Dana 30 Rear Axles in Opels?

[Manta Rallier]

Has anyone done any research about putting Dana rear axles under an Opel? (These are commomly used in Jeeps; the CJ's and maybe Wrangler's.) Any thoughts or opinions? The reason would be to take advantage of the numerous gear ratios and differential options.

Edit: and it's not the Dana 30; that's the front axle!

Regards,
Mark B.

[asdasc]

Along these lines, I was under my dads Kaiser last night working on the circuit to get his overdrive working right, and thought how great it would be to have a set up like that on my GT. It is a seperate Borg Warner unit on the output of the transmission (3speed manuel) that automatically kicks in an overdrive unit once you let up on the gas for a second or two above 25mph. When you are getting on it, it never comes into play, but for cruising it works great.

[GTJIM]

1) The Dana series diffs in the smaller sizes (Model 23 & 27) would suit but have the same problems that any non-Opel (or Isuzu!) diff have - getting around the torque tube 3-point mounting. Have to fabricate a good 5-point mounting for non-Opel difffs.

2) Opel made a four-speed, electric overdrive unit that was used in some of the European models. Had a Laycock-DeNormanville overdrive unit sourced from the UK. Pic attached.
The Getrag 5-speed box is so much more available though - and much more compact!

[baz]

i think for the work you would have to do to put the dana in any of the opels i would put that little extra into it and go it an IRS like the bmw one (theres a thread about puttiing one in and it looks not to bad a job) you would get a far better rear with an IRS and a system that would handle more power if you choose right

this is a pic of a jaguar IRS under my gt ,it is an almost bolt in change ,you have to drill the rails to fit plates to carry the cage by its origonal mounting holes (i used the orig mounts rubber carrier after i removed the rubber and flattened them ) or you can remove it from the cage and mount the diff to a plate welded to a cross member in the car where the gt has one to carry the shocks and drill holes to carry a shock in the new mounting place (there are 2 /side on the jag but 1 / side will do for the gt ) the opel trailing arms can be adapted to mate up to the mounts on the jag and you have a system to work with up to 500 bhp and 700 lb/ft of torque with lsd as an option

btw if anyone wondered i found some of my old shots of the 3.4 s6 jag work i did to my GT and have added them to my garage its a shame i dont have any from when it was finnished just a few from when i was mocking it up

[opelwasp]

Baz do you have any mor pics of the Jag rear? Can you do a write up, or some basic project instructions? It looks very intriguing. Now that I am working in a metal shop I may actually try it.

[Manta Rallier]

Some interesting suggestions from Jim and Baz in particular. Maybe I should detail the application a bit more. This is for rallying of Manta and Ascona A's. I have considered an IRS, but one thing that everyone should keep in mind is that being able to put a good rally shock in the car is far more important to rally performance than live vs. IRS (at least from what I have found). So I need to look into the shock packages as well as overall system. Doing a 5 link system is not a real problem as we do some modest modifications and fabrication as it is.

The appeal of the Dana axles that made me look into them is the simplicity and availability of parts. When you are rallying, you are usually waaaay far our from parts, like in NW Maine or the Sandhills of SC, in the UP of MI, or even northern Quebec. Getting a part for a Jag rear end would be pretty nigh impossible.

Also, we are not looking to do monster HP. In typical rally surfaces, the rule of thumb is that trying to put down more than 90-100 to the road surface is a losing battle. So no 500 HP rear ends needed! But I will look at the BMW conversion; thanks for that pointer.

So with that perspective, any more thoughts and ideas to share? Fairly light, easy parts, LSD's and a variety of gear ratios in the 4+ range are items to consider.

Many thanks for the interest,
Mark B.

[oldopelguy]

My top choices of solid axles:
-GM 7.5, get an S10 one but drill and tap the bosses so you can use a modified Camaro torque arm.
-Toyota 2Wd pickup, drop out center section means you can bolt a torque arm to a ring fabricated to bolt onto the existing bolts.
-Suzuki Sidekick, also a drop out center section, slightly lighter than the Toyota but plenty of gear choices, usually already equipped with a gear ratio in the mid-4's.
-Jeep Wrangler, not easy to add a torque arm, but cheap and plentiful.

For IRS:
-Miata's use a drop out rear subframe, just about perfect width, RX7 difs fit, and they are 4x100 already.
-BMW 3-series also already the right bolt pattern, though there is a bit more to mounting the dif and swingarms.
-The new Pontiac Solstice has a complete rear IRS sub-assembly that's [retty reasonably priced on e-vil-bay. I'm probably not going to brave the $600 first, but it would bear a good look.

