nut case idea

[supertiga]

ok --this is what i think im gona do.need input/advice ect.
a friends son totaled his bmw 1982 320 i with245/5 getrag.
he made a gift of trans including flywheel back.
lets put that sucker in da opel!
this is only worth doing because trans is free and all machine/weld/ect can be done "in house"
the ratios look beter than the opel getrag.
bmw--3.68/2.00/1.33/1.00/.81
opel5-3.77/2.019/1.316/1,00/.804
opel4-3.64/2.12/1.336/1.00
this ratio info might be wrong but best i could find.


things i think will work
1 cut bell housing off bmw trans and machine front of trans flat--bolt or weld opel bellhousing to trans--may need spacer.front trans case will chuck up in my brake drum lath
2 instal hard sleve on bmw input shaft to use opel pilot bearing.
3machine and drill opel flywheel for bmw clutch and pp.
4 if spacer is used(beel to trans) i think i can stay with opel throw out brn--if not will have to adapt bmw throw out brn.
5 shifter mod--no problem.
6speedo--will solve later
7the PROBLEM--out put of bmw is flanged with no provisions for plunge(sliding splines)the opel has some plung at pinion end of drive shaft--this might do it but is probably a no no. have not pulled flange off yet to see if its removel will cause a thrust problem on output of trans.if it doesnot and splines are deep enough i think i can make it work
or possibly use a cvc joint at the back of trans ?(bolted to flang)
#7 is my biggest problem at the moment--any ideas?rallybob?
8 need dissasembly info on trans
Thanks
David

[spdkilz02]

if u feel u can do it urself, then go for it. especially when u really shouldnt have too much of an out of house cost.

[supertiga]

opel bell and bmw trans mated!
bmw nose modified for opel throwout brn
shift linkage modified and narrow gated
now looking at modifying opel/bmw speedo to keep opel ratio.

lots o work--should be more than worth it.

David

[benncojr]

Any photos of the work??

[dcm013]

"7the PROBLEM--out put of bmw is flanged with no provisions for plunge(sliding splines)the opel has some plung at pinion end of drive shaft--this might do it but is probably a no no. have not pulled flange off yet to see if its removel will cause a thrust problem on output of trans.if it doesnot and splines are deep enough i think i can make it work
or possibly use a cvc joint at the back of trans ?(bolted to flang)"

From what I know about Getrags, that flange does hold the mainshaft assembly together. You'll have to figure out another way to provide some plunge.

Don

[opelbits]

As I recall, the Alfa Romeo Spiders had a drive shaft that had the 'plunge' or 'slip' built into the driveshaft. Each end had a flange and the shaft itself was basically telescopic.

If I remember right.......I know one of the Alfa models I used to work on had that type of driveshaft. If it wasn't the Spider/GTV (105 series), then it was the DeDion/transaxle Alfetta/GTV6/Milano series.

[jeff denton]

I don't think you need any "plunge", do you? The Opel's suspension/torque tube setup shouldn't cause any fore and aft movement of the driveshaft.
Correct me if I'm wrong. Also, is "plunge" really the term for this movement? I've never heard a name for it!

[namba209]

Actually, the drive shaft on the GT has a spring that goes inside the yoke between the tranny output shaft and the yoke that puts a preload on the driveshaft assembly, keeping the splined end of the driveshaft, where it goes into the differential seated. I think. At least that's what all the drawings I have shows. As the rear suspension goes up and down the yoke shaft slides in and out of the tranny tail shaft housing but still maintain a preload on the shaft.

[opelbits]

Jeff-
I think there actually is some fore and aft movement. As the axle goes up or down the distance from the pumpkin to the center joint (carrier) gets shorter or longer, but the torque tube does not change length, this means it pushes forward on the driveshaft. I think the center joint does allow some movement.
It may not be much, but it doesn't take much to break things.....

