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This past weekend I put my rebuilt transaxle (original to my 1985 GTV6) with a clutch hosing from a Verde. When I went to put on the rear Guibo it wouldn't fit over the front shaft nipple. I then looked through my collection of parts and found that there are at least three different sizes. The one on my car (from the Verde) is the largest of the 3. It's OD is about 20mm, vs 19mm for the next largest and a smaller size for the others.

I drilled out the rear metal bushing in the Guibo so it fit, but of course now it doesn't ride on the nipple. It seems to me it will stay centered anyway and should work fine. What do you guys think?

Hold on, trying to add the picture

So, I am the only one who has run into this...really? Or perhaps this forum is just slowly dying, which would be sad.

I have never seen it actually.

I think you will have problems with vibrations if you remove the pilot completely, the guibo itself will not center the assembly enough.

I think you might be right. It's just strange that this one assembly has the larger flange. There must have been different donuts in production at one time. The current catalogs I have looked through only have one part number for the rear donuts on Milanos and GTV6s.

For example IAP's part number is 15023 for a rear Giuibo for a 1988 Milano 3.0 and a 1985 GTV6, yet there is a difference, and it's a big enough difference that the GTV6 part won't fit on my car. I guess I'll have to just machine these things out to the right spec.

Greg

Maybe a twin-clutch housing?
I have the workshop manual in my garage, I'll have a look in there. Tons of drawings and measurements available.

The smaller shafts seem to be from GTV6s which had twin clutches, at least in the US. The part I can't figure out is why one is larger than all the others. So large that the available rear giubos wont fit. It's close, like .5mm, but that's enough to prevent something from fitting when dealing with steel parts that don't squish.

Greg

Greg,

You are indeed correct. The diameter of the clutch input shaft centering connection does vary from my experience. It has been a while but I can recollect measuring various sizes from around 17.5 to around 19mm OD.

As Mats has said, this shaft is a LOCATOR and in combination with an accurate fit into the rear coupling centering bush, keeps the oscillations to a minimum and thereby the vibrations.

If you have drilled out the back of the coupling, that is a no-no.

Keep in mind if you intend to machine this part, I believe it is a hardened bit of steel which will make it a little more difficult. The closer the tolerance, the better the chance of reducing vibrations.

..naturally, balancing the clutch and flywheel will eliminate the quandry of whether any future vibration is due to the imbalance or from the coupling union to the shaft.

The Forum is slowing down but still performing a great communication link for us all I believe. That in part is due in my opinion to the forum discussing every part of these transaxle cars inside out and back again and so it is almost functioning like an information vault-and what an asset it is.

I also think that centering bushing is pretty important. I had to drill it out in order to get the car back on the ground. I didn't have time to do anything else and I didn't want to leave the driveshaft just hanging there. The car won't be running for a while anyway.

I don't think it will be tough to machine, my drill press went through it like butter. The problem is that shaft isn't the same size as any standard drill bit. It's like 19.5mm.

Greg

Oh ,I see we are not on the same page.

You are thinking enlarge the coupling union.

I am saying take the input shaft off the flywheel, place it in a lathe and turn down the spigot to fit the coupling opening size. Given its hardness, I would think it may respond well to sanding and polishing as opposed to cutting. With the coupling in your hand, this would allow progressive trial and error fit until it was the correct diameter for the specific coupling.

Sorry about that. I should have said this in the first place.

I know the shaft is fairly hard because at one time I made a special experimental shaft rear coupling using a Mercedes coupling and locating the centering bearing on the front of the shaft instead of having one in the coupling. This meant turning down (in the lathe) the clutch input shaft.

If you want to go further and change the rear coupling to something a bit more robust, you could use a universal joint by altering the shaft as per photo. If you did this, the input shaft could remain as is and you would just make up the locating insert at the back of the U.J. to suit it. The shaft will need a re-balance.

Yup, I am looking at enlarging the coupling end. That's a lot easier, and I just got that transaxle in there, I don't want to pull it out again.

Greg

This forum can't die!

<Off topic>

I'm not sure if you also got an email from RJR but he got suspended for saying something not so complimentary to the moderator on the BB. He didn't even say anything bad. Suspended for crissakes!

No such things happen here.

Here we just delete those users, all their posts, and it never happened

We're a cool bunch of guys and the technical knowledge over here is simply astounding! And the moderators are cool as hell too

This forum is alive! (well sort of)

</Off topic>

While off topic.....

It does seem that Alfisti are rather ENTHUSIASTIC about whatever it is they are discussing on their cars....

Which does make for some enjoyable reading....

ok back to topic now.....

MD, I like your idea, but my goal is to build a max power car with as few mods as possible. I am using stock pistons, rods, and just about everything else. I plan to blow a lot of boost into the motor through a Sprintex blower.

The plan here is to have a parts combo that's easy for others to emulate, hence I want to avoid u-joints or other more serious alterations.

Greg