Help mating zf and dart block!!

Pat

Supporter
I have never owned a ZF but read on this site daily.

There are some ZF boxes with a slightly longer input shaft….they were made for BMW M1 cars.

If you happen to have this type of box or input shaft it may be bottoming out in the crankshaft.

There is actually a thread on here somewhere a thread about this and the car being driven and damaging the box and crank shaft.

Could this be the cause of your interference?

Ian
That’s curious. I did search some old threads and saw where they were used in M1s and had longer input shafts. My ZF was for a Pantera as I had to get Ron McCall to flip it and had him tear it apart while he was at it to go over everything. I’m curious now what the input shaft length should be for our car (for a ZF from a gt40 or Pantera)? Anyone know? Will try digging some more.
 

Rick Muck- Mark IV

GT40s Sponsor
Supporter
That’s curious. I did search some old threads and saw where they were used in M1s and had longer input shafts. My ZF was for a Pantera as I had to get Ron McCall to flip it and had him tear it apart while he was at it to go over everything. I’m curious now what the input shaft length should be for our car (for a ZF from a gt40 or Pantera)? Anyone know? Will try digging some more.
Yes, my post about an M1 ZF going into a Safir MK I. Took the thrust bearings out in less than 3 miles. You learn more from your failures than your successes if you can afford the tuition!
There is actually a thread on here somewhere a thread about this and the car being driven and damaging the box and crank shaft.
Yes, my post about an M1 ZF going into a Safir MK I. Took the thrust bearings out in less than 3 miles. You learn more from your failures than your successes if you can afford the tuition!
 
Yes, my post about an M1 ZF going into a Safir MK I. Took the thrust bearings out in less than 3 miles. You learn more from your failures than your successes if you can afford the tuition!

Yes, my post about an M1 ZF going into a Safir MK I. Took the thrust bearings out in less than 3 miles. You learn more from your failures than your successes if you can afford the tuition!
A good friend of mine likes to say “education is never free”… ;)
 

Morten

Mortified GT
Supporter
Yes, my post about an M1 ZF going into a Safir MK I. Took the thrust bearings out in less than 3 miles. You learn more from your failures than your successes if you can afford the tuition!

Yes, my post about an M1 ZF going into a Safir MK I. Took the thrust bearings out in less than 3 miles. You learn more from your failures than your successes if you can afford the tuition!
And nobody aknowldeges ones successes, only the failures… my ex boss
 

Julian

Lifetime Supporter
I’m curious now what the input shaft length should be for our car (for a ZF from a gt40 or Pantera)? Anyone know? Will try digging some more.
That likely depends on what bell housing you have, Pantera orientation -2 ZF's are flipped all the time for GT40 application with aftermarket bell housings designed for such. I cannot recall if the original GT40 -0 ZF had the same length input shaft, the -1 does not and requires an adapter. Does the ZF mate up without the bearing in place?
 

Pat

Supporter
Well Christmas has come and gone and I got my bushing. Of course I could ]not find the correct size so I needed to get one cut down a little to size. Put everything back together today hoping for a Christmas miracle but Murphy’s law is strong at my house. Same 1/4” gap!!! Had to walk away as the sun was setting and my back was screaming being hunched over this thing.

With what little I could see with the Borescope is the throw out bearing is just about to touch the clutch fingers. I know it fits without the bushing and clutch. I know the bushing fits the the input shaft on the zf. My brain know is telling me it’s one of two things

1- the splines on the input shaft are bottoming out on the outside clutch disc and therefore not allowing the the trans to go any deeper. This is why I actually think it is now. Of course it will have to get ripped out for me to measure to confirm. I’m confused because everyone uses this McLeod double clutch with zf/safir bellhousing. Are there deeper spline input shafts for the zf and somehow I have a ‘shallow’ one? I need Ron McCall’s brain. If so I could either swap out input shafts (after completely having this thing rebuilt or go to single clutch and space out the throw out bearing.

2- the bushing is still too thick. I doubt this is it. Right now the bushing is 10mm thick and that gap is I’m guessing right now about 6-7 mm. That bushing would become a washer!!

Any thoughts from anyone?
 
Take the clutch off completely and reinstall the ZF and ensure the thing mates up and sits correctly into the pilot bearing. Does the bearing or bushing go onto the end of the ZF - did you test fit it first? There is only one input shaft for the -2 and hence only one length shaft.

