Lotus Elan and Lotus Elan Plus 2 Forums

I was installing a laygear shaft and noticed that on one side of the shaft, both ends where the rollers run, it is a bit more worn than the other. Using the rear "lug" for reference that would be "top" & "bottom'. So, which side wears the most? Thanks

Fit a new layshaft and the 40 needle bearings + 4 thrust washers + 2 new thrust bearings.
There's only one way the layshaft can fit.
Alan

The top side will show more wear, usually the outer (towards the ends of the shaft) edge of the needle roller path fatigues and flakes off.
Having said that, the lay shaft, thrust bushings, and 40 needle rollers should be replaced at a minimum.

The end of the layshaft that has the flats on it needs to go towards the rear. The flats need to be orientated so they align with the cutouts in the extension housing - their purpose is to stop the shaft from rotating in it’s bore. The shaft needs to be tapped in from the rear and not from the front. (All this from memory 20+ years ago so other’s feel free to chip in if I’ve said something wrong)

joe7 wrote:I was installing a laygear shaft and noticed that on one side of the shaft, both ends where the rollers run, it is a bit more worn than the other. Using the rear "lug" for reference that would be "top" & "bottom'. So, which side wears the most? Thanks

Hi Joe
This queston has caused a lot of confusing responses

My interpretation is that you have observed uneven wear around the lay shaft where the needle rollers run and the excess wear lines up with the long sides of the end lug but different sides at each end. This uneven wear is not to be unexpected as it probably aligns with the reaction force on the layshaft from the gear tooth thrust force. I would expect the maximum wear point to be about 90 to 120 degress apart due to the different thrust angles on the layshaft input to output gears and this is further complicated by having 3 output gears whose loads will go into the lay shaft differently.

I dug through my old layshafts and a couple of photos follow. The black shaft was nitirided and the uneven wear can be clearly seen between the two photos. Its hard to show in a phtoto but the wear patter is offset by around 90 degrees. The other shaft has a similar wear pattern but it is impossible to see in a photo






cheers
Rohan

I have just fitted a new Layshaft from TTR and they also have an extra Pin across the end. Next to the machined flats. TTR also do heavy duty Thrust Pads in bronze better than the original ford ones.
Alan

Thanks for the replies. The reason I asked is that I have an almost new layshaft similar to the "black" one in Rohan's pic. "Almost new" is only about 20% of the ends that show a bit of wear through the outer coating so I don't think a new shaft is required. I will put the shaft in with the slight wear on the bottom. Given the slight wear I don't think it would really matter much if I put it in either way. I was trying to understand the theory behind the wear pattern.