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Opeler
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Type of rear suspension to use

I picked up the rear axle assembly upgrade today. It came out of a 91' Volvo 240. It is 3.73 ratio and I believe it's a 7.65" ring gear (Dana 30). The complete assembly cost me $100, and they pulled it! Now I have to decide whether to transfer the spring buckets and shock perches from the opel axle to the volvo and make a torque arm in order to recreate the original rear suspension, or if I should try to adapt the volvo rear suspension which looks to be a type of five link set up. Or do I build a combination with the opel spring buckets and the volvo upper links? Any opinions on which will work better?

Note: The volvo axle has an upper and lower mounting ear for a torque arm setup that is used on the 740s and 940s. I put a red circle around the upper earin the picture.


Mod Edit: Posts copied from A Call for SR20 documentation thread
 

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Opeler
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Discussion Starter · #2 ·
Someone had recently asked me for an update so here it is.

I've got all of the mounts cut off both axles and I'm in the process of welding the Opel mounts to the volvo axle. After that I'll fabricate a torque arm or upper links and put the locking differential carrier in. View attachment 30386 View attachment 30384 View attachment 30383 View attachment 30385

Don't let my slow progress fool you, replacing the opel axle with the volvo 240 axle is really not that hard. I have just not been able to dedicate much time to it and I've spent more time trying to decide how I wanted to do it than actually doing it.
 

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Opeler
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Discussion Starter · #3 ·

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Opeler
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Discussion Starter · #4 ·
It's been slow going this summer on the rear end swap I really didn't plan to take this long but other things keep coming up making it hard to spend much time under the car.

I have finally have some good progress to report on. I have the torque arm 99% figured out and have mocked it up including the forward mount to the body. The set up will be similar to a BMR aftermarket torque arm for a Camaro or Firebird with a tubular construction and a large rubber forward mount that the arm can slide in and out of as the axle travels up or down. I will fabricate a cross member for the mount to attach to that will double as a drive shaft loop and will mount where the original center joint did. I have made a mockup out of cardboard so I can prove the design before I start bending and welding metal.

I also finally made it back to the local Pick n' Pull to get the donor parts I need for the drive shaft. It need a nissan yoke at the front and a volvo yoke at the back so I either needed to get two shafts or one shaft plus the opposite yoke. The volvo shaft was long and kind of puny, less than 2.5" dia., but it had larger yokes and the u-joints are removable. So I nabbed the rear yoke off a Volvo 240 and then went searching for a nissan shaft. What I found is that the distance from the tranny tail to the diff pinion flange on a late 80's 300zx (5spd trans) is almost the exact same as the distance on my GT with the volvo rear end in place. So all I'll have to do is install the volvo yoke on the nissan shaft. This should be simple enough since I already had to do something similar with the other shaft I used with the original rear end. I can use the u-joint cup adapters I had made for the other shaft. I'll just have to machine the outside diameter down about .060" to fit in the volvo yoke. (see the last picture)
 

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Opeler
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Discussion Starter · #5 ·
I went back to the junkyard and crawled under a few more cars until I found on with smooth u-joints, then exchanged the other drive shaft for it. So that problem is solved. I do have another question: with this standard style rear end do I still need a spring in the tranny tail shaft to push out against the driveshaft??

I finished the torque arm and took the axle back off and finished welding the spring buckets all the way around. I also adjusted the angle of the pan hard rod mount and cut off the brackets for the upper volvo links. This had to be done because the brackets interfered with shocks.

I may have already said this but I made the torque arm out of the 2 upper volvo links and the volvo pan hard rod. I cut one end of the pan hard rod and one upper link, and both ends off the other link. You can see in the pictures the complete torque arm and the clearance between the arm and the body when the suspension is bottomed out.

Now I need to install the differential carrier with the locker and re-drill the hubs for the 4 bolt wheels. And I need finish the forward torque arm mount.
 

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Opeler
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Discussion Starter · #6 ·
I thought some people might be interested, so here are a couple of pics of the forward torque arm mount. I used the forward mount from a Camaro and welded on some appendages to bolt it securely to the underside of the GT. It fastens to the same two bolts holes that the opel torque tube center joint did plus one more that I added about 8" outboard near the e-brake cable guide bracket.
 

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Samdog and I had a long conversation last night about the ability of a stock Manta/Ascona rear end to hold up when coupled to a 200+ HP motor. He is currently having problems with the rear end in his Ascona and I am thinking about upgrading the one in my wagon.

I pulled bigbens Volvo 240 swap posts out of his "A Call for SR20 documentation" thread so they would be easy to find and the info would be in its own thread as Ben's mods seem pretty straight forward.

