Mfi ???

[redbull760]

I have a 2.2 1970 911 engine with MFI. It ran great until Sunday. I have put a hole in one of the pistons and now needs a rebuild.

I will rebuild it over the winter. I also have a 2.4 from a 1973 car with Zenith carbs which i am intending to install. I am having real trouble finding the manifolds and linkage for the carbs.

Will my MFI from the 1970 2.2 fit a 1973 2.4?

If so is this my best option?

Which will give best power, performance, fuel economy etc...

[KevinG]

Redbull -

You need to determine what type of motors you have and the model of MFI pump you have on the 2,2l motor. The MFI systems are different based on whether the motor is a T, E or S - primary difference is due to the cam used and matching the MFI pump to it.

You can look up all the information on MFI that is readily available on the Pelican Tech Article database. I have a 2,2S motor, and the MFI pump has 009 as the last 3 digits. My spare 2,2E pump has 010 as the last three digits, and ran OK on my S motor for a brief period of time while I had the S pump rebuilt. Double check on the part numbers, I am at work and my brain is old.

As to your last question - MFI rules (but I am biased).

The only possible limiting factor on using MFI on the 2,4l motor is if the heads are set up to accomodate the FI injectors.

[Grady Clay]

Stuart,

You have lots of options.

First some questions:
What is your 2.2 MFI – T, E, S?
What was the ’73 2.4 before it got carburetors – T, E, S, MFI, or CIS?
How do you want to use your 911? Daily driver, tours, track events, other?
What is the condition of the 911? What year, type?
You need to know your budget.

The fastest-to-get running option is to install the 2.4 with carbs. You will need to buy a carb fuel pump or a pressure regulator (preferable.) You will need to really carefully clean your oil system in case there is metal contamination.

I’ll reserve other options until you post more info.

Best,
Grady
gradyclay@hotmail.com

[redbull760]

Its a 2.2 E and the 2.4 T

I just want to get the car running again. I need the manifolds which are hard to find and expencive.

I wondered if the MFI would fit straight on then I have all the parts.

Its a weekend car, which I enjoy driving not a racer.

[69911e]

Your entire 2.2E MFI system should bolt onto the 2.4T engine and run alright with some mixture adjustment, if you have the pump drive on the left cam on the 2.4.

[Grady Clay]

Stuart,

I’m assuming the carbs are out of the picture because of the cost of linkage, manifolds, air filter assemble, etc.

I’m also assuming the ’73 2.4T was a MFI engine originally and not a ’73 ½ CIS engine. The MFI engine has threaded holes in the intake runners for the nozzles.

Here would be my first choice:
Replace the T cams with the E cams.
Find a matching 2.2E piston & cylinder and install the E cylinders on the 2.4. (It will still be 2341 cc but higher compression.)
Install the 2.2E MFI on the 2.4. The pump is capable of being suitably adjusted.

This represents a lot of work and I wouldn’t want to chance a bearing failure. I would disassemble the bottom end (crank & rods), do the recommended upgrades, bring the heads back to new condition (valve job, and guides if necessary), and whatever else necessary. Check the bore ID of the 2.2E throttle bodies to the 2.4T head intake ports and match the diameters.

You will have a nice 2.4 911E with higher compression. A great road 911; fast and reasonable mileage.


I think the least expensive route is to find a complete used set of carburetors and intake from a 2.0T or 2.2T for the 2.4 engine. Also, you can buy just the parts you need from PMO:
http://www.pmocarb.com/


I wouldn’t recommend just putting the 911E MFI on the 2.4T engine. You will never get it to run properly and there isn’t provision for the pump drive on the left (1-2-3) T cam. Definitely don’t install the E cams with the T pistons without careful checking of piston-to-valve clearances.


Is there a good MFI engine available?

Best,
Grady