Utahcarguy

In the picture below, how does 531370 stay attached to 531371? I currently have the spring attached to 531371 and 531366 directly. The spring has tension all the way through, so I don't see a way that will cause an issue. yes I want to correct it eventual, but am I hurting anything by not using 531370 and 531367?

Frankie the Fink

The C1 clutch arrangement is ALL about geometry. Small things can have large affects. That famous hairpin clip in a properly configured system will not go anywhere. The spring's upward tension and the angle of the clip keep it in place and its done so on many cars for 50 years. Without 531367...the small tab for affixing the spring to the Z-bar at the top you are placing add'l stress on things when the spring goes over center. Its probably making the clutch somewhat harder to operate and possibly stressing the rubber clutch rod bushing a little more. If the spring slips off at the top or bottom due to the mis-configuration you may well be on foot.

Its all of $10 in parts and 20 minutes work to fix it so why even run around with the thing set up wrong ??

Utahcarguy

How does 531371 stay in place? From the picture, it looks like it would just pull out under tension.

I'm headed to an event in one week, so that is why I posed the question of "will it work as is". I'll order the parts and hope I can get them installed in time.

As far as 20 minutes of work...it was quite the ordeal to get that monster spring back on. I took off the clutch rod and had someone rotate the crossbar with the spring attached and then hooked the clutch rod back on. Is that the best process?

Frankie the Fink

531371 is the bracket; I think you mean the hairpin clip. It's simple physics so don't overthink it. The gorilla spring pulls on the clip backwards locking it into place...the spring never goes vertical which would pull it out. PARTLY BECAUSE Part #531367 KEEPS THAT FROM HAPPENING !!!! You NEED that part !!!

Trust me - if its in right it ain't goin nowhere.

The ST-12 covers removal of the gorilla spring (Section 6r) -- in short you put a crescent wrench on the Z-bar outlined in red as shown with the clutch pedal push rod disconnected from the bushing on the Z-bar. You just 'rock' the Z-bar forward with the wrench and you'll find the 'sweet spot'' where the spring almost falls off.

Will it work as is ? Well hell no - as evidenced by your clutch issue in your other post. You can't adjust free play to get the hard gear engagement issue fixed PROPERLY until you undick the linkage geometry.

Utahcarguy

You're right, I was talking about the clip. I understand what you're saying. Part on order! Thank you.

Frankie the Fink

Read the bold part I just added in my post...you need THAT piece...
It makes the spring travel through a shortened arc which keeps the spring secure and reduces pedal effort.

Utahcarguy

Thanks Frankie! I have that part. I think the previous owner was using 531367 without the hairpin clip, making shifting possible, but difficult without 531370.

When I went to put the clutch back together after the engine build, I couldn't figure out how 531367 would work with the spring (and without 531370). I get it now and the parts should be here in time for me to get her on the road this weekend. Thanks again!

Frankie the Fink

Final word...the gorilla spring is the most mis-understood part on these cars (except for maybe the wiper/washer systems). It does not increase clutch pedal effort...it 'smooths' out the "force over distance" curve so the clutch action is equalized throughout the pedal range.

vettsplit 63

Frankie- I was a little confused as to how the 62 clutch linkage hooks up, as the OP was. The 531367 swivel arm had been hooked on to the hairpin at the bottom by the guy who had restored the chassis on the car I just bought. He had the spring attached directly to the top where the swivel arm should be. I changed everything around and it looks as though it will work a lot better.

Frankie the Fink

Its bound to work better. As JohnZ will tell you this setup is a 'single shear' system unlike a clevis setup like a brake pedal pushrod....it's a poor design and needs all the help it can get which means everything has to go together a certain way and be adjusted properly.

Still crazy that these restorers won't just look at the AIM and see how this stuff goes instead of how they THINK it should go...

Utahcarguy

531370 part gets here today, giving me all the parts I need to properly install the clutch. Once everything is connected, what is the best way to adjust free play?

I have previously had issues with getting the car into gear. Now that I have all new components, I would think it's all about adjustments now...

jimh_1962

Underneath the car is the rod where you make the adjustment. Remove the pins and twist it out or in whichever way you need to adjust it.