[supertiga]

im fairly sure plunge is proper term.when talking to engineers they understand the word--i will ask if its proper.

not as much plunge on opel as most cars due to torque tube setup

I was originaly going to use a cvc joint for this problem but now think im going to use spitfire sliding yoke and drive shaft end to adapt to opel drive shaft.adapting the spit ujoint flange to gear box will save lots of work over the cvc version.also can put spring in splined part of assembly.the only drawback is possibility of splines locking(not sliding)under heavy load.may wind up doing cvc thing later.

no pics yet--will take some before assy.warning-camera dosnt take pics where aimed!(el cheepo)

current--have modified opel speedo drive gear for bmw--now have to move centerline of driven gear for proper mesh.

thanks for input!
David

[namba209]

Dave, just a bit of info for you that may assist in what you're doing. On Willit?, my V-6/T-5 swap, I was really concerned about having my drive shaft so short, about 2" between the u-joints. So I put the rear of the car on jackstands at the jacking points and dropped the rear-end all the way down so the shocks bottomed out full length and measured the angle on the shaft. Then I took out the springs and jacked up the rear-end until the car came off the stands and measured the angle again. it was less than five degrees. As far as fore and aft movement of the torque tube and the rear-end, I believe it is in the fractions of an inch. If you think about it, the rear end is 4-point mounted, by the trailing arms, panhard rod, and the torque tube, with the pivot point being the torque tube mount at the body and any fore and aft movement is probably taken up by the bushings in the trailing arms and the panhard rod. Just for curiosity's sake when I put the engine tranny back in, I'll do another check to measure fore and aft movement, using the same criteria I did before.

[baz]

with 2 trailing arms and a torque tube i dont think it can move for and aft apart from the squash in the rubber bushes so most it can be on a car with good bushes is a couple of mm. bad bushes might give you 3-4 mm.

the most movement i can think of is the engine and box mounts would give 10 mm or so as they deal with a 300lb lump of loose iron that twists side to side and for and aft(drag cars dont have solid mounting plates for nothing)

[supertiga]

converted bmw 245 is in the car.it all works except 1 problem.

didnt notice when i modified opel speedo gears(so that i kept proper ratio and opel cable conection) for getrag that the driven gear is on the WRONG side of drive gear!

it works(speedo)but only in reverse!

what would be best is to buy a reversing box--spent all day on phone and net-result-no one i found can do it so that i can mount the revers box to trany and then cable to box.

any ideas on who might do this for 18mmx1.5 mm threads(opel speedo conection threads)?

if worst comes to worse i can machine a box if i can locate some gears for it.

i am tired of machining parts for this project and dont recomend this route to anyone!and i like doing machine work!

buy a bolt in from ogts so you can have fun instead of work!

this project generated enough metal shavings to fill a 2x2x2 box full!
the only advantage was i have only spent about 100bucks
this does not include my labor and machine/welding work!

thanks guys!
keep those opels roaring!

David

[BQS4]

David;
Any pictures?

[supertiga]

had some pics in digital camera(el-cheepo)
went to download to cpu and nothin!battery seems to have died in camera.
will get some in car pics soon.

have not found anyone to do reverse speedo box for resanable $
have gears ordered for making my own.

drove car yesterday.
1st feels normal(no speedo yet)
2nd seems a little tall
3rd is real quick
4th normal
5th(od) might be tall(need to hit the interstate)

I think i have a good rally rearend that should make it better in 2nd and od

had to extend shift lever to get it in reach--longer throw than i wanted but not to bad.used mgb wallnut?wood shiftknob.

more later
David

[rallye73]

What about converting to an electronic speedo or modifying the existing gauges to be electronic?

[supertiga]

we have thought about going eletronic on speedo but realy would like to keep this car all 70s tech.

i think my son found some one to make that makes box to do what i need and will make myself if nessary(days work)

currently driving with no speedo---i think im gona get a ticket!when i deop down to 4th to estimate speed i find im doing 80 in 55!makes trip to town shorter!

the 5spd is great!


David