240 General: New (to me) 1980 Volvo 244

[Othen]

Originally Posted by Laird Scooby

As for the bit about the B21F, it was a lot further down into that document.

Notwithstanding the above about me trying to measure the final drive ratio (and getting something daft).

I'm still researching the B21a/AW71 combo Dave, here is a page from my Autodata manual, have a look at the FEBRUARY 1984 paragraph:



... this would seem to indicate that the AW71 was available on the B23E engined models, but there is no mention of the B21a. It is unclear whether the 2.1 continued as a 3 speeder after 1984, or perhaps the auto was only available with the 2.3 engine. This makes some sense as the 2.3 motor has about 10% more torque, and as we know 500RPM lower in the range. More work needed (on my part) I think.

I found the piece in the Green book about the B21FT model (I just missed it last night, I was both tired and dim), it was on pp 8 amongst the stall speed information:



... so it looks like the AW71 was mated with the B21, but only in turbocharged form as the B21FT. That makes sense as well because a turbo would have been a lot more powerful (162 HP I think) and so could have easily turned the higher gear.

I'm still far from sure about this, but it seems that Volvo didn't fit the AW71 to the B21a motor, and my suspicion is that it didn't produce enough torque - that is only my hypothesis, I hope I'm wrong. That doesn't mean it can't be done of course, just that it needs a bit more planning.

If that hypothesis turns out to be right, and I still want a 4 speeder I have a few options:

a. Get a used AW71 plus a prop shaft from Worcester and just nut and bolt it in with the current drive train. The good news is we know it must fit (somehow) because Volvo did it with the B21FT. I'm thinking I could just use the existing radiator set up and get two flexible hoses made up to go from one end of the AW71's cooling pipes - a short distance (maybe a foot or two) to the existing radiator pipes. The prop shaft and its centre bearing might need a bit of modification. It would make sense to change the engine's rear seal whilst it is apart (it isn't leaking, it just makes sense whilst I have the access). I quite like this idea because it is cheap - a few hundred perhaps. There is some risk in that it might end up as an over-geared 244 that can't pull top gear because the motor doesn't make enough torque.

b. Get a AW71 as above, but change it and the live axle at the same time (once I work out the ratio I have at the moment - then a lower one, probably 3.91:1) - so I'd sort of end up with a 740 drive train. This would probably take quite a bit more engineering mating parts that were not designed for the car or each other. It would be a better solution at the end though in that 1st, 2nd and 3rd gears would be lower than they are now, making for more spritely performance, but top would still be higher making for a better cruising car.

c. Swap the whole engine and drive train for a B23/AW71 from a 740 - much more ambitious, with decisions to make and dangers all over the place.

... lots of thinking for me to do over the winter - your thoughts would be much appreciated (also about the final drive measurement problem I had above).

Alan

[Othen]

Originally Posted by 360beast

Nice to meet you and Bob the other day Alan, glad you had good trip and got very good economy for a 40 year old automatic car.

To clear a few things up it is an AW71L not an AW71 so it is a 4 speed with a hydraulic lock up that acts like a fifth gear, this kicks in at 64mph and drops the revs by a few hundred.

My 940 has a 3.73:1 axle and does 70mph on the speedo at 2400rpm in lock up.

Yes, good to meet you - and many thanks, I think the wheels will come up fine (the tyres are off already).

Many thanks for the info on the AW71L - as you may see we are discussing whether my B21a would have enough torque to pull such a high gear with the current final drive. Your comments would be most welcome :-)

Alan

[Othen]

Originally Posted by Laird Scooby

That's the 3.73:1 diff then Alan. Because of the differential action the output is halved so multiply 18.75 x 2 = 37.5, divide my 10 = 3.75:1, we know that's not a ratio from Volvo so it has to be 3.73:1 which is within the bounds of accepted error for manual measurement.

If the other wheel had been off the ground as well you would have seen it rotate in the opposite direction as you turned the left wheel, usually the left hand wheel has a direct connection to the crown wheel in the diff but seems not this time.

I reckon on that basis it'll handle the AW71 quite happily, whether it's a 71 or 71L as Luke has mentioned. The lock up doesn't alter the ratio in 4th/OD but simply uses a mechanical lock on the TC to give direct drive through the TC instead of having the "fluid flywheel" effect.

