Hello, New to the 911 experience!

[klrskies]

Hi to everyone,
At 50 years old, I'm in the process of chooseing and then working on a mid 70's 911S. This will be my first Porsche, and I'm very intrested in what are some of the more common modifications that work well with these engines? I've built some modified A/C VW engines and the porsche engine has similarity, although more complex and expensive!
I'm sure there is a tremendous amount of knowledge from people here who know the 6 cyl boxer inside and out. I look forward to getting to aquanted, and thanks in advance for your thoughts and comments!
Regards,
Ken

[RWebb]

there is not a whole lot you can do rel to a VW - Porsche did most of the hotrodding itself on the Early cars.

if by mid-year you mean '74 and later, then your state's emission regs will control what you can do - a fair portion f these motors have already blown and been replaced

bigger displ. is the obvious one, followed by the highest compression (often with twin plugging) that your local gasoline can take

it sounds as tho you have not bought a car yet -- some info:

1970 & '71 - best gearbox shift pattern (type 911 trans.); highest compression motors, 2.2L
1972 - larger, 2.4L, but lower compr. motor; stronger but heavier and bad shift pattern gearbox (type 915); xlnt body has funky ext. oil filler
1973 - last of the beautiful - and now expensive - cars with the classic body lines; same as '72 but no nice ext. oil filler access door ; midyear (1973.5) cars have the horrible CIS intake system, a hydralulicly based early fuel injection system

1974 - the first year of the ugly bumper cars; but this car is still pretty light wt. - a diamond in the rough if you know what you are doing

1975 - PNW cars are a lot like the '74s. Calif. cars have thermal reactors, etc. which damage the motor quickly. consider getting an SC rather than a Calif. car.

1976-77 - similar; consider getting an SC

You will also care about body galvanizing. Do a search for ino and a lot of mis-information gets posted on this also. Overall, there is more and more of it
each year, until event he roof was treated, by late in 1977.

[klrskies]

thanks for the information. Looking at 76 model. How much displacement increase is practical?

[RWebb]

be careful, with most 2.7's you will spend the FIRST $10k to bring it up to shuff

most people with a good 2.7 will take it to 2.8

I would (and did) gt a 3.2L Al cased motor (the 2.7s are Mg cased) and build that up - you can even find yourself a nice 3.8L RS motor and drop that in.

a '76 should be pretty cheap or I would not buy it

Buy Peter Zimmerman's book on the buy a 911 first.

NEVER buy one before getting a thorought PPI from a mechanic experienced with 911s not "porsches in general" not VWs"....

Look at dozen before you buy one. The later in the fall or winter it gets the more prices will drop

remember the 2.7L motor is esp. tricky and has all sorts of ways to literally pull itself apart

Bruce Anderson, maybe the top expert on these cars, once told me that Mg was like "congealed butter"

[klrskies]

how did you modify the 3.2, and was it a difficult swap?

[azasadny]

Ken,

Welcome aboard, you're in the right place! You'll get a lot of good advice and you'll be in a better position to make a good decision. Enjoy the ride!

[klrskies]

one car's engine is a modified 2.7 with webbers, high compression (10.3), cam change, exhaust, dilvar studs, nikasils, claimed 225HP...but I haven't done the ppi yet...about 15k$ for the car w/ less than 80K miles.

[klrskies]

Thanks for the welcome and encouragement Azasadny!

[RWebb]

Originally Posted by klrskies

how did you modify the 3.2, and was it a difficult swap?

It is very easy - I use carbs. If you keep the DME, which makes it emissions clean & gives a LOT better mileage, then it is a bit harder but not much.

Almost everything that CAN be done on these cars has been done and is documented on this bbs. The degree of expertise is amazing.

N.B. You will be spending a LOT of time and a fair amt. of $$ to bring any old car back up to snuff - e.g. replacing all the bushings in the suspension, which will need to be done.

