely. That’s especially so with pre-1961 cars; B and C-spec SP250s had stronger rear axles with a trio of drain and filler plugs on the casing. The earlier cars had just a pair. It’s likely that the axles’ tubes will have started to separate from the axle casing, as they’re not especially well secured. The obvious signs are leaking oil and plenty of clonking and wheel wobble.
STEERING & SUSPENSION
The cam-and-peg steering doesn’t give any problems unless the box has been allowed to run dry – or unless somebody has filled it with grease instead of oil. A certain degree of play can be adjusted out, but if the box has been overtightened there will be stiff spots and wear will be worse. There’s little to worry about at the rear, aside from leaking dampers and sagging leaf springs. At the front there are potential problems because the trunnions and vertical links can both wear if they haven’t been greased every 1000 miles or so.
While the trunnions are available new at just £35 each (they’re the same as on the TR3/4), the vertical links are only available on a refurbished basis and are a horrific £1350 apiece. You can check for wear by jacking up the front wheels and using a crowbar to check for play between the wheel and the vertical link; any detectable movement means new trunnions and/or links are needed.
WHEELS & BRAKES
All SP250s were supplied with steel disc wheels, although wire wheels were available as an option. You need to make all the usual checks where the wire wheels are concerned; rusty, worn, broken or missing spokes can all strike. Unusually, the steel wheels can also give problems as they’re prone to cracking around the mounting holes – which is why many owners fit Minilites or wires. However, some owners substitute Triumph TR items instead if they’re keen to stick with pressed steel.
There are Girling disc brakes at the front and rear, without the aid of a servo. There’s not much to go wrong, although you need to check for the usual problems of scored, warped or worn discs along with sticking caliper pistons. The easiest way to check for all of these is to listen for untoward noises under braking while also feeling for juddering from the brake pedal.