You say the T/O bearing is not hitting the pressure plate fingers? Are you sure? Can you rotate the shaft and feel movement of the T/O bearing contacting the fingers? Are the fingers flat to the surface of the pressure plate? They must be within 0/050".

IF you have the correct clutch discs, floater plate, pressure plate, T/O bearing and pilot bearing to work with the Safir Bellhousing, there should not be a problem. Did you buy the entire assembly from Safir? If not, do you know you have the correct part numbers?
 

Mike Pass

Supporter
Maybe try putting a straight edge on the block and on the bellhousing and measure the distance of everything from this datum line using a digital caliper. Do a drawing of the block, flywheel, clutch side and the bell housing,input shaft, splines side. This maybe the best way to figure out what is going on with the assembly as you can't actually get to see any problems, clashes, interference etc. I figured my clutch set up this way.
Cheers
Mike
 

Ian Anderson

Lifetime Supporter
Is the clutch plate in the right way around? ….. no idea if this is even possible on a multi plate clutch, but seen someone do it on a single plate clutch.

Ian
 

Pat

Supporter
In case anyone is keeping track I’m somewhere in the neighborhood of 60-70 attempts of mating and unmating these two with zero success and just a much worse lower back. So I took it all apart and started with basics - assembly one piece of the puzzle at a time until I figure out what the problem is. So I stripped it down taking off the transaxle, clutch, bushing and bell housing. Inspected everything and noticed scuff marks at the bottom of the bell housing from the flywheel???? I wasnt sure if this was from one of the many time of putting it on and off or was it rubbing?? The teeth on the flywheel all look ok.




So now the fun begins and slapping things back together. I’m leaving off the bushing and clutch and putting the bell housing on the ZF to see if it will fit……and it doesn't quite fit. Stick a Borescope in the starter hole and sure enough the flywhell is in contact with the bell housing!! The ‘tight’ fit when I initially installed the bell housing to the block I thought was from the two locator pins on the block fitting into the bell housing, as that where i tapped them on. I’m guessing now it was that and the lower end hitting the flywheel. So now what’s the problem?? Wrong flywheel? Flywheel assembled backwards? Wrong bellhousing or spec’s wrong? I checked the flywhell and its 143 tooth with the beveled side facing the block. Will need to reach out to Safir this week and hopefully figure out what’s wrong. I’m still not sure if this is the only problem as it still got on closer now than it did with the clutch and bushing.
 

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Brian Kissel

Staff member
Admin
Lifetime Supporter
Wow, what a journey Pat. I for one certainly appreciate you documenting everything as you go. This will help all as they may experience something similar.

Regards Brian
 

Pat

Supporter
I just counted the teeth in my picture again and it is 142 teeth so it’s the right size flywheel. Maybe the bell housing want cut right?
 

Julian

Lifetime Supporter
Something doesn't look right with the mounted flywheel, it's stood off the backing plate a long way and the center doesn't look to be located on the crank deep enough?
 

Pat

Supporter
Something doesn't look right with the mounted flywheel, it's stood off the backing plate a long way and the center doesn't look to be located on the crank deep enough?
That’s why o was wondered if it was mounted backwards? That’s the way it came with the clutch. On the other side is flanged. I was wondering if the flange side should face away from the block? See if I can take a picture of it.
 

Rod Dittmar

Supporter
Pat,
I had a similar, but not so extreme, experience mating a ZF to a Dart block via Safir's SBF Clutch pkg. Everything assembled and appeared OK, until I torqued the Bellhousing to the block and ZF to the Bellhousing. Everything then 'locked up' and the crankshaft wouldn't move. I checked & re-checked everything a number of times, just as you have, to no avail. I finally discovered the flywheel WAS slightly in contact with the bottom of the bellhousing and ground enough off to negate that situation. I also discovered that the ZF's input shaft seemed to be bottoming out on the end of the crankshaft, so took apptox. 3/32" of the end. Not sure if those 'fixes' were a bodge masking some other problem, but everything mated & torqued up nicely after that. I now have about 1000 miles on the car and it all seems to be working as it should.
Also, note that Bob Wood at Safir was a great help to me with any questions I had on the proper assembly order of the clutch components.
HTH, Rod
 
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