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MG MGA - Clutch Issue: Drop in RPM's

1958 MGA, stock.

Four months ago I had a major issue where the gearbox locked up, caused by worn selectors allowing the box to be in 2nd and 3rd at the same time. When the wailing stopped I installed a good gearbox with all new clutch components: plate (501-015), disc (190-140) and bearing (190-290).

The problem: since that install: at idle the car has a 3k +/- drop in RPM's from a normal 10k idle speed when the clutch is depressed. When shifting through the gears I don't notice it. I'm getting more oil leaking between the mating of the engine & gearbox than I'd like. Seems not to be coming from the gearbox drip hole although I believe it's open. The source I believe is the gearbox, not the engine although I'm not sure.

So far I've checked the engine's throw out bearings by watching the crankshaft pulley when the clutch is depressed with the car not running.... no movement forward. I'm wondering whether oil is on any of the clutch component surfaces and if that would cause a "grabbing".

I'm intuitive enough to know this is likely a wear/resistance issue. If I'm looking at an early replacement of the clutch components I'd like to understand the possible causes of this issue so I can fix the problem.

Thanks for any input.

Brian Denis
Brian Denis

Engine losing idle speed when the clutch is depressed is almost always a result of one carburetor running rich and the other one running lean. Standard tune up should fix it.
barneymg

This thread was discussed on 09/10/2018

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