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Does your clutch engage smoothly - your experience with clutch disk types?

bondtimbond

Member
Joined
Nov 4, 2004
Messages
14
Location
Houston, Texas
Corvette
1967 SB Conv
I started a thread like this in the C2 section but know that this question applies to C3's as well so I am posting here also:

I am looking for words of experience with clutch disks. Long story short I have been wrestling with clutch chatter problems on my 67 327 Vette but the same applies to C3 cars also, and I have pulled things apart now for the third time! Somewhat independent of that problem, I discovered that different clutch disks and different facing material on the disk can result in either smooth engagement or abrupt engagement. The photo attached shows the difference in an older GM disk (on the left) from around 1985 or so that I removed from my car, and a new LUK disk on the right. When I installed the new disk, I noticed that the engagement was much less smooth and downright grabby feeling. Even with some drive time it never did smooth out. When I pulled out my trans the second time last year (uugh!), I put back in the original disk shown on the left. The result was a much smoother engagement.

Now I have the clutch out again for the chatter problem, and I have purchased all new AC Delco clutch hardware. With new kit is actually a SACHS unit and disk with Valeo friction material. I have to decide which disk to put in...

Here is what I am looking for input on from this Forum: Are most people happy with the feel of your clutch after recent clutch hardware changes with disks that look like the one in the right of my photo shows?? I am trying to decide whether to put back in the original disk again (which has some life left but does show some wear), or put in the new SACHS disk that came with the kit. If the general feeling is that folks are happy with the newer clutch disks and have no problem with engagement, then I will put in the new disk.

Attached below is a photo of the two types of disks. The one on the right is a LUK disk, but my new Delco/Sachs disk looks similar. Any comments and experience would be greatly appreciated!!

Diskcomparison.jpg
 

bossvette

Gone but not forgotten
Joined
May 19, 2003
Messages
3,233
Location
West Unity Ohio
Corvette
1968 1997
I'll bet Cetenterforce is popular here as well, mine is in my 76 and has over 30,000 troublefree miles on it
 
Joined
Oct 7, 2006
Messages
295
Location
South Dakota
Corvette
76 Coupe
I used a LUK when I had the 4 speed in the car. No problems at all and very smooth. sounds like maybe your flywheel wasn't resurfaced properly when you installed the clutch last time. That could cause chatter.
 

The73vetteman

Well-known member
Joined
Oct 13, 2003
Messages
339
Location
Michigan
Corvette
'73 L48 4spd
I put a LUK in my car just a few weeks ago. I've not done 200 miles on it yet, so it's probably too early to be fair but here's my $0.02 ....

Overall the I like the feel. It's firm without being too hard and I'm not getting any grabbing. That said, it doesn't slip like the old one did (when I wanted it to!) and I am experiencing a little judder as I creep up my drive and into the garage.

I'm putting this down to having cut corners when I replaced the clutch - I cleaned down the flywheel but didn't have it resurfaced. I'm hoping that it will bed in over the next few hundred miles. If not I might end up going down the same road as you!

Hope this helps somewhat.

J
 

Phill

Well-known member
Joined
Apr 20, 2007
Messages
216
Location
s.florida
Corvette
1979 Blk L48
first thing i thought of was the flywheel. if it wasnt resurfaced it could cause chatter.
 

black_81_vette

Well-known member
Joined
Dec 1, 2002
Messages
295
Location
wisconsin
Corvette
black 81 corvette 4-speed
True id resurface the flywheel but its not totally neccesarry,I did mine with a more or less buffing using a die grinder with a rolox abrasive pad to remove the glazing . The flywheel wasent heat cracked and wasent gouged so thats what I did and it worked for me.The clutch set I have is a zoom performance set and it works perfect. One more thing to look at is if the flywheel has been turned alot and enough material has been removed you need a shim to put between the crank and flywheel,napa has them. The reason I say that is I had a 80 camaro that had clutch chatter issues big time.I found out the flywheel was too thin and need either replaced or use the shims. I put the shims in and it was good to go.I cant remember where I found the spec for the min machined hight at but its something thats overlooked alot and by checking it can save you alot of grief.
 

Artsvette73

Well-known member
Joined
Jan 24, 2004
Messages
174
Location
New Jersey
Corvette
1973 Silver coupe, 1977 L48
If the flywheel wasn't resurfaced I would look at that. I have a centerforce and the engagement is smooth.
 

bondtimbond

Member
Joined
Nov 4, 2004
Messages
14
Location
Houston, Texas
Corvette
1967 SB Conv
Thanks for the replies. I have good news in that I think I have finally fixed my problem! In the course of the last year or so, I have checked just about every items mentioned in this thread, but still had chatter.

This weekend I reinstalled everything with another new clutch and pressure plate set. This time I used a AC Delco set (made by SACHS) part number 381146. I also had the flywheel resurfaced again by a different shop, and also balanced as a set with the clutch parts. All of this I had done before, but this time used a different shop. They got the runout of the flywheel down to .002" (from .004 or .005" before). I installed the new clutch plate that came with the kit, which looks like the one on the right in the photo at the start of this thread.

On first drive engagement seems smooth and no chatter so far. I am crossing my fingers. I suspect that my first clutch set which was by LUK, had a defective pressure plate. That would be my guess. My flywheel runout is nice and low now, but wasn't too bad even before so I am not sure that was the problem. Thanks to all for the comments!
 

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