Volvo 850 Engine Swap

2ndGenVolvos · Post by **2ndGenVolvos** » 20 Jun 2022, 13:09

Hello again everyone,

It's been about a month and a bit since my last thread where I was toying with the idea of swapping the head on my 96 850 wagon from a 10v to a 20v. In that time I ended up buying a parts car from Toyota Mississauga (Ontario Canada) and am now just going to drop the engine into my 850 since it runs much better than we first anticipated. They were going to scrap the car since they didn't want to go through the trouble of getting someone to buy it, but luckily I was able to talk them into selling it to me for what the scrap guy would have given them ($1,000 CAD). The car is a 20v NA motor with an m56 transmission, so not only do I get to swap my car to a more powerful engine, I get a manual transmission to boot.

So, the project has changed from converting the already existing engine in my car to 20v to now swapping a motor.

I have a few questions about this project before I start though. I know the subframes are the same, so I can just drop the two and bolt the s70 subframe into my 850 chassis, but I'm curious about the fuel lines. My car is currently on the Fenix 3.2 system and I would be converting it to m4.3 as that is what the 20v engines use. My question is, do I need to swap all the fuel line stuff from the engine to the pump from my 98 s70 donor car?

Also, has anyone else done this swap and has any advice or words of wisdom? I have full access to a shop and will be doing most of the work on weekends.

As I'm planning out when and in what order I'll do the work, this is what I've got so far:

Week 1: pull the subframe/motor/transmission from the 98 and pull the lines, send the body to be scrapped, store the motor, etc.
Week 2: Pull the 850 engine/subframe, pull the fuel lines, and install the m4.3 lines. Then store the motor/pull whatever I can salvage/part-out and send the motor to be scrapped. (I assume I'll be able to find a buyer for the 4-speed auto transmission eventually)
Week 3: Install the motor/subframe, hook up the lines, install ECU, etc etc. (The installation process might / will probably need to be split into two weeks unless I can work on the car a couple of evenings during the week as well.)

How does this sound?

Thanks!

Post by **Chuck W** » 20 Jun 2022, 13:30

The fuel lines shouldn't be of any consequence. Both engines *should* have a couple of fittings on the back of them where the fuel lines come up from below and attach to the lines on the engine. It's just a feed and return line, so no excessive drama is probably going to be needed, regardless.

You'll want to verify where the pressure regulator is on the 98 vs the current set-up. You don't want to toss that out with the car. I think on the '98 NA cars, it's under the car in front of the right rear wheel. I seem to recall it was in the same location on the '96 NA car I had as well.

The 96-98 NA 20V motors are M4.4, not M4.3. Not much of an issue, seeing as you'll have a donor car.

Pull the '98 engine-side harness from the ECU box. Seeing as you're swapping a manual, you'll be able to remove the engine-side transmission harness completely. You can just leave the body-side alone. The manual '98 car will have blanking plates in it which you can use to block off the hole left by the engine side of the trans plug.

2ndGenVolvos · Post by **2ndGenVolvos** » 20 Jun 2022, 19:09

Chuck W wrote: ↑20 Jun 2022, 13:30 The fuel lines shouldn't be of any consequence. Both engines *should* have a couple of fittings on the back of them where the fuel lines come up from below and attach to the lines on the engine. It's just a feed and return line, so no excessive drama is probably going to be needed, regardless.

You'll want to verify where the pressure regulator is on the 98 vs the current set-up. You don't want to toss that out with the car. I think on the '98 NA cars, it's under the car in front of the right rear wheel. I seem to recall it was in the same location on the '96 NA car I had as well.

The 96-98 NA 20V motors are M4.4, not M4.3. Not much of an issue, seeing as you'll have a donor car.

Pull the '98 engine-side harness from the ECU box. Seeing as you're swapping a manual, you'll be able to remove the engine-side transmission harness completely. You can just leave the body-side alone. The manual '98 car will have blanking plates in it which you can use to block off the hole left by the engine side of the trans plug.

My understanding is that the motronic systems don't have a return line and the fenix system does. Maybe I'm wrong, but if that is the case, wouldn't that mean I need the lines for the motronic system?

I'm fairly certain the pressure regulator is in the same spot. Is it a different part number though, is what I'm curious about. I assume it wouldn't be because they use different ecu's.

Post by **Chuck W** » 20 Jun 2022, 20:50

They for sure have a return line. It's just a matter of where it's located. The 96-98 20V cars have a pulse damper on the fuel rail, with nothing attached to it. The regulator, back by the tank will have a return line.

Why they're different PN's, I have no idea.

454cid · Post by **454cid** » 21 Jun 2022, 01:57

I would not get rid of the parts car until you have your project car running. There will be something you didn't plan on, that you'll end up needing.

2ndGenVolvos · Post by **2ndGenVolvos** » 23 Jun 2022, 11:29

Chuck W wrote: ↑20 Jun 2022, 20:50 They for sure have a return line. It's just a matter of where it's located. The 96-98 20V cars have a pulse damper on the fuel rail, with nothing attached to it. The regulator, back by the tank will have a return line.

Why they're different PN's, I have no idea.

'98 should run in the same place, but I'm not 100% sure because of the different systems used.

Post by **gnalan** » 24 Jun 2022, 19:46

Is the 10V head still in good shape?

2ndGenVolvos · Post by **2ndGenVolvos** » 27 Jun 2022, 11:36

gnalan wrote: ↑24 Jun 2022, 19:46 Is the 10V head still in good shape?

I believe so, I haven't taken it off the block in a while and when I did I didn't really inspect the head. It burns oil though, so I assume the stem seals are bad.

Post by **foggydogg** » 27 Jun 2022, 14:40

You MAY run into an issue with the pedals, I'm not sure the (shaft-typo) shift setup is the same, 850 vs. S70.
+1 on holding onto the donor car, unless space is an issue. If so, harvest absolutely everything you can carry - ask abscate about the do-not-leave items too.

2ndGenVolvos · Post by **2ndGenVolvos** » 27 Jun 2022, 15:40

foggydogg wrote: ↑27 Jun 2022, 14:40 You MAY run into an issue with the pedals, I'm not sure the shaft setup is the same, 850 vs. S70.
+1 on holding onto the donor car, unless space is an issue. If so, harvest absolutely everything you can carry - ask abscate about the do-not-leave items too.

Yeah, my plan was to strip the body absolutely clean. I'm storing the parts car at the Volvo dealership my dad works at. The owner is kind enough to let me keep the car there while I undergo the project, but I don't want to inconvenience him too much or take advantage of his kindness.

I've got the swap megathread saved and bookmarked and I'm pretty much going off of that for all the manual swap bits I need from the car that are external to the transmission.

As for the engine swap I've found a few threads that highlight the things I need.

I'm also going off my dad's knowledge of these cars, as he's worked for Volvo in one capacity or another for nearly 30 years.