Would a Boxster/Cayman engine fit an early 911?

somnas · 10:45 AM

Hi there,

I'm trying to pursue the dream of building a reliable early 911, but it has proven difficult to find a nice 3.2 engine with some sort of history on paper.

Therefore I'm looking into the possibility of building a car on a chassi from a 1974-1986 911 with one of the new Boxster or Cayman engines, the MA1.22 or .23 (2.7 and 3.4l), with the manual 6 speed gearbox.

EDIT: A key reason for doing so is that I want to keep the car for as long as possible, hopefully 10-15 years. If I were just planning on keeping it for a year things would be different.

I'm working on the water cooling plumbing, but I'm positive I will solve that.

As I have no access to these new engines or the outer dimension specs of them, can anyone help me with some input?

The first problem: Will the engine fit the engine bay?
Second problem: Will the gearbox be short enough to clear the torsion bar?

All help appreciated, and if the grammar is a bit off it's because I'm Swedish.

Thanks

Erik

Charles Freeborn · Charles Freeborn's Garage

In a word, yes. Anything is possible. Just bring money.... lots of money...

gtc · gtc's Garage

1. They won't fit.
2. They aren't reliable.
To fix those two problems you would spend more time or money than if you simply purchased/built a good stock engine and transmission.

chrisbruck · chrisbruck's Garage

I think a 3.2 would be a whole lot easier to deal with. Simpler to work on even if you find a sketchy engine and need to rebuild, more reliable than a newer water pumper, and more or less should bolt right in.

Not saying you couldn't make the other engine fit..... get ready to custom fab pretty much everything to make it work.

somnas · 03-03-2017, 10:32 AM

Thank you for the answers. If I may ask, saying "it won't fit", could you elaborate on that? Everyone realizes it wouldn't be a bolt on fit, but would require cutting and reorganize the whole frame? I'm a good welder and confident I would be able to fabricate a nice engine mount, but I don't want to reconstruct the whole frame/chassi.

Also interesting the comments about the new ones not being reliable. I know about the M96/97 problems, but they seem to be solved with the new ones.

One key fact I forgot to mention: I'm planning to keep this car for as long as possible, hopefully 10-15 years. That's why I'm investigating the possibility to add a drivetrain that will be serviceable for reasonable money in the future.
The 3.2 engines are approaching 40 years old...

DaveE · 03-03-2017, 10:45 AM

You'd need to fab some sort of front transaxle mount. A watercooled 911 transaxle would save you the issue of swapping the ring/pinion, although I'm not sure it's a big issue in those gearboxes. I think the watercooled gearboxes are longer than say a 915, but I also think the engines are shorter so total length may not be a problem. If it is you could go with coilovers in the rear and do away with the torsion tube I think?

darrin · 11:04 AM

since the boxter/cayman is mid engined with the engine in front of the transaxle, how would this work when the engine's installed behind the transaxle (suspect that's where the watercooled 911 r/p comes into play)? Also, would one be able to handle the hydraulic clutch using an 87-89 carrera pedalbox, or would that need to be fabbed up too? And, how would one go about fabbing exhaust headers/etc. -- seems this too would require starting from scratch.

Seems from a $$$$ (and fabbing and time/etc.) standpoint, that the OP would like come out WAY ahead by finding a 3.2 carrera engine (even if in unknown/poor shape), having it completely rebuilt to spec (or hotrodded with bigger p/c, dual plugs/etc.) by a reputable engine builder and getting it shipped (ready to go) to sweden for installation behind a stock 915 transmission.

porschenut · 03-03-2017, 11:56 AM

With so much custom fabbing required, including radiator, plumbing and hydraulics, I don't see how a Franken-car is going to end up being more reliable than just using an aircooled 911 engine. Buy a tired 3.2 and rebuild it. It will be as reliable as any new engine, will cost a lot less than what you are proposing, and will take about 1/4 of the time. Also, the car will retain more of its value in 10-15 years and would be serviceable by any shop or DIYer with the usual manuals.

timchar · timchar's Garage

3.2's are around... Be patient and start looking. Tim

J-Mac · J-Mac's Garage

I'm pretty sure you could buy Dan's completely rebuilt 3.2 engine F.S. 3.2 Carrera engine. (complete) and have it shipped to Sweden for way less than it would cost to install a boxster/cayman engine.

darrin · 03-03-2017, 01:18 PM

Quote:

Originally Posted by J-Mac

I'm pretty sure you could buy Dan's completely rebuilt 3.2 engine F.S. 3.2 Carrera engine. (complete) and have it shipped to Sweden for way less than it would cost to install a boxster/cayman engine.

don't rule out a 3.6 from a 964/993 -- VERY straightforward conversion for these too

J-Mac · J-Mac's Garage

Exactly. I meant you could spend $30k on an aircooled engine and still be ahead costwise versus the waterpumper install cost.

pmax · pmax's Garage

Quote:

Originally Posted by somnas

One key fact I forgot to mention: I'm planning to keep this car for as long as possible, hopefully 10-15 years. That's why I'm investigating the possibility to add a drivetrain that will be serviceable for reasonable money in the future.

No crystal ball here to predict future servicing costs for the aircooled but the recent trend has not been promising.

However, assuming all the WC plumbing issues and related fabwork are taken care of, I would do this instead of using the Boxster6. Looks like it fits nicely and mates up with the 915 as well.

putting a 3.3 in my SC

And if cost is no object ...

PVX build thread: one view from the slope

LakeCleElum · 03-03-2017, 02:33 PM

Quote:

Originally Posted by timchar

3.2's are around... Be patient and start looking. Tim

It took me a year of patience to find a great high compression 3.2 for my 73.5. I'm very happy with the result. You could buy a core 3.2 and have it rebuilt for less time/trouble/money of going the Boxster route.

Cook&Dunning · 03-03-2017, 03:20 PM

Is the Subaru motor the same/similar to the Toyota supplied motor to Lotus? This seems worth checking out. Some threads on Subaru gearbox here on Pelican.
Interesting stuff.

Sboxin · Sboxin's Garage

Erik,
This friend's car has a 996 engine and transmission with lots of water plumbing.
Yes, it fits and it is fast. They sold it after racing for 2 seasons.

I don't have any better pictures of the engine layout.
Good luck with your project.

Regards,

dicklague · dicklague's Garage

A reliable 911? the 911 is reliable.

Buy a good one and enjoy it. Why ruin a good aircooled car with one of them watercooled engines??? Makes no sense......and ruins the value of the car.

targa44 · 03-03-2017, 09:08 PM

I seem to recall someone getting ready to put a 911 shell on a Boxster - a year or so ago. Always wondered what happened to that project. If you've got good welding skills - cut down the middle and make a wider 911 on a great platform.

dicklague · dicklague's Garage

Quote:

Originally Posted by targa44

I seem to recall someone getting ready to put a 911 shell on a Boxster - a year or so ago. Always wondered what happened to that project. If you've got good welding skills - cut down the middle and make a wider 911 on a great platform.

maybe less work than putting a boxster engine in a 911!!!!!

kent olsen · kent olsen's Garage

I too was looking for a reliable engine for my 1972 911. The most reliable engines I saw was the 3.0L aluminum cases. I bought one from a wreck and built it with all the later upgrades that add reliability. I built it to drive to the track for DE's and drive home, just changing the oil and adjusting the valves once a year. It gets driven a lot. I have about 16,000 on the engine (238,000 on the chassis) and it has been bullet proof.

This car will never be sold, it will be given to my grandson.