Early 544/Amazon back axle

[Salop Farmer]

Unfortunately I have an ENV 4.56 : 1 back axle on my B18 converted 1960 PV. Great for acceleration, hopeless for Motorway cruising and fuel consumption. I have been offered a 4 : 1 crown wheel and pinion set from a Spicer axle. I am guessing these parts are not interchangeable between the two axle types. Does anyone know if this is in fact the case. If so do any members have a good 4:1 gear set from an ENV axle lying around please?

[142 Guy]

Spicer has turned into Dana. I don't know for sure; but, it is probably a really good guess that the the Dana parts will not fit your ENV axle. Even the later Dana 30 parts are not backward compatible with the earlier Dana 27 axle.

The path to resolving your problem appears to be changing to a later Dana 27 or 30 rear axle. 30 is probably a better choice if you need rebuild parts because Dana 27 parts other than things like bearings and seals don't appear to be commonly available. Here is a starting point for your exploration:

https://turbobricks.com/index.php?th...cation.317015/

If all else fails contact Amazon Cars UK. They may be able to give you a faster answer than scrounging around on the Internet.

[Salop Farmer]

Thanks for information but this way forward is more involved than I want to go right now as I am a bit worked out after 2 years of renovating the PV. I have thought about increasing the tyre sidewall height on the rear from 65 to 80. Hoping if I do this on the rear only I won’t have any bodywork contact issues! My calculations tell me this height increase will give the effect of a 4:1 diff ratio instead of 4.56:1 ratio with the 65 height tyres. I have been in contact with Amazon Cars regarding axles in the past but nothing was available at the time.

[Derek UK]

Your '60 PV would have had cross plies, perhaps 6.40 x 15. I'd have to look it up. Standard radials are 165/80 x 15. You mention 65. What size do you have now? There were some B16 PV's with 4.10 axles, I had one. I think they may have been sent to overseas markets. Parts book shows small batches of chassis numbers with the 4.10 axle. Rally drivers would generally prefer 4.56 or even lower so they may be a source for a 4.10.

[Salop Farmer]

Am positive my car has 4.56:1 axle as it originally had a B16 A engine + 3 speed gearbox. Tyres fitted on minilites at the moment are 185/65 R15 but was thinking of trying 195/80 R15 on the rear to give the effect of the higher axle ratio. I know I can’t fit these on the front axle as they rub the wings on any lock. Not sure about any tyre to body contact with 2 adults in rear of car! But thought it might be worth a try as I already have the taller tyres.

[142 Guy]

I am currently dealing with an almost exact replica of your dilema. On my 1971 142E the car was retrofitted with a 4.56 rear end some time ago - 'because that was the way to go'. I am also running the same 185/65 15 radial tires. The combination makes for rather noisy / unpleasant highway cruising and that is with over drive!

The 4.56 to 4.10 is about an 11% drop in engine RPM at any speed. In North America, 195/80R15 is very rare and all the tires seem to be light truck oriented with very open tread patterns. You might end up exchanging less engine noise for more road noise with those tires. 195/70R15 is more common and is available as an all season tire. Based upon typical specs the 195/70R15 turns about 808 revolutions per mile and the 185/65R15 turns about 852 revolutions per mile which gives you a 5.4% drop in RPM.

Your post implies that you would just fit the larger diameter tires to the rear of the car. Don't do that. Raising just the back end of the car alters the caster angle of the steering. Vintage Volvos come with the minimum amount of caster that is 'safe' in order to reduce steering effort. Volvo typically specified 0 to -1 degree. Put larger diameter tires on the rear and you can cause the caster to go positive which will make the car overly responsive (unstable) to steering inputs at highway speeds. Modern cars typically come with a nice safe -4 to -5 degrees of caster along with power steering to manage the increased steering effort.

I am currently waiting for the parts to arrive so I can do a complete rebuild of my Dana 30 and change the 4.56 rear end to a more highway friendly 4.11.

[Salop Farmer]

Good point, I had not thought of that! So I have two choices :- 1/ Modify a Spicer/Dana 4:1 Amazon axle I already possess. Although I’m a little concerned that welding additional brackets onto top of diff housing may cause distortion of the axle ?! Or 2/ Hoping someone on this site has a ENV diff cassette of 4:1 ratio that I could purchase and fit in my axle. I suppose I could modify the front wings to accept the 195/80 R15 tyres, then fit them all round. But this would be a last resort solution as I don’t want to start chopping the car about!

[142 Guy]

I don't know the details about the ENV back axle. If you are currently running a B18 with M40, see if you can find out where the differential carrier 'breaks' - the height changes for the pinion center line. The Dana 30 rear end breaks at 3.73 and above so the standard Dana 30 on Volvos can typically take a 3.73 R&P. If the ENV rear axle is similar, this might open up some options if nobody has a 4.10 R&P for the ENV. With a B18B engine it probably has enough torque to manage a 3.73 R&P as long as you are not doing a lot of big hills or trying to tow things.

I would still be inclined to call up Amazon Cars and quiz them as to whether there is an easy(er) path to achieving your objectives.

[Salop Farmer]

Just discovered my Spicer/Dana axle is 4.56 ratio same as ERV on car. Have been offered a 4.1 CW and P from Dana axle. Will check with Amazon cars if parts are interchangeable but I will be pleasantly surprised if they are!

[142 Guy]

So you have a Dana rear axle and a ENV rear axle or just a Dana rear axle that you thought was an ENV rear axle. If you have a Dana, check the axle tubes outer diameter. I believe 2" is Dana 27 and 2.5" (my 142) is Dana 30. If you have a Dana 27, as far as I was able to determine the more commonly Dana 30 parts are a non fit. Checking with Amazon cars should confirm and they may be able to advise on or provide correct parts.

If you go searching for Dana 27 parts on line there seems to be a bit of a black hole. I think VP Auto has a 4.88 for the Dana 27 if you need to use your PV to pull stumps out of the ground.