Engine/tranny compatibility

[Kwlittle]

Folks

I'm reassembling a 1969 body with parts from various Spider generations all provided by the former owner. Of the two engines, one is a rebuilt 1756 cc Lancia engine that former owner assured me was "identical to the Fiat engines". Except that when I tried to mate up the transmission input shaft to the Lancia engine, the input shaft is slightly larger than the receiving hole in the 1756 engine. So, I'm wondering whether the Lancia engine is not in fact compatible, or perhaps even a Fiat 1756 engine isn't compatible with this transmission either? The input shaft does fit the receptacle on another (1400 cc I believe) engine that came with this package, but that engine is of unknown condition. (It is not frozen up is all I know.).

Thoughts? How can I use the larger, rebuilt engine with this transmission? If I overcome this obstacle, are there more incompability problems lurking ahead? (The engine blocks are currently separate from heads, water pumps, etc.). Could,I have a machine shop take a small amount off the shaft to fit?

Thanks for any insights and suggestions.

[seabeelt]

Engine height in relation to the hood. I think one of the venders sells shorter engine mounts to compensate. Later cars with larger size engined had bumps in the hood to accommodate some of these issues. Namely the distributor I think

[Kwlittle]

Good point that I'll check on. Thanks. Right now my concern is how to fit tranny to engine given the slightly different male/female diameters on the input shaft and receptacle.

[bradartigue]

The Lancia and FIAT 1756cc engines are essentially identical...but the devil is in the details. Some Lancias were transverse mounted and had things like camboxes with a different tilt (to keep the oil level when at a tilt) and some had transaxles and didn't mount up like the inline engines did. So "it depends" on what car that Lancia block came from.

Easiest solution if the motor is out may be to get a 1756cc crankshaft from a FIAT that fits your transmission and swap it. The basic engine block is the same between the FIAT and Lancia.

I do love P.O. testimonials though: "I never touched that fuel injection manifold" - so said the P.O. to me upon buying his car that wouldn't run. A week later the greasy fingerprints inside the manifold told a different story.

[Kwlittle]

Hmmm. Thanks, Brad. I was hoping not to have to go into the rebuilt block. What would be the harm of my Plan B, having the shaft end ground down a millimeter or so? It would seem that the shaft end itself --past the spline part that holds the pressure plate -- is not under any load.

[bradartigue]

Hmmm. Thanks, Brad. I was hoping not to have to go into the rebuilt block. What would be the harm of my Plan B, having the shaft end ground down a millimeter or so? It would seem that the shaft end itself --past the spline part that holds the pressure plate -- is not under any load.

Whatever makes it fit should be fine; replacing the crankshaft with the correct one (if you can find it) isn't hard to do either.

[vandor]

You need to have the end of the input shaft supported in the crankshaft. Measure the ID of the crank ans see if you can get
a bearing that will fit. If not then you may have to machine the end of the crank to be able to fit a bearing.

[djape1977]

lancia twincam was FWD so it doesn't have pilot bearing for gearbox input shaft.
124 gearbox needsa that bearing otherwise it will eat away at input shaft bearings at phenomenal rate

[Kwlittle]

All
For those of you following this thread, Here's some very insightful input from Jon Logan of Midwest-124, Ltd:

Use the 1756 engine....with some changes..

The block is exactly the same as that used for the 124 but the cam boxes are not. The cam boxes for the Lancia are designed with the 20 degree tilt of the engine taken into account so the exhaust cam boxe's drain-back holes for the oil are much higher up on the box and the intake cam box they are lower so the oil would not overflow. These need to be swapped out for the 124 cam boxes. Also, the Lancia's engine will have the distributor drive on the intake cam, not the exhaust so you have to use the Fiat cams if you want to use a cam driven distributor. The early 1438 cc cars ran distributors off the block on the intake side. if you plan to run with that set up, either set of cams will work but I would advise the cam box type distributor.

Now, the other item will be the flywheel and the pilot bearing. the Lancia's did not have an input shaft extending into the end of the crankshaft so to align the flywheel, they used a bronze bushing. This will need to be removed from the end of the Lancia crankshaft and replaced with a RWD pilot bearing. Once this is done, you can use the Lancia engine's flywheel mated to the 124 transmission.

Finally, the transmission bellhousing.... the 1438 cc and 1756cc engines used different flywheels. The 1438cc was much smaller (and lighter!) and used 10mm bolts and a smaller clutch. The 1756 could be either 10mm or 12mm bolts (they changed in 1976) but either way is a larger diameter. In this case, you would need to make sure the bellhousing for your transmission is not the early 1438 type, but the later/larger 1756 type. You can mix and match if your 1756cc crank has the smaller 10mm bolt holes. If so, you can mount the smaller 1438 flywheel and clutch and use the early bellhousing...

Sorry if this is confusing... There are a lot of interchangeable items but they have to be used in the proper combination...

1756 will yield MUCH more toque and driveability, and there are many more components available for the 1756 engine than the early 1438.

My reccomendation, given the 1756 longblock is known good and you have a later flywheel type 124 transmission...
1756 shortblock with camboxes and cams swapped from a 124 with distributor drive on the exhaust side. (anything really from 1608cc and later cars)
Get a points type distributor from a 1975-78 car (I have these if needed) and convert to electronic using a Pertronix Ignitor ignition set up
Run the 1756 flywheel and clutch with a correct transmission (you can even swap just the bellhousing if you have a known-good early type transmission and a questionable later gearbox, you can swap the larger bellhousing to the early box)
Pull the Lancia's crankshaft bushing with a blind hole puller and replace with a 124 pilot bearing.

Tansmission will bolt right up with those changes.

Good luck!!


Jon W. Logan
Owner, Midwest-124, Ltd.