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1961 Volvo PV 544 to EV 544 - Build Thread

15397 Views 206 Replies 14 Participants Last post by  jclars
Hello All!

I pondered what to do to this car for over 1 year since driving it home. Yes, it was the first project car I had not needed a trailer for! I have travelled as far as Southern Cal. to pickup other projects with a trailer in tow. Never one only 15 miles from home! And so cheap ($2500) for a running vintage car!

Because the starting point was so favorable, it was tempting to simply do a stock restoration. But then I started digging and found the engine and tranny were not original, coming from a newer Volvo. I felt like it opened the door for a restomod. I am soon 72 years old and have always enjoyed a challenge. My last build was a traditional hot rod which included at totally fabricated frame and flat head V8. Parts were either already in my shop or sourced from multiple swap meets and online sales The various parts spanned years 1928 to 1962 in vintage. I also upgraded a 1958 MGA Coupe to a 2000 Miata drive train. I have done a 1956 F100 PU with a 90's era drivetrain from a T-bird SuperCoupe. This past May I drove Rte. 66 in it. 6000 miles round trip. So major technology jumps with previous projects has been accomplished. And I drive the things! But ICE to EV??? Before last year I didn't even know what those acronyms stood for!

I reviewed the topics I was to cover with my first post, and I can see the logic to determine where everyone enters this EV game. So I can fabricate, I can visualize, I can drive. But this EV thing was a bit intimidating. Then I took a ride in a modern EV and got sucked in! With your help, I hope to make this car an almost daily driver. I am planning for 80 - 100 mile range. I also want to approach this incrementally, both for affordability, but also because I like to mock up restomods to present a car look like it could have come from the factory that way. I have become adept at doing this, but it has always been by trial and error with lots of cardboard and wood mock-ups. I have fabricated things multiple times to get it looking right (as well as for structural integrity!).

I hope I can present this EV conversion similar to my other less radical projects. I want the motor with controller to take center stage, so no battery box on top of it, even though there is a lot of room under the bulbous hood. Likewise, I doubled the HP and Torque on that MGA mentioned above, and it suddenly became a fun (not to mention dependable) sports car! While I will only have a marginal HP jump in my chosen EV gear, I am pretty sure the torque value and dependability factors will be satisfying enough!

That all said, I have been working with EVWest to gain a system understanding and with a local Electrical shop that has dabbled in EV development for the last 10 years. EVWest had done a Volvo P1800 several years ago and just this past week we were able to confirm a match to my Volvo bellhousing and flywheel. So I have the adapter/coupler on order with them. I also have a Hyper 9 HV motor system with chill plate and front motor mount on order with the local shop. Saved much on freight by finding a local source for that! I have other components pre-selected from both EVW and locally, but again will use these first major pieces to anchor the mock-up stage. So because the adapter is a long lead item, I will probably be doing more restoration type stuff in the interim, so bear with me.

I attach pix of the car, the voluminous engine bay and similar trunk. I do plan to put at least some battery packs in the rear where the gas tank came from. However only 100-120 lbs or so to help keep within original weight trim. Which I think will be okay, with so much room in front. But again, I want to showcase the motor. Not the battery packs.

Looking forward to hearing comments from this valued knowledge base in the months ahead!

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John Larsen
Lynden, WA
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I have a space in front of the motor which will have to deliver 2/3 my power in a 22"x22"x10" space. Any thoughts?
A 22"x22"x10" rectangular space has 80 litres of volume (4840 in³ or 2.8 ft³), which could ideally hold about 160 kg of cells (because lithium-ion cells have a density of roughly 2 kg/L), with a capacity of 32 kWh (because lithium-ion cells weigh about 5 kg per kWh of capacity); if that's 2/3 of your battery then your total capacity would be 48 kWh. In the real world you won't be able to pack cells in nearly that well (because they never come in just the right dimensions), and you need space for structure, cooling system, interconnecting wiring, and control devices (contactors, fuses, BMS components), so you might fit a bit better than half of that capacity if you find the right battery modules. I think you need more space...

