ALFAGTV6.COM

[killaz]

Interesting mod MD! What material would be recommended to make this space-nut?

[MD]

I suppose 6061-T6 aluminium. Others may have a different opinion.

[Jim K]

This alloy is good enough. Alexis Walter, the guy making and (now) selling these, swears by them after having successfully completed more than 3 full racing seasons with his 290hp gtv6.
For the middle/rear maybe GKN has some kind of solution if someone would care to ask them.
We have a guy here in Athens with ~550+hp in his 75T who is still desperately looking for an unkreakable solution to the driveline problem...hasn't found a permanent fix yet. Note this is an everyday driver but serious drag car...I'm not sure but I suspect he'll never find a total solution to the problem; when the driveshaft holds up, the gearbox will go...I still think transaxle Alfas were never meant to be dragsters; to me its an abuse. There are many more suitable crap-boxes out there able to handle all kinds of punishment, ricers, cossies etc. Different strokes....
Jim K.

[MD]

JK,

A personal plea.

With the "departure" of Barry or to put it better, his inability to interact with the Forum like he used to due to new work commitments, there is now major vacuum for advanced technical input. We seem to be a collective of guys who certainly know a thing or two about our cars but just need some steering corrections sometimes so we don't get derailed. I know you have been standing back a little of late and just observing developments but I cannot help feel that you are sort of on the come back trail.

So my simple hope is that if you could step up to the plate(and are willing) a bit more often when you see guys needing a leg up with advanced technical issues. I am not at all sure I could not have put that in a better way but I hope you get the idea of where I am coming from.

..besides that, just when I am about to chuck another bit of dung on ya, you're gone like a fart in nylon hose. What ya say big fella?

[Mats]

For the middle/rear maybe GKN has some kind of solution if someone would care to ask them.
Jim K.

The problem is not the torque, CVs and cardan joints are not designed small enough not to take 600Nm all day, every day. It's the speed that is the problem really. Grease leakage.
GKN, Rotorion, NTN, AAM and all the other suppliers all have solutions but it takes more then just an adapter to fit them so it seems to make it unavailable to most of us.

Composite? Sure, if you can redesign the gear lever and e-brake to fit a large diameter shaft in the tunnel. And have the clams of course...
Torque tube? Sure, if you don't mind the incredible weight penalty and can du the engineering to make it work with bearings and end pieces that fit the engine and gearbox to keep it perfectly true and center in all load cases. Not an easy task I'd say.

[Carter Hendricks]

These might be interesting...

http://www.torqline.com/product_detail_9.php

--Carter

[do we still need rubber somewhere?]

[Greg Gordon]

The new Nissan GTR has a rear mounted transaxle, lot of power, and no torque tube. Perhaps we should look at what they are doing.

Greg

[Jim K]

MD, you are correct, I have been staying mostly away from the sites due to shortage of time. Now and then I take a look though and when I can butt in I do, but it can't be anything like the old days. The 3M though should keep all tech searchers happy (Mats, Micke, Mautrizio) Between them I can't see anything staying unanswered!
Jim K.

[ar4me]

Step 1

1 To test this, machine up nine tube spacers equal to the width of the standard rubber coupling.(Three for each coupling section)
2 Substitute the spacers for the coupling by placing the tubes over the 3 fixing bolts as if you are going to bolt them in place but do not tension up the bolts fully. Leave the tubes to move freely enough to insert a feeler guage.
3 Bring the yoke faces together as close as possible to each other and against the edges of the spacers now between them.
4 Using a feeler guage, measure the spacing between each yoke internal face and the edge of the tube. If the measurement is the same, your shaft in that section is correctly aligned for the componenet it is coupling to.
5 Rotate the shaft with tubes in place for 36o* and test along the way to be sure. Although a 3 point measurement would be accurate enough anyhow.

Step 2

1 Leave the spacers in place and tension bolts up. This section in now correctly aligned to say, the flywheel.
2 Repeat the process for the centre section and then finally the clutch input shaft.
3 Raise or lower components by packing/spacing or fabrication of mounts if necessary to get the aliignments correct.

If the measured spacing between all three bolting places is not the same, the yoke faces will not rotate as a parallel set . This will cause a stretch in the coupling ( like a "shimmy" on a bent bicyle wheel) as it rotates due to the wrong alignment not only stressing the unit but causing vibration as well

Do this test for all three yoke couplings and you have your alignment done. This simple geometry test will ensure a correct alignment in both the horizontal and vertical planes.

MD and others,
On the Milano the method of replacing the couplings with tubes of a length equal to the thickness of the couplings does not work for the front and rear couplings. The bolt holes of opposing yokes are on circles of different diameter! The yokes on opposite sides of the center coupling do line up. For the front and rear couplings one would have to make solid couplings (e.g. slices of alu drilled with correct 2 hole patterns (each of 3), with a center bore accommodating driveshaft pilot bearings, etc). So, tubes work for the center coupling, but for the front and rear a solid alignment coupling is required. Making the front and rear solid alignment couplings, it then becomes critical to get the two 3-hole patterns on circles with identical centers (otherwise the alignment is offset)!

Hopefully, this will save others the trouble of making the tubes for front and rear just to realize that there is no cigar.

Note that this is for the Milano. Although I haven't tried I would think it applies to the GTV6 as well. Not sure about other Alfetta models...

Jes

[MD]

Jes,

On the Milano the method of replacing the couplings with tubes of a length equal to the thickness of the couplings does not work for the front and rear couplings. The bolt holes of opposing yokes are on circles of different diameter! The yokes on opposite sides of the center coupling do line up.

I would never has thought that in a million years...!! That is just too weird for words. Please examine this commercial coupling from a racing supplier. All the holes appear to be in the same radius. Having said that, I just measured a brand new V6 front coupling and yes you are correct. Be damned !!

It's not a problem on Alfettas and 2 litre GTV's as they do line up.

Well to get around this, it is a little more involved. You would have to machine up front and rear solid ali. rings to match up each of the yoke bolt radii and centre hole cut out and make your measuremens off that. Anotherwords, make up what would be a solid aluminium donut with flat side faces and measure off that instead of tubes as I said before. The principle does not change.

Wow, glad somebody's awake !!

[Mats]

Look closely on that replacement donut and it's clearly visible actually, now that you mention it Jes.

[TS_turbo]

a bit off topic but look at this pics i snapped from friends SEI 2.5 TD, reinforcement plates on front guibo ... and this is F.M. gearbox , no crazy rpms
sei prop is almost half the lenght and double the weight compared to 75 one

[Giuliettaevo2]

with the gearbox up front the shaft makes more rpm actually... the gearing of the fifth gear is in most times something like 0.8:1 so the shaft actually turns something like 1.25 times fatser as the engine. 6000 rpm for the engine then becomes 7500 rpm for the propshaft.

Sei uses heavy stuff ... have three diffs laying around here, very heavy indeed, but also indestructable i hear.

Sei TD is a RARE car...

[Mats]

How often do you see redline in fifth?

[Giuliettaevo2]

depends on your engine spec, type of car and place you live... My '74 alfetta sedan with a 3.0 164 engine and a 75 Tb gearbox has reached the revlimiter quite often in fifth gear. German autobahn nearby...

But under normal conditions you're absolutely right... didn't think about that part of the story.