Sunbeam Alpine V6 Restomod: Rear End Rebuild

The Sunbeam had started to build momentum. Many small projects were adding up to big wins in getting the car at least to running condition. The engine compartment was getting close to complete, but the rear end we had was still a mystery. We decided to get to the bottom of our apparent Dana 44 rear end we already had installed in the car. After some digging, I found some markings on the rear end. I found two telling numbers on the rear end. At the bottom were the numbers “B65-2617” and further up on the rear end I found the code “4HA 004”.  The first number set didn’t reveal anything, however, the 4HA revealed the truth. We had a Salisbury rear end which is the English equivalent of the Dana 44. This was comforting knowing we didn’t need to source another rear end. 

However, we had one afterthought. An experienced hand, Jose, who had developed the V6 conversion had mentioned the Dana 44 rear end might be too robust for the application. Ultimately he didn’t think it would be a problem but recommended something lighter. He recommended just changing the gearing of the original axle but since we didn’t have one and would have to start from scratch, we had to go with what we had.

*** A small update on the Salisbury rear end that came up recently in April 2023. I am part of the California Association of Tiger Owners which sends out a monthly newsletter. In this newsletter, they had an article decoding the Salisbury rear end. In the newsletter, it was explained that the Sunbeam Tigers included the installation of the Dana 44 differential mounted in a Salisbury-produced rear end. The Salisbury factory was only six miles away from the Jensen Assembly Plant where the Tiger bodies were assembled. The interesting part of this newsletter helped to fully confirm this axle was indeed Salisbury rear end. As mentioned before there was the marking “B65-2617” on the axle. According to the newsletter, the letters A through M (minus I) represent the months January through December followed by a two-digit numeric representing the year. After the month and date identification, the consecutive unit number was indicated. Based on this new information, the rear end was manufactured in February 1965 and was the 2617th manufactured rear end. According to the Jensen ledgers, 758 rear axles were made during this month. I am going to ask the club to see if they have a Tiger Vin number we could pin this car to which is completely wild to me. Stay tuned.  

Markings on the bottom of the "unknown" rear end

The parts car we purchased also came with a rear end. This was from a 1998 Ford Explorer which had been shortened to fit the Sunbeam. The Explorer rear end had a disk brake setup which was appealing. However, we knew nothing about this rear end. We didn’t know the gearing, the condition of the gears, and the specs the rear end was adjusted to. The previous owner had also installed a 5 lug set up in the rear end and we were going with 4 lug wheels. There were just too many unknowns and too much customizing to be done to make it work. We knew the rear Salisbury Dana 44 worked in its current condition and we would only have to get an adapter kit to install disk brakes on the Sunbeam. In doing some research, we found a shop in Riverside that sold the exact kit we were interested in. This was the final nail in the coffin for the modified Explorer rear end. We decided to update and restore the Salisbury Dana 44. 

Dale's Restorations yard
Couple of pristine restorations Dale was working on

We decided to call up Dale from Dale’s Restorations in Riverside. We got to talking and had exactly what we needed for a disk brake setup on our rear end. The kit is a Wilwood caliper and disk setup with a couple of custom brackets and lines specially designed for the Dana 44 rear end. Dale also confirmed there would be no problem with his kit working with or Salisbury. We put our deposit down and a few weeks later we went to his shop to pick up all the kit. We asked Dale for a shop that could completely refresh the gearing and shims for the rear end. Dale had just the guy. He recommended an older gentleman who went by the name “Pucky”. Pucky used to own an old suspension shop year ago and has since retired and does small jobs out of his garage. Pucky was also quite familiar with Dale’s kit. After a phone to Pucky we ended up at his shop with our rear end and Dale’s kit.

Pucky's sheet for determining RPM per each gear ratio
Pucky pulled off the cover to inspect the state of the rear end

Pucky was a wealth of information in setting up our gearing for the rear end. He had a detailed sheet showing how to set up the gearing for the car. The sheet had a couple of factors we needed to input into his equation. We input our tire diameter at 23″, a different cruising speed of 65-70-75-80, and made sure the RPMs wouldn’t be much higher than 3,200 but didn’t want to choke off the engine because we’ve been told the engine really comes alive around 3,000 rpm with the cam we are using. The transmission we are using has an overdrive ratio of .72. This means the rpm number generated by the table should be multiplied by .72 to get the final rpm value. 

Using his chart, we landed on two ratios, 373 and 3.91. Cruising at 80 mph using the 3.73 ratio, the rpm would be at 3,138. Cruising at 80 mph using the 3.91 ratio the rpm would be at 3,290. The RPMs were pretty close so we opted for a shorter gearing for better toque. We realized we would most likely be ripping through the gears around town rather than cruising on the freeway. Another change we ended up making was the tire diameter. We eventually needed to replace the dry rotted 23″ tires and replaced them with a Kumho Ecsta PA31 175/65R15 which has a height of 24″. These tires paired perfectly with the Panasport 15×6 rim. This also lowered the rpm at 80 mph to 3,153 which is exactly in the sweet spot for the engine.

Pucky was extremely helpful during this whole exercise and walked us through each step. He even pulled off the cover to ensure everything was in good shape. He estimated it would take a few weeks because he had to make/obtain some shims for the axles but we were in no rush. He tried talking us into a limited-slip differential but my dad and I both knew we wouldn’t be pushing the car hard enough to even justify the cost. 

Completed read end loaded on Pucky's custom jack
Completed Wilwood brake installation

A few weeks later we picked up the rear axle with the adjusted ratios and the disc brake kit installed. The kit went on perfectly and the axle install went in without any issues. Pucky had a few issues with shims but in the end, he figured the shims out. Pucky also had a sweet electric lift and carrier which made putting the heavy rear end into my truck. We paid the man and went on our way. 

Painted rear end ready to be installed
Refreshed/painted the hardware for the rear end

After I got the rear end home I removed part of a partially cut off bracket and ground the axle smooth. I then prepped the axle for paints by sanding and cleaning the surface. I put a coat of primer and paint onto the axle and mounting hardware. The whole assembly cleaned up really nice and looked so nice I was afraid to scratch the paint. All that was left to do was install the rear end into the car. 

Reinstalled rear end on the Sunbeam Alpine
Installed disks with Wilwood calipers

The installation of the axle wasn’t too difficult. My dad and I had fun wrestling this beast of a rear-end into the car. There is some truth to this axle being too beefy for this car when you start moving it by hand. Once the rear end was fully installed, all that was left was to install the custom parking brake cable, disks, and calipers from the brake kit. When everything was finalized, we held our breath and installed the wheels onto the car. It fit like a glove. All of the research and running around had finally paid off and looked amazing. 

Completed brake package with wheel installed

The car was almost drivable. We only needed our wiring harness hooked up, brake lines, fuel line, and a clutch line installed. All of this was completely beyond my mechanical knowledge. I wanted to do most of this myself, but if we were ever going to get this project done, we might have to have it done by a shop. Stay tuned for the next blog when the car has its first drive in over 6 years. Motor on.