Clutch: cable or hydraulic?

[Greybeard]

I bought my Vega this year that was equipped with TH350/3000 rpm Stall combo. Although well suited to the engine, not so much to the new owner. The car came off the transport in a cloud of smoke. "Must have been the transport people" because it was "perfect" when it was loaded according to the seller. The "big mother thumper" cam had flat lobes, and it Had considerable leakdown. A major inconvenance when you buy a car, but I've raced and built sbc engines for 50 years and thus, this was not the end of the world. Might have wanted to smack the seller for being "less than honest", but he may have just been ignorant........ Sure.
Sorry. Guess I had to get a little rant in there.
The engine as it is now. All forged bottom end, custom Comp hydraulic roller, aftermarket heads with behive springs, should make near 450hp @ 65-6600 rpm. 7200 valve float. It's higher on a desktop dyno, but the Sanderson shorties with 1 5/8 tubes aren't ideal.
I received, with the car, the original clutch pedal, under dash brackets, cable, and an bellhousing I've yet to identify. I've used the L88 clutch assembly several times in the past, and was quite pleased with it. With a light car and limited traction I may not need the holding power of the L88 clutch, but I like to row through the gears and it won't do to have a cheap diaphram clutch hanging up.
I'm 71, and in another 10 years they may be wanting to take my toys away. The car won't see a lot of miles, <10k is all I'd guess. I need a clutch system that is dependable. I'll probably use an m21 Muncie, or a super t10.
So after all that, the question is: can a cable or modified cable work, or will it need to be hydraulic?
Thanks
Mike

[Smiley]

I did the same thing, bought a V8 automatic on Ebay and changed it to a Muncie 4 speed.
The stock Vega cable and pedals will bolt right in and work with a Monza V8 bellhousing , which takes Muncie/T10/Saginaw 4 speeds and a 10.5" clutch. I use the L88 flywheel and like it.
The cable setup will flex and crack the firewall if you try to use a heavy tension pressure plate.
The pivot is adjustable on the Monza bellhousing and when properly adjusted it works very well.
Centerforce and B&B style pressure plates are not reccomended.
The best option for Hurst shifter is a 72 Chevelle Competition Plus it sits low and close to the trans with an offset shift handle mount so minimal cutting is required.
Look for a 69 Camaro non console oval boot and a Hurst 538-9015 round stick to work with that boot its 8" tall with 3" rear offset.
The Chevelle shifter body moves the stick mounting point 2" up and 2" to the right so the 8" will feel like a 10" on other Hurst shifters.
You should get the trans you want to use before ordering a shifter as there are small differences in Muncies that need different mounts and shift levers.
Later Muncies went to the larger TH400 spline output shaft so they are stronger but require a different yolk on your driveshaft.
Later Muncies went to pass side speedo cable hookup and bolts to retain the shift arms.

If you are going to sell those Sandersons let me know.

Since you already have front motor mounts Hooker 2129's will work, they have 1.75" x 31" long Primary Tubes and 3" x 10" Collectors.

[BadBowtie]

Stock cable system has the advantage of bolting in, unfortunately i cant comment how well they work or reliable they are, i know there are plenty of people out there using it. Going hydraulic does mean some custom work to get the hydraulics attached to the pedal, in my case I moved the fuse box over and modified the firewall.
This is the same setup I used : http://www.chevyhardcore.com/tech-stories/ignition-electronics-efi/rice-rat-rod-quartermasters-hydraulic-release-bearing/

You can see my modifications : http://forums.h-body.org/viewtopic.php?f=20&t=30039&start=60
However i did end up using a 7/8" master because there wasnt enough pedal travel, pedal feel is a bit heavy but I dont mind.

[cjbiagi]

One thing to realize is that with a mechanical or hydraulic system the they are designed to "push" the clutch fork while a H body bellhousing and fork require that you "pull' the fork. So, keep that in mind when switching systems. A cable system works fine even with a upgraded clutch package. I run a complete Hays setup with their steel flywheel and "Street" 10.5" clutch assembly. This is all that fits into the H body bellhousing. Considering this is the same clutch used in much heavier Chevelles, Camaro's etc it is more than adequate for a light wieight H body. Going to anything heavier is unnecessary and may start to put too much strain on the firewall. I reinforced my firewall where the cable enters by running another brace from the firewall where the cable enters to the heavy frame area on the wheelwell. A hydraulic setup is probably a better setup but you have to consider the obstacles and costs invlolved.

