Have anybody a second-hand 4th gear ? My 4th gear cone is not good so the synchro is not working. I think maybe I can use the cone from the 5th gear to. Here is a picture of 4th and 5th gear with the cone. Harald Image Unavailable, Please Login
Please elaborate on how you came to the conclusion they're bad . .. from the pic they look okay to me.
Hi With new synchro the 4th gear have no clearance. The 5th gear is better and have about 0,4 mm (or 0.35mm) with the new sychros. I have try two different synchros on the 4th gear, but still the same. It looks like the old synchro was OK and the problem was the cone.? Maybe this pictures is better. Image Unavailable, Please Login
Yeah that does sound like a problem . . . how many miles are on that gearbox? I might have an extra but it was my understanding there might be several gear tooth profile itterations. I'll measure that feature on my high mileage 308 gearbox for comparison.
My car have 82 000 km. I be very happy if you have one to sell to me. I have tried to measure the cones but it's not easy. Harald
Make sure that your synchros are smooth inside, ie: DO NOT have grooves like the gear cones. There were 2 types of cones & synchros for 4th & 5th gears: 1. Gear cone has grooves, synchro is smooth inside. 2. Gear cone is smooth, synchro has grooves With clean gear cone & a new synchro, there is typically over 1mm of clearance between the synchro & the side of the gear. WSM specifies a minimum clearance of 0.4 mm for a new synchro. luckydynes is correct, there were quite a few different gear profile varients. The SBs state that only matching gear pairs can be used, otherwise you will get excessive gear noise. However, The cone/dog teeth ring is pressed onto the gear. Dennis McCann once told me that he had a tool made so he could press the worn dog tooth ring out & press one in better condition in. Luckily 4th & 5th gears usually have very light wear, so you should be able to readily find good used ones, or maybe see if Dennis McCann can find a good used pair, & press the teeth from them into your gears if you send them to him.
I was measure the thickness (see picture) of the new synchro and it was 6,85mm. The old one was 6,4mm. So If I take the new synchro down to 6,4 I will get 0,45 more clearance, and from before I have 0.1mm. Total 0,55mm Maybe it's working??? Image Unavailable, Please Login
That feature is 6.35mm on mine .. . good thing is they're cast iron so easy to grab with a magnetic chuck on a surface grinder to remove that .5 mm . .. hopefully that isn't much into the tooth profile of the synchro . . . probably can't get the supplier to do anything since it was installed already (I think you mentioned). Sean
I have now used a grinder and remove 0,5 mm and the profile of the tooth are still very nice. Have now 6,35 mm like you have. When I measure the clearance I have 0,65 mm. I will try it like this and see whats happens.
