Author Topic: GEAR LINKAGE QUESTIONS 1974 TCS and tire recommendations.  (Read 5269 times)

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Offline ottocycle

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GEAR LINKAGE QUESTIONS 1974 TCS and tire recommendations.
« on: Saturday,November 02, 2013, 11:01:20 PM »
Hello all,

I am recommissioning a 1974 TCS that has been off the road 20 years and I have a few gear shift linkage questions. Currently it is difficult to find 1-2 and 3-4 with regularity and predictability and I find that there is little resistance to finding reverse when looking for 2nd or 4 th. At the rear, where the universal joint slides over the gearbox gear selector shaft I seem to have about 15-20 degrees of rotational slop in the linkage. This seems like a lot to me but I do not know if it is normal, a reverse indent mechanism in need of adjustment or play between the universal and the selector shaft. I picked up a new roll pin for that area and a new nylon bushing set for the base of the gearstick in hopes of curing the problem. There is a bellows over the selector shaft that makes it difficult for me to determine if there is play between the UJ and the selector shaft due to the roll pin hole being wallowed out.

My questions are these:
1). How best to set up the reverse detent. The manual is vague and without the ability to confidently select gears it is difficult to determine which gear I am in for setup purposes.
2). Is the rotational play excessive?
3). Where else and how can I take up rotational play on the linkages.
4). To remove the gearshifter do I remove the 2 screws at the top front of the tunnel top and the 2 nuts and bolts that hold the choke and heater knobs in place (its a pity captive bolts were not around in 1974).

Any tips?
BTW: Who make a good tire for this car?

Offline EuropaTC

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Re: GEAR LINKAGE QUESTIONS 1974 TCS and tire recommendations.
« Reply #1 on: Sunday,November 03, 2013, 01:16:43 AM »
Hi there,

I'm assuming you have the 5 speed box with the car being one of the last models, and I only have experience of the 4speed 352 box but I'll comment in the hope that the same things apply across the range.   Gear changing isn't what you'd call a strong point with these cars, and if you're coming from a modern car then it's going to feel awful. That said, you do adjust with practice but I'm really saying that you might have to "manage your expectations"  :)

Reverse detent; on mine there's not much that can be done, it's simply a case of assemble the spring & ball and that's it, no adjustment.  I suppose you could fit a stronger spring, but there's nothing I can see otherwise.  Having assembled it, if you try to twist at the gearbox selector shaft end then there's notable resistance, but by the time you have all the linkage in place with the weight of the tubes on it, I agree that at the gear lever end it feels like very little resistance and I think that's normal.

But it's not what I'd call "slop", which I'd interpret as the linkage moving but not the gearbox input selector shaft.  The trouble is that we can get free play in too many points;

1. Gear lever bushes
2. 1st UJ by the exhaust downpipe
3. Rose joint (Heim joint ?) and supporting swivel bush
4. Final UJ at the selector input shaft end.

Sadly, you need all these areas to be tight to give you half a chance and the even sadder fact is that there's no adjustment other than replacing with new. Gear lever bushes probably make the most difference and are normally the first area for attention.

You can assess the UJs by twisting both shafts and feeling for movement, basically there shouldn't be any. A small amount is normal (a few thou') but you're aiming for none at all, just as in a driveshaft UJ. I believe you can still get replacement parts, or it's possible to overhaul your originals using donor parts from steering joints but you'll need a press or vice for that.

The last time I pulled mine apart I did the following;

1. Remove centre armrest pad, scratch your arm to pieces by undoing the nut holding the gearstick to first section of the tubular shaft. That drops the shaft into the tunnel.
2. uncouple the gearbox Uj
3. Uncouple the swivel bush from the engine/bellhousing
4. slide the complete linkage out of the car.

I think I once managed it by leaving the gearlever attached to the linkage but just releasing it from the chassis (4 bolts underneath the lever gaitor) but that's more of a hassle to angle the mounting plates through the centre tunnel.  However you do it, it's not something that you'll want to do twice so my advice would be to make a careful assessment and replace anything that's even slightly worn.

Try this page for some more hints,

http://lotus-europa.com/manuals/index.htm

if nothing else it'll show you that you're not alone with the problem  ;)

Brian


Offline pboedker

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Re: GEAR LINKAGE QUESTIONS 1974 TCS and tire recommendations.
« Reply #2 on: Sunday,November 03, 2013, 03:45:46 AM »
Hi 'Ottocycle',

I also have a couple of additional tips for tuning the TC gear linkage.  :)

It sounds like you're already halfway to a good solution with the new parts you bought. When fitting the new nylon bushings, make sure that the clevis on the gear linkage and the lower part of the gear lever are polished and in alignment with each other. You'll know what I mean when you see it. Mine looked like they were cut with a hack saw and then polished with grit 20! And a welding spot had to be grinded for the shoulder bolt to fit OK!

If the new roll pin is not enough to secure the rear UJ to the control shaft, you might have to drill a hole and cut a slot in the rear UJ so that the bolt will clamp the control shaft. It can be done, and I think there are pictures of it on the net. But try with the roll pin first.

Yes, the rotational play sounds like too much and you probably need to be 2 persons to really see where the rotation happens. The gearbox control shaft is free to rotate freely from side to side, but the Lotus detent mechanism sets up an unnecessary force that wears out the linkage over time. The gearbox has no springs to guide you to the gate 3/4 like on new cars. Anyway, with a good linkage the gear lever will move without much resistance from side to side, and the rear of the linkage will change direction as soon as the front of it does.

