Engine transplant 911s

[mjf]

I have a 1976 turbo bodied 911s 2.7 that was fitted with RS pistons at its last rebuild. ( A lot of the upgrades to do with the fan and vavle covers were done at that time.) It was originally the 165 hp US version . I have been told that the motor now produces 173 hp at the rear wheels. My dilemma is that the motor will need another rebuild in the future and I need to clarify my options.

Do I rebuild the present 2.7 motor with further modifications to increase the hp or put a 3.2 or newer motor in.

I have the opportunity of purchasing a damaged 1985 3.2 Carrera with a 231 hp motor in it.( The engine has 86k kilometers on it and will be fully tested etc.. prior to purchase if this is the option taken.) The damage to it was not that severe that it could be road tested with the front guards and hood removed. I was surprised how little difference there was in low end performance to my 2.7, however I was not able to really put the vehicle fully through its paces and am told that the power really kicks in at higher levels. Also my 911 is supposedly much lighter as it has few add on's.

There are some further specific questions that I would like help with.

1. Will the original heating system work after a refit to a 3.2?

2. Will a 3.2 gearbox fit into the transmission tunnel of the 2.7 without modification.?

3.Will the original tachometer work or will the 3.2 model have to be fitted causing a mismatch on the dash?

4. I understand that the 3.2 has a hydraulic clutch, how will this be incorporated into the older model.?

5. Will the suspension points on the 2.7 need altering in any way to accommodate the 3.2 motor and transmission.?

6. As I am in New Zealand our emission controls are less stringent than that of the US. If I rebuild the 2.7 and fit say an earlier exhaust system what sort of power gain should be expected.?

Any additional comments on the pros and cons of fitting a later model engine would be greatly appreciated.

[Wayne 962]

Glad to see you got the forums to work!

The 2.7 is a surprisingly snappy motor. There are many who believe that a 2.7 "feels" more "torquey" on the lower end than an equivalent 3.0L. It's tough for me to weigh in on this as I haven't driven them on equivalent cars side-by-side. You can't go wrong with the 3.2 though - the Motronic is the best of the pre-89 systems and is very reliable, and will get you the most HP (particular if you push the margins and install a chip).

1. Should be no problem - you might have to use spacers on the exhaust studs or swap them out. Make sure you get the brain and harness from the donor car.

2. The 3.2 used both the 915 and the G50. The 1985 transmission that is mated to your 3.2 should be a direct swap in for your existing 3.2. Off the top of my head, I can't think of anything that would need to be changed.

3. Make sure you get the 3.2 tach - it's specific to that engine.

4. Only the late 3.2s have the hydraulic clutch (1987-89). Not a concern here.

5. It should bolt right in, if your car is a stock 2.7

6. The 911RS engine pushed out about 210 HP with MFI. With a bump in compression from the RS spec, and carbs, you should be able to achieve this or slightly more HP.

Hope this helps,

Wayne