Help mating zf and dart block!!

Pat

Supporter
The crank end position had crossed my mind previously, I had an engine builder screw up on thrust washers once, that was a very short lived engine.... You definitely don't want the ZF input shaft inducing any thrust on the crank.

Perhaps you could mate the bellhousing to the engine and mount the starter to see where it engages on the flywheel as a further data point? On that note a spacer between engine and bellhousing would alter the starter to flywheel engagement, but honestly this should be solvable without the need for spacers.
I was thinking this that a spacer between the bell housing and the block would essentially ‘push’ the transaxle and bell housing back while adding the spacers. In theory the starter and flywheel would be in the same ‘space’ in relation to the block? Am I thinking this correctly?
 

Julian

Lifetime Supporter
I was thinking this that a spacer between the bell housing and the block would essentially ‘push’ the transaxle and bell housing back while adding the spacers. In theory the starter and flywheel would be in the same ‘space’ in relation to the block? Am I thinking this correctly?
Thinking about it as long as the spacer incorporates the starter mounting (similar to the block plate) then you'll be okay. What's the thickness of that plate, you could potentially double up or get a thicker one.
 
Here's another critical measure I took that you may confirm. Assembled bellhousing onto ZF. Added back plate. Put straight edge across the opening and measured the amount the ZF input shaft sticks out beyond. I get 7/8" exactly.
 

Pat

Supporter
Here's another critical measure I took that you may confirm. Assembled bellhousing onto ZF. Added back plate. Put straight edge across the opening and measured the amount the ZF input shaft sticks out beyond. I get 7/8" exactly.
My plate is behind my flywheel which I don’t feel like pulling right now but I mic’s it at 0.060”. Putting the bell housing on the zf and measuring the stick out of the input shaft and subtracting for the thickness of the plates 0.060” I also got 7/8” (actually I got 0.878”)

Which got me to measuring the other way also using the flywheel and the plate on the block as reference points. First I measured from the flywheel to the plate on the block, then to the flywheel to the bottom of the center crank hole, subtract those two tp find the distance from face of block plate to face of crank center hole. Now I go back to the Input shaft stick out length of 0.878” and add the 0.060” for the plate that I removed and added in the last step to give me my new slightly longer stick out length. When all is said and done I find out I’m 0.149” too long but of course with the caliper I’m able to get a lot deeper than the actuall input snout so could easily throw in another .1” or round up to 0.3” for good solid clearance for any heat expansion.

I have found a Quick Time spacer plate for a Ford 302 that is 3/8” thick (0.375”) so after removing the original 0.060” plate that would give me an additional 0.315”. That should solve the problem but I dont know why I have the problem which bothers me. I dont;t want it coming back to bite me in the ass down the road. We know how that goes.

I’ve called Bob Wood (thanks again David!) so hopefully he’s run into this before and can help guide me and let me know what’s going on. Two months ago I just wanted to mate these together, throw them in the car and start working on the fuel tanks!!!
 

Pat

Supporter
Good news is that Bob was gracious enough to quickly return my phone call this evening. Turns out he too had the exact same problem with his car. His input shaft was also the same length too long and he ended up cutting the end of the input shaft off to get the clearance needed. I guess I wasnt losing my mind after all these weeks after all.

For any that run into this problem he cut his off with a dremel tool and them chamfered the edges. I’m thinking now about doing the same because that 0.3” might come back to bite me when the transaxle is sticking out too far in the back or something else down the road.
 
Very interesting information -- your thread certainly enlightened me prior to doing the same thing. That's a pretty hard shaft to cut with a Dremel?
 
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Mike Pass

Supporter
As previous use 1 mm metal cutting disc in an angle grinder. Cover everything to avoid ingress of grindings. Put the box in gear and rotate the input shaft with the outputs. Use a normal wheel in the angle grinder and hold it firmly as someone rotates the shaft to get a nice clean chamfer.
Cheers
Mike
 

Pat

Supporter
Nothing is ever easy. I asked Bob if it was hardened steel. He said it took some time and was was harder than some steel but cut through just fine with the dremel.
Still thinking which way is better. Since I already ordered the spacer I may try fitting it up and see how it fits. That way obviously puts the transaxle further back which affects the throw out bearing, transaxles, mounting points for ZF, possible interference with exhaust pipes, etc, etc, etc.
Cutting the input shaft may be smart move.
 

Julian

Lifetime Supporter
I have a ZF mated perfectly to a Ford block without cutting, dremeling or any other kluges or bodging. Sorry to be so blunt, but the root cause is Safir's bellhousing looks to be a total piece of crap.
 

Pat

Supporter
I’ve been thinking over Julian’s statement last night in my head. My ZF and 302 block are the exact same dimension as the ones they used roughly 60 years ago. The only puzzle piece that isn’t the same here is the bell housing and spacer plate. So why should I cut the input shaft on my ZF that is exactly like the ZF from the 60s? (Except it wasnt a -2 but thats neither here nor there, anyway). I have got to assume that the castings have gotten worse over time as copies have been made and the bell housing has gotten out of spec. That’s why it interfered with my flywheel and also now is too short for the input shaft. I guess I’m saying is I’ll be going with the spacer and keeping my ZF input shaft intact.

Sorry for the post kind of convincing myself that my theory is correct but hopefully this will help someone down the line.
 

David Garton

Supporter
Pat, I know there are a few out there that have not bolted there Safir bellhousing on yet and possibly could put theirs out and lay it flat block side down and measure from the block side up to the back side of trans mating surface. That would tell total depth and you could measure yours . Mine is all together so I can't get an actual measurement for you. Lee Patterson might be one that comes to mind. Hope this helps. I would not add a oversize spacer and would pinpoint the issue instead of compensation for it. These parts are not cheap and you should get what you paid for. It the bellhousing is shallow then I am sure Bob would exchange it.
 
I measure mine at 3.957" approximate. I believe the conflict is with the varying crank pilot hole dimensions as some builders herein have not experienced this issue. But your's has certainly made me aware of what to watch for when I get to this point. If it were me, I would trim the end of the ZF input shaft.
 
For what it's worth, the ERA build manual says the bellhousing must measure 4.0" face to face. It also says this about the -2 ZF:

1736106629026.png
 

Pat

Supporter
I took off the bell housing, laid it flat on my welding table which is 1/4” flat steel plate and took numerous measurements around the interior (zf portion) circumfrunce depth to the table. All readings were between 3.93 and 395”. With cold weather and me doing that quickly I’ll call that 4”.

Does the ERA manual give the actual length of the shaft? It looks like we have the same length rare shafts Lee…..how fortunate of us!!!
 

Pat

Supporter
Just took me 10 minutes to figure out how to open that ERA manual on stupid new IOS system!!!
 

Pat

Supporter
Found it. Right under that statement that Lee posted in the ERA manual about the rare -2 with longer input shafts they show a picture with how to measure the input shaft and show 4.7”. Well I measured mine. Anyone want to guess how long it is?????
 
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