T56 Clutch Problems and Recommendations
Thread Starter
Intermediate
Joined: May 2019
Posts: 48
Likes: 6
From: North Shore Massachusetts
T56 Clutch Problems and Recommendations
Vehicle Info:
Last year, I upgraded from a fairly mild 350 to a Blueprint 400 Stroker. At this time, I also upgraded from a GM Clutch (OE for the LT1 Z28), to a McLeod Super StreetPro & billet steel flywheel, in order to accommodate for the additional HP and TQ being delivered from the BP 400.
Within 200 miles of break in, I noticed that there was brake fluid weeping from the bottom of the bell housing. Upon further inspection, the slave cylinder had begun leaking and the boot was completely torn. After replacing the slave and master with new replacement parts (all parts were OE for the LT1 Z28), I was able to complete the break in procedure for the clutch.
Fast forward to now:
With 700 miles on the new clutch, it slips incredibly bad above 4k RPM. The McLeod clutch is rated at 500HP, which I know I am slightly above. Is it entirely possible that I am making too much power for this clutch? Sure.
However, I have another theory that I'd like some opinions on…
For the 200 mile period where brake fluid was leaking from the slave cylinder and collecting in the bell housing, is it possible that brake fluid found its way onto the clutch, resulting in damage and the current slipping condition? I have not pulled the clutch to inspect yet, nor will I, until I decide what to do next. Which leads me to a couple questions…
Questions:
- Car: 1979 Corvette
- Engine: Blueprint 400 Stroker - 525 HP and 550 TQ
- Trans: T56 6-Speed swapped form an LT1 Camaro
- Clutch: McLeod Super StreetPro - Pull-Style Clutch w/ external slave cylinder
Last year, I upgraded from a fairly mild 350 to a Blueprint 400 Stroker. At this time, I also upgraded from a GM Clutch (OE for the LT1 Z28), to a McLeod Super StreetPro & billet steel flywheel, in order to accommodate for the additional HP and TQ being delivered from the BP 400.
Within 200 miles of break in, I noticed that there was brake fluid weeping from the bottom of the bell housing. Upon further inspection, the slave cylinder had begun leaking and the boot was completely torn. After replacing the slave and master with new replacement parts (all parts were OE for the LT1 Z28), I was able to complete the break in procedure for the clutch.
Fast forward to now:
With 700 miles on the new clutch, it slips incredibly bad above 4k RPM. The McLeod clutch is rated at 500HP, which I know I am slightly above. Is it entirely possible that I am making too much power for this clutch? Sure.
However, I have another theory that I'd like some opinions on…
For the 200 mile period where brake fluid was leaking from the slave cylinder and collecting in the bell housing, is it possible that brake fluid found its way onto the clutch, resulting in damage and the current slipping condition? I have not pulled the clutch to inspect yet, nor will I, until I decide what to do next. Which leads me to a couple questions…
Questions:
- How many of you are running the T56, with similar (or more) power, and have had success with a single disc clutch? If yes, which clutch did you use?
- The other option I am considering is upgrading to the LS push-style clutch, with hydraulic TOB, and running a McLeod twin disc set up (RST or RXT). Based on my power levels, I believe this is overkill for my application. Any opinions here?
- Pedal feel is quite similar with the McLeod to that of the OE GM clutch that was in there prior (I was expecting a heavier pedal, and less forgiving clutch engagement).
- The clutch engages quite high on the pedal stroke, same as it did with the OE GM clutch (Seems to be a common theme with the pull-style T56 clutches).
- I modified the master cylinder arm, in order to accommodate the clutch pedal and stroke (The same modification was done by the PO on the old MC).
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
If your Hydraulic Throwout Bearing was leaking of course it will soak the clutch disk. I'm using a ACT 11 inch manual clutch and 22 pound flywheel for tko 600 and it is not H assisted and it is very easy on the left leg. You need to call them to get the correct spline count. Mine is for over 1000 hp motors
Burning Brakes
Joined: Apr 2013
Posts: 1,194
Likes: 109
From: Las Vegas NV
I'm really happy with my clutch setup. HP in high 300s, TQ in low 400s. Specs in my signature below. I have a fairly lengthy thread about my T56 swap here:
https://www.corvetteforum.com/forums...o-my-79-a.html
https://www.corvetteforum.com/forums...o-my-79-a.html