Doh! It had occurred to me that it must be twice the ratio I'd measured (yes, 3.73:1 is the one) - I could not think of any reason why the pinion did not have a direct connection with the crown wheel with one wheel suspended. I'll have to find a diagram of a live axle and work it out for myself, but that will wait for another day.

So, step 1: I have identified the final drive as a 3.73:1, so I can jack the car down.

See my notes later on about the options - I still think the humble B21a might struggle a bit :-)

Alan

[360beast]

Originally Posted by Othen

Yes, good to meet you - and many thanks, I think the wheels will come up fine (the tyres are off already).

Many thanks for the info on the AW71L - as you may see we are discussing whether my B21a would have enough torque to pull such a high gear with the current final drive. Your comments would be most welcome :-)

Alan

B230, twin webers and 4 branch manifold

[Othen]

Originally Posted by 360beast

B230, twin webers and 4 branch manifold

I sort of have a feeling we might end up there one day :-)

[Laird Scooby]

Originally Posted by Othen

I found the piece in the Green book about the B21FT model (I just missed it last night, I was both tired and dim), it was on pp 8 amongst the stall speed information:



... so it looks like the AW71 was mated with the B21, but only in turbocharged form as the B21FT. That makes sense as well because a turbo would have been a lot more powerful (162 HP I think) and so could have easily turned the higher gear.

I'm still far from sure about this, but it seems that Volvo didn't fit the AW71 to the B21a motor, and my suspicion is that it didn't produce enough torque - that is only my hypothesis, I hope I'm wrong. That doesn't mean it can't be done of course, just that it needs a bit more planning.

If that hypothesis turns out to be right, and I still want a 4 speeder I have a few options:

a. Get a used AW71 plus a prop shaft from Worcester and just nut and bolt it in with the current drive train. The good news is we know it must fit (somehow) because Volvo did it with the B21FT. I'm thinking I could just use the existing radiator set up and get two flexible hoses made up to go from one end of the AW71's cooling pipes - a short distance (maybe a foot or two) to the existing radiator pipes. The prop shaft and its centre bearing might need a bit of modification. It would make sense to change the engine's rear seal whilst it is apart (it isn't leaking, it just makes sense whilst I have the access). I quite like this idea because it is cheap - a few hundred perhaps. There is some risk in that it might end up as an over-geared 244 that can't pull top gear because the motor doesn't make enough torque.

b. Get a AW71 as above, but change it and the live axle at the same time (once I work out the ratio I have at the moment - then a lower one, probably 3.91:1) - so I'd sort of end up with a 740 drive train. This would probably take quite a bit more engineering mating parts that were not designed for the car or each other. It would be a better solution at the end though in that 1st, 2nd and 3rd gears would be lower than they are now, making for more spritely performance, but top would still be higher making for a better cruising car.

c. Swap the whole engine and drive train for a B23/AW71 from a 740 - much more ambitious, with decisions to make and dangers all over the place.

... lots of thinking for me to do over the winter - your thoughts would be much appreciated (also about the final drive measurement problem I had above).

Alan

If you also check on the page you've got the screenshot from above Alan, you'll see the AW70 (near identical to the 71) was fitted to the B21F - no turbo!

Do you know the kerb weight of the RB? From memory i think they're about 1250kg fully loaded? The 740 is about 200-250kg heavier so the extra torque (not a lot but maybe enough to make a difference) from the 2.3 won't make much difference. In fact i'd expect the B21A 240 and B23 740 carb to give similar give similar performance with the same gearboxes.

As for more grunt, if you're going to the trouble of changing the engine, ideally you'd be looking for an early 740 2.3 carb and autobox to minimise the other alterations you'd need to do. Failing that it's either a twin-choke Weber (as already discussed) or as Luke suggests, a brace of 40DCOEs and then add a 4 branch manifold and possibly a cam change as well. I'm not sure if the V cam from the later B230/B200 engines would retrofit your B21 head but if not i expect Volvo do a similar profile for the B21 which would give more torque and power as well.
The other alternative would be aftermarket fuel injection, some kits use you existing carb as the throttle butterfly with a discrete Throttle Body Injector (TBI - Throttle Body Injection) and is commonly known as single point ijection, others use multi-point injection but still using either your carb as the throttle butterfly or Weber throttle bodies that mimiic the DCOE carb in appearance.

https://www.classicfuelinjection.co.uk/

Some more info there on aftermarket fuel injection. There is a Jetex exhaust system from the manifold back available but you'd probably still want a 4 branch manifold to make the most of it :

https://www.partsforvolvosonline.com...oducts_id=4753

More food for thought!

