I just posted this on another forum but though it may be useful here also, so shameless copy-paste:
To whomever it may concern...
www.944-20v.nl
As can be seen on my website pictures, I have a n.a. 5-cylinder 20v (engine code 7A) in my type1 944.
The biggest problem is the bit between engine and transaxle of course:
Bellhousing used must be 924 or 931 (= 924turbo), it's hole pattern fits the Audi inline-5 (well enough anyway). Difference between 924 and 931 is that the 931 has a hydraulic clutch and 924 cable operated. I used the 931 bellhousing because my 944 used a hydraulic clutch also originally.
I used the original Audi flywheel, pressure plate, and clutch release bearing. This is quite different from the Porsche setup as there the bearing is pulled rather then pushed
for clutch release. Hence I made myself a clutch fork that creates a push motion on the release bearing when activating the clutch cylinder on the bellhousing.
Clutch plate is one off an Audi 2.8 V6. Has the same outside diameter as the stock 7A plate but fits the 944 transaxle.
The 7A flywheel has a pilot bearing in it (so its not in the crank) and it has the correct diameter for the transaxle. However, it does not line up properly with the transaxle. Also, the Audi clutch assembly does not fit inside the 931 bellhousing because there is not enough clearance/depth. Here two issues can be dealt with in one go by using a 10mm spacer plate between the engine and the bellhousing. It is a standard
Audi part off an S4 2.7 V6 bi-turbo (you can see it in the pictures). With the spacer in place the clutch assembly fits in the bellhousing and the transaxle lines up with the pilot bearing in the 7A flywheel.
The 931 bellhousing fits the 944 transaxle.
I made my own engine mounts. While having the engine hanging from an engine hoist, bolt the bellhousing to the transaxle. Then simply weld up brackets that fill the gaps between the standard engine bolt holes for the stock mounts and the position on the cars rubber mounts on the front subframe.
As can be seen in the pictures, my 7A has a custom oilpan, exhaust header, and uses an turbo intake manifold from an AAN engine.
The original Audi oilpan nowhere near clears the 944 front subframe, neither do any other available pans. Because I cannot weld aluminium (stock 7A pan is alu) I took a steel 10V pan, used its rim (the bit with the hole pattern that mounts to the engine) and welded up a pan that does fit. Of course the oil pickup inside the pan also has to be modified.
The stock 7A intake manifold runs over the valve cover and has it's throttle body on the right hand side of the engine. Advantages of the AAN manifold are that it puts the thottle body close to where it was originally in the 944 making things easier with regards to the throttle cable and mounting the airflow sensor and airfilter. This manifold also accepts standard Bosch injectors whereas the 7A manifold only accepts Hitachi injectors (which are crap..). It also allows much easier access to the valve cover for valve adjustment. Oh wait, they're hydraulic.....
Downsides are that the short intake runners should theoratically hurt low rpm performance compared to the long intake runners of the stock 7A manifold (have not noticed this, the cars pulls strong in low rev band). The stock 7A water manifold that is mounted on the cylinderhead (and to which one of the radiator hoses connects) does not clear and has to be reworked, and the stock 7A throttle body does not fit (made an adapter).
The stock 7A exhaust manifold, which can be a cast iron piece or a tube header both do not clear the 944 firewall because these have the downpipe at the very back of the engine. In an Audi this is not a problem because the engine is mounted very much forward. Hence I welded up my own manifold and downpipe. It all connects to a standard (but stainless) endpipe.
I re-used the stock 944 radiator with electric cooling fan. Because the hoses for it connect to one (the left-hand) side of the engine and the radiator has the hose connections on left and right, I used some stainless pipe and flexible water hoses to connect everything. There is a lot of space to work with on the front of the engine because the 7A 5-cylinder is actually shorter then the Porsche 4-pot!
The alternator is mounted in the standard location on the 7A engine. I made custom brackets for the powersteering pump so this is mounted on the right hand side of the engine where it is normally located on a stock 944. Belt size will obviously depend on your bracket design but many different length belts can be bought so this should not be a problem.
I'm using a non-standard startermotor. The standard 5-cylinder starter motor has its solenoid sticking outwards of the engine (to the right). This provided me with very little clearance for my custom exhaust manifold between engine and engine bay. I found that an Audi 4-cylinder starter (off a 4-cylinder, 2.0 liter Audi 80) would also fit my engine (same gear & rotation direction) but the solenoid would point straight up where there is plenty space. Only one of the two threaded bolt holes in the starter line up with the engine though so the starter does have to be reworked a bit.
Wiring was a bit of a problem for me because the loom was entirely disconnected from the engine when I bought it. With help of people on a German forum I found the right location for each connector though. I will add photo's of this on my website soon. Linking the loom to the 944 wasn't difficult. I actually use a bit of the stock 944 wiring for the starter, alternator, and battery, and only linked up the Audi loom for power and ground to the injection computer, ignition, etc.
I probably forgot a lot of other issues, but I think is this the general procedure. Hope it is interesting for those interested