[oppositelock]

Mark, I am actually going to be eventually putting a Volvo Dana 30 into my Ascona B rally car for the same reasons you cited. Parts are expensive and hard to get for the Opel axle (ie: ZF LSD parts and 4.75 ring and pinions.) When I broke my 4.75 ring & pinion years ago I was lucky that my friend had a spare (from my old Manta rally car I sold him). Also, since the B chassis cars use a wider rear axle than the A chassis if I bust a half shaft I'm screwed since there are no spares in this country.
The Volvo axle has stronger halfshafts and is generally beefier overall than the Opel axle. Plus, gears and diffs are dirt cheap and there is a wide variety.
I already have the Volvo Dana 30 with 4.88 gears and a freshly rebuilt ZF LSD. It came out of John Lane's 600hp turbo V6 Volvo rally car when we put in the Ford 9 inch. I'm going to plasma cut the spring/control arm brackets off an Opel axle and weld them to the Dana 30 axle. I am also going to take the opportunity to do a proper 5-link setup and get rid of the torque tube like Opel did with the Ascona/Manta 400. The width of the Volvo axle was pretty similar to the Ascona B axle IIRC, but it's been a while since I took measurements. It may be kind of wide for an A chassis but I'll check. I'll get back with some measurements as I have all the parts out now.
Another advantage of the Volvo axle is that it comes with rear disk brakes, even though I already have those on the rally car. However, it was a conversion done in England and it has nice alloy AP calipers, I have no idea what the rotors are from. I figure I can put the AP calipers on the Volvo disks.

[baz]

what are the specs of the rear discs
dia
thickness of disc
pcd
hight from back of disc to top of hub
centre hole dia
dia of hub
# of holes (stud and mounting if it has them)
i may be able to find out what they are off

[CoriolisSTORM]

Rear axles in Wranglers are Dana 35s or 44s. A few years also used the AMC model 20s, although they are undesirable due to 2 piece shafts. 3 point ones are done all the time by rock crawlers and such, and there are many places to get a custom rear axle done. A narrow track CJ rear might be an idea worth looking into. That being said, most Wrangler guys (myself included) hate the Dana 35s. The low spline count leads to problems when running lockers and anything above 33s usually. Dana 35s in Wranglers usually had drum brakes, while some of the Cherokee 35s used discs. Also, from 97+ the Dana 35s are designed for coil springs. Anything before that was leaf springs, unless it has been converted to coils. Dont sound like a bad idea, I'll see if I can get you some measurements and such from a jeep forum or something. edit: Gearing in stock 97+ Dana 35s with 2.5Ls was 4.11, in the 4.0L versions it could be 3.73 or a lower ratio I cant remember right now. edit: A lot of jeep guys actually give away Dana 35s from their jeeps, or they sell them at a really low price. They're certainly not expensive, so this might not be too bad of an idea if your fabbing skills are up to it, or you can get a shop to modify it for you.
last edit: Found a tad bit of info: Dana 35c Also, forgot to mention that these are also C-Clip axles, and they are available in spring over and spring under applications.

[oppositelock]

Jeez, why does everyone want to use truck axles? Volvo Dana 30s are dead simple and plenty strong for any HP an Opel motor can dish out.

So anyway, I got out my tape measure and it turns out I had it all backwards. The Volvo Dana 30 is pretty much exactly the same width as the Opel A chassis axle. Axle flange to axle flange they are both 1390mm give or take a mm or two. For those that are not metric literate that's about 54.75". So that's good for you guys. Bad news for me, looks like I'll have to use wheel spacers on my Ascona B. The rear axle in it is about 58mm or 2.25" wider.
Oh, I forgot to mention in my earlier post another reason I want to convert to the Volvo axle is the availability of cheap rwd offset 15" alloy wheels. I'm going to keep the 5 lug bolt pattern and use Volvo alloy wheels. Up till now my car has used 14" wheels but 14" rally tires are hard to come by, 15" is the most common and easiest to find. There really aren't any factory 15" wheels that are 4x100 bolt pattern and the proper offset. Mostly all fwd offset like VW or Honda. I've got some aftermarket VW 15" alloys that I bought for cheap. They will fit but the offset is not ideal. I could buy custom aftermarket wheels with the proper offset but now you are talking around $150-$200 per wheel. You need a lot of wheels for a rally car so that's cost prohibitive. The Volvo alloys are strong and cheap.
However, if you wanted to stick with the 4x100 bolt pattern the Volvo axle flanges could be easily redrilled.

