[Kjetil]

Hello,
I have a -66 Duetto with the original clutch/gearbox and a 1750 engine. The gearbox is worn and I have another in good shape. The problem is however that I have the old mechanical clutch actuation while my "new" gearbox requires a hydraulic clutch actuation. I do have all the hydraulic parts needed except for the -69 pedal box, which I understand is hard to source.

I believe quite a few of you out there have experienced the same issue. Do you have some experience to share?

 

[Bill S]

Your new gearbox does not require hydraulic clutch actuation if you use the bellhousing from your old gearbox. There are a couple of changes to make: different bellhousing seal for the input shaft and adapt the reverse light switch actuation for a short rod tranny but it's a LOT easier than installing a hydraulic clutch. If this car was already running with a 1750 then there shouldn't be any issues with the flywheel and ring gear.

Usually, it's people installing a 2L engine in an early 105 that switch to a hydraulic clutch. The 1750 has an eight bolt flywheel like the 1600 and 1300, which makes it a lot easier.

 

[Kjetil]

Thanks, that's good news! What about the thrust bearing? Can I use the old one or do I need to do some modifications?

 

[60sRacer]

Choice of thrust bearing has to do with the clutch disc, nothing about the TX behind it. If you have the diaphram disc (hydraulic) with the 1750 flywheel, use the mechanical linkage and get a TO bearing adapter from Centerline. This adapts a hydraulic clutch TO bearing to fit in the fork of the mechanical clutch. BTW - I prefer this for racing use anyway. Much more positive feel of the clutch then ever possible with the hydraulic unit. Keep your 66 bell housing (mecanical clutch fork and linkage).

Robert

 

[Bill S]

Nope, use the mechanical clutch throwout bearing and clutch fork and you'll be fine. I'll see if I can find the part number for the different bellhousing seal that you'll need.

Have a look at your replacement transmission and see if it has the long or short actuation rods to see if you'll need to do any mods to your mechanical clutch bellhousing for the reverse light switch. Alfa changed from long to short rods around '74. If the newer transmission still has the bellhousing attached, see if the reverse light switch screws directly into the bell or if it is mounted on a bracket.

Thanks, that's good news! What about the thrust bearing? Can I use the old one or do I need to do some modifications?

 

[Kjetil]

Even better! I believe there are 2 different spacers. One is a few millimetres thick while the other is more like sheet metal. The original gearbox/flywheel use the thick one.

Kjetil

 

[tom shewchuk]

The pedal boxes are the same from '66 to '69.

 

[Alfajay]

The pedal boxes are the same from '66 to '69.

No Tom, they aren't. At least not for US model cars:

- From the earliest 105's through the 1967 model year - that is, all cars that came with 1600cc engines - the pedal box is designed for mechanical clutch actuation.

- The 1969 model year only - first year for the 1750's - the pedal box supports hydraulic clutch actuation. The '69 boxes have a shaft & bushing that extends toward the outside of the car, through the frame rail. There is a lever at the end of that shaft that operates a long pushrod and in turn, the clutch master (see first photo below). The clutch master is bolted to the outside of the frame rail underneath the driver's seat (see second photo below).

All this may be different on European and Canadian cars. Certainly different on RHD cars.

For people wanting to put 2 liter engines (or 1750's with the big clutch) into a 1600 105 chassis, the '69 pedal box and clutch master, plus a few holes through the frame, solves the problem.

 

[60sRacer]

Don't need nearly so much stuff. To put a 2L engine in a 1600 body, you use the mechanical clutch bell housing and its transmission. The 2L engine has a diaphram clutch plate; You use the mechanical linkage and fork, and add an adapter for the throwout bearing - Centerline has them. This uses the diaphram clutch TO bearing. Here's the piece - currently listed at $170.

Another choice is to use a flywheel adapted for the swap. Alfaholics (maybe others) makes a really neat lightweight aluminum flywheel that fits the 2L crankshaft but uses the mechanical clutch pressure plate and disc. Somewhere in the $500 to $700 range, and you get all the benes of a super strong and super light flywheel.

