A 26+ year old 2.4/2.7 as a long term prospect...

Hello,

I'm now in a position to realize a lifelong dream - the purchase of a 911.

I've got a shortlist of 911's that most appeal to my (cursorily) educated tastes, and my budget. This is the list:

1969-1973 911 S
1973 911 Carrera RS 2.7 (replica!)
1974 - 75' 911 Carrera 2.7 Euro (RS) specs

I know a good deal about the characteristics of most 911 engines, but the point of this topic is to canvas some knowing opinions about the reliability of the 2.4 - 2.7 MFI units. I am aware that the magnesium cases can fatigue prematurely, but I have been told it's more of an issue with CIS 2.7's fitted with 5-blade fans and thermal reactors.

If either a 2.4 or 2.7 is in a healthy state, i.e., recently rebuilt, how much of a life should I expect from this engine under normal to moderate driving conditions? Can they be as bulletproof as an alloy case SC engine (250,000+ miles), or do the magnesium engines truly operate on a different clock?

I have found a very healthy 1974 (Euro) Carrera 2.7 with high compression pistons and 280,000 genuine kilometers on the dial, 90,000kms post an unnecessary engine rebuild in its native Germany so the high compression pistons could be added. I have been told with good authority that the engine is as bone dry as a 2.7 can be, and is very clean and clear out of the tailpipe. I’m also told the engine runs as cool as a 3.2, even in summer. However, I won’t be buying the car unseen and unchecked, but I want to make sure the trip is not fated to be futile!

So, should I expect the engine to go for another 100,000+ miles, or will the age of the crankcase bring the engine to its knees a lot sooner?

I expect the 911 I end up buying will be strictly an excuse for weekend jaunts, and the occasional track excursion. Will the latter have a significant influence on the interval between the next rebuild, or will an aging magnesium crankcase be the sole factor?

Any advice/opinions will be most appreciated from what I consider to be a magnificent bulletin board.


- Julius

Hi Julius. Great to see you're finally on your way to owning one of the most fun cars ever made. I doubt you will regret it.

Your concerns are fairly universal ones, and pretty much are the worries we all had when contemplating buying an ancient 911.

I personally think you have to keep it all in perspective. Each model has its pros and cons. Which model do you lust after the most? Get that one, or you will probably regret your decision later.
I love the early cars, so that's the one I bought. They are all old now, and plenty of things will go wrong. Do you like tinkering and repairing or do you think you'll need to go to a shop? This is very important, as even mundane repairs will cost an absolute fortune if you farm them out. The flip side is I think 911's are fairly easy, and certainly extremely pleasing, to work on. If you have some mechanical aptitude and can read/find the right info you'll be ok. You'll also become a tool freak as you collect the right ones to do all the jobs properly.

I consider early 911's to be classic cars, and as such need to be treated with a little more respect than perhaps an SC- not saying they don't require it also!

The longevity of the engines is indeed an issue, and lots of words have been said on it. I suggest you read Bruce Andersons 911 Performance hand book for the low down on the problems of each model.

I have heard that the magnesium motors are getting long in the tooth now, but quite what that means in metallurgy terms is a difficult question. Go to Paul Wier's web page to get some understanding on the machining requirements (especially the 2.7's) of these blocks after the've had a long hard life.

The bottom line is Porsche motors are built to last. They're strong and mostly reliable. I doubt they have nearly as many problems as equivalent manufacturers, they sound awesome and are beautiful to look at. Magnesuim is an awesome product even if outdated now. It's a work of art. Mahle (the block's makers) won a Magnesuim design award for the largest die casting of its type in the world at the time. That's cool! So is the MFI unit. Annoying sometimes, but definately a marvel. I often pop the engine cover and look at what lays within just for the pure pleasure........

Other people on this board have different ideas and different models. Listen to what they say and make up your own mind. It will be your car after all.

Good luck!



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'72 911 TE

2.4 / 2.7 MFI engines will last about 125,000 miles between rebuilds. Not as bullet proof as an SC, but nearly so, due to plenty of fuel to cool the forged heads and the lower displacement engine. Just make sure you have a radiator type front oil cooler, change the oil every 1,000 miles and you'll be fine.

Randy

'72 S, '72 R/3.2