Opening the bonnet of an SM has been known to drive a grown man to tears; there’s just so much of it! But it isn’t anything like as bad as it looks.
The Maserati engine is reliable if it has been regularly and properly serviced, you should always check for a history of bills on any car you look at. Don’t be put off by hisses and clicks from the hydropneumatics but the engine itself should not make any noises. If it is breathing heavily this is a sign of tiredness. Most parts are available or can be re manufactured.
Try to find a car that has not been thrashed but has been well maintained and regularly used. Due to age the sodium filled exhaust valves, which are still used in modern engines and aircraft, can fail by dropping their heads if they are not changed, which can cause serious and expensive engine damage. This usually occurs particularly after cars have been standing for four or more years, and is worse on EFi cars and those with Merak SS engines. The current solution is to fit solid valves and it is recommended that these are fitted if you are not sure of what is in the engine and during an engine rebuild.
Listen for rattles from later EFi models as this could be from the butterflies. It is worth checking the EFi injectors as the early ones were prone to leaking causing under bonnet fires, so always carry a fire extinguisher, which should be normal practice for any classic vehicle that you cherish.
There is also well reported problem is with the timing chains, which on the SMs Maserati engine there are three. The Primary chain at the back of the engine has a tensioner has a tensioner, the original version of which was not adequate, possibly due to the fact that no one told Renolds, who designed and supplied the chains, that this chain was also diving via an intermediate shaft the hydraulic pump, alternator and air conditioning pump. Modern tensioners and chains can last up to 100,000 miles, but the chains should be checked every 10,000 miles and the top chains re-tensioned. If you are buying an SM and there is no record of when the chains were replaced assume that they should be.
The original York Air Conditioning pump can also cause problems with the chains as this was a two cylinder pump, which when worn can put extra strain on the primary chain as it switches on and off and if it seizes. The main problem is that the original design brought the air conditioning pump on whenever the ventilation control was moved into the cold area. You should check that any car has a cut off switch for the air conditioning if fitted. It is a simple task and you can usually find a blank on the dashboard where a period switch can be fitted. If you want to regularly use air conditioning in your SM then it is a sensible modification to fit a rotary air conditioning pump as these are easier on the chains when they switch on and off.
The original oil pump shaft was also a problem and should be replaced with a stronger version if this has not already been carried out.
The original distributor contact breakers are in a twin cassette and can be difficult to set up without specialist equipment, plus wear in the distributor can cause timing issues. Most cars now have electronic ignition fitted. such as Lumenition and it is a worthwhile investment if you intend to use your car for the purpose it was intended.
The gear box was derived from the Citroën DS design of 1957, but with a fish gear added. It continued in use in the Lotus Esprit until 1987 over ten years after SM production halted. So it is fair to say that it seems to have been reliable, although listen for any whines, after all it is now over 40 years old
Most of the cars that are currently on the road have had the above modifications carried out, but if you are buying an SM check it out.
