2.4 engine with 901 assembly

[bjmullan]

In the near future I intend to take out my 2.0 engine from my '69 911T and as a stop gap while some work is being done replace it with a 2.4. The question is will the 901 assembly bolt straight onto the 2.4?

[Grady Clay]

Brendan,

Yes, it is easy.

It is not difficult to allow your ‘69T to use the MFI of the 2.4. More on that later.

The easiest is to use your carburetors, clutch, engine oil cooler, engine wiring harness & alternator, fan shroud and tin on the 2.4. All you would need is to plug the MFI nozzle ports (readily available screw plugs).

If the 2.4 has a MFI electric fuel pump, fuel filter & console, and not much else you can convert the car to MFI (the return fuel pipe should be in the car). You will still need to swap oil filter, clutch, and wiring.

Depending on what you do, you will need 2.0 flywheel bolts, oil cooler O-rings and assorted gaskets, some oil and not much more..

What are you doing to the T engine?

Best,
Grady

[bjmullan]

Thanks for the advice, the 2.4 is actual on Webers at present so I that should make it even easier then.

I need to at the very least replace the timing chains and may also take of the heads to check the valve guides as I have a lot of blue smoke on engine overrun.

[210bhp]

Will the starter motor from the 2.0 bolt right onto the 2.4?
Regards
Mike

[Grady Clay]

Mike,

Yes.

There are two starter motors for all the early years; the standard 0.8 hp version and a 1.5 hp version. Either will work just fine with the normal 2.4.

The only really strange version was for the early '64 901s that used the "6-Volt" tooth pitch on the ring gear and starter.

Best,
Grady

[Grady Clay]

Brendan

You are correct, that is much easier.

You can temporarily re-use your 2.0 flywheel bolts on the 2.4 IF the 12-point wrenching feature is good. When you reinstall the flywheel back on your 2.0, you will want new bolts.

The fitting on the oil coolers is different between the engines, hence the swap.

1969 has a unique engine wiring harness. The ’72 won’t adapt to the car. It will be easiest to change the wiring harness from the ’69 engine onto the ’72. The reason for the alternator swap is to insure alternator-to-voltage regulator compatibility.

You may also want to measure a single piston-to-cylinder clearance. You can do this without taking the cylinder completely off the piston. Simply slide the cylinder up until the piston skirt is exposed, and measure the piston. Using that dimension, set a bore gauge and measure the cylinder from the top. Also measure the cylinder for out-of-round.

I hope you understand the likelihood of doing a complete rebuild, possibly with new P&Cs. Not inexpensive but a better option than reassembling it and have it both smoke and have a rod bearing fail.


While you have things apart, I encourage you to pull the transmission and remove the differential for inspection. Your 911 originally came with a “simplified differential.” The differential spider gears pin was retained by a pair of “tits” on the end of the axle flange stretch bolts. These wore allowing the pin to slide out while driving. This totally destroys the transmission. In ’71 there was an update to prevent this. You can get the update parts out of a salvage 914 (and other) transmission.


What is the general condition of your T, in terms of rust and prior repair?

Best,
Grady

[bjmullan]

Hi Grady

Thanks for the excellent advice, the other poster (210bhp) will be assisting with the transfer and even donating the engine! We really have a great bunch of early Porsche people here in the UK the meet up under the DDK banner.

The 911T is in general excellent shape with good body work and a good interior as well, 210bhp who often follows me on the road in his RS often comments on how square it sits on the road. I bought the car in San Francisco 3 years ago for born2bfast and cannot complain about the car. As this will be our first engine drop I'm sure that we will post some pictures later...

[Grady Clay]

Brendan,

I too am a DDK member (#1345), just a long way off.

Good luck with the project. Feel free to email me if necessary (gradyclayathotmaildotcom).

Best,
Grady