For an example, two layers of modules in the VDA 355 format (355 mm long, 152 mm wide, and 108 mm tall) with four modules per layer (3 side by side and one turned 90 degrees to them) could barely fit in a 22" x 22" x 10" (or 560 x 560 x 255 mm) box, with an empty corner for wiring devices; the height would be marginal with cooling plates. At 2.2 kWh each, that would be 18 kWh; at 12 kg each, that would be about 100 kg plus structure, wiring, and devices. I used the VDA 355 format as an example because those modules are relatively small (sometimes called "shoebox" size), are an industry standard (which is rare in this industry), and are available from a couple of sources (including salvage from the Jaguar I-Pace); however, it's just an example to illustrate the packaging challenge.

Also, with the motor in front of the original transmission, "in front of the motor" is likely too far forward for all of that mass to allow for good handling.
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Would it be viable to build a frame from front mounts to tail mound to replicate what the original distribution might have been?
It is a good idea structurally to use original mount locations, but the mount locations don't determine the weight distribution.
Optimum for handling is a 50:50 distribution.
50:50 is not universally the most desirable weight distribution, but it's a reasonable place to be. Did you mean optimum for this specific model of Volvo? Many vehicles routinely carry more weight on the rear axle when fully loaded, even with identical tires front and rear.
One reason for going with the original transmission was that an adapter and coupler had already been designed, so initial cost was favorable. I am also not sure the existing rear end would be able to handle direct drive in terms of rpm's.
The rear end will see the same speed regardless of the motor and/or gearbox ahead of it, because the axle input speed is directly proportional to the road speed, tire radius, and axle gearing.... regardless of the transmission.

Do you mean that it isn't practical to change the rear axle to much higher reduction ratio to enable direct connection of the motor to the axle's pinion shaft input? If the ratio is available, it will be usable.

The clutch might also provide a measure of flexibility in terms of "cushion" on alignment.
Not really. The clutch disk can provide rotational "cushioning" (they usually have a spring hub), but does not forgive alignment error.

Also, no pilot bushing was provided for the transmission input shaft - Is this typically omitted? It appears I could fit a bushing/bearing in the end of the coupler. Once I get it on, that is...
I don't know what is typically supplied with a kit, but if the transmission shaft is piloted in the flywheel or crankshaft (which it typically is in conventional longitudinal transmissions), you need that bearing or bushing.
In my view the Hyper 9 is not powerful enough to do a direct drive. The highest voltage version outputs 220 Nm.
The original B18 in first rear would put 3,1 x 150 Nm (ok, at higher rpms) = 450 Nm onto the driveshaft.
With clutch slipping, the engine can deliver that torque (through the clutch) at any road speed up to that corresponding to to the torque peak engine speed in the current gear.

Unfortunately for the Dana or Spicer axle there is no replacement rear diff gear to compensate that.
Availability certainly does vary greatly depending on the final drive (axle)! Most don't have a short enough gear set (high enough reduction ratio of the ring and pinion) to make sense as the only reduction for most electric motors.

In my rebuild I’m 100% sure I will eliminate the gearbox. That was a noisy and one pedal drive spoiling thing.
More info here Rear wheel drive EV conversion motor options - Voltvo
Interesting page - thanks for sharing that. It doesn't mention any final drive or tire information, which is a bit strange considering that they are critical to comparing motor and transmission combinations, when one of them has its own final drive.

I don't know what gearing is this PV544, but I have seen references to 4.56:1 (early years) and 4.10:1 or 4.11:1 (later years). With 4.1 gearing and 6.00 x 15 tires (26" or 660 mm tall, or 2 m circumference), propeller shaft (transmission output / axle input) speed at 100 km/h (60 MPH, 28 m/s) is 3440 RPM. For most reasonably sized electric motors, that's too low by a factor of about 2 to keep the motor in the most effective speed range, and so torque to the wheels at low speed is about half of what it could be.
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I used a M400 gearbox without pilot bearing.
The M40 and M400 gearboxes are classic longitudinal designs, in which the input shaft clearly requires support at the front. That's what the pilot bearing (or bushing, but Volvo uses a ball bearing) are for, although one might get away with supporting and locating the splined shaft adequately.
How about putting a de Dion tube from a Volvo 340/360 at the rear?
An interesting possibility, but would the de Dion tube clear the drive unit? Following the same general design but with a custom beam (tube) is an alternative.
🤔 Not sure. The CVT in those cars is rather voluminous though.
Yes, but it's quite narrow at the back, so something like a Leaf drive unit might not clear the beam on the right-hand side where the de Dion beam bends forward and the Leaf inboard CV joints is displaced to the right to clear the motor.

Nice illustration. :)(y)
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