Originally Posted by 360beast

B230, twin webers and 4 branch manifold

Mmmmmmmmm, me like!

[Othen]

Originally Posted by Laird Scooby

If you also check on the page you've got the screenshot from above Alan, you'll see the AW70 (near identical to the 71) was fitted to the B21F - no turbo!

Do you know the kerb weight of the RB? From memory i think they're about 1250kg fully loaded? The 740 is about 200-250kg heavier so the extra torque (not a lot but maybe enough to make a difference) from the 2.3 won't make much difference. In fact i'd expect the B21A 240 and B23 740 carb to give similar give similar performance with the same gearboxes.

As for more grunt, if you're going to the trouble of changing the engine, ideally you'd be looking for an early 740 2.3 carb and autobox to minimise the other alterations you'd need to do. Failing that it's either a twin-choke Weber (as already discussed) or as Luke suggests, a brace of 40DCOEs and then add a 4 branch manifold and possibly a cam change as well. I'm not sure if the V cam from the later B230/B200 engines would retrofit your B21 head but if not i expect Volvo do a similar profile for the B21 which would give more torque and power as well.
The other alternative would be aftermarket fuel injection, some kits use you existing carb as the throttle butterfly with a discrete Throttle Body Injector (TBI - Throttle Body Injection) and is commonly known as single point ijection, others use multi-point injection but still using either your carb as the throttle butterfly or Weber throttle bodies that mimiic the DCOE carb in appearance.

https://www.classicfuelinjection.co.uk/

Some more info there on aftermarket fuel injection. There is a Jetex exhaust system from the manifold back available but you'd probably still want a 4 branch manifold to make the most of it :

https://www.partsforvolvosonline.com...oducts_id=4753

More food for thought!

Mmmmmmmmm, me like!

Many thanks,

The 244 is 1285kg, 740 is 1310kg, both unladen, so there is hardly a difference in weight. I'm still thinking the B21a (and particularly a 40 year old one) will be underpowered to drive a top gear a third as high again - otherwise Mr Volvo would have probably fitted the AW71 to both the 2.3 and the 2.1 back in 1984.

Anyway, I have months to mull over this one. I would not want to risk spoiling the RB, it has turned out too well.

Now, let's get those wheels sorted with the pressure washer :-)

Alan

[Laird Scooby]

Originally Posted by Othen

Many thanks,

The 244 is 1285kg, 740 is 1310kg, both unladen, so there is hardly a difference in weight. I'm still thinking the B21a (and particularly a 40 year old one) will be underpowered to drive a top gear a third as high again - otherwise Mr Volvo would have probably fitted the AW71 to both the 2.3 and the 2.1 back in 1984.

Anyway, I have months to mull over this one. I would not want to risk spoiling the RB, it has turned out too well.

Now, let's get those wheels sorted with the pressure washer :-)

Alan

Hmmm, i obviously had heavy 740s then as they were (from memory) about 1430kg and my 760 is 1490kg.

My pragmatic point of view would be to fit the AW70/71, it's unlikely to change into 4th/OD until near 70mph given the current info we have but as i understand things, that's where you'd not only want it most (more relaxed cruising) but would benefit most from it too.

If you found it a bit lacking in power then either some mild engine tweaks or a lower (3.91:1) axle) would be the way to go at that point, maybe a comnination of both.
The intermediate gears wouldn't really be effected so to that end wouldn't detract from the RB but would enhance it where you want the enhancement.

I would like to point out though that mine changes up earlier than the set points indicated in the relevant sections on mine by about 10mph, 15mph if i'm extra gentle on the throttle.

However, i do understand the need and want to fully investigate everything, it's no good cobbling together a package that will be unusable and intractable. Did you get a chance to research the M46 manual overdrive ratio by any chance?

[Othen]

Originally Posted by Laird Scooby

However, i do understand the need and want to fully investigate everything, it's no good cobbling together a package that will be unusable and intractable. Did you get a chance to research the M46 manual overdrive ratio by any chance?

