Rust in battery area is common but is so accessible (compared to sills) that fixing it is easy.
924's rust in the area where mud lodges at the base/rear of the front wings. There is a 10mm bolt that goes through the bottom flange of the wing and into a short bracket welded to the corner of the floor/innerwing panels. If you explore this area and there is no rust you are lucky. If you look underneath the car in this area you will see a 2" diameter metal 'doughnut' - I think this may be where the factory located an assembly line lifting jig for the shell alone as there are also two at the rear. They are NOT jacking points and if you have rust in the aforementioned area it may well extend under this 'doughnut' (ask me how I know). If you find
no rust here then get a plastic or hard rubber spacer washer about an 1/8th of an inch thick and uncrew the 10mm bolt. Slide spacer in between sill and main body, put copper grease on bolt threads and refit. The gap will mean that when you hose the car down you can flush out the mud and grit from this area.
Look
very carefully at the semi-enclosed box section, underneath the car, where you have spanner access to the large nut that holds the rear torsion tube outer support. This is about 12 to 14" forward from the back end of the outer sill. If you find big flakes of rust coming off the sheet metal or indeed signs of freshly applied underseal then suspect it is going thin in this area. Repairs are time consuming (£££'s) because of access. It may also be a sign that the inner sill in general is suffering.
Cambelts on the 924S and 944 intrigue me. Just what did Porsche get
so wrong in the layout and design of cam and balancer belts that their life expectancy is so short (the Americans having persuaded many people that 30,000 is the limit) ?
The first set of belts and pulleys on my (FSH) '86 924S were changed at 75,000 miles. Another 924S with FSH was on eBay recently with " .... all belts changed at 76,000".
A much thrashed rep's car (an OHC Cavalier) that I bought some years ago still had its original belt functioning at 120,000. I checked through the very full history of this one-company-owner car and due to a 'cock up' it had NEVER had the belt changed.
I have a 1.8T 20 valve DOHC turbo Passat (150 bhp) that had its first tensioner and belt change at 80,000 miles.
A previous generation 2 litre OHC Passat that I bought for my wife had its first cambelt changed at 82,000 miles.
So ..... just what
is technically wrong with the Porsche set up that has led to such a staggeringly low figure of just 30K? I do, by the way, understand that there was an early and rectified issue with a projection on the cover that allowed a belt to rub.
Based on the two examples of 924S's doing circa 75K
from new - is it fair to conclude that if fitted and retensioned
as per Porsche requirements, then they are totally fit to do a 'normal' 75K - and that it is later owners skimping on proper servicing that may have led to failures ?
One 'expert' on Rennlist suggested that "antifreeze leaks will rot the rubber belts".
Again I am puzzled. Given that many, many 924's and 944's are on their first set of rubber radiator hoses at 20 years plus and 120,000 plus miles ..... would the cam and balancer belts really be made of such inferior 'rubber' and Kevlar that antifreeze could affect them ?
As to tensioning devices for DIY (although 90 degrees twisting works perfectly for many, many cars with toothed OHC belts) some Americans use a cheapish tool called a Krikit which you could import. I believe Optibelt in Europe sell a very similar device.
There is also the 920X sold in the USA for about £80.
See
http://www.arnnworx.com/new_tensioning_tool.htm
My local motor factor now stocks a very neat cambelt tensioning gauge made by Laser tools and it costs a meagre £39.
Provided that you could initially cross reference its reading with correctly tensioned Porsche belts then it seems to represent a very economical piece of kit when compared to the very expensive Porsche P9201 tensioning gauge ( £300 + ?).
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