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MG MGB GT V8 Factory Originals Technical - pedal effort with Mcleod/ Weber HTOBrg.
|i hope to join the ranks soon with my 78 "B" powered by a energized,lightened Ford 5.0, T-5, & 8.8 R/E (93 mustang narrowed). i have the OEM clutch M/C (approx 5/8"+). The effort to activate the HTOBrg. is a bit excessive. what mods, if any did you make to lighten the effort? i will install the pedal "stop" to limit travel, but an attempt to change the geometry of the pedal seems very complex. please share any ideas to lessen the pedal effort w/o major mods. also; any suggestions on mods to emergency brake cables to use the existing handle and the mustang cable and R/E.|
Where in Tennessee are you?
I use a 5/8 Girling MC with a Weber HTOB and my pedal effort is lighter than the old MGB 4 cylinder/4 synchro setup. Are you sure you have a 5/8" MC? I first used a stock MGB (3/4") MC and also found the pedal effort to be excessive.
|In the instructions you got with the Bearing, it remmends a 3/4 MC The 5/8 works just fine in the B due to the pedal ratio which is 7:1 They recommend 6:1 |
If you want a lighter pedal then change your MC with a 3/4 MC
|the M/C appears to be almost 3/4" when i measure the bore. i know it is OEM or Std. M/C since i purchased a rebuild kit. can anyone advise the std. size and i will have a better idea. perhaps the pressure plate is a very strong one. i purchased a running,driving total loss mustang and operated it a few miles prior to removing the entire drivetrain,EFI controls and ECM. Dan, i live in fayetteville, 25 miles north of Hsv. al. met you in townsend but you were too sick to remember . thaks for replys so far!|
|I cannot speak directly to the Ford clutch, but as far as the Chevy setup is concerned, it depends upon the clutch, or rather the pressure plate used.|
The MGB clutch master is 3/4". Using the stock Chevy S-10 pressure plate, pedal pressure is O K. Using the Camero pressure plate, pedal effort is on the heavy side, but tolorable. Using the Webber HD pressure plate, pedal effort is too heavy for stop & go traffic jambs where you move 10 feet, stop, then move 3 feet. I think it is too heavy in general, & would only recommend it for drag racing.
Using a smaller bore M/C such as a 5/8" would work fine & reduce pedal effort regardless of the pressure plate used. The Girling is a bit different in design compared to the stock M/C & appears to have a smaller fluid capacity. Apparently, several are using the 5/8" M/C, so perhaps capacity is not an issue.
|I have a "stock replacement" clutch on my 5.0 I find the pedal on the hard side. But not too much wors than a late 80's Ford Ranger truck which also uses a HTOB system from what I have been told.|
|Kelly I agree with Jim. I have some hard numbers from my experiments. I have a 3/4 stock M/C and a WEBER HTB, with a Weber pressure plate #360116 from D&D the pedal pressure was 65lbs. I changed to a 5/8 M/C and pressure went down to 45lbs (as my calculations predicted) but engagement was right at the bottom of the stroke, so I couldn't use it. I changed to a Centerforce II pp and pressure is 50lbs now. Stock pressure is 45lbs. the centerforce plate is longer than the Weber so I had to space the trans back .120" but I think I could have turned down the bering retainer to get the clearance. My measurements come out to a 5/1 pedal ratio. I have an early car and I don't know if that has changed. Hope this helps.|
|Go to the gym and exercise your left leg, it helps.|
Listen to Jim. Pressure plate is key. Run the lightest pressure plate that will still keep the clutch from slipping. These cars are light. Drag clutches are not needed even with lots of horsepower. Can't get enough traction, anyway.
Welcome aboard. Are you in Fayetteville? Dan & I are in East TN.
|It seems to me opting for the S10 slave and fork makes much more sense than all of the above.|
You get the lever action of the fork (less pressure), and the easy access of the slave..this will of course require a SLIGHT tunnel mod next to the accelerator pedal.
|The more you cut the fork lever down, the higher the pressure , of course.|
|thanks for all the info and replys. seems the 3/4" MC wil be a bit heavier than i thought. i guess i can live with it and pump iron to stiffen the left leg (only). perhaps if use it enough, i will actually like it. this will be a daily driver as was the 4 cyl. BTY, i spoke with a Mcleod/Weber rep at the SEMA show recently regarding the failure(leakage) of HTO Brg. He advised to exercise the brg at least every 2 weeks due to the front o-ring getting dry. it is only lubed by minute fluid leakage past the rear 2 rings (there are 3 o-rings). hope to be ready for V8 2005 in Ind.|
|Kelly, I used a Wilwood retracting slave cylinder mounted between the cable boss on the bellhousing and the throwout arm. It works well on my '95 302/T5 combination using a 7/8" Girling (now Lucas) master cylinder. Even the alloy cover from a Mustang fits on! Advantage is it is very easy to service/adjust compared with the concentric types. Pedal effort is moderate but a smaller bore m/c can give problems with insufficient clutch throw. It has been very simple and reliable so far. Bob Elwin|
This thread was discussed between 16/11/2004 and 18/11/2004
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