ALFAGTV6.COM

[Maurizio]

That's a neat design. Should be easy to build too.

Somewhere in my head was brewing something similar and time learns again that someone already did it....
The rubber only has to take pull and push forces, no bending, undestructable!!!! Only disadvantige, the aluminium coupler would be bigger in diameter than original don't know if there is enough room...
Ok, who has all three donuts laying around, to make up a drawing for the aluminium rings.



http://www.maedler.de/katalog_de/katalo ... b16c03.htm

It can take a misalignment of 15 deg! For a a inside of 13mm the outside would be 30 mm, so the coupler would become ~25 mm lager in daimeter. I have only one laying around of a 4cil (don't know which one it is) but the outside dia =114mm so alu coupling would become ~135 mm .....
Max static torque for 3 of them (3x1760Nx46mm =)230 Nm is a bit low

[Zamani]

But isn't the Alfa driveline misaligned as standard I mean the alignment of the engine and gearbox.

I'm interested in all forms of mods. Throw out all ideas here and we can decide which one to pick.

[Reale]

I have used the CF driveshaft for a whole race season with no issues. I had a vibration issue initially, but it was due to a bad front donut. Once replaced, it has been trouble free. I have run it up to 7400 RPM, but I usually shift at about 7000. It is rated for over 700ft/lbs, which I won't be putting through it any time soon. I use the stock front donut, and an Alfetta rear donut. The Alfetta unit has a integral centering bushing, which is replaced with the donut, instead of the OE GTV6 one which stays on the shaft. It has been used in other racing applications by Richard Jemison extensively without issues. I would consider using a reinforcement plate as described by Junglejustice if you are having problems with donut failure. The bushing idea is an excellent one, we actually considered doing exactly this but so far it has not been necessary.
-Allen

[jema]

you would have to replace all three at once with the aluminium-thingy, otherwise the one not replaced will take all the force instead of 1/3- of the force...

But I like the ideae! If someone come up with .cad drawings on each donut, i would almost pay a quarter or two to get it!

Keep it up!

[MD]

Zamani wrote:

quote]But isn't the Alfa driveline misaligned as standard I mean the alignment of the engine and gearbox. [/quote]

Can't see if anyone has provided a reply here. It's something I am interested in too.

I believe universal joints are meant to work at an angle of between 2-4 degrees. I would like to know what the factory alignment actually is or a technique on how to accurately measure this. It has always been claimed that using universal joints causes vibrations in this application. Could it be that it is simply using the wrong alignment?

All replies greatfully accepted. Any specific reply from JK will automatically get shredded.

[la_strega_nera]

Can't see if anyone has provided a reply here. It's something I am interested in too.

I believe universal joints are meant to work at an angle of between 2-4 degrees. I would like to know what the factory alignment actually is or a technique on how to accurately measure this. It has always been claimed that using universal joints causes vibrations in this application. Could it be that it is simply using the wrong alignment?

All replies greatfully accepted. Any specific reply from JK will automatically get shredded.

Easiest way to measure would be put the car up on stands, driveshaft out, measure the crank and input shaft angles with a magnetic base inclinometer, measure the heights from ground of the crank centre and input shaft centre, measure distance between, sketch it all up.
The vibration issue with unis would largely be from the input and crank shafts not being parallel, when at an angle they do not maintain a constant length as they rotate, and this varies with angle. Of course, the *very* soft mounts at both the engine and gearbox make it all a bit academic....
There are also concerns with the torsional vibrations, but i'd suspect that they're more to do with the lifespan of the uni joints, the needle rollers don't really like shock loadings.

[MD]

Hey Ben,
Your reply has been greatfully accepted. Please go past "Go!" and collect your $200.
Been giving some serious thought to your suggestion. So far the only chink that I have a problem with would be the base reference level to start all the measuring with. If you used a floor, most floors would not be accurate enough in level so you would somehow need to create an artificial level reference me thinks.

As for using an inclinometer well that is something I would need some coaching with. Notwithstanding the problems, it would be worthwhile to get this info because it is common across all the transaxle models and so for modification purposes, very usefull info.

[Barry]

Guys,the shaft does run out of line here..A simple way of checing it is to use a 5dollar laser pionter.I machined a goody up that fitted to the clutch spigot and yoke and mounted the laser.switch on and measure..You got to drop the engine a load to get it straight..
Mike,this we did with Jose`s car,the one I sent you the pics of..

[MD]

Hi Barry. Was hoping you would chime in sooner or later. Glad you got the jump on JK. I understand he is very busy of late researching who invented foreskins.