Read this:
http://forums.pelicanparts.com/porsche-911-technical-forum/189572-long-term-commonly-neglected-maintenance-post2955054.html#post2955054

Rust proofing:
Galvanizing on Porsche 911s - A History

[tcar]

Couple or errors (and different opionions to) the above.

The 70/71 911S had a 901 transmission, not 915.
The 901 shift pattern is NOT universally perceived as the best pattern.

Emissions are state-by-state, check Indiana. Here, 74 and earlier are exempt, other states even newer cars are exempt.

Carbs may be an emissions issue (not allowed) in some states, some years.

Make sure the car you buy will pass emissions BEFORE you buy.

The CIS injection system 73.5 - 83 is VERY, VERY far from horrible. Many of us have had few issues with it, easily remedied. There are SC's w/ CIS running w/ 300k miles on them and the original CIS working well.

Dual plugs are pretty rare. Would not recommend it for a novice.

2.7's here came with 5 blade cooling fans. Should be upgraded to 11 blade.

Full body galvanizing from late 76 on. But it's not a absolute guarantee of a rust free tub.

Everyone on this board has their own opinions.

[Flieger]

He said 911 trasaxle for 1970 and 1971, not 915. 911 is correct. Pull type clutch and Magnesium case version of 901. Shift pattern is subjective. I like 911 best.

CIS gets good mileage and is less finicky but I think MFI is far more visceral and fun

Twin plug is easy for a machine shop to do by simply machining a second spark plug hole. This is provided you are already in there with the heads off and being worked on for other things like valve guides. You can always plug the hole with a spark plug but hook up the second ignition system later, when funds and compression make it wise to do so.

[RWebb]

Originally Posted by tcar

Couple or errors (and different opionions to) the above.

The 70/71 911S had a 901 transmission, not 915.
The 901 shift pattern is NOT universally perceived as the best pattern.

Yes, I did say type 911. Some call the type 911 trans a 901 but it is better to be more specific, as there are some substantial differences.

I cannot imagine why anyone would want the 1-2 gears in line [915 style], unless they spent a lot of time in heavy traffic, in which case, one is better off in something other than an old 911 sports car. The factory cited heavy traffic as the reason for the shift pattern change from the famed road racing pattern with 2-3 in line, which allows much easier and faster changes for curving roads -- or tracks.

[tcar]

Originally Posted by RWebb

1970 & '71 - best gearbox shift pattern (type 911 trans.);
.

He said 911 trans, not 915.

Assumed he was talking about the transmission as he said gearbox and shift pattern.

But... it's possible I don't have a clue. And I did have a typo (can't find my glasses)



Edit: I do live in the big city, drive in traffic, and have never used a 901 shift pattern. I like it, but, might like the 901 better, I can see the advantages if you rarely use first. (Guess it would eliminate your 'friend' pulling down from 5th tp R.

[450knotOffice]

Nice to meet you, sir! When you do finally decide on a car, post pictures here. We all look forward to seeing the "new" cars.

Also, don't discount a good '84 to '89 Carrera. These are essentially the most fully developed old school 911's - before the almost totally new 964's and beyond came out. They are strong, are usually rust free, they have relatively big, robust engines that make excellent power and torque and get good mileage. Many still have working air conditioning, if that's important to you (mine has been removed). Lastly, because so many were built (relative to the earlier cars) and are still on the road, prices are still pretty reasonable, with $15K able to buy you a pretty nice example, if you look carefully.

[RWebb]

There are certainly different opinions.

But I don't think I posted any factual errors above - in fact "Full body galvanizing from late 76 on" is in error - read my _documented_ rust-proofing thread. IF tcar knows differently, then please post the facts and the sources they are derived from as I did.

I certainly agree re emissions.

CIS was a fine solution to provide good fuel mileage and lower emissions in its day. But that day was over in 1984 (DME introduced with its much more sophisticated control and sensor technology).

CIS has very poor throttle response which makes it anathema to a sports car.

