Volvo 850 10v to 20v Conversion.

[misha]

I would go with 10w40 semi-synth in this case.
Always replace oil filter.

But...if PCV is clogged...it will smoke.
PCV test first!

[2ndGenVolvos]

I would also remove the spark plugs and have a look at the plugs for condition. They may give an indication on what is happening in the cylinders. Then do a compression test.

Are you sure the smoke is oil and not fuel? Does the temperature gauge read correctly?

Try changing the oil. If someone used too thin an oil, then it will blow by the pistons into the combustion chambers. Put a fresh oil filter in and try filling with 10W-30 high mileage oil and see if there is a difference.

Neil.

Oil filter is brand new, actually. But typically blue/grey smoke is an indication that the motor is burning oil, and given the valve stem seals often go bad on these cars that would be my first assumption. Of course, I haven't done a thorough look over and I've just fiddled with the car for a day or two. But given that the head will more than likely need work (due to overheating and burning oil) I'm going to do some serious research into the schematics of both the 10v and 20v motors and see if its possible to run a 10v head with the stock ecu. If not, I might just swap out the sensors and the harnesses and the ecu and proceed with the 20v swap.

[2ndGenVolvos]

I would go with 10w40 semi-synth in this case.
Always replace oil filter.

But...if PCV is clogged...it will smoke.
PCV test first!

Yes as soon as I have time I will definitely do a PCV test. No point taking the motor apart if I have to clean the PCV anyway

[2ndGenVolvos]

Okay!

After lots of forum digging I've found that, mechanically, this conversion is possible.

I'll need the 20v head, exhaust manifold and intake manifold from a 20v engine, and pistons from a 20v engine as they have 2 releases for the valves.

My question now, however, is this: Is it possible to run these parts without having to swap out the ECU from a 20v car? Of course, this would also mean that I'd need to have sensors, harnesses, etc. swapped out as well.

[2ndGenVolvos]

Okay!

After lots of forum digging I've found that, mechanically, this conversion is possible.

I'll need the 20v head, exhaust manifold and intake manifold from a 20v engine, and pistons from a 20v engine as they have 2 releases for the valves.

My question now, however, is this: Is it possible to run these parts without having to swap out the ECU from a 20v car? Of course, this would also mean that I'd need to have sensors, harnesses, etc. swapped out as well.

Well,

We've found the answer to the ECU question.

The 20v head uses electronic fuel injection which means that we will need an ECU. This means all the engine management sensors will need to be replaced as well, and any relevant harnesses. FUN

[Chuck W]

The harness splits at the ECU box. If you have the engine side of the 20V harness from an appropriate donor, that should get you most of the way there. Compare the "A" and "B" side pinouts of the ECUs. "A" is the engine side and "B" is the body side.

The body side *should* be pretty much the same.

What system is your 10V using? One of the Fenix ones?

[2ndGenVolvos]

The harness splits at the ECU box. If you have the engine side of the 20V harness from an appropriate donor, that should get you most of the way there. Compare the "A" and "B" side pinouts of the ECUs. "A" is the engine side and "B" is the body side.

The body side *should* be pretty much the same.

What system is your 10V using? One of the Fenix ones?

Yes, it's got the Fenix Siemens 5.2. I think I can find an ecu and harness fairly easily. There is an 850 in a junkyard up the road from me that I'm going to check out. Fingers crossed everything is there and in good condition. Although, I should be able to find an ECU on ebay fairly simply. The harness I may be able to get a brand new from Volvo. I'll need to look into that. Sensors are easy enough, just a pain in the ass to swap out.
My dad wanted to try to run the 20v head with the Fenix ECU but I don't think that is possible. I think the ECU wouldn't recognize the 20v injectors, assuming they're different than the 10v ones.

[SirBrickWagon]

Or swap in a 20V engine if you want the power! I think the turbo swap is feasible too, for the monkey wrencher

i see you've come around to the turbo swap!

[xanthefin]

Okay!

After lots of forum digging I've found that, mechanically, this conversion is possible.

I'll need the 20v head, exhaust manifold and intake manifold from a 20v engine, and pistons from a 20v engine as they have 2 releases for the valves.

My question now, however, is this: Is it possible to run these parts without having to swap out the ECU from a 20v car? Of course, this would also mean that I'd need to have sensors, harnesses, etc. swapped out as well.

Well,

We've found the answer to the ECU question.

The 20v head uses electronic fuel injection which means that we will need an ECU. This means all the engine management sensors will need to be replaced as well, and any relevant harnesses. FUN

10V aka Fenix 5.2 uses fuel injection exactly same way as Motronic.

The harness splits at the ECU box. If you have the engine side of the 20V harness from an appropriate donor, that should get you most of the way there. Compare the "A" and "B" side pinouts of the ECUs. "A" is the engine side and "B" is the body side.

The body side *should* be pretty much the same.

What system is your 10V using? One of the Fenix ones?

Yes, it's got the Fenix Siemens 5.2. I think I can find an ecu and harness fairly easily. There is an 850 in a junkyard up the road from me that I'm going to check out. Fingers crossed everything is there and in good condition. Although, I should be able to find an ECU on ebay fairly simply. The harness I may be able to get a brand new from Volvo. I'll need to look into that. Sensors are easy enough, just a pain in the ass to swap out.
My dad wanted to try to run the 20v head with the Fenix ECU but I don't think that is possible. I think the ECU wouldn't recognize the 20v injectors, assuming they're different than the 10v ones.

Just use injectors from 10V?

ECU doesn't check Injectors on gasoline sides usually. Thats just DIESEL thing for the ex. Fords you need code them as because "common rail" tech or similar. On gasoline side i haven't end up to that in these year of models ever yet. ECU on these usually knows what size they are if that and thats it on petrol.


The issue if you run mixed injectors usually are that you get wrong amount fuel in the mix as it tries use different size what injectors originally was there.

[hausmeister]

My 10v 2.0 (fenix) had a MAP sensor, I think the 20v with motronic used a MAF sensor? That is something I would definitely check.
Pretty sure you can try to run it with the Fenix, but if you gain anything regarding power - who can say if that will work.
I hated the Fenix ecu as it is very hard to find a reader that will work with it. Shops where I live also can't read it any more (too old)

I would not do this, if you really are doing all this work just put in a turbo engine (or turbo the 10v ), then it is at least worth it. The 20v vs the 10v will most likely only have more power in the higher rev band. So if you don't plan to rev it beyond ~4k much then I don't think you will gain anything from this at all. But this is mostly speculation on my part, so maybe I am wrong