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Discussion Starter #1 (Edited)
I am setting up my clutch system right now before I put the drivetrain back into my chassis and I need some help. Here is what I have:
350 SBC, Sm420 tranny, cast bellhousing, cast fork, Wilwood 3/4 bore master, CNC 7/8 bore push type slave, long throw out bearing, coil spring pressure plate (3 finger type)

The coil spring pressure plate was origional to my donor engine (along with manual linkage) so I am reusing it however with all of the above components the clutch pedal is fairly hard. It takes a full pedal to disenguage the clutch but when I turn the t-case yoke I can hear the clutch dragging on the flywheel or pressure plate slightly.

Should I replace my pressure plate with a diaphragm type with all the release fingers? How will the pedal feel be? I like a little resistance in my cluch pedal but definately less than my current setup. Lastly, will I also need the short throw out bearing even with my straight cast fork if I use the diaphragm type? Thanks
 

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You should have bought a clutch kit with the pressure plate and replaced it at the same time.

Yes, the pedal will be far better with a diaphram clutch.
 

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Discussion Starter #3
I did get a new clutch and had the old pressure plate rebuilt at a local clutch shop. I have the option of bringing it back and outright exchanging it for the diaphram type.
 

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On the rig I'm building now, I used the same push style CNC 7/8s slave but I have a 3/4" CNC master. It is pretty stiff like you said, but I just figured I'd get used to it. To get enough throw out of the slave I had to make the adjuster really tight to the fork and I also had to adjust the clevis on the master all the way out on the threads. For sure it isn't a perfect combo....I'm not sure if a bigger diameter master would be better to move the slave faster or not because I think the pedal would get even stiffer.
 

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Brian1 said:
I did get a new clutch and had the old pressure plate rebuilt at a local clutch shop. I have the option of bringing it back and outright exchanging it for the diaphram type.
In this day and age I have never heard of rebuilding a pressure plate, nor have I heard of a clutch shop. Bring it back and get yourself a new diaphram clutch.
 

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Bahahahaaaa

My god, this sounds EXACTLY like a post I put up in Jeep Talk about a month ago. I too have a 420 behind a 350. I bought a brand new Borg & Beck clutch assembly. I also converted to hydro on the clutch, using stock Jeep stuff, matched 3/4" bore on slave and master. It wouldn't disengage fully until I moved the slave over on the cast fork to the inner position. It worked OK like that, but I didn't like it. Yesterday I bought a new diaphram clutch kit and I'm putting it in tonight. I found that the pivot ball had backed out some, so I tightened that down. The rest of the system looked great though. I just think the B&B style clutches are made for a mechnical linkage where you have more adjustability on the fork movement. My theory anyhow.

I would recommend replacing what you have with a diaphram style, much nicer (softer/easier) engagement and it'll be new.

I went with the 3 finger design because I thought it would hold better, however, I read on the 'net somewhere that in high torque, low speed (read RPM) apps, the diaphram style is actually better, holds better. Has to do with how the fingers spread the load versus just having the HD springs on the 3 finger design. I dunno for sure, but it sounded good. LOL

I'll post up once I get the new one in and let you know how she works out.
 

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UPDATE:

I got my new clutch installed this weekend and drove it. Works MUCH better than before and is a lot easier on the leg.

Ken
 

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Discussion Starter #9
Cool, thanks for the update. I also changed mine (pressure plate) a few days ago. Pedal is a little softer and the slave throw is much better now with the new diaphragm pressure plate. Once I get it in the jeep I am sure it will be fine. I had a ghetto setup to test the pedal feel on my garage floor.
 
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