Many people will defend CIS but hate the idea of an electric installation in a 911. You'd be better off with an electric 911 than with CIS.

Another problem with CIS is that one more increase in Ethanol levels in our fuel may just knock it out completely.

[overman]

Hi Ken... Stop now and save your self, I mean welcome to the board!

Good luck with your search... You've received a lot of good info above... I'll add, be patient!

Wayne.

[klrskies]

Thanks so much to all for the information and warm welcoms!

I'm have my own small machine shop at home and I align bore and prep A/C VW cases for big bores ( spigot bore increase and case-saver installation), open up cyl heads for big bore, re-surfaceing, and full-flow oil system addition. I'll likely want to modify my porsche engine as well.

I have built and tested ( with their "stimulator") a mega-squirt stand-alone engine management fuel controller, but truthfully, I'm a bit of a dynasoar, and not a big fan of electronic control systems...yet.... I've never installed it on anything yet, but likely will sometime. I like german cars, having modified VW's, air cooled and a 83 GTI. I stripped the CIS off of it and went to dual sidedraft dellortos after adding a cam with enough overlap that CIS wouldn't function correctly. I've heard this dysfunction is due to pulsations in the intake tract from the increased overlap from more aggressive cam profiles. I've also heard of people modifying their CIS to levels of satisfaction...perhaps it's dependant on the individual and what they will prefer/tolerate...It's all intresting!

I have a 89 BMW 325is with motronic 1.3 and it functions pretty well, although there is no functional editor for modifying the e-prom. I have an e-prom burner and am able to read / store /write the binary, but without a good editor, it's not feasable for me to modify the maps. I spoke with the developer of the "Motronic Editor" and it was developed for Porsche Motonic applications, so that's a nice possibility when considering tuneing modified engines fitted with motronic.

Being a vw guy, I'm a bit concerned about the magnesium 2.7 case. Were there any aluminum 2.7 cases? If building a new engine perhaps it may be desireable to start with a aluminum case and more displacement capability from a later engine? How much modification is there installing a later engine into a 76 911 car?

Thanks to all for the warm welcome and for shareing your thoughts!
best regards,
Ken

[RWebb]

sounds like you could do the machining for the twin plugs with no problem - it is still spendy due to the distr. you will need. it is not required until you start upping the CRs in the wider combustion chambers.

all 2.7L and most previous motors were Mg - P AG always tries to save wt. -- they even used Be in some race car brake systems (risk of killing off track workers put an end to that one)

it is not hard to swap any motor (any later, Porsche air cooled motor) into any earlier 911 - with your backgnd it should be a snap.

what you REALLY need to do is decide where on the cost vs. power "map" you want to be.

also how much labor do you want to do? willing to do a lot of rust repair? body work? interiors? etc.

cheapest thing is always to buy somebody's completed project for 1/2 what they put into it - you likely know that

[klrskies]

True, it's easier to pick up where someone left off.
My real concern right now is the time...at 50 years old I now have better finacial resources, but the time and energy to spend on an extensive project becomes difficult. I guess it's always something!

After hereing/reading about some concerns over the magnesium case engines, I feel it likely best to find a car already having a 3.2 installed...either a swapped early car or a car with a 3.2 as the stock engine. These engine parts are incredibly pricy, so putting alot into a magnesium cased engine feels uncomfortable.

How much HP / TQ do the more common modified 3.2's make?

[RWebb]

mine has about 250 hp - which is fine for a street motor

do you have a lift?

I am older than you and find that lying on my back on cold concrete is not nearly as much fun as it used to be...

you can always get a car with a 2.7 and drive it till it blows up... not the cheapest thing to do but a 2.7L that has always been in OR, WA or Canada should last a long time. BUT how to trace back without being able to do a carfax (they start only for the more recent cars).


OTOH, you don't want to wait years for the right car then wait years as you fix it up - you'll be too old to get the same kick out of it. Believe me, I've thought about all of this...