780 Bertone D24T conversion

[v8volvo]

A little slow on the forum lately, guess everyone is busy in the summer.

Figured it might be fun to share a new project idea I am working on. My 745 and 764 are both still running (more or less) and healthy (more or less) but I now have a couple of parts cars as well, and have been trying to figure out the best use for them. I have always wanted to build up a really nice diesel Volvo 700/900 series and the two old 7's I have now are great cars but will never be "nice" (body damage, rust, etc). So I decided I wanted to figure out the right chassis to start with for one I could invest some good parts into, plus maybe be a subject for a modified engine, intercooling, exhaust, bigger turbo, etc.

I also wanted it to be a newer year Volvo than the factory diesel models we got through 1986 here. The later '80s and early '90s cars got better wiring harnesses, better interior materials, better brakes, ABS, and in some cases even limited slip differentials and independent rear suspension systems. Big improvements to the platform, in other words. I figure if I want to put some effort into something it would be nice to have some of those newer updates.

Last of all, I decided I want to start with a chassis that has a turbo gas engine and automatic trans from the factory. That will provide turbo suspension parts (sway bars, etc) and trim, which I like the look of, plus it puts the battery and airbox and ABS unit in the correct locations for easy diesel conversion. The NA 4cyl and 6cyl cars have the airbox/battery locations reversed which creates more work. I plan to run a ZF automatic behind the D24T for the swap so starting with an automatic car is preferable there.

I set out to identify a model and year that checks all the boxes above. I thought about a late 80s turbo gas 740 or 760 wagon as a starting point, but then I realized that would be somewhat redundant as I already have a wagon and don't really have a use for two. I also already have a 760 sedan and have had several 740s so didn't really see the point in going with one of those. I like the look of the 940 sedans, but they are very hard to find in good shape, and the late style '90s dash is harder to set up with diesel instruments. There is a single-year model, the 1991 940SE, that had the independent rear suspension which I am interested in trying out. I got interested in those but they're almost impossible to find and have the same challenge with dash adaptation.

Finally a new idea occurred to me: a 780 coupe. These were a limited production model from 1987 to 1991 built by Bertone in Italy. They were all automatics, had the independent rear suspension from 1988 onward, have the early type 700 series dash that a diesel cluster drops right into, mostly came with the B230FT turbo gas engine (some V6, plus some diesels in Europe), and as Volvo's top luxury model, they have all the optional features like ABS and limited slip diff in final year '91 models. They are also full of fancy Italian interior pieces and have a unique body design. I'm 50/50 on whether I really like the styling, but at least it's interesting and won't be redundant with the two other diesel cars I already have. I like the idea of having something different. And the driving experience with the coupe body and independent rear suspension should be great.

I started looking for a 780 in good condition, which turned out to be an easier task than I expected, since these coupes were bought as collector's items and tend to be preserved in ways that the workhorse sedans and wagons usually aren't. Mostly garaged, etc. So even though they were produced in small numbers, there are more good 780s left now than 740s seemingly. I found a nice 1991 needing some mechanical work not far away, in a color combo I like. Planning to pick it up in August, drive it for a while as a gasser to work out any chassis/interior bugs, then swap it next year. I will keep a project thread going!

Here is the car I'm going to be building up. Anyone ever played around with one of these?

[ngoma]

Great idea! Personally I like most all Italian automobile styling.

One thing to keep in mind is that it is a one-off body produced in small numbers so replacement parts might be hard to come by in case they are needed at some point.

[v8volvo]

Yes, that is a concern for sure. The total production was only about 7000 cars. I wanted to be sure to find one to start with that is complete and not weathered/rusty/sunbaked so that as many of those unique pieces as possible could be intact and in good shape, but in the event of any kind of damage or even routine wear I know it will be a challenge to find replacements. You are right that not only is every body panel and trim piece special to the 780, most of the interior pieces are as well.