I attatched some pics. First pic shows the Opel axle housing below the Volvo axle housing.
Second pic shows an Opel axle shaft on the left next to a Volvo axle shaft on the right. Notice how the Opel axle tapers up to a fatter diameter than the Volvo axle. The Volvo axle is 1 pound lighter than the Opel axle even though it is stronger. That's 2 lbs less rotating weight!
Third pic shows the difference in spline count and diameter. The Opel on the left has 25 splines and is 26.3mm in diameter. The Volvo on right has 27 splines and is 29.4mm in diameter. Notice the twisted splines on the Volvo axle. That's what 500+ ft/lbs of wheel torque from a turbo V6 Volvo will do! The 9 inch Ford rearend that is now in that Volvo has 35 spline Moser axles that are 38mm in diameter!

[oppositelock]

Originally Posted by baz what are the specs of the rear discs dia thickness of disc pcd hight from back of disc to top of hub centre hole dia dia of hub # of holes (stud and mounting if it has them) i may be able to find out what they are off

Thanks for the offer but once I put the Volvo axle in I won't be using them anyway. Maybe I'll pull one off and take pics and measurements anyway, you never know. They're probably off some obscure British car...

[Manta Rallier]

Originally Posted by oppositelock Jeez, why does everyone want to use truck axles? Volvo Dana 30s are dead simple and plenty strong for any HP an Opel motor can dish out.

Good reasoning. I really don't see a whole lot of diiference in these axles; the stock Volvo rear discs is an advantage.

We're committed now to a Toyota 8" rear axle from an early 80's 4WD. The 30 spine 4WD axles shafts are a bit larger than the Dana 30. Going to coilover shocks and a 4-link plus panhard rod setup. The axle has the merits of: strong, cheap and plentiful gear sets and parts from several sources (like the Dana); and a large diameter 6 bolt lug pattern on flanges that are more easily turned down to 4 or 5 lug patterns. (We're sticking with the 4x100mm pattern). Brakes will have to be adapted but we are converting to dual MC's anyway.

Total axle and rear suspension weight will be very close to stock.

We agree on the 15" tires for rallying; I think we are going to be able to find some 4x100mm BMW wheels with the right offsets. The fender flaring will be interesting!

Don't worry about spacers; we use 1/2" spacers on our Celica Alltrac; we installed Speedway Engeineering long studs and deep nuts to go with them.

Keep us posted!

Mark B.

[ddoyle]

Are any of the volvo units LSD or Posi. Plenty of older volvo in the boneyards, and prices are lower than the toy units.

Dan

[Manta Rallier]

Originally Posted by ddoyle Plenty of older volvo in the boneyards, and prices are lower than the toy units. Dan

How much for a Volvo axle out there? Make sure you are thinking of Tacoma axles......

[RabidPanda]

Hmmm very interesting. There are many volvo's in junkyards around me plus my mechanic father in law is a volvo nut he has 7 or 8 volvo's himself in varying ages.

[oppositelock]

Originally Posted by Manta Rallier We agree on the 15" tires for rallying; I think we are going to be able to find some 4x100mm BMW wheels with the right offsets. The fender flaring will be interesting!

I have molds of the Ascona 400 flares. They would work on an Ascona A alright but I'm not so sure about a Manta. Something that might work well for the Manta A are Escort Mk2 forest arches. You can get them in aluminum cheap and easily in England. Escort Mk1 bubble arches might work even better.

Don't worry about spacers; we use 1/2" spacers on our Celica Alltrac; we installed Speedway Engeineering long studs and deep nuts to go with them. Keep us posted! Mark B.

The only reason I worry about wheel spacers is because the reason my car retired from the 1986 Olympus WRC rally is because the rear wheel came off when the wheel studs sheared. It had big 20mm wheel spacers on it but really the problem was they were not hub-centric on the rear because of the rear disk brake conversion. It's got some adapter that makes the center hub flush so the wheel is only centered and supported by the wheel studs. The first thing I did when I bought the car was to get rid of the spacers and install big 14mm studs. When I convert to the Volvo axle that problem will be eliminated so I won't worry about it then. H&R has some nice hub-centric 25mm spacers that bolt to the axles for just about any car.

[BQS4]

Originally Posted by oppositelock I have molds of the Ascona 400 flares. They would work on an Ascona A alright but I'm not so sure about a Manta.

Are these any different than the Stiemetz flares? I have a set of the street flares for the Ascona A.
Gene

[RallyBob]

Originally Posted by BQS4 Are these any different than the Stiemetz flares? I have a set of the street flares for the Ascona A. Gene

Very different Gene.

[Manta Rallier]

Originally Posted by BQS4 Are these any different than the Stiemetz flares? I have a set of the street flares for the Ascona A. Gene

Oooh ooooh.....are you planning to use them????? Are these the old flares like were used on the early 70's Opel rally cars? Or oare those the Steinmetz flares?

Mark B.