 

[Alfajay]

Don't need nearly so much stuff. To put a 2L engine in a 1600 body, you use the mechanical clutch bell housing and its transmission. The 2L engine has a diaphram clutch plate; You use the mechanical linkage and fork, and add an adapter for the throwout bearing - Centerline has them. This uses the diaphram clutch TO bearing. Here's the piece - currently listed at $170.

Another choice is to use a flywheel adapted for the swap. Alfaholics (maybe others) makes a really neat lightweight aluminum flywheel that fits the 2L crankshaft but uses the mechanical clutch pressure plate and disc. Somewhere in the $500 to $700 range, and you get all the benes of a super strong and super light flywheel.

Well, we all have our preferences. Sure, that approach will work also.

But, what do you mean "all that stuff"??

Your approach requires that the 2L flywheel be machined down to accept a 1600 ring gear. A 1600 ring gear cost $150 and the TO bearing adapter cost $170. And the machining will cost something. Or you can spend $532 (325 GBP) on that custom flywheel plus $170 for the TO bearing adapter.

And after all that, you're forced to use a puny starter designed for a 1600cc engine to crank over your high compression two liter.

My way uses factory two liter components throughout the drivetrain. Sure, you have to source a '69 pedal box (which admittedly isn't easy), buy a clutch master cylinder, drill three holes in the chassis, and run some hydraulic lines. But to me, the benefits of going with the hydraulic clutch outweigh the cost and effort required.

 

[60sRacer]

No fussing with the ring gear. Just get one of the 1.1 HP late 2L starters along with its support bracket (for the engine mount end) to use with the 2L flywheel. You only have two bolt holes in the bell housing, but the it all fits just fine. Mine has worked great for 30+years.

There are some benefits to using the Alfaholics lightweight flywheel, but that is a separate issue.

Personally I find the mechanical linkage more precise and better feel than the hydraulic.

Robert

 

[Alfajay]

No fussing with the ring gear. Just get one of the 1.1 HP late 2L starters along with its support bracket (for the engine mount end) to use with the 2L flywheel. You only have two bolt holes in the bell housing, but the it all fits just fine.

Robert:

Hmm, that's interesting. So you are saying that the distance from the axis of the crankshaft out to the axis of the starter is the same on a 1600 bellhousing designed for a 105 tooth ring gear as it is on a 2L bellhousing designed for a 131 tooth ring gear. I must admit that I have never measured this, and just assumed that the 105 tooth RG was smaller in diameter than the 131.

So even though the blurb in the Centerline catalog about the TO bearing adapter says that you need to swap ring gears, you're saying that you really don't. Here's the relevant text from the CL catalog, which can be found at: http://www.centerlinealfa.com/cgi-local/SoftCart.exe/online-store/scstore/p-CP501.html?L+scstore+hbbc5738ffd467d4+1314557796

Our adapter is designed to allow the use of a 1750/2000 engine and clutch in a 750, 101, or 105 chassis Alfa. ....... This requires machining a 1750/2000 flywheel to accept a 1300/1600 starter ring-gear.

I like your approach of using the 1.1hp starter with the front brace - the brace sort of compensates for the 1600 bellhousing having only two starter mounting holes. Even someone performing this type of swap using an early 2L engine (which came with a .7hp starter, 130 tooth RG, and no front brace) should probably fabricate a front starter brace to reduce the liklihood of bellhousing fracture.

 

[60sRacer]

...So you are saying that the distance from the axis of the crankshaft out to the axis of the starter is the same on a 1600 bellhousing designed for a 105 tooth ring gear as it is on a 2L bellhousing designed for a 131 tooth ring gear. I must admit that I have never measured this, and just assumed that the 105 tooth RG was smaller in diameter than the 131.

I confess I didn't measure either. But it bolted together fine and has worked without problem since installed in ca 1980 something.

Robert