Lotus 5 speed gear stick threads

[gjz30075]

Well, I've been breaking in my new 4 to 5 speed Lotus gearbox conversion and mentioned here that I felt
the shifting from 1-2 is really hard. I've changed to MTL GL4 and doesn't seem to help, but, because of of
the difficulty shifting, apparently I'm lifting the stick because it pulled right out of the 'box. Looks like stripped
threads in the 'box because the threads look good on the blue plastic thing and I tried another and it, too, doesn't want to fully thread in and seat.

So, I think I have a couple of solutions and I'm sure the collective Lotus 5 speed community here has more.

1) Use the Loctite product called Form a Thread. From reading the reviews, it may not stand the stress of
movement, ie, moving the stick around constantly.
2) Use several sheet metal screws and screw through the metal tabs, in various locations, to hold the blue
plastic thing down.
3) convert, somehow, to a T9 shifter with the plate and three holes used for bolting down, to eliminate the
threaded parts.

How difficult is it to remove the top plate in situ? Any other solutions welcomed

[Davidb]

GJZ: I don't know about the thread repair but I don't think you should be using a GL4 rated oil in the box. Once you have fixed the problem try something different. I have had great success with Penzoil Synchromesh but there are other, similar oils.

[mbell]

Are you sure there isn't some kind of selection problem with the box?

I would have thought there would be very obvious thread damage for the stick to come out under normal operation. So makes me wonder if problem is amount of force you having to use to select a gear rather than the thread.

You can get a quick shift that has a metal fitment but that not really suitable for a rust car.

I suspect if a little tricky to get the top plate of in situate. Cleaning and putting it back on however would be very difficult.

[gjz30075]

Mark, I'm not sure if there's a gear selection issue or not because I've never felt a Lotus 5 speed before. Selection
of 1st and 2nd is very difficult, most of the time. 2-3-4-5 is really nice. Forget about going into 2nd on a downshift from third. I rebuilt the master and it still engages/disengages close to the floor but I don't think that's the problem because I can go all day on shifts using 3-4-5 easily.

I'm sure its the threads because both screw in blue plastic things screw in with some resistance and never
bottom out. It gets a bit snug near the bottom, but will continue to turn. With the plastic thing fully bottomed,
I can pull out the stick with some wiggling.

I fear what one of the posters said in my 'lube' thread that it could be the end play of the first motion shaft.

I will try MT-90 next, or the Penzoil Synchromesh, as davidb suggests (easier to find) after I can get the stick to stay in the hole. I may use the sheet metal screw idea. IF the box has to come out, then a proper fix will be done, whatever that is.

[Donels]

The plastic threads will be weaker than the aluminium threads in the casing so it's unlikely that the casing is stripped. You may have two worn plastic nuts. From experience with these they can easily be damaged or worn so before drilling the casing I suggest you try a new plastic nut. As a short term fix try wrapping the plastic thread with PTFE tape.

[mbell]

The gear stick thread should thread all the way down. They do tend to get chewed up and very hard to get threaded right. PTFE tape sounds like a good idea, as sounds like your threads may be past it.

End play on the 1st motion shaft is most likely to cause selection problems for 4th gear. As 4th locks 1st and 3rd shafts together, 1st shaft play can cause the shaft to move away when trying to get forth and therefore it doesn't engage properly. Had this very problem on my box but was do to a missing spacer in the nose housing rather than any other problem and only effected 4th gear.

[gjz30075]

I'll try the tape and change the fluid to the Penzoil Synchromesh.

Thanks guys!

edit: the threads on the plastic piece are perfect on both of them. I happen to have an Elite 5 speed tail
shaft (on ebay right now) and these plastic pieces screw in TIGHT, in this tailshaft shifter hole, from start to finish and bottom out tight.

[rgh0]

If just the change into second gear is a problem I doubt it is the oil that is the root cause. I would start with getting the change lever working correctly and properly located.

cheers
Rohan

[Mick6186]

It's not too much of a problem to remove the top plate with the gearstick removed. You need a spanner with a slight bend in the shaft. Be careful you don't drop a bolt or washer into the gearbox. The problem arises when you replace the plate. I found it impossible with the gear-lever in situ as the lever is in the way. With the plate on the bench make sure the big plastic nut & plate threads are clean and the nut screws fully in to the plate. Replace the plate and screw the lever in, using a screwdriver to push the locking tabs to fully tighten before locking,
Mick

[mbell]

Does the elite tail housing have the same plate?

If so I'd consider "just" swapping them out as last resort. Will be poa job and very hard to get good seal but better than pulling the box. If you do have pull the box can re do it then.

[vincereynard]

My shift was difficult to select 3rd.

I found a major factor was the alignment of the cross shaft. When attempting to select third with the lever resting against the 5th / Reverse spring it was also fouling the 1st selector. (Tying to engage both.) I noticed that the 1st/2nd selector was also not lined up very well.

Packing the shaft out by 1mm on the right and similarly packing out the spring by 1mm allowed it all to line up much better. Not much help I'm afraid unless you can get the top off.

I suspect you may have great trouble taking the top plate off in situ as the right rear bolt would not have sufficient clearance to clear the chassis. At least that is the case with the Spyder chassis, and I imagine the Lotus chassis is even worse.

Making the lever "stripable" makes fitting the cover far easier, as you only have a short lever stub to contend with rather than fighting with the whole assembly.

https://www.youtube.com/watch?v=xSyhX_8Lv9I

[gjz30075]

Well, in situ, here's how I secured the shifter. I couldn't get enough PTFE tape on the threads to make up the
difference. Drilled four holes to take sheet metal, self tapping screws. It's not going anywhere now!

Mark, unfortunately, the Elite top shifter plate and the Elan's are totally different. Hmmm, maybe the threaded
holes are different sizes, too?

Vince, I think you're the second person to mention alignment of the forks. After experiencing the reverse
'lock up', which was a fork problem, I'm dreading the thought.

Thanks all for the ideas.

[mbell]

That will do it...

JUST had a thought, hour much pre load is there on the bellow on your stick?

I could see too much meaning it doesn't compress enough or requiring a lot of pressure causing a high side load of the gear stick thread that could pop it out. It could also make gears like 1st hard to get. Given relative access to the bellow I'd
suggest it being worth experimentation auth it to see if there any improvement in shift effort.

[gjz30075]

Pictured is the stick in its current configuration. There is some compression of the bellows. My machinist
put a groove in the stick to accept a large circlip. The groove is really low, ie, close to the bottom. In order
to get this circlip on, I have to pull the stick all the way up. I will try it without the circlip also, and compress
the bellows with the bush from above, if, after a fluid change, it continues. Thanks!

[rgh0]

Preload on the 5 speed bellows is critical to a good quality change across all 5 gears.

To little preload and the change is vague and sloppy
To much preload and one or more gears can be hard to select as the lever needs to move up and down a fraction as you select gear.

Overtime with age the rubber in the bellows loose preload so most 5 speed changes are on the sloppy side. I shim with washers under the standard C clip location to get the optimum bellows compression. It sounds as if yours has been compressed to much with a new tighter location rather than a small adjustment on the standard location.

cheers
Rohan