Technical Start 126A engine with no transmission attached?

[kcjeeves]

After many years of my 500f sitting in the garage, I finally have some time to spend on it. It's got an original running 110f motor in it, with what I believe is a failing/failed generator, plus the generator bracket has broken as well. I've also got an old 126A motor sitting on my shelf, that we found in a chicken coop in Italy, and brought back in our HHGs, lol. Anyway, it's got an alternator and of course almost 100cc more oomph.

Since replacing the generator on my installed motor, more than likely "should" require removing it from the car, I figured it might be a good time to see if the 126A is worth looking into as a straight swap, but I'm curious on how you can get it running if it needs to be attached to a transmission since that's where the starters are mounted.

First thought was an impact driver on the crank pulley, but of course that won't work since the oil filter is there, is there a flywheel bolt that would do the same? but then once the motor starts, you've got to be pretty quick on the draw to get your impact off the bolt before the engine carries it off.

Thoughts?

 

[fiat500]

After many years of my 500f sitting in the garage, I finally have some time to spend on it. It's got an original running 110f motor in it, with what I believe is a failing/failed generator, plus the generator bracket has broken as well. I've also got an old 126A motor sitting on my shelf, that we found in a chicken coop in Italy, and brought back in our HHGs, lol. Anyway, it's got an alternator and of course almost 100cc more oomph.

Since replacing the generator on my installed motor, more than likely "should" require removing it from the car, I figured it might be a good time to see if the 126A is worth looking into as a straight swap, but I'm curious on how you can get it running if it needs to be attached to a transmission since that's where the starters are mounted.

First thought was an impact driver on the crank pulley, but of course that won't work since the oil filter is there, is there a flywheel bolt that would do the same? but then once the motor starts, you've got to be pretty quick on the draw to get your impact off the bolt before the engine carries it off.

Thoughts?

If you have the starter-motor, but not the transmission, you can still bolt the motor to the engine and use a few washers as spacers under the bolt-heads t make up for the missing thickness of aluminium.

 

[the hobbler]

After many years of my 500f sitting in the garage, I finally have some time to spend on it. It's got an original running 110f motor in it, with what I believe is a failing/failed generator, plus the generator bracket has broken as well. I've also got an old 126A motor sitting on my shelf, that we found in a chicken coop in Italy, and brought back in our HHGs, lol. Anyway, it's got an alternator and of course almost 100cc more oomph.

Since replacing the generator on my installed motor, more than likely "should" require removing it from the car, I figured it might be a good time to see if the 126A is worth looking into as a straight swap, but I'm curious on how you can get it running if it needs to be attached to a transmission since that's where the starters are mounted.

First thought was an impact driver on the crank pulley, but of course that won't work since the oil filter is there, is there a flywheel bolt that would do the same? but then once the motor starts, you've got to be pretty quick on the draw to get your impact off the bolt before the engine carries it off.

Thoughts?

For a start the 126A engine is NOT a straight swap with the 500 engine. You will require a 126 bell-housing and starter assembly. With these fitted, you will be able to start and (hopefully) get the 126A engine running. Being that you are the other side of that large pond, these parts are not readily available, or easy to find. I can supply you with a company in the UK who probably would be able to supply the required parts ( but 2nd hand). If you DO get the 126A engine running, the 126 bell-housing can be fitted to the normal 500 gearbox---it is not too difficult a job. In the meantime, there is always the option that Peter suggested---take the starter off the 500 and see if you can fit it too the 126A engine, using washers to replace the thickness of the bell-housing and space the starter out.

 

[kcjeeves]

For a start the 126A engine is NOT a straight swap with the 500 engine. You will require a 126 bell-housing and starter assembly. With these fitted, you will be able to start and (hopefully) get the 126A engine running. Being that you are the other side of that large pond, these parts are not readily available, or easy to find. I can supply you with a company in the UK who probably would be able to supply the required parts ( but 2nd hand). If you DO get the 126A engine running, the 126 bell-housing can be fitted to the normal 500 gearbox---it is not too difficult a job. In the meantime, there is always the option that Peter suggested---take the starter off the 500 and see if you can fit it too the 126A engine, using washers to replace the thickness of the bell-housing and space the starter out.

well, guess it's kinda lucky that I also have the accompanying transmission and bellhousing from that 126A motor as well, lol. Any advantages to using the 126A transmission vice the standard 500 tranny? Did they use a different starter than the 500?

 

[the hobbler]

well, guess it's kinda lucky that I also have the accompanying transmission and bellhousing from that 126A motor as well, lol. Any advantages to using the 126A transmission vice the standard 500 tranny? Did they use a different starter than the 500?

The starter on the 500 (110) engine sits on top of the bell-housing, whereas the 126 starter sits at the right-hand side of the engine (looking from the REAR) The starters are different and bolt on slighty differently.The 126 gearbox will fit into the engine bay, no problem as long as you remember to change the drive-shafts---the 126 shafts are too long (by about 1-1/2ins each side).This is not a difficult job, just a bit tedious. Being that you have the 126 bell-housing, I would suggest that you remove it from the body of the gearbox (which you will have to do anyway to fit the 500 drive-shafts) and obtain a 126 'PULL' starter, dust-shield, back-of-starter brace and 126 specific "3rd bolt" for the starter. In many ways, the original 500 gearbox is better than the 126 box. Sure, you have to double-de-clutch on down shifts, but that is no problem. The 126 diff will fit into the 500 box, thereby giving you a slightly higher final-drive ratio.

 

[fiat500]

well, guess it's kinda lucky that I also have the accompanying transmission and bellhousing from that 126A motor as well, lol. Any advantages to using the 126A transmission vice the standard 500 tranny? Did they use a different starter than the 500?

...you get synchro on three gears (if you're lucky). . Depending on age, you might have an option for a reversing switch and slightly better selector shaft sealing.
The 126 starter has three mounting holes, which, with the side mounting, makes for better chances of not getting cracks in the bellhousing. The starter is available in a solenoid and a cable-operated version; both types are physically interchangeable with each other.
The differential ratio is slightly different to match the increased power output, so some ( maybe all?) gear ratios are changed.
With a bigger engine, using the matching box is a no-brainer.

 

[kcjeeves]

Guess before I go swapping engines, riddle me this. With my current generator, it doesn't seem to be charging the battery, but also no batt/gen light on in the dash, could be burned out I guess. but when I disconnect the wires from the dynamo and apply 12v, it does in fact spin like a DC motor, which from what I'm hearing on youtube, means the dynamo part is good, but then when I do the "test" of jumping the two terminals and running the actual motor, or spinning it with a drill at 2k rpm, I get like 4v, coming out of it.
Can it "pass" the spin like a DC motor test, but not be able to make adequate DC voltage when running as a dynamo?

"DC voltage test" = jumping the two terminals, and measuring terminal to ground with engine running, no rectifier in use. Should be a steady climb in voltage, right?

 

[myoshik]

Regarding the engine swap, there's a few things I had to change besides those already mentioned above. I also had to change quite a few things that most people didn't seem to (e.g. cables, wires, heating tubes, the bolt studs on the timing cover, plugging the fuel return, etc. etc.)? I found several posts on this forum that were extremely helpful and got it done.

I too went through a number of electrical issues on my 500 and similar issues with my generator. I had to get it re-built. I also found that I had a faulty voltage regulator as well as a problem with the wiring, which the previous owners seem to have completely neglected.