75 280Z - 5 speed swap from 81 280ZX - any catches I should be aware of?

[HusseinHolland]

New issue - I don't recall anyone mentioning an issue with the slave cylinder but the offset is wrong on mine. I used the clutch complete intended for the 81 300ZX, and the throw out lever, pivot and bearing.

Anyone else experienced this? I'm assuming the operating throw is the same, just a longer rod required?

Edited July 2 by HusseinHolland

[Patcon]

This is what the factory driveshaft bolt looks like

 

[HusseinHolland]

I went through my collection of hydraulic clutch components.

Datsun

Hnoda

Volvo 700

Fiat X1/9

The Volvo one may be just long enough. It also has a wear resistant head. Otherwise, I mod the  Fiat one.

Old clutch

The old disc is significantly thinner than the new - I didn't check the stack height of the whole clutch though

Cleaned up the spacer plate and heat sheild

New rear main installed

installed & torqued the flywheel - 105 ft/lb . Volvo flywheel lock tool from the 70's

Disc centered, PP torqued to 15ft/lb

New PP  only uses 6 bolts like the original 

3 Guide pins made it easy to set the trans on the motor. That was a nice tip

Shifter attached. I had to shave one of the top hat bushings to get it to fit in the fork

Trans in place, mount set. Took a bit with that, I had to leave the mount loose on the trans to get everything to align as it was lifted into place. Think I had it backwards first time around

Speedo cable attached, all new seals

Reverse light switch swapped over from the 4spd.

Cleaned & primed the left frame rail - looked like brake fluid must have stripped all the paint at some point

[Zed Head]

3 hours ago, HusseinHolland said:

New issue - I don't recall anyone mentioning an issue with the slave cylinder but the offset is wrong on mine. I used the clutch complete intended for the 81 300ZX, and the throw out lever, pivot and bearing.

Anyone else experienced this? I'm assuming the operating throw is the same, just a longer rod required?

The potential problem is the fork bottoming out on the hole before release.  Your picture shows quite a bit of distance.  Eurodat has posted the slave cylinder throw before, I think it's shown in the Clutch chapter of the FSM.  If you don't have that amount of free space behind your fork that could be a problem.

[Zed Head]

It would be pointless for them to show possible stroke so I assume that what they show is the travel achieved when the pedal is pressed to the floor.  I'd remove that boot and take a measurement.

[HusseinHolland]

1 hour ago, Zed Head said:

The potential problem is the fork bottoming out on the hole before release.  Your picture shows quite a bit of distance.  Eurodat has posted the slave cylinder throw before, I think it's shown in the Clutch chapter of the FSM.  If you don't have that amount of free space behind your fork that could be a problem.

 

1 hour ago, Zed Head said:

It would be pointless for them to show possible stroke so I assume that what they show is the travel achieved when the pedal is pressed to the floor.  I'd remove that boot and take a measurement.

 

Thank you for finding that - I have more than 1.5" off the backside of the fork to the back of the casting opening. I need about 1/2" extra rod length to take up the slack. I don't see any difference in PN listings for the slave cylinder between the 280Z & the 280ZX. I know ZcarDepot sells one with an adjustable rod, so I assume this has come up for others. The new disc is substantially thicker than the worn one, I want to say at least 1/6th inch, which would draw the fingers in, since they move rearwards as the disc wears. Not seen this symptom on any other car I've installed a clutch (that was listed/intended for the vehicle in question) on though. I'll play with a longer rod & see if it disengages as expected -have to put the exhaust, etc., back on to test it running of course. Hopefully it's not all coming back apart.

[HusseinHolland]

Waiting for Z parts.

Getting ready for a retake of the Ithaca trip in the pickup. Yesterday my wife pointed out that there was a bad noise coming from under the passenger side - the cat was disintegrating. I don't have another cat to put in - so today  I modified a resonator to fit

Test  fit - cut the flange and extension pipe off the dead cat - tacked to resonator

welded, added bung for O2

all good.

good offset on the O2

Also had to fix my Mum's weed whacker - the lower shaft wouldn't stay in the main body, so I just drilled it & put a set screw in there

 

Edited July 4 by HusseinHolland

[HusseinHolland]

I did install the longer slave push rod from the Volvo - that one fit perfectly, and pedal feel & travel is good. I used the Honda boot - had a little more travel allowance

[Dave WM]

nice fix on the cat.

[Zed Head]

Good luck with the longer slave cylinder rod.  Hope it works well.  If you consider the contact points on the fork ends you might be getting close to the edges there.  Plus there wil be some "unengineered" loads on the fork itself, especailly the spring clips that hold it to the pivot ball, due to the more extreme angle at full disengagement.

Just some thoughts to have in mind if thngs feel odd later on.  You're outside of the design envelope but might be just fine.

Borrowed some pictures from the internet.  Just fun stuff to think about.

https://maseraticompound.com/collections/datsun-280zx/products/datsun-280zx-clutch-fork-throw-out-bearing-and-clutch-spring-set

[HusseinHolland]

On 7/4/2024 at 3:15 PM, Zed Head said:

Good luck with the longer slave cylinder rod.  Hope it works well.  If you consider the contact points on the fork ends you might be getting close to the edges there.  Plus there wil be some "unengineered" loads on the fork itself, especailly the spring clips that hold it to the pivot ball, due to the more extreme angle at full disengagement.

Just some thoughts to have in mind if thngs feel odd later on.  You're outside of the design envelope but might be just fine.

Borrowed some pictures from the internet.  Just fun stuff to think about.

https://maseraticompound.com/collections/datsun-280zx/products/datsun-280zx-clutch-fork-throw-out-bearing-and-clutch-spring-set

 

Since I still have the complete 4 speed with fork & bearing/collar, I could measure the revised fork rest position & then observe the fork/collar contact over the 1.25" or so travel required to disengage the clutch. I might out of curiosity's sake. As long as it lasts a year or so, that's really all that matters. As the clutch wears the fingers will move rearward, reducing the fork throw anyway - but, I am unlikely to put enough miles on it for that to come into play before the whole mess comes out for the V6/CD009 swap.

[HusseinHolland]

Lever offset - approx 4 /34" with new clutch

Going to the old trans & setting the fork to the same offset, then extending fork 1" rearward

fork to sleeve contact at 1" extension

Sleeve offset at the 4.75" setting

I guess I could mod the pivot pin (move it forward/extend the seat) so that the lever is moved forward. That would reduce the travel of the sleeve & move it back closer to stock.

I honestly don't know why the new clutch setup (intended for 81 280ZX NA) has a different stack height than the old clutch & T/O. I'm not going to take it all apart, as no matter what I find I would have to return / replace the clutch to hopefully find a resolution to the issue of the changed lever offset. 

 

Edited July 8 by HusseinHolland