850 Engine swap?

He had it for sale here without the G13B twincam.

Other things of note in that thread if you go farther back are the techniques he used to replicate missing parts/rusted panels which was pretty smart.
 
I know this is almost two years after the OP asked about engine swaps, but a Honda D16Z6 rotates the proper way, is fuel injected, and makes 125ish stock horsepower. With modern maniacs turbocharging these things, there's no reasonable upper limit on available power.
 
With no real experience but having had a number of conversations about engine swaps, in general, and having read this thread several times, it seems like the first critical decision is whether to retain the Fiat transaxle or switch over to a VW transaxle. The VW transaxle would seem to offer more engine options, more gear ratios, greater strength, and call for relatively little fabrication or modification of the body. I do suspect that a significantly larger engine would require a larger radiator in the front of the car. But perhaps that could be avoided with a slightly larger radiator in the stock location and greater air draw.
 
I know this is almost two years after the OP asked about engine swaps, but a Honda D16Z6 rotates the proper way, is fuel injected, and makes 125ish stock horsepower. With modern maniacs turbocharging these things, there's no reasonable upper limit on available power.
I do not know anything about the 850 and I realize this thread is about a 850 engine swap, but the mention of a Honda "D" engine is interesting with regards to the X1/9 also (sorry if I'm going off topic). For the X we've seen a number of Honda "K" swaps, and some Honda "B" swaps, but no "D" swaps. And in general I haven't heard much about the Honda "D" engines. As I understand it, in the past they weren't extremely popular for performance applications (in any car) due to having a lower power output than other Hondas. However the cost of "K's" has gone up considerably and the "B's" are getting harder to find. While the "D's" are plentiful and cheap....like the "B's" used to be. Therefore lately it seems the "D" is becoming more popular as performance mods and aftermarket support grows for it. The relatively low compression ratio and strong bottom end makes it a excellent candidate for a small turbo addition (as @fiatrn said). Plus it is smaller and lighter than the "K". Therefore it might be a good option for a affordable swap - 850 or X.
 
VW transaxles are starting to get scarce and expensive. A cheaper and better alternative would be an Audi gearbox from one of the inline models and go straight to a mid-engine conversion. Better than a big lump hanging out the back!
 
I installed a 124 twin cam, but had to go mid engine to make the direction of rotation correct. Really had to cut it apart and rebuild. Bell housing and clutch was easy to get. Never could get the shift linkage right. Would never do it again.
 
I installed a 124 twin cam, but had to go mid engine to make the direction of rotation correct. Really had to cut it apart and rebuild. Bell housing and clutch was easy to get. Never could get the shift linkage right. Would never do it again.
Why didn’t you reverse the rotation of the twin cam? That’s been done many times.
 
I found this video on YouTube. They put a Subaru 1.8 into a 500. It fits.They did not describe thetransmiion but it surely is not the Fiat's because the revs are audibly low. Another vide that is eluding me today had the entire subary drivetrain in the Fit 500. They reversed the rotation of the transaxle using a kit from ........ The car still had its rear seat and they noted thaat the package fitted easily. I know the 500 has its fuel tnk in front and that might be an issue with an 850 Spider but,the 500 is a much smaller car.
 
So, I have learned abit more about this. The company making Subary transaxle reverse kit is Subarugears, in Australia.They can also remanufacture a revers transmission an d axle for you. $$$$$$. Manual transmission require a reverse ring and pinion. Automatic transmissions are reversed via the interlocked gears just forward of the transfer case being switched out totwo sprkets and a chain.
Subaru engines in VW beetles are relatively common and connect the engine to a VW transmission via a kit built by Kennedy Engineering , here in the U.S. There also exist Subary to VW engine and transmision mount kits which, while surely requiring modification, could still simplify the process. The Subaru engine is 28.5 inches wide which should fit, albeit closely, between the fiat frame rails that are set about 36 inches apart.
That's all I got for now.
 
So, I have learned abit more about this. The company making Subary transaxle reverse kit is Subarugears, in Australia.They can also remanufacture a revers transmission an d axle for you. $$$$$$. Manual transmission require a reverse ring and pinion. Automatic transmissions are reversed via the interlocked gears just forward of the transfer case being switched out totwo sprkets and a chain.
Subaru engines in VW beetles are relatively common and connect the engine to a VW transmission via a kit built by Kennedy Engineering , here in the U.S. There also exist Subary to VW engine and transmision mount kits which, while surely requiring modification, could still simplify the process. The Subaru engine is 28.5 inches wide which should fit, albeit closely, between the fiat frame rails that are set about 36 inches apart.
That's all I got for now.
I hope that you eventually come to your senses. There is a shrinking number of running 850's. If you've got an incurable urge to do an engine swap, why not a chevy v8 into that subaru? Nobody will miss another subaru.
 
Last edited:
Hi everyone! I’m new to this forum and this is my first post. I’ve been looking into buying a classic Italian spider. There’s an 850 that got my attention…
Car doesn’t run and floors need to be replaced.
Trying to get ideas for an engine swap. Got some useful info reading these posts.
Was wondering if the GM 2.8 and getrag transmission from a fiero gt could be an option too.
 
Hi everyone! I’m new to this forum and this is my first post. I’ve been looking into buying a classic Italian spider. There’s an 850 that got my attention…
Car doesn’t run and floors need to be replaced.
Trying to get ideas for an engine swap. Got some useful info reading these posts.
Was wondering if the GM 2.8 and getrag transmission from a fiero gt could be an option too.
Welcome.

The 850 is a very narrow car, much narrower than the Fiero which used a transversely mounted engine and transmission. The 850 has a longitudinal engine and transmission placement meaning inline with the length of the car and in this case with the engine hanging out the back.

I am not saying it can’t be done but it would require significant rework of the car. There isn’t much room between the back of the seats to the rear wheels, there isn’t much room for an inline engine much less a V motor. Then there is the width issue. The track width of an 850 is 48” where the track width of the Fiero is 58.7”, this is the distance from the center of each of the rear wheels.

Back in the day the 124 engine was swapped into these cars, both the pushrod version and the twin cam version. I have seen a variety of engines attached to a VW transaxle installed in an 850. This transmission is often used because the ring and pinion can be flipped to accommodate a clockwise (most engines) or counterclockwise (Honda B series and a few other Japanese engines along with the 850 engine) rotation engine.

Anyway it would be a difficult swap with the real difficulty being making enough room or actually widening the car enough to fit the engine/transmission assembly.
 
Back
Top