Well it was a good, bad and ugly kind of day for the first proper run of Svetlana at the Dubai Autodrome. First session with me in the driving seat went pretty well, only one significant problem which was the rear springs were way to stiff and as a result rear grip mid corner was non existent. The car just wanted to chuck itself sideways, which it duly did in a nice half spin on the last corner. Nothing at all to do with the inept driving, honest! Still the engine was stonking, the brakes excellent and the front end handling was nigh on perfect, so pretty happy considering the potential unknowns.
Second session Gareth took it out for a run and was well impressed by how torquey the engine was, but reported a vibration at high speed, which I had also felt, but otherwise all seemed to go pretty well. He also reckoned the rear needed to be softened up a lot on the spring rate.
Last very short session was Gareth's brother Llyod, who came in after 3 laps to report oil fumes entering via the gear box tunnel, smelling distinctly of gear oil. A quick jack up showed some leakage from around the rear seal on the gearbox and a bit of play on the prop shaft nose. So we decided to call it a day and head over to a2b Garage for a quick inspection. After all Gareth had planned to spend the afternoon there building his MK2, so might as well use his lifts.
Jacked up the car, changed the rear springs from 300lbs to 190lbs, nice easy 20 minute job from underneath a lift. Took off the prop shaft and lo and behold a very phuqued looking bearing inside the tail housing of the gearbox.
Dropped the gearbox out and stripped off the tail housing, pressing the bearing out to see the full extent of the damage.
The Mazda MX5 box has a long bi-metal bearing with oilways and holes for lubrication.
It looks like my prop shaft has over heated and siezed on the bearing ripping it up a bit.
The problem is I can't quite figure out the root cause, it's a bit pointless fixing it unless I can understand what caused it. So far we have the following options:
1: Too tight propshaft on bearing
2: Too loose propshaft on bearing causing vibration and over heating
3: Vibration from prop shaft
4: Lubrication (although enough oil came out the back in the end)
5: Alignment, although you would think the UJ would compensate.
So any enlightened ideas would be much appreciated. Also does anyone know of a decent Mazda scrapyard in Sharjah??