Anyone have ideas or info (width, ratios available, etc.) to add?
 

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Anyone have ideas or info (width, ratios available, etc.) to add?
According to a post on Turbobricks.com

"The Volvo 240 rear axle width is about 55" mounting surface to mounting surface."

According to another post on the same site the ratios available in 1984 were

M46 Manual
3.31:1
3.54:1
3.73:1

AW55/BW55 Auto
3.54:1

AW70/AW71 Auto with O/D
3.73:1
3.91:1
 

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I picked up a rear end from a 1990 Volvo 240 with a 3.73 ratio and will be putting it in my 24 valve Ascona wagon.

I drilled the axles to a 4x100 pattern today (5x108 is stock) and a G80 locker carrier will be here tomorrow.

As of now, I'm leaning toward doing an install similar to bigbens, using the Opel spring buckets with adjustable arms and a torque arm going up to the Opel center joint mount. This will allow the Opel shock mounts and panhard bar mounts to be used.

Another option was sent to me by dsmith which needs more looking into. In that GT install, the Opel springs were mounted on the Volvo trailing arms and the arms matched up to the Opel front mounts. Two links from the axle to the training arm stabilized the axle. Shock and panhard mounts were relocated.

The brake system on the rear end needs replacing. The Volvo e-brake uses brake shoes on the inside of the rotors and both were in real rough shape. I need to price out replacing it, calipers and rotors vs. using (and replacing) the VW/BMW rear disc setup I have set aside for my GT.
 

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The cost of replacing my VW/BMW brake setup was twice the cost of new Volvo parts. Rock Auto and Advanced auto will have all the Volvo brake parts here by Thursday.

I installed the Eaton G-80 locker today. When one wheel spins 100rpm or more than the other, the diff locks and both wheels pull until you back off the pedal. When you go over 20 mph it stays one wheel drive. There are mods that can be made to the unit so it will stay locked to a higher speed. I'm going to wait and see how it performs before modifying it.

Brake rotors fit on my Smithy Drill/Mill/Lathe so I was able to open up the rotor I.D.

That last pic is the exhaust fan I added last Fall. Makes a huge difference when welding or grinding.

While I'm waiting for the brake parts to arrive, I will be pulling the Opel rear end out. Using the Volvo trailing arms is looking more promising...
 

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Opel Tinkerer and Rescuer
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The power of the moderator.. :)

Thanks for this BTW Gary.. Atlas may need to go this route later.
 

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Hmm, It might be possible to do this swap with any welding needs happening on the Volvo trailing arms only. This would make it much easier for those who do not have a welder to bring the two arms to a welding shop and no Opel rear ends will be harmed in the process.

Volvo/Dana 30 parts are readily available and fairly inexpensive.

Stay tuned, film at 11:00
 

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Opel Tinkerer and Rescuer
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THAT Gary would frigging AWESOME !!
 

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Great work
I just bought these wheels
7 15 front and 8 15 rear
They are both 4x100 and 5x108 ie multihole so you could use them for your rear without redrilling the hub
They were only 220 pounds on ebay.uk and they have more available
They send overseas as well
keep up the good work

http://i.ebayimg.com/t/15-SILVER-POLISH-LIP-D-LUX-RS-ALLOYS-7J-8J-STAGGERED-FORD-RENAULT-VAUXHALL-VW-/00/s/NzY4WDEwMjQ=/z/9iQAAOxygPtSsCFG/$_58.JPG
 

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In with the New

Temporary fitting shows the Volvo 240 rear end fits nicely. The Volvo trailing arms will line up close to the Opel arm mounts. The shocks will be able to be mounted to the rear of the trailing arms and the Opel springs will locate in front of the axle on the trailing arms.

The rear bushings in my axle were shot. I ordered poly ones. Once they arrive I will be able to get further into the mounting.

Time for a cigar!
 

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The axle is all clean and POR'd. A test fitting showed me that the Volvo trailing arms can be used.

After installing poly bushings at the rear of the trailing arm, they were attached and with little alignment, adjustable rod ends will line up with the Opel mounting location. The springs will line up in front of the axle and with spring hats installed on the arms, they will sit ~1 inch higher than original. I'll need to either use a shorter spring or cut one down.

Lower shock mounts will be on the back of the trailing arms.

Adjustable links will go from the axle mounts to the trailing arms and a new adjustable panhard bar made up.

Of course the wheels I am using hit the axle so I had to get longer studs and a 10mm spacer. I opened up the 4x100 Honda spacers to fit the axle today so tomorrow the wheels will go on and I can center the axle and get accurate locations for the rod ends and spring hats.

The link and panhard components will be here Thursday.

It is coming together. Going to be a busy week!
 
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