MG Sports Cars

engine swaps and other performance upgrades, plus "factory" and Costello V8s

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Skip Campbell
Westerville OH
(1 posts)

07/16/2020 09:36PM

Main British Car:
1979 MGB Roadster 1961 Olds 215

1979 mgb roadster
Posted by: SkipCampbell
Date: July 24, 2020 02:20AM

Iím new to this website but just purchased this car with a olds 215 and aMuncy 4 speed. Project was started in 1992 and never finished. I have been helping this 82 year old to get it on the road. Iím retired so donít have anything else to do except play with my stock 69 B. This car has been on jack stands all this time. The engine was professionally built. I have been all through motor,brakes, fuel systems and the car starts and runs. Problem is the clutch. Bought new slave cylinder but having issues getting it working. The slave has been plumbed over to the drivers side to match the muncy tranny.Iit uses the stock MGB slave cylinder. Is anyone knowledgeable about this conversion? The slave cylinder is bolted to a piece of angle iron that is bolted on the tranny.
Any knowledge of this conversion would be most helpful or a different way to do.
Thanks font help.

Curtis Jacobson
Portland Oregon
(4483 posts)

10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: 1979 mgb roadster
Posted by: Moderator
Date: July 24, 2020 02:30PM

I'm not sure I comprehend the nature of the problem, but two things come to mind.: (1) With the current mounting, is the bleeder on the slave cylinder pointing upward or downward? If it isn't pointed upward, you might find it helpful to fashion a remote bleeder.
Ol Phartz Parts sells a remote bleeder for MG Midget. You might call them and ask if it would work for an MGB cylinder. ref: [] (2) If the mounting bracket for the slave cylinder is flexing appreciably, the throwout bearing may not move far enough. In my case, I installed a brace to supplement the main bracket. The brace is just a straight link to one of the oil pan bolts.

Two other things that come to mind are that (a) the relative size of master cylinder piston to clutch cylinder piston might not be optimal, and (b) the master cylinder might have issues... but I think these are less likely problems.

I'm curious to know what sort of pressure plate you're using. I started with a three-finger pressure plate, and later used a diaphragm pressure plate. Either should work, but in my case the diaphragm pressure plate significantly reduced pedal effort.

I'm also curious about whether you're using a stock clutch fork. I chose to shorten my clutch fork to make packaging work out... two bad effects of that decision: (i) due to having less leverage, my clutch fork modification resulted in higher pedal effort, and (ii) the connection of my slave cylinder to my clutch fork is in single-shear vs. double-shear as it really ought to be, and that results a tiny bit of extra slop in the system. (Neither of these prevent the system from working, but they're things I'd try to engineer better next time.)

If you throw in the towel with regard to the MGB slave, there are lots of other options. On this board and in the photo gallery you'll particularly find pull type slave cylinders and various mounts for them along the side of the transmission. I find these very much preferable to "hydraulic throw out bearings". (Simpler, cheaper, more serviceable.)

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