Tweet
As far as I can determine (and I've been building 4spds for 35+yrs), the 63-69 Muncies did not get a drain plug (but all cases had the boss for one), except for the M-22 version. Then in 70, all Muncies got a drain plug. Anyone care to take a shot at why the 63-69 Muncies didn't get a drain plug installed? When I rebuild a Muncie without a plug, I always install a magnetic drain plug and remove the donut magnet (unless the customer says not to do it).
-
-
Re: Muncie drain plug-----------or lack of
Tom -
Probably cost twenty or thirty cents to drill and tap the hole and install the plug, and Chevrolet watched every penny; they probably "caved" in '70 from dealer complaints (who were used to using the drain plug in T-10's since 1957). -
Re: Muncie drain plug-----------or lack of
Tom and John-----
Also, GM never specified a fluid replacement interval for manual transmissions used in "normal service". The M-20 and M-21 were designed and intended for use in "normal service". So, in addition to the cost savings generated by leaving out the drain plug, they also eliminated a "leak source" and the possibility that the plug might be left loose and fall out (with catastrophic consequences). Since there was no SERVICE requirement to drain the transmission and replace the fluid, from that perspective, the drain plug was better left out than included.
63-79 Corvette rear axles never had a fluid replacement interval specified, either. None of these were ever fitted with a drain plug.In Appreciation of John HinckleyComment
-
Re: Muncie drain plug-----------or lack of
Mr. Tom
Why does my 57 Nassau/Daytona car have full clutch pedal pressure without the frame mounted clutch spring? 3 spd.
My experience with other 57's is that the pedal goes straight to the floor without that spring in place.
Curious!
JoeComment
-
Re: Muncie drain plug-----------or lack of
If you have the full clutch linkage connected from the pedal all the way to the throwout bearing fork, then the clutch pressure plate has sufficient pressure to push against the linkage and return the pedal back up.Comment
-
Re: Muncie drain plug-----------or lack of
Tom
I will check it out..and let you know what I find....JoeComment
-
Re: Muncie drain plug-----------or lack of
You STILL need that spring to keep the pedal all the way up to the top. When a clutch is properly adjusted, there should be about 1in of play in the pedal when it is all the way up, and that spring takes out that little bit of slack, plus, it helps with the return of the clutch pedal all the way through its travel.Comment
-
Re: Muncie drain plug-----------or lack of
Tom..are you talking about the small spring under the dash as a helper spring or the heavy duty spring in the engine compartment?
My car does not have the heavy duty spring in the engine compartment although the frame bracket is there. It still has what appears to be normal pedal pressure without the heavy duty spring.
JoeComment
-
Re: Muncie drain plug-----------or lack of
The majority of the pedal pressure is from the clutch pressure plate so that will be unchanged. The spring in the engine compartment pulls back on the clutch release fork so that the throwout bearing isn't constantly riding against the pressure plate - saves wear on those parts. Get a spring - not that expensive - and will save you from problems with the throwout bearing later.
Hope this helps,
MarkComment
-
Re: Muncie drain plug-----------or lack of
Joe -
That "Godzilla spring" and its associated Rube Goldberg design serves two purposes; at the upper portion of pedal travel it's a pedal return spring, to keep the pedal up against the rubber bumper and the throwout bearing off the clutch fingers (which is why the pedal free play adjustment is important), and as you depress the pedal and the spring goes over-center, from that point down it's an "assist spring" intended to slightly reduce pedal pressure required to disengage the original 3-finger coil-spring Borg & Beck-style clutch. The "assist" feature would occasionally cause the clutch pedal to stick on the floor during high-rpm shifts with early replacement diaphragm clutches, so many folks who replaced the original clutch with a diaphragm clutch disconnected the "Godzilla spring" and replaced it with a simple direct-acting pedal return spring like the C2's used (they all had diaphragm clutches).Comment
-
Re: Muncie drain plug-----------or lack of
John..I think I now understand...the point about the dual purpose and the over the center idea.
I remember trying to reinstall one in another 57 and running into the problem..of the godzilla spring both holding the pedal up but then pulling and holding the pedal down after going over center. Contraption is right.
The car has not been started in many years..but I plan to some time in the near future.
Maybe it could be a workshop at the Florida meet if I get the car down there.
Thanks,
JoeComment
Comment