What you are saying makes sense but only up to a point. Not sure if you are simply a bad spell checker or you are using some form of slang but I do not fully understand your explanation. The other one of course is that I am simply dumb which is the most likely prospect. (JK, blow it out of your ear !)

For arguments sake, the laser could align the centre of the crankshaft with the centre of the gearbox input shaft. So far so good. However as Ben has pointed out and I agree with it, the engine and gearbox could still be misaligned. I will expand it like this.

If you had two perfectly flat discs such as say, two fly wheels, one on the engine and one at the opposite end on the input shaft which were both correctly centred and fixed. Now as you rotate the discs, unless both faces rotated exactly parallel to each other, you would not have correct alignment.

So effectively, what is needed is the ability to position such items in place and a means of measuring the constant distance betwen the rotating faces as they move around for the 360 degrees. This would achieve perfect alignment in every plane provided the distance between them remained constant.

If your laser set up does that, don't leave town, I am getting a Quantas flight over It may well do but as I say, I didn't get that from your explanation. So let it rip son..

[Mats]

If the center of the engine flywheel is pointing at the center of the clutch flywheel and the other way arount they are perfectly aligned.

A garage buddy has a Lotus Elan, it has guibos as driveshaft/halfshaft joints. Talk about misalignment.
Edit: And torque!
Edit2: Maybe not on that application though.

[la_strega_nera]

Hey Ben,
Your reply has been greatfully accepted. Please go past "Go!" and collect your $200.
Been giving some serious thought to your suggestion. So far the only chink that I have a problem with would be the base reference level to start all the measuring with. If you used a floor, most floors would not be accurate enough in level so you would somehow need to create an artificial level reference me thinks.

As for using an inclinometer well that is something I would need some coaching with. Notwithstanding the problems, it would be worthwhile to get this info because it is common across all the transaxle models and so for modification purposes, very usefull info.

The Idea with measureing relative to the floor is to gain a reference for the driveshaft angle.. the errors are fairly small against the length of the shaft (assuming a 1 piece shaft is the goal)

In the situation where the centre of the clutch and centre of the gearbox are *perfectly aligned* ie, the shafts are not only parallel, but colinear, the uni joints do not move through any angle at all, and as such will suffer from it as the needle bearings will not be moving (Most uni joints have a minimum recommended angular misalignment to operate under)
Basically, aslong as the two shafts (crank and input) are parallel, and the uni joint is "timed" (aligned correctly on the driveshaft) correctly, it will work.
The Laser pointer method Barry describes I believe works great for achieveing ideal alignment (ie you could eliminate the unijoints if you neglect bodyshell flex and solid mount the engine and box), and with carefull measurement it can also be used for parallelism by measuring the "offsets". ie the offset from the laser pointer spot to the centre of the shaft would have to be an equal amount at each end (however one will mark below the centre, one will mark above).

Hope thats clear enough?

[Barry]

[MD]

One more go to get the point across Baz.

Refer to diagram by Michael Angelo below.

In the Elevation View, the centres are aligned and assumes a face to face parallel conditon.

In the Plan View, the centres are aligned as before but due to say the sideways torque movement of the engine, the faces are now not parallel even though the centres are aligned.

It's having to set the optimum angle of 2-4 degrees for universal joints in both the elevation and plan conditions simultaneously thats the bug and then trying to keep it in that conditon for all operation conditions of the vehicle.

Times like this, I really wish we could all just meet up at the workshp and nut it out

[la_strega_nera]

Oh dear. I'd fogotten about the stupid bloody angle the Alfetta motors are mounted at
Too much Vino by the designer? or was the welding jig builder the culprit?
Nothing you couldn't fix with a welder/grinder/powerdrill

[Barry]

Ben,finally!!!!!!!!!!!!!!!!
A logical solution,no engineering mumbo jumbo!!!!!!!!
Welcome to the real world!!
Joking mate,but its good to see you post grinders,cutting torches an stuff..

Yes,the engine is slightly skew,but nothing that cannot be fixed..A simple way of checking how skew it is,is to put a broom stick cut to about 1 ft. in the flywheel...(This is now a South African b/stick as per mother in law issue here..)It will show up immediatly..

Mike,as for movement during operation,well,the tighter the mounts and all other goodies,the less movement..Im now talking replacement mounts as we have now dropped the engine lower(I use ,amongst others,1970 circa Ford f100,f150 mounts..)Im actually l;ooking at some Mazda 20l mounts...Theres a s.load of stuff we can use...

Note in the pic above,Jose used a type of torque bar...