Resources for 2.7 to 3.0/3.2 conversion

[concentric]

Hi there...
I am a new Porsche enthusiast (this is my first post) that has "graduated" from VWs. I worked at a German Auto shop (Mesa West in Costa Mesa) as an "intern" for a while, that's how this whole thing got started. Anyway, last week I decided that I was interested in purchasing a '74 911 that we have in the shop. It's currently having the 2.7 motor rebuilt, which should give me some good running time before I have to do anything substantial with the car.

As an aside here, what sort of performance can I expect from a stock 2.7? 0-60 mph? Top speed?

I'm thinking of moving up to a 3.0 or 3.2 motor, primarily for longevity of the motor and to get some extra oomph from the car. Since the car is a '74, I don't think I'll have to smog it, which will be nice. I'm looking for any on-line or printed resources that cover issues related to this conversion.

Do you have any resources you can point me to? Feel free to drop me an e-mail at jason@concentricrotation.org

Thanks!

[dd74]

What sort of rebuild is being done on the 2.7? Standard, "S" or "RS?" If it's an "S" rebuild with correct head porting and compression, you'll have exactly 5 horsepower less than a well-running 3.0 engine. If it's an "RS" build, there'll be no comparison to a 3.0. A regular 2.7 is a nice engine too - when it runs properly. The magic of these cars is in the ring and pinion and not necessarily the engine.

Either way, if the 2.7 is being rebuilt, you've got a good deal on your hands - cost of the entire car providing - because the engine will have been freshly rebuilt and should last a long time.

[concentric]

Originally posted by dd74
What sort of rebuild is being done on the 2.7? Standard, "S" or "RS?" If it's an "S" rebuild with correct head porting and compression, you'll have exactly 5 horsepower less than a well-running 3.0 engine. If it's an "RS" build, there'll be no comparison to a 3.0. A regular 2.7 is a nice engine too - when it runs properly. The magic of these cars is in the ring and pinion and not necessarily the engine.

Either way, if the 2.7 is being rebuilt, you've got a good deal on your hands - cost of the entire car providing - because the engine will have been freshly rebuilt and should last a long time.

I'm pretty sure it's just a standard. The cylinders are a low-milage used set, which is not optimal, but I just want to get it on the road and driving at this point.

Can you tell me a bit about what the differences between standard, S, and RS? I'm assuming RS is the pinnacle. Can you get aluminum cases for the 2.7? I would think that someone must make them.

I got the car for a song, comparitively.

JCM

[dd74]

Difference between the S and RS is the RS is the same engine used in the 1973 Carrera RS - 210 hp. The S in ROW form, puts out 175, but has the same compression as the RS. Difference is the S uses CIS. The RS uses MFI.

Aluminum blocks are good for extreme engine modifications. They are more robust than the magnesium block of the standard 2.7. They are not prone to the heat-related warping that magnesium blocks have, etc. However, the magnesium block is lighter than the aluminum by about 25 pounds, and is prone to warping only in extreme heat, as when thermal reactors are used in the exhaust system.

If your engine is a 2.7 from 1974, you should have very little trouble with this problem. It was present in the '75 to '77 model years, particularly those in CA.

[KTL]

marcesq personally did a 2.7 to 3.2 conversion in his '77 911. He could tell you the details about this swap.

[MotoSook]

Originally posted by concentric


Do you have any resources you can point me to?

You just found it.

If you perform a search here, you will find that a number of guys have made the swap, 3.0, 3.2 and 3.6.

Marcesq has a website dedicated to a 3.2 swap.

A 3.0 is a great engine in a mid-year (74-77) 911

[IROC]

I just swapped an '88 3.2 into my '76 to replace the stock 2.7. Marcesq's site is an excellent primer for what is involved in the swap.

As for performance, I can't really speak for the "standard" 2.7 of '74 which had the lower 145hp or so, but I think you're going to find that it is a pretty good performer assuming everything is in good working order. The 7:31 ring and pinion (vs the later 8:31) will really help.

Mike

[Randy Webb]

The 3.2L will have a lot more torque. YOu should start with Bruce Anderson's book on Performance 911 mods and Wayne's Engine book -- both for sale here. The rebuilt 2.7 will give fine longevity (if done right).

What you will really need to research is what sort of mods to do to the engine(s). I like carbs as they give good power, good response and are simple. Some go for MFI. Or you can go for EFI. Just kill the CIS if you can. Swapping in a stock 3.2L with EFI is more trouble due to the computer etc. but quite a few have done that, and you will have a nice clean motor with good driveability, unlike carbs.

If you are in SCal as your sig says, you will no doubt have to stay with a stock engine and the 3.2L is your best bet.

[dd74]

Would a 7.3:1 ring and pinion hold up to the 3.2's torque?

[concentric]

Thanks for the suggestions, resources, and information!
Much appreciated.

I'm chomping at the bit to get in this car and drive it! I just hope it comes soon, or I might burst.

JCM

[HotPorsche]

Check out this site from Pelican. http://www.pelicanparts.com/911/911tech_articles.htm