New clutch?

Plasticman

On a C1 V8 Vette, the open bottom bell housing design makes it easy to see where the throw out (TO) bearing is in relation to the pressure plate fingers. Take the dust cover off the bottom of the bell housing, and make sure you have at least 1/16" clearance from the TO bearing to the fingers (when the clutch pedal is "up").

Once you have it adjusted to that point, have an assistant press the clutch all the way to the floor and keep it there. Then look up between the flywheel and pressure plate, and you can see the edge of the clutch disc. Have your assistant put the trans in neutral (still with the pedal to the floor), and then see if you can easily move the edge of the clutch disc (a screwdriver will work). If it does not easily move, then the adjustment needs to move the TO bearing closer to the pressure plate fingers (or there is too much slop in the clutch linkage), when the pedal is "up".

Bottom line is you do not want the TO bearing touching the pressure plate fingers (a TO bearing will not last very long if constantly spun) when the clutch pedal is "up", but the clutch must have full release when the clutch pedal is "down". Hopefully you will see those 2 conditions, and then can move the adjustment either way for a comfortable pedal throw. I like to see .090" clearance at the TO bearing, and yet still get full clutch relase way before the clutch pedal nears the floor. On other C1's, we have seen where that was impossible (too much linkage slop, or perhaps a new clutch disc with excess marcel).

Edit: Here is a good definition of "marcel" from another webpage:

By far the most critical element of the disc in eliminating chatter is the "marcel". This is the term given to the crimped plate, or wafer, between the 2 clutch linings. The purpose of the marcel is to prevent clutch chatter by giving the clutch disc some "give" during clutch engagement. The marcel also helps prevent the lining from sticking to the flywheel and/or pressure plate (due to the spring effect of the marcel) when the clutch is being disengaged. The marcel thickness (the distance the linings are held apart by the marcel when the disc is not under compression) will vary depending on the type of use the disc is designed and built for. Basically the thicker the marcel, the smoother the clutch will engage and the spongier it feels to your foot. The absence of marcel makes the clutch grab, but makes for a much more postive lockup (less slippage and ability to handle more horsepower). As the marcel thickness increases, it will require more clutch lever travel to engage/disengage the clutch. A pure drag/race car clutch marcel will be from 0.000" to 0.010" since engagement is quick and abrupt and chatter is not a problem. Truck clutches use marcels in this area also. A street/strip clutch will generally have marcels from 0.015" to 0.025". Pure street clutches will use marcels in excess of 0.025". A super soft clutch uses marcel in the neighborhood of 0.030" to 0.040". Mine is 0.025" and works well with no slippage and no chatter. When the marcel gets up to 0.030" and more, it may require as much as 60% of the clutch travel to engage.

Plasticman

Utahcarguy

So I asked a car guy about the above post and this was his response. I'm just trying to learn here...

"Once you have it adjusted to that point, have an assistant press the clutch all the way to the floor and keep it there. Then look up between the flywheel and pressure plate, and you can see the edge of the clutch disc. Have your assistant put the trans in neutral (still with the pedal to the floor), and then see if you can easily move the edge of the clutch disc (a screwdriver will work). If it does not easily move, then the adjustment needs to move the TO bearing closer to the pressure plate fingers (or there is too much slop in the clutch linkage), when the pedal is "up"."

DISAGREE – If the above was done, you have no place to go for additional adjustment because you will lose clearance between the TO bearing and the Pressure Plate fingers (Free-play) when the clutch wears and with no free-play, the TO bearing will be spinning all the time the engine is running which will lead to failure of the TO bearing. Something else is wrong. Not the adjustment. It is not uncommon to adjust the clutch as the clutch wears to ensure that you ALWAYS have pedal free-play.

"Bottom line is you do not want the TO bearing touching the pressure plate fingers (a TO bearing will not last very long if constantly spun) when the clutch pedal is "up", but the clutch must have full release when the clutch pedal is "down". Hopefully you will see those 2 conditions, and then can move the adjustment either way for a comfortable pedal throw. I like to see .090" clearance at the TO bearing, and yet still get full clutch relase way before the clutch pedal nears the floor. On other C1's, we have seen where that was impossible (too much linkage slop, or perhaps a new clutch disc with excess marcel)."

