BritishV8 Forum

I think I am about 6 weeks away from pulling the original engine and tranny and starting my 5.0 Ford and T5 swap in my 1980 MGB.

I am still struggling a little with clutch "linkage".  Is this the way to go for a slave cylinder system?

 http://www.novak-adapt.com/catalog/clutch/kit_hcrf.htm

That pull type slave might be a solution - the clutch M/C is 3/4" bore, so you'd need the 3/4" bore slave.
Be advised that the clutch fork length might be problematic with tunnel clearance and interference needs to be checked.
A lot of us use a push type slave with about 3/4" cut off the fork end.

I think the photos in this article do a particularly good job illustrating clearance issues for the MGB/SBF/T5 combination, and how a Nissan truck pull-type slave (like Graham's) helps to solve them: http://www.britishv8.org/MG/MartynHarvey4.htm

Ah yes, I see the difference.  Any idea what Nissan Truck that part comes from.  It looks like the most compact solution.

Keith,
     Here's a typical ebay auction for the Nissan clutch slave...Readily available from Rockauto or any major auto parts store.
http://www.ebay.com/itm/Clutch-Slave-Cylinder-Nissan-Datsun-521-620-720-Truck-/320951135949?pt=Motors_Car_Truck_Parts_Accessories&fits=Make%3ANissan&hash=item4aba2daecd&vxp=mtr

That Nissan setup is a push cylinder, just to avoid confusion (probably obvious).  I did something similar, but of course I made it much more complicated and painful than it needed to be.  I'm good at that.  

Push cylinder does package much tighter than a pull setup.  


Graham, Is that your setup?   What are you attached to other than the tab below the reverse lamp switch?

Second attachment point is the other tab (hole added of course)......evident from another photo angle.

Very nice.  I decided against that slave cylinder because the bleed fitting was on the bottom, but I should have went with it.  Much cleaner.  My setup works very well, but the bracket is much crazier.

QuoteI decided against that slave cylinder because the bleed fitting was on the bottom...

True...but it actually bleeds very well.

After having done this, I don't see how it can be done without shortening the arm.  My attempt!


Paul

That's pretty slick!

My kids, more often than not tell me I'm wrong about everything, so I thought I'd ask.  I was told that the actuation rod should be adjusted so the throw out bearing rides against the pressure plate.  Is this correct?  I had planned to use a return spring like Graham but was told, by the same people, that with the bearing against the plate I didn't need a spring.  Being an "Old School" kind of guy I'm a little uncomfortable with that, but as I said, I'm often wrong.  What do you think?


Paul

I'm not sure but I believe it's dependant on the bearing you're using.  The one I got did say it was designed to be stay in contact with the plate.  I'm going off memory, but I belive it said 4-5lbs of pressure.  I don't have a way to measure that so I just adjusted mine to be in light contact.  4.5k miles so could prove to be wrong still, but so far seems to be working fine.

QuoteI was told that the actuation rod should be adjusted so the throw out bearing rides against the pressure plate. Is this correct?

The Ford release bearing is of the "constant running" variety and is installed with a 4# pressure against the clutch fingers -( no bearing to diaphragm clearance required)
My return spring is installed just for assurance that the whole linkage remains in contact (but in theory not required)

Great question, and I'm glad to see the answers you guys have offered.  My To-Do list has "Decide about return spring for TOB".  
Other than wear, I've also seen comments on noise.  If it sounds OK, I'll go without one.  I used a "Perfection" clutch kit (nothing fancy).

If it was me I'd use Paul's linkage and Graham's bracket for the perfect setup.
The return spring is more of a personal preference thing.
Pretty much every throw out bearing available these days is capable of "constant contact" use.
The deciding factor is your slave cylinder.
Most newer designs have an internal spring in them to force the piston out.
This takes up all of the linkage clearance and gives you a constant contact system.
The advantage is no more clutch adjustments and no pedal free play.
The clutch feels much more direct and with no free play the leverage can be increased slightly for a softer pedal.
The down side is a minor acceleration of clutch finger and throwout bearing wear. As well as wear to the clutch arm from the constant movement.
For slaves without the internal spring your only option is the return spring with an adjustable link for free play.
Setting this type of slave up for 0 clearance is an invitation for disaster.
It's called an interference fit. Because when it goes wrong it interferes with your bank account.
The advantage is longer component life.
The down side is regular clutch adjustments and the loss of movement due to the necessary pedal free play.
That probably just muddied up the water. But you know, I gotta say something.

Cheers
Fred

I have a CNC slave cylinder and have no idea if it has a spring in it or not.   I've decided to run a spring and connect it to the cylinder bracket.  By the way it has a real rod on it now rather than the bolt.



Paul

The CNC slave cylinder does not have an internal spring.

What are the Pro's and Con's of the CNC not having an internal spring considering an external spring is used?  Obviously the external spring keeps the return pressure on the rod so the piston can't retract and the rod fall out.  I assume the internal spring pushes the piston back as well???


Paul

Internal spring pushes the cylinder out, so it does the opposite of a return spring.  It make sure the system doesn't go slack, where the external return spring makes sure the sytem does go slack (if it's adjusted with slack in it).

Just finished taking out an IHTO, and going external on my 300 Buick with GM T5. I used the Nissan 3/4" bore slave with internal spring. Wow! I should have done this years ago. Lighter pedal with way smoother engagement.

I think I'm hearing it might be a good idea to replace my 7/8" bore non-spring CNC cylinder with something else.  I've also thought of changing my -3 AN line to a -4 but I'm not sure it would make that much difference.  Opinions please.


Thanks Mike, I'm rather proud of my linkage and throw-out arm; the bracket not so much, though it works ok, it's a bit ugly.

Paul

Paul,               Dorman part # CS37498  Rockauto.com for less than $10

Paul,
If you already have the parts, then I see no reason to change them.
The spring type slaves exist only to remove the need to adjust the clutch from time to time.
This lowers warranty claims for the OEMs dramatically at a very small cost per unit increase.
If a cable or mechanical self adjusting mechanism could be made reliably and cheaply. We would never have seen a hydraulic clutch.
Put a return spring on your current setup. And check the pedal free play every once in a while. Just like the old time mechanical linkages that we (most of us) are all used to. And your dancing in the rain.
As far as the -3 line. That's 3/16ths which is more than big enough for a 7/8ths slave.
If you're fighting a slow actuation then you have a much faster left foot than I do.
Cheers
Fred

Thanks for providing the part # Capt'n  Been trying to decide what to use for a slave cyl and that looks perfect .
Hope You don't mind your idea being used on a Triumph. ;-)