I'm thinking about swapping a 968 engine into my 1989 944S2 and thought I'd ask if anyone could confirm the parts I need and what needs to be done.

-968 engine, ecu and wiring harness
-968 throttle cable pivot assembly
-968 MAF
-hosing to connect MAF to stock airbox
-944S2 crank nose
-944S2 bellhousing, clutch and flywheel
-944S2 oil cooler housing bolted to 968 block

I already have an S2 bellhousing, clutch and flywheel so I believe I'm set there. I know power has to be supplied to pin 7 of the 14 pin connecter in the passenger footwell, where do I get that switched power from? Pin 5 in the footwell in an S2 is used for 12V from fuse 17 but connects to an A/C relay in the 968. I wonder if I could just move that wire down to pin 7 and supply power that way. I'm also aware of the fact A/C won't work unless I do some more extensive rewiring. Last, the ignitor behind the drivers headlight needs to be disconnected with the wiring looped since it's integrated into the 968 ECU.

Anything else I might be missing or forgetting about?

 

youll want to keep the S2's crank harmonic balancer and bolt that onto the 968 engine since you're not using the 968 dual-mass flywheel

 

Here are the notes I have for myself when I do my swap into my 944 2.5. Hope it helps.

Shopping list

968 motor
Engine harness
Oil cooler
MAF sensor
DME
S2 clutch/flywheel set up
S2 transaxle/turbo transaxle (optional)
951 radiator (optional)
Throttle cable
Header
Custom Fuel lines
Fuse tap
Coolant line- Reservoir, TB, WP

Exhaust
- Stock exhaust can be used, but flanges on 968 header needs to be rotated

Cooling
- 951 radiator is 1" taller and may help with cooling

Drivetrain
- Stock transaxle can be used, but turbo/S2 transaxles are built to take more torque. Use stock torque tube, stock bell housing, S2 flywheel/clutch.
- Balance clutch and flywheel
- Use S2 harmonic balancer

Fuel
- Make custom fuel lines through Rennbay or Lindsey Racing

Electrical
- 14 pin connector at brake booster
o Pin 7 on chassis harness must not have 12V. The 944 models have term 85 grounded directly. Remove this wire or you will fry the DME! Pin 12 will need a 12V switch source
- DME plug at footwell
o The 968 will have 14 pins (smaller one is for tiptronic)
o 944 connector will be a 4 pin
o 968 DME pin 7 will need a 12V switch source
- According to 944s3.com
o DME pin 18 needs continuous 12v power, while pin 27 needs "key on" 12v power.

- The 968 DME plug's pin 27 (black wire) needs "key on" 12v power, that is the key switch term 15 (black wire)

in some models the pin 7 (black/yellow) in the foot well may connect to 968 DME plug's pin 27 electrically (it does in early 968's)...just be sure it is coming from key switch term 15 (black wire)...else you may drain the battery

- Changes/revisions to Todd's chart :

Pin #7, which provides 12vdc power from the chassis side was just capped. Instead of using that "hot" wire, I ran a wire from term 85 from the back of the fuel relay.

Just to let you know, you only have to ground out term 85b (pin#5), term 85 runs great off of the fuel relay.

If you pull the ground from term 85b, or disconnect term 85 from the fuel relay, the fuel pump stops working.

The alarm pin (#7 next to the pass footwell) needs to be supplied with term 15 power.

Pin # 12 next to the brake booster needs to be supplied with term 30 power.

- http://members.rennlist.com/tholyoak...wap_wiring.htm

- https://rennlist.com/forums/924-931-...ting-fuel.html

- https://rennlist.com/forums/924-931-...t-problem.html
Misc
- 968 flywheel sensor on S2 mounting bracket

 

Karl,

pardon, but what befell your engine rebuild?

are you going to pick up Gary's low-mile 3.0?

 

That's a good question. At the moment it tends to overheat when the car is stopped, is going thru oil pretty fast even though I can't find any leaks and it doesn't appear to be coming out the exhaust, and vibrates a lot at idle when warmed up. I've been going back and forth about spending the time to fix it or just buy another S2 or 968 motor to drop in so I can sell it for a decent amount. I bought an S2000 last fall so the 944 has basically been replaced as my autocross/fun car, but if I could get it to run properly for more then a week and was able to enjoy it for once I might change my mind about selling it.

The engine I'm looking at is for sale by David Pagan at Promotion951, I know there's at least one thread on the forum questioning his business practices but I figure since I'm not actually having him do the work it's not much of an issue. Do you have a link to Gary's 3.0?

 

Lots of good information in your post jonvo, thanks. I'll have to read thru it and see how much relates to my situation as there are some wiring differences.

 

in case you havent seen this,
http://members.rennlist.com/tholyoak...wap_wiring.htm

 

PM me I have a 968 in a 89 S2

 

I have seen that wiring page a few times in my searches, but I'm not sure how valid it is since the wiring of S2s apparently changed at some point. I've tried to look thru the service manual electrical diagrams but I don't have the proper background to find the information I need.

 

Karl,
Here's a link to the Ebay auction for my 968 engine:
http://cgi.ebay.com/ebaymotors/ws/eB...%3AMESELX%3AIT

I've posted info about it in a couple of threads here and would be happy to answer any questions about it.

Alan,
Thanks for the mention.

 

Sounds like a good deal Gary, but I'm not close enough to pick it up and I wouldn't know where to begin when it comes to setting up shipping.

 

The wiring changed in 91 to the same as a 968. So the engine wiring harness will just plug into a 91 S2 dash harness. That chart does work. I also have some other stuff printed with notes. I'll have to dig it out.
I liked the upgrade to the 968 engine from the S2. The added power was great but a SC would be nice.

 

Did you replace the 89 dash harness in your car with a 1991 harness then? Or did you just rewire it in order to make the proper connections?

 

+1

 

Didn't replace the harness. I 3 or 4 jumpers. Taped the 2 connectors together, side by side and crimped pins on the jumper wires. The wires are short and I taped it up and had no trouble with it. One is for the tach one for 12v not sure on the others I have to look at my notes.
I'm running the stock S2 oil cooler but you have to have custom oil lines made. Not cheap so get the 968 oil cooler but I'm using the stock S2 duct work so there is a plus.