Porsche sold around 150,000 of the 924 series cars and this success put the Company back on its feet financially. Originally designed by Porsche as a commission for VW/Audi - it naturally used many VW/Audi mechanical parts. The project was sold back to Porsche when VW's new management changed their plans.
It used a 2 litre o.h.c. 4-cylinder Audi 100 engine. Not a VW engine, nor indeed a "van engine" as the clever-clogs critics claimed. The 2 litre actually went into the VW LT van after the 924 was launched. As part of the Porsche upgrading for the 924, the engine received a forged crankshaft and larger main bearings and uses Bosch CIS injection. It has an iron bock and an alloy head.
The 924S used a 2.5 litre all-alloy 4-cylinder engine of Porsche's own design - essentially half of a 5 litre V8 engine from the 928.
eBay is, week by week, full of adverts for 924's (and a few for the rarer and faster 924S models) at prices ranging from £56 for a 'project' car to dealers asking £2,000 to £3,000 - and upwards.
With classic insurance available at sensible figures, these cars are a popular choice as a cheap classic with decent performance.
BUT like any old car you will find problems.
"No rust because it is galvanised". Simply NOT true.
Although after 1980 they were theoretically galvanised throughout, you will find rust on most cars.
It is common to find rust in the mud-trap at the lower rear corner of the front wings. There is a 10mm bolt attaching the bottom flange of the outer wing to a bracket on the floor pan. It is very common to find rust in this area, usually it rots away under the PVC factory underseal and produces both a rusty outer wing and a hole through into the main structure. Another common rust area is around the open box section just in front of the large nut that secures the rear suspension outer mountings. If you use a torch and a mirror to look up into the area about 12" forward from the rear of the sill, just inboard of the lower flanged edge, you may well find more than light rust. Sometimes you will find it has penetrated through into the inner sill - this then becomes a difficult repair because access is so limited. You can also remove the black plastic grille on the rear face of the door opening and use a torch to look down into this sill area. Many cars have had to have complete sills replaced and you should check carefully all the way along the lower flange and the adjacent floor edge.
If the centrally placed jacking point is not level or the bottom edge of the sill is bowed upwards in the centre - then that probably means the sills are weakened by internal rust.
It is common to find corrosion in the sheet metal that the battery sits on. Access is good so repair is straightforward.
Rust on the exposed lower front spoiler is fairly common thanks to chipping. With the youngest 924's being over 20 years old it is common to find cars failing their MOT because of leaking petrol pipes and fuel tanks due to corrosion.
Other rust patches on doors and wings could well point to accident repairs where sanding has removed the galvanised coating - or non-galvanised repair sections have been used .
Interior trim. It is rare for a 924 to NOT have splits in the front seat fabric. Sellers often state that "stitching has come undone and is easily repaired". Not so. Virtually always it is the edge of the cloth or the vinyl seat material that has actually torn along the edge. Even if you take the cover off, you would have to be re-sewing so close to the torn edge that it would split again as soon as the seat was used. It is equally rare to find a dash panel top that has not got splits radiating out from the corners of the air vent openings. Exposure to sunlight makes this top surface brittle.
Many, many, many false and wild claims of "low mileage"are made on eBay every single week. You will have to make a judgement if the seller is being truthful or downright dishonest.
It is perhaps the biggest single issue with 924's (plus the 924S and 944 models) - or more correctly with the sort of sellers who now own these very cheap cars and seem all too ready to pretend that the current speedo reading is all the car has done ..................
The 924 mileometer only reads up to 99,999 miles - then starts again from zero. So if a car shows 45,000 or 65,000 or 75,000 - it has probably done at least 100,000 on top of this. Unless the seller can show you cast-iron proof in the form of service-history and MOT's to verify a low claim then you almost certainly are being mislead. If the front seat covers are split and worn then claims of "45,000 only" and "55,000 only" are a sure sign that the seller is trying to pull a fast one.
It is common for a small cog to break in the mileometer as well so if it is not working you will have to guess at the true mileage.
Electric mirrors play up but often it is just dirty or eroded contacts in the door switches.
Secondhand engines regularly appear on eBay claimed to have only done 60, 70, or 80,000 miles. The same thing applies - you will need certain proof in terms of a V5C (to check engine number against registration number) AND a full service history. If a seller starts making vague promises about 'chasing up paperwork' then assume the car was at 160,000 before being broken for spares.
Cam belt change is a cheap and an easy DIY job on the 924. Do change the tensioner pulley as well because they will sieze and rub through the belt. The 924 is a non-interference engine.
On the 924S you have two belts, several expensive pulleys and usually a water pump if you are wise. NOT an easy DIY job because of the care needed over tensioning, plus expensive parts - and if neglected you risk a totally destroyed engine. The 924S is an interference engine, so, with a 924S it is vital to have written proof that this job has been done relatively recently by an expert. American owners insist it needs doing every 30,000 miles. And if just the belts have been changed and not the pulleys - then the previous owner has been cutting corners to save money.
Failure of seals in the 924S oil/water intercooler can lead to the two mixing - as can head gasket troubles - so check oil and coolant carefully.
The 924S uses fluid filled engine mounts and it is common for the offside one to collapse due to the heat from the exhaust manifold. Vibrations at tickover or as the engine slows down after switching off are signs that this mounting is duff.
On the 924S a smoking engine is a big worry as they have an aluminium block and the aluminium bores have a special acid-etched silicon crystal surface. Re-boring is not something that your average engineering shop can carry out.
Unlike the 924 which has a conventional clutch centre plate with coil springs , the 924S has a rubber shock absorber built in. This breaks up with age and use and eventually will cease to drive. If the service history show that it has been fitted with the later coil-spring centre plate that is a big bonus as replacement would leave no change out of around £600+.
Gearboxes (it is actually a transaxle at the rear) after 1980 are generally very reliable but quite a few boxes are now "whining" due to bearing wear. So many cars are being broken for spares that other used gearboxes are available - but again you want a cast-iron guarantee that it is a quiet one as it is a fairly big job to change one.
924 Turbo's are fast but a failed turbo unit will cost a packet (£1200 to £1500) to rectify because of the hours of work and difficulty of access. Some experts put the life of the turbocharger at just 40,000 miles so check the service history carefully.
"Whirring" noises in the transmission tunnel can mean any one of the 4 bearings that support the drive shaft are worn - a major job. Or it may be the clutch release bearing - again a major job to actually get to it. See also above re. rubber damper on 924S models.
There are excellent Forums on the net (924board and Rennlist, both in the USA) which can provide a great deal of technical help. The Haynes manual is, in my opinion, of questionable value. The 924 issue was done using an American car ... with many of the photos and job descriptions done with the engine out of the car. The reality is quite different. There are howlers that could mislead. There is no Haynes 924S manual - so you need a 944 manual for the engine details PLUS a 924 one for the rest of the car.
Values are changing all the time. The 924 is at rock bottom now (2007) with many cars being scrapped for spares so there is plenty of choice and an enormous range of prices. Typically a running but scruffy project car will be around £150 - £400, a decent runner with service history £500 - £1200. Anything more than that has to be a bit special - either proven low mileage and/or small number of previous owners and masses of service history. Or possibly had major restoration work. You might get a project 924S for £500-£600 but as a general rule they will fetch quite a bit more than the plain 924. Be very careful with 924 Turbo's because of the potential for bills that are as big as the purchase price for the whole car.
The best advice is actually to join a UK forum and then post a query giving details of a car you may have seen. You will soon be told whether it sounds promising, sounds a bargain or just possibly - wildly overpriced.