early 901 vs late 901 for 2.7/3.0/3.2 conversion

RichMason · RichMason's Garage

I have searched all over the archives for a definitive answer on this but I haven't found one yet. I am planning an engine conversion for my 69 E and I am not sure if I can use my existing transmission. Some people have reported that the early 901 (69 and earlier) can not be mated to later engines while others seem to be using 67, 68 and 69 901s with all sorts of late model engines. Is this just a question of finding the right adapter pieces or is there a fundamental question of compatability? My preferred route is 3.2 with my existing tranny but if I need to add $1000 or more for the tranny conversion, a 2.7 RS or something like that may make more sense. I need to resolve this soon as my throttle bodies need rebuilding and that $750 could be better spent in several directions.

Also, accoring to Wayne's book, the tranny mounts are completely unavailable new for 69 and earlier cars. Is this true? Is there an aftermarket solution? If not, is this a good reason to go with a later transmission?

silverc4s · silverc4s's Garage

Rich,
Hi! Not sure if this helps you, but when I upgraded my 69er to a 73 2.4 engine, we used the flywheel, clutch, etc from the 69 2.0L, and everything bolted up fine.
On my 73 with 87 3.2L, I am using the 73 915 box, notched for the DME sensor mounting, but otherwise using 73 flywheel, clutch, etc..as best as I can recall. Good Luck with your swap!...;-)

jstobo · 03-31-2003, 08:01 AM

Rich,
The problem is the torque of the bigger engines. The 901 was not designed for the higher torgue. The mechanic I used put a 2.7 in a 68 with the 901 and they and transmission repairs until he put in a 915. If you are planning on more than the 2.7 I would seriously consider upgrading to the 915. Although I like the old shift pattern better. Have fun.

jim

Randy Webb · 03-31-2003, 02:40 PM

Rich, I am doing the same things (almost -- a 3.2 hot roded engine into my '73 car, with a 901 for the shift pattern and light wt.). If you don't drag race then the 901 should do fine. The two man issue among the 901 iterations (ie the 911) are [1] the push vs. pull clutch, and [2] the Mg case and covers of the later (911) 901 type tranny. I think your '69 would be all Al, not Mg, but that is not a big fitment problem. Both Kennedy Eng. and Patrick Motorsports make conversion clutch kits to mount the 901 with the 3.2L engines. Can you replace the entire bracket for the tranny with a newer model? The mounts are definitely available for those as I just bought some from the dealer.

- Randy (E me directly if you have either more info (I'd like to know) or have more specific queries).

chuckw951 · 04-01-2003, 06:59 AM

See post below

chuckw951 · 04-01-2003, 07:00 AM

I am in the process (still) of transplanting a 3.0 into a 69 911E

From what I understand, the 69 901 transmission will NOT bolt up to a 3.0 or 3.2. It's just not the right size. I had to use a 70/71 transmission which brings a whole new set of problems. It required the transmission (of course) a different clutch cable, a new clutch package ($450!) and a special oil line. From what I've read in 1970 porsche used a slightly larger clutch to handle the additional torque from the bigger 2.2 motor. And as you know in 1972 they switched to the 915. I am using an early oil tank and an early engine oil cooler on the 3.0 motor. I will also have to install an external oil cooler under the front fender. I should also say that I didn't look into the parts offered by Patrick Motorsports...if they have a clutch package that works, then well that's much easier! Probably worth a call.

The car still isn't running...but should be on the road soon. I will be using the CIS system. Since it is a 1982 motor it has 9.3 to 1 compression and I will be using SSI exhaust so I expect it to be very quick. To adapt the 3.0 a new fuel pump was needed and the engine wiring harness needed to be spliced to the existing harness.

RichMason · RichMason's Garage

Chuck,

I was hoping you would weigh in here as it was your email that sent me on this rant. From other posts I have read, people say that they slap the 69-69 flywheel and clutch on whatever engine they are using and just bolt them togther. What I hear from you is that there is some type of interference - either the tranny and engine case won't match up or something else is going on. Anyone else have a thought on this?

JWest · 04-01-2003, 07:50 AM

If you use an engine up to 1977, slap the '69 or earlier flywheel and clutch on and it will work in the '69 or earlier 901.

If you use a 1978 or later engine (3.0 or 3.2), you can get a conversion flywheel to use the '69 or earlier clutch. The difference is the crank to flywheel joint was changed.

Another option is to use a '70 or '71 901 trans, which uses the later style push clutch. The trans is the same except for the mounting bosses for the clutch cable and throwout arm. The flywheel from a '70 to '86 911 can be used with the clutch components from a '70 or '71.

If a 3.2 is used, notches will have to be cut in the bellhousing to clear the DME sensors.

'69 901s are magnesium. Earlier ('68 and prior, I believe) were aluminum.

RichMason · RichMason's Garage

There's the answer I was looking for. Thanks James. I assume the adapter flywheels come from Kennedy or Patrick.

JWest · 04-01-2003, 08:28 AM

I believe that Wayne has them here under the 914/6 conversion section - I don't know who actually modifies them (I think it as a machined and redrilled early flywheel).

steveW · steveW's Garage

What box was on the 'R' surely it was a 901 derivative and that motor had beeeg horses?

RichMason · RichMason's Garage

It looks like Pelican has the 3.0 flywheels but not 3.2s.

JWest · 04-01-2003, 12:46 PM

My mistake, the 3.2 needs the sensors ring gear. Check those other places - one of them has it.

Jim Smolka · 04-01-2003, 06:25 PM

Kennedy Engr has the 3.2 clutch assy to mate to a 901 gear box...

Alan.UK · 04-02-2003, 02:00 AM

Hi all,

I have been following this thread, as it is something I am considering. From what I have read it seems that the 69 901 box can be used if you buy an adapted fly wheel and then use the 69T clutch.

This leads on to my questions. I know this has been touched on before but is the 69 box up to the job of running a 3.0. I am looking at potentially using a later 204 bhp 3.0 with an early SSSi exhaust system and webers. Also is the 69 clutch strong enough.

But you can use a 70/71 pull type 901 box but this requires a different clutch cable and the associated clutch.

Or you can fit a 915 box, heavier and requires some hammering to fit into an early car.

Finally is there anything else I would need to consider in using the 3.0, ie tach, temp gauge, oil pipes... Also will the 3.0 need any extra front wing cooling or is the standard single oil cooler ok.

Sorry to ask so many questions. Beats working anyway!!

Any advice is much appreciated.

Alan.UK

JWest · 04-02-2003, 05:44 AM

Alan, as to the 901 handling the torque of the 3.0, that is a debate that will never have a definitive answer.

There are many 914s running around with 3.0s and 3.2s and the 901s last just fine, other people destroy 901s with an 80 hp 4 cyl. First gear should never be abused in a 901, the rest of the box seems to hold up OK most of the time. Otto races a big six with a 901 and swears by it, other people say they have killed 3 or 4 of them.

But, 901s are cheap to replace and shift easier than 915s (and they have a cooler shift pattern

). It just depends how you plan to drive (abuse) the car and how much risk you are willing to take that it might break one day.

You can get push clutches from Kennedy that will hold more torque.

Not sure if anything special is needed to do the tach - I have heard different things - do a search. You need to use the temp and pressure senders on the engine that match the gauges in the car - '69 gauges use the '69 senders ont he 3.0 engine.