Engine and transmission compatibility.

[Wodza]

I am putting an 1800cc pulled from a 78 in my 73 spider 124. The engine I pulled out of the 73 is a 1592cc 132ac.40.3. My question is what would make the most sense to do. Use the engine and transmission combo from the 78? Or bolt the ‘78 1800cc to the 1973 transmission? Or does it matter? I’m looking for the easiest swap I can as all of this is very new to me.

The engine swap is happening because the 1592cc needs a rebuild, I can’t afford that right now, and I thought I might as well update to 1800 or 2L. So I found a used 1800cc.

[18Fiatsandcounting]

The short answer is that I think all the components you're talking about are "interchangeable", so I don't think it matters. The longer answer is that I would pick the transmission that is in the best shape in terms of synchros, bearings, etc. If it were me, I'd go ahead and rebuild the engine and transmission, but I understand if that option isn't in your budget at this point.

One question: Do you know that the 1800 engine doesn't also need a rebuild? If so, you're kinda back to square one, but with a larger engine.

I do suggest putting in a new clutch while you have the engine and transmission removed. Clutch disc, pressure plate, and throwout bearing.

-Bryan

[Wodza]

Thanks Bryan,

You’re right, I don’t know for sure if the 1800 needs a rebuild, but we were able to turn it over with the starter in the rusted out donor car and it had good compression throughout all cylinders. I was able to drive with the old 1600cc engine for a while before it went and the transmission worked well. My thought is that I’m hoping I can get some use out of the 1800 without needing a rebuild but if I do need to rebuild it at least I’ll be rebuilding an 1800 instead of the 1600. Thank you for the response.
Ryan

[18Fiatsandcounting]

Ryan, this is Bryan.

Since you know the transmission is good in your '73, I'd stick with that rather than go with the riskier transmission from the 1800 car (while this transmission might be just fine, you don't know for sure). While there are some unknowns in installing the 1800 engine, such as bearings, head gasket (coolant or oil issues), general condition of oil seals and gaskets, and so forth, it's worth a try.

There may be differences in emission control plumbing and such between the 1592 and 1800 engines, but you can sort that out.

-Bryan

[SteinOnkel]

I would recommend a leak-down test on both engines and then decide.

On the other hand, as the old saying goes...there ain't no replacement for displacement...doggonit.

[Wodza]

I’ve already done a leak down test on the 1600. It failed horribly. Why I haven’t done one on the 1800 yet I can’t say. I had the head off and should have done it right there and then. Maybe I’ll pop it off again and do that.
Thanks.