[Greybeard]

Thanks for the replys.
I'm familiar with cable to a point, having owned and driven a Cosworth for a couple years. My experience was that it worked, and I never had to touch it. Knowing I needed to step up because of the huge difference in torque, I've read hundreds of posts by using the search engine and searching "clutch". I was aware through the searches that there were some cable issues but fewer than I had imagined.
Where do People buy the cables?
I have always wished there was a way to compare clamping force. I've been more than pleased using oem L88 stuff having had several motors that really turned up without once having one go over center and hang up. I'm sure the aftermarket street stuff is much better now than back "in the day". I'd much rather have a clutch slip a little than hang up and I float the valves. My history with engine failure has always been from the top down. A street diaphragm clutch that doesn't over center is perfect. Maybe a pedal stop is the answer to a soft clutch and 7 grand shifts.

[Smiley]

You can adjust the pivot and the cross nut at the end of the cable so it releases an inch or so off the floor making it the overtravel stop.

[Greybeard]

Thanks Smiley.
If I choose to go racing again, I'll be sure to check with you before changing out the Sandersons. Those headers you showed are what my engine needs to reach its full potential.

I looked at the Hays clutches, as well as finding some specs on the old L88 clutch. The hays has approximately 1/2 the clamping force. The L88 clutch material included woven linen or something quite organic. Perhaps I can find a disc with more friction potential that will work with the light pedal pressure of the hays and contain the horses as well.

[Smiley]

Centerforce would fit the bill but I have heard there were some clearance issues with the counter weights rubbing on the fork or something.
Maybe look into it a bit further.

[cjbiagi]

You only need enough clamping force to prevent slippage when the clutch is engaged. Any additional force really isn't doing anything. So, it really depends upon your engine torque, vehicle weight, gearing etc. A light weight car with a smallblock does not need a real heavy clutch. A very heavy clutch only makes is more difficult to drive and puts a lot of strain on the linkage, either mechanical or cable. You need a clutch that will handle the power and a good 10.5" one will do that unless you are really building something wild and have the traction. The H body bellhousing is limited to a 10.5" one, so you may be able to juggle the clutch disc material if you think you need more grip. There are options out there but I think you'd be fine with a high quality clutch from the major clutch companies.

[Greybeard]

I've looked at the Hays clutch, and I'm thinking I'll go with their "street" clutch pressure plate with its light pedal pressure. That will work better using a stock cable. I think I had my mind wrapped around what I was going to do before I Posted. I was looking to see if someone would jump in and say "you can't do that". That didn't happen.

On another note. I've spent may hours reading thread after thread, researching and gleaning information. One thing that has stood out is the people who are consistently helping, and sharing what they know. The same people show up in thread after thread. I just wanted to say thank you. You are appreciated

[cjbiagi]

There is also a lot of confusion on the proper way to adjust the clutch pivot ballstud and cable. I have written and posted several threads on getting it all adjusted correctly as well as choosing the correct "short" ( there are different lengths even between short bearings) throwout bearing to help get the proper clutch fork angle. I can help when you get to that point.....

[Greybeard]

Thanks,
I'm sure I'll have questions.
Mike

[Smiley]

https://hurstshiftersonline.com is a good resource for shifter parts and kits.
This is the 69 Camaro boot, it fits nicely on the narrow Vega tunnel.
It is designed for the round stick, Hurst now offers round sticks in 3 shapes.


538-9015 stick- 8" tall with 3" rearward offset.


Shifter #3918014 for early 70's Chevelle has a 90 degree offset stick mount for better tunnel clearance.



70 and later Muncies with the larger output shaft don't use the "U" bolt mount they require the 3 bolt mount like this:

[Greybeard]

Thanks Smiley
That Camaro has the cleanest looking setup I've ever seen. Too bad we don't have room in our cars for the larger pedals.