If the clearance is a mere .090 between the TO bearing and the pressure plate fingers, as the clutch wears, the TO bearing will come dangerously close to the pressure plate fingers. As the clutch continues to wear, you will have contact which will spin the TO bearing all the time the engine is running. More wear on the clutch and the pressure plate fingers will be pushed further by the TO bearing until the clutch actually begins to slip with your foot off the clutch. As the clutch wears, the fingers on the pressure plate begin to move aft (Toward the TO bearing).

"Edit: Here is a good definition of "marcel" from another webpage:
By far the most critical element of the disc in eliminating chatter is the "marcel". This is the term given to the crimped plate, or wafer, between the 2 clutch linings. The purpose of the marcel is to prevent clutch chatter by giving the clutch disc some "give" during clutch engagement. The marcel also helps prevent the lining from sticking to the flywheel and/or pressure plate (due to the spring effect of the marcel) when the clutch is being disengaged. The marcel thickness (the distance the linings are held apart by the marcel when the disc is not under compression) will vary depending on the type of use the disc is designed and built for. Basically the thicker the marcel, the smoother the clutch will engage and the spongier it feels to your foot. The absence of marcel makes the clutch grab, but makes for a much more postive lockup (less slippage and ability to handle more horsepower). As the marcel thickness increases, it will require more clutch lever travel to engage/disengage the clutch. A pure drag/race car clutch marcel will be from 0.000" to 0.010" since engagement is quick and abrupt and chatter is not a problem. Truck clutches use marcels in this area also. A street/strip clutch will generally have marcels from 0.015" to 0.025". Pure street clutches will use marcels in excess of 0.025". A super soft clutch uses marcel in the neighborhood of 0.030" to 0.040". Mine is 0.025" and works well with no slippage and no chatter. When the marcel gets up to 0.030" and more, it may require as much as 60% of the clutch travel to engage."

You already seem to be having a problem with total throw for movement of the TO bearing and this is what concerns me. I am not familiar with the marcel, but if the marcel is in fact 60% of your total throw, then what’s left? You need to add free-play on top of that 60% and let’s face it, you do have a floor on your car, so you can’t push the clutch pedal to the ground to get the throw you need. Let’s start with setting the free play first. That’s your baseline. Most people agree that at least ¼ inch to ½ inch of free-play at the pedal is a good starting point. Keep in mind that the ONLY thing the linkage springs do is assist in reducing the pedal effort. It can’t change the throw or the free-play.

Plasticman

You obviously know more than I do.............sorry I was not of any help.

Plasticman

JohnZ

Adjust the swivel on the lower rod (Z-bar to clutch fork) so you have 1" of free play at the pedal between the full up position (against the rubber bumper) and where you feel resistance when pushing down on the pedal (beginning to engage the TO bearing).

128racecar

My 57 does not have the arm from which part 531367 hangs on. Does the yellow end of the spring attach to the notch in the front of the top of the assembly instead?

Marc in Indy

Utahcarguy

Marc, if your assembly is the same as the '61, then you need that part.

Utahcarguy

PLasticman, please re-read the post. That was information given to me by a gearhead friend of mine...not my words. Your help was greatly appreciated.

I got everything back together and properly installed. I started the car in neutral and the engine sounded great. When I pushed in the clutch, I heard a high pitched rubbing sound (not good!). I thought I might have installed the clutch backwards and would have to drop the trans to fix it!

Turns out, after thinking on it and troubleshooting for an hour, the arm that holds the throwout bearing was rubbing on the pressure plate when I got to the last 1" of pushing in the clutch.

After more freeplay adjustments, everything runs and shifts fantastic! Now, I am off to Hot August Nights in Reno to show her off and enjoy some sunshine!

Thanks for all the help through my engine ordeal and clutch issues. The people on this board are amazing.

adurso19@yahoo.com

My 1960 has a "weak" clutch spring that attaches to the notch in the pin on top, and to a notch in a small welded bracket on the frame. Is my 1960 different from a 1961 or did a previous owner jury rig the spring set up?