... sorry Dave, I forgot all about the M46 OD ratio.

[Othen]

Originally Posted by Laird Scooby

Hmmm, i obviously had heavy 740s then as they were (from memory) about 1430kg and my 760 is 1490kg.

My pragmatic point of view would be to fit the AW70/71, it's unlikely to change into 4th/OD until near 70mph given the current info we have but as i understand things, that's where you'd not only want it most (more relaxed cruising) but would benefit most from it too.

If you found it a bit lacking in power then either some mild engine tweaks or a lower (3.91:1) axle) would be the way to go at that point, maybe a comnination of both.
The intermediate gears wouldn't really be effected so to that end wouldn't detract from the RB but would enhance it where you want the enhancement.

I would like to point out though that mine changes up earlier than the set points indicated in the relevant sections on mine by about 10mph, 15mph if i'm extra gentle on the throttle.

However, i do understand the need and want to fully investigate everything, it's no good cobbling together a package that will be unusable and intractable. Did you get a chance to research the M46 manual overdrive ratio by any chance?

Hi again Dave,

I've just come in from cleaning up the new wheels (quite therapeutic) to find the rugby isn't on TV - why do we bother paying a licence so the crooks at the BBC can not bother covering our national team playing a test match? Ho hum, I'll listen to it on the wireless instead (grrr!).

I just googled the weight of a 740 - I've never owned one.

The wheels are coming up pretty well, 20-30 years of caked on brake dust and crud but they are nearly ready for rubbing down now. The wheels are a bit fussy to clean - much more so than the Virgos - so I don't know whether it would be sensible to change to them in the long term. They look really nice though.

You are right, I do have to be pragmatic about the RB. The whole project has turned out rather better than I could have hoped for when I bought it only 9 months ago. I was really impressed with it when Bob and I drove to Worcester last week. The cabin is a really nice place to be, it steers and brakes well, it doesn't leak or burn any oil (pet hates of mine), it keeps up with modern traffic really well and isn't too bad on fuel for a big and heavy car. I'm enjoying the car, and perhaps that is the reason for my slight reticence about the AW71 modification - it is so nice I don't want to spoil it.

Saying that, if I plan the change carefully enough (and I have plenty of time to do that) then having a 4 speed transmission would make the car significantly better without detracting from all the nice parts of the motor car. Luke is planning to swap the AW71 out of his 740 in February, so the timescale could dovetail in very well. I can register the RB as an historic vehicle in April, and if I've acquired the AW71 box plus any other bits I need by then, I could have a really good solution in late spring 2021.

As you know, my concern is that I might spoil what is a really nice 40 year old motor car. The change itself might cause a few little issues like fluid leaks - but they won't take long to resolve, the real disappointment will be if my 40 year old B21a doesn't have enough torque to make the overdrive top gear viable. I take your point in that the lower 3 gears are exactly the same as the BW55, so even if it runs as a 3 speeder I won't have lost much, but I know I'd then have to fix the issue - which would mean changing the final drive.

If that happened it would be far from a disaster, I'd just have to either find a 3.91:1 or 4.10:1 back axle or change the gears in mine, the result of that would be a much, much nicer car (lower 1st, 2nd and 3rd plus a higher top) - so better acceleration and much nicer cruising.

I'm so pleased with the RB; it has already achieved my aim when I first thought of getting an historic car at the start of 2020, so one might argue the end has been achieved so I should just relax and enjoy the motor car for the next 20 years. I think you know though, that is not really my way, there will always be something, however small, to improve matters.

Where will the RB end up (maybe in 10 year's time)? Well, almost certainly it will have an AW71, the final drive will probably be a bit lower, it will probably have a vinyl roof and there might be a few engine performance enhancements (not as far as turbocharging, certainly not FI, but still the B21 with better carburettor and exhaust set ups I should think).

As the RB is a keeper there is no time imperative to any of the above. There is however a window of opportunity next spring when Luke will have an AW71 available, and I should have a plan for any other things that need doing. If I decide to have another year or two enjoying the RB the way it is that is not a problem, there will be another AW71 available later.

So, I think you knew this already, this is where I'm coming from with the RB project: it has turned out really well and will continue on its upwards trajectory, the only issue is how quickly.

:-)