AC Owners Club Forum
AC Owners Club Forum => Ace, Aceca & Greyhound Forum => Topic started by: AcecaRacer on June 10, 2011, 20:03:29
-
I have just finished rebuilding my race motor and it has speced out at 144BHP. I have a standard gearbox and overdrive. In my first race last weekend, I found my gearbox starting to slip when under load, eventually becoming completely useless halfway through the race.
I do not believe it is the clutch as the clutch is new and there was no smell at all. My mechanic believes it is the OD. I did not hear any sound, bang or anything when I eventually lost the ability to move forward.
Prior to the rebuild, the OD was working fine with no sign of slipping. However, I was running about 85 BHP at that time.
So, my questions are these:...
Has anyone else experienced this? Do you think it is the OD?
If it is the OD, can I just pull the OD off and put on the non-OD tail shaft with a shorter drive shaft and be done with it?
Is there an OD designed to handle higher HP? I don't need it for track racing, but I do need it for rally's and road racing.
Any help would be appreciated!
Cheers,
Rob
-
Rob.
What clutch are you running ..[?]
Most of us in the UK especially for competition use upgrade to a 8.5 inch Heavy Duty Diaphram Clutch and use a 8.5 inch Competition friction plate. ( MGB GT )
The throw on the clutch release has to be measured and adjusted/ shimmed accoringly.
If the O/D unit burns out and ceases to function I would have thought you would still have drive, same as if O/D was not engaged [?]
I could be wrong.. [;)]
What sort of noise and gearchange problem did you experience prior to loss of drive ..[?]
Keith ..[:)]
-
I actually received no real noise at all. The gearbox just started to slip. Acted a bit like wheel spin. I would press the accelerator and the car would move forward then the revs would jump up and then it would catch and then the car would move forward. A bit like if I were to rest my foot on the clutch a bit causing a slight slip.
Again, I did not smell anything like a burning clutch. I did not hear anything like grinding gears. It just started slipping to the point where it acted as if the engine and gearbox were no longer connected.
-
Rob
Four questions for starters:-
Could you change gear or engage gear from nuetral .[?]
What free play have you on the clutch pedal and the clutch slave cylinder.[?].
Level of clutch fluid in the reservoir..[?]
Looking through inspection cover on top of bellhousing has the clutch gone over centre..[?]
Just trying to establish cause of problem without being hands on.
Have you constant pressure on the clutch pedal, does it fade or improve by pumping... sorry thats question 5 and 6
Keith..[;)]
-
It looks like we have found the problem...broken stub axle.
The Woodruff key has shorn.
So...a couple of questions arise from this:
Where can I get replacement parts?
Are the stock stub axles strong enough?
Has anyone upgraded to cobra stub axles?
Thoughts?