1969 2.0 911T capacity Increase

[adwarrior]

Hi There,

I have a 1969 911T (2.0). I have been offered a brand new set of Mahle 2.7 pistons and cylinders. I understand that in order to acheive 2.7 litres I would have to change my crank, though I prefer not to do this and can live with the increase to only 2.5 litres.
I was wondering if anyone can tell me the pitfalls involved with this operation. I understand that (according to Bruce Andersons performance book) I may have to have some machining done. Can anyone explain exactly what needs to be machined, as I was hoping to keep the "T" heads and just change the pistons and cylinders?

[aws]

The early 2.0 mag case can not be cut for the 90mm cylinders reliably. The early case does not always have enough material on the # 3 cylinder at the flywheel end of the case and may break thru when bored for the larger cylinders. The other problems may be piston to valve clearance if the pistons are for CIS injection and lower compression ratio caused by the short stroke crank.

aws

[Bobboloo]

Unfortunently the motor you have is not really a good starting point for building a bigger motor. The case, crank, rods, pistons, cylinders and even the heads are not ideal for what you want to do. In short virtually the whole longblock.

Best thing I can think of is you should try and find a good 2.7 longblock. Then you can use your carbs, alternator, fan assembly and exhaust on the the larger longblock. It'll be much cheaper than trying to convert your motor.

If your motor number matches the chassis then just store it until you decide to part with the car.

[deathpunk dan]

Store your # matching original engine and buy a freshly rebuilt later engine 1/3 of the money it would take to get a 2.0T to run like a stock 2.7