Buick V6/sm420 Help

I am struggling.

I have a 64 CJ5 with the dauntless V6. It had a t14 and a Dana 20. The engine, trans, tcase and axles all came from a commando.

I swapped the t14 for an sm420 and a Novak adapter for the D20. With a 1 1/4 throw out bearing I still have no free play. Bearing bottoms out in the trans and makes contact with the clutch fingers.

If you start the jeep and shift into gear with clutch in it try’s to drive. Clutch will not release.

I have compared several flywheels, bell housings and transmissions and the are the same.

From what I measured I need a 1 1/16 throw out bearing which doesn’t seem to exist. Or I need a shorter pressure plate.

I have tried the clutch that was there with the t14 and tried a brand new clutch from Jeepsterman.

Any ideas? I have found a few post with people having the same issue but no answers that help.

 

Is it a borg and beck or diaphragm style clutch cover? They are different and come in different lengths. You also need to have the correct front retainer
on the transmission to give full travel. I went through trying a couple bearings to get what I needed. Mine was a little different as I went hydraulic
with a cast arm and adjustable pivot ball. Give Novak or Advance a call. Lugging the SM420 in and out can be a workout.

 

It is diaphragm and I am using a hydraulic kit from Jeepserman. I did not know the front retainer could be different. I have access to a few other 420’s and all are the same dimensions. Will give Novak and Advanced a call.

 

You could become good friends with the local parts guy. Mine is a diaphragm also. I will look tomorrow to see if I have the box still.
The front retainer I believe was just for the OD that fits the bellhousing. But you may to check that the bearing has good rear travel.

 

Check to see if the clutch disc hub is bottoming out on the input shaft splines.
The hub could be to thick lengthwise is that makes sense.
Yes, it happend to me with a LUK clutch kit.

 

We could add that the springs face the clutch cover.

 

This happened with the original clutch.

 

Spent over an hour this morning with my guy at NAPA. The bearing travel is what I am stuck with. I have the shortest bearing I can find at 1 1/4 and it is bottomed against the trans and riding against the diaphragm.

I think a 1 1/16 throw out bear would work but that doesn’t seem to exist.

 

The best I have right now. Toward the bottom of the page. Looks like N4008.
https://www.novak-adapt.com/knowledge/clutches-etc/
For more reading put this in your fav search engine.
site:earlycj5.com throw out bearing
One more but doesn't seem too helpful.
https://4speedconversions-com.3dcartstores.com/0.799_clutch_release_bearing.html

 

The box I have is a Crown relabeled AETNA bearing. The Crown number does not cross to anything. Not sure I can get the label off and
it looks like I tried before. Maybe some water and a heat gun. All this was done pre-internet and was dealing with catalogs and the two
adapter companies. The bearing face must be rounded. What happened to the original bearing? Some bearings can be taken apart and
added to the existing sleeve portion.

 

The clutch and bearing that were in was a Chinese eBay clutch. The bearing with the new setup was way too long.

I sent an email to Novak this morning and will call advanced tomorrow and see if they can offer some help. I know the answer is simple, this is not an exotic swap.

 

Called Advanced. They said they have never had this issue but the do sell a bell housing and clutch arm but they are back ordered at least 4 months.

Novak said “huh, never heard of this before.”

 

Can you provide pictures of your fork, pivot, bearing. Then sort of angled to see pressure plate, disk, pilot bushing, and flywheel thickness.

My gut says your disk is backwards.

 

Man I hope it is something as stupid as that but I don’t think you can put the disk backwards it would be riding off the flywheel.

I will drop pictures later. And fingers crossed you are correct.

 

X2.....

 

The Crown labeled Aetna box did not reveal Anything. It was an inked number that looked to have had a paint pen crossing
out the number. What I could see of the AETNA number does not show on their list and the Crown number does not exist
anywhere I could find. Clutch covers can vary by a bit depending on the manufacturer or origin. In my case, it was a
Centerforce clutch and cover. Some of the new style diaphragm covers have curved tangs and can use a flat face bearing
which are easily available. The short convex face bearings are looking to be a challenge to find. Maybe some older GM
vehicles used them. You may be able to get a short assembled bearing and swap the bearings on the sleeved if they are
both two piece. The same manufacturer may be helpful. Barring that, you may need to find a different source for your kit.
Does yours look like either one of these?

 

It turns out that the Crown number is actually a GM number. G.M. 907588 which makes the illegible portion of the AETNA number into A2765.
The GM number has been superseded several times but has replacements available. It is the short bearing shown.
The new number is 908093.

 

^^^Thanks! I have a couple of both bearings above. To get things to fit as is I need one of those above bearings with zero shoulder between where the bearing is and where their arm rides.

Taking it apart this afternoon. I will compare what I have to your above notes.


I appreciate all the help. This thing should be such an easy swap and it has fought me.

 

In that case there is one other one to look at and that is the N1716. Though it is a flat face, it is shown for diaphragm clutches.
There are several sources but this link says for Diaphram Style Pressure Plate.
https://www.supershops.com/products/transmission_drivetrain/clutch_hydraulics/parts/CTFN1716

 

I had a similar issue whdn i did my dm465 swap you need a different pressure plate. There are two types, one has raised fingers that thd theowout bearing pushes against snd ond has flater fingers. You might need the second kind to give you more room for bearing travel. Do you have a picture of the pressure plate your using?