911 rs engine

[goldsc78258]

Guys I'm planning to buid a 911 rs clone and I was wondering what would be the best engine to start with for this project

2.2 MFI From a 1970 911E

2.4 MFI From a 1973 911t

or non of the above

[Bobboloo]

Probably the 2.4T because the case will atleast be a 5R/4R or maybe if your lucky 7R. This means it will be stronger and it will already have piston squirters.

The 2.4 also has the 70.4mm crank you need.

Either injection pump can be used.

The 2.2E stacks are cheaper to modify than the 2.4T stacks but it's cheaper to just find some S stacks.

So I say get the 2.4T. These cases fair pretty well. I rebuilt one a while back and the case needed very little work.

[goldsc78258]

Thanks Bobby

[Peterfrans]

I was told that the 2.2 mfi pump cannot be modified with a RS spacecam. I would opt for the 2.2 setup

[Wayne 962]

Early aluminum 901 case...

-Wayne

[Walt Fricke]

I'm with Wayne.

While the early aluminum sand cast case doesn't stand up to rod bolt failures and other similar disasters any better than other cases (they all get pretty busted up), it is a great case. Maybe it doesn't have quite the extra ribbing and support the 3.0 has, but you can't use a 3.0 case anyway for a 2.7 engine.

Drawbacks over the 2.4T are that you for sure have to machine it for the squirters. Both will need the oil pressure mod, but that's trivial. Both of course will need the cylinder spigots bored out. However, with the alu case you won't need to worry about head studs pulling, case inserts, and that lot. You also will not need to worry about line boring. The 2.4T case might measure out just fine too, but chances are nearly certain that the alu case will not need line boring. You need the harder to come by early intermediate shaft, or you need some welding and machining or other clever modification done so you can run the later IS shaft. Other than that, the lack of bearings is not an issue.

You'll want to install another stud and some stud bushings so you can use later style chain housings.

And it is heavier and not "authentic."

But for a race motor you plan to twist hard and for many years, the early alu case is hard to beat.

Walt Fricke