The main saving grace is that at least all of the mechanical parts are standard 740 parts bin items so if I can just keep the body and interior in good shape, keeping the rest of the car going should be no challenge.

And the other saving grace is that the worldwide 780 guru (runs the owners' community at 780coupe.com and has a barn full of spare parts and parts cars) is located not far away in Boise Idaho -- and the car I am set to buy is one of his that he is selling, with the understanding that if spares are needed he can help. So hopefully that arrangement lasts as that gives me more confidence. These worries were what has always kept me from ever seriously considering one of these cars in the past but I think given the circumstances it's about the best situation I could hope for to own one for long term.

We'll see. I will be curious how the Italian coachwork holds up to age vs the regular Swedish-built Volvos of the same era. They were supposedly assembled to a high standard of finish when new. Price for these new in '91 was almost $45k.... Over $100k in today's dollars, so premium iron one way or another.

[ngoma]

Originally Posted by v8volvo

And the other saving grace is that the worldwide 780 guru (runs the owners' community at 780coupe.com and has a barn full of spare parts and parts cars) is located not far away in Boise Idaho -- and the car I am set to buy is one of his that he is selling, with the understanding that if spares are needed he can help. So hopefully that arrangement lasts as that gives me more confidence.

OK, looks like you have the most vexing possible downside mitigated-- Proceed with my blessing!

My experience with several 60s-80s era Italian cars is that the design priorities were (in descending order): 1. Performance; 2. Style; 3. Functional. Inventive solutions were abundantly evident, and (contrary to popular stereotype) the workmanship and choice of materials was actually quite high. OTOH, there was a run of Fiat 128s that used Russian steel that decomposed in no time though.

[Goteborg Vapenfabrik]

https://greenbay.craigslist.org/cto/...770948507.html

A D24T/ZF4HP22 in a 164. No more broken power steering brackets, a small benefit to what would no doubt be an enormous customization and adaptation project. This 164 is a very nice candidate.

[Goteborg Vapenfabrik]

Scratch that benefit of no power steering. This 164 has power steering. I had a 1970 145S, no power steering, with a big steering wheel, it was no strain steering it.

[v8volvo]

Always have liked the 164 for sure. A swap into one of them would be interesting. Not sure how it would work out with the different front suspension on the 1xx series cars. No factory 2xx series mounting provisions would work to bolt in the engine so yes big custom project no doubt. At that point you could swap the engine and trans into just about anything.

Part of the hope with this 780 Bertone project is that it would be doable using all standard 700 series TD factory parts.... everything from mounting and driveline pieces to plumbing for inlet, exhaust, fuel, cooling, A/C, etc, using the donor 744 I mentioned plus a few other pieces as needed that I have been sitting on and need to put to use somehow. One of those is a 16-valve front crossmember that is the updated style to prevent cracking so that will go into it and avoid that issue out of the gate. The only unusual step I think might be necessary will involve the driveline, since the rear half of the driveshaft might be different for the independent rear end in the 780. I may need to take a diesel front half (to mate up the ZF trans in place of the gasser AW71) and the 780 rear half and combine them, then have the assembly balanced to match the new front and rear sections to each other.

Once done, it should be a nice cruising car, much smoother than it came from the factory with the redblock 4-banger gas engine and hopefully with some tweaks approach the same performance as the stock turbo gasser. I might look at adding an intercooler to this and maybe a few other changes to improve output.

Scheduled to pick up the Bertone coupe in about three weeks and see what I am starting with. Should be fun to get to know it. Interesting comments on the trends of Italian vehicle production. This will certainly be the first vehicle of any Italian background I have ever owned, so a new venture for me. Obviously lots of heritage for performance cars from Italy so a nice tradition there. The reputation in my mind is for beautiful and exciting designs handicapped by fragility and quality problems, although it sounds like you suggest some of that is undeserved. Either way that is the opposite of the standard Volvo stereotype -- solid but dull -- so it is an interesting marriage and I will be curious to see what the cultural combination is like.