I believe the linkage has to come out of the car, and it's not that difficult. After removing the center console as you mention, cut a slot in the end of the 2 bolts behind the choker/heater bracket. On refitting you can now turn the bolt with a screwdriver from outside the tunnel insted of using 2 wrenches, one inside the tunnel.  8)

The gear lever is held with a circlip and once removed the lever can be tapped gently through the bearing. After that it drops down into the tunnel and is free to follow the gear linkage out through the back of the car.

I've found that the middle UJ and the sviwel bracket for it is not that important for the precision. Of course new parts will always be nice, and the rotational slop does add up but I would say that the UJ should be really lousy before I would take the risk of dismantling mine again. When I did, I broke one bolt going into the linkage tube and then had to secure it from rotation with a nut instead.

Also, have a look at the following link/thread: http://www.lotuseuropa.org/LotusForum/index.php?topic=127.msg706
(Warning: I'm trying to sell you something ;))
After having made too many downshifts into reverse gear I completely removed the reverse/5th gear detent - and hence the unnecessary wear of the linkage - and made my own solution for it. With it, the gear lever can be moved to the left ready to select 1/2 gear or it can be moved to the right ready to select 3/4 gear. It can't be moved further to the left (reverse gear) unless I lift up on the rubber bellow. For the 5th gear I have been using my own internal spring loaded detent all through 2013, so now the gear lever feels like a modern car when selecting 5th gear. I need to disassemble it during winter to evaluate how it has worn or not. If there's any interest I can speed up this process.
« Last Edit: Sunday,November 03, 2013, 04:48:46 AM by pboedker »
Peter Boedker
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Denmark

Offline Bainford

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Re: GEAR LINKAGE QUESTIONS 1974 TCS and tire recommendations.
« Reply #3 on: Monday,November 04, 2013, 07:12:12 AM »
Well, I can't add further to any of the excellent advice already provided. In fact, I plan to try to improve my shift linkage accuracy soon with a rebuild of the linkage, so I am grateful myself for the advice given here. I also plan to try peter's reverse lockout device when I do. Though the shifting is not necessarily 'slick', I have become quite used to it and don't really have a problem with day to day driving, but I know there is much improvement to be had. My biggest problem is accidentily finding reverse when shifting into second from any gear, or shifting from 5th to 4th (!). It makes a sound I really don't want to hear again. Also aggravating is the high effort required to push through the 5th gear detend when selecting 5th. (Peter, I'll be interested to know how your 5th gear detent mechanism has fared.)

However, I can provide a recommendation for tires. I've been buying Falken Sincera tires from Discount Tire, 175/70 for the front and 185/70 for the rear. For some reason I couldn't find them on the their website, so I bought them through ebay by putting the tire size into the search field. The price is quite reasonable, and I believe the shipping is free in the US. They are a good touring type tire and seem to be good handling and are decent in the wet as well.

The Twin Cam plays the symphony whilst my right foot conducts the orchestra. At 3800 rpm the Mad Pipe Organ joins in.

Trevor

Offline ottocycle

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Re: GEAR LINKAGE QUESTIONS 1974 TCS and tire recommendations.
« Reply #4 on: Monday,November 04, 2013, 04:08:44 PM »
Thanks guys for your advice. I appreciate the input and pboedker, great idea with slottinng the bolts. I changed the gearstick bushings and tore myself up doing so. I am a big guy and could barely fit my arms into the tunnell. It was like building a ship in a bottle!!!
I was ready to test drive the new setup, but when I put the key in the ignition the damm buzzer would not shut up. It operated on only the door switch before but it will not go off when I close the door or disconnect the switch. I did not have time to check further but I will study the wiring diagram to figure it out. I may have disturbed something when I was in the tunnel or it could be the Ghosts of Lucas!!!!!
What is the proper name for the buzzer and what systems should trigger it?
No good deed goes unpunished!
Thanks.

Dermot

Offline Bainford

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Re: GEAR LINKAGE QUESTIONS 1974 TCS and tire recommendations.
« Reply #5 on: Tuesday,November 05, 2013, 05:59:48 AM »
My car also has a sensor under the passenger seat cushion that causes the buzzer to go off (occasionally) when someone is sitting in the seat (or a heavy bag) without the seatbelt fastened. I read that there should be one in the drivers seat also, but didn't find one on mine. Likely a previously owner became annoyed and ripped it out.
The Twin Cam plays the symphony whilst my right foot conducts the orchestra. At 3800 rpm the Mad Pipe Organ joins in.

Trevor

Offline 3929R

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Re: GEAR LINKAGE QUESTIONS 1974 TCS and tire recommendations.
« Reply #6 on: Tuesday,November 05, 2013, 08:53:25 AM »
When removing the shift linkage, be sure to tie a rope to it.  This will make threading it back into place a breeze.  (if someone already suggested this, sorry for the repeat)
Mark
Salt Lake City, Utah, USA

Offline pboedker

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Re: GEAR LINKAGE QUESTIONS 1974 TCS and tire recommendations.
« Reply #7 on: Sunday,November 17, 2013, 05:59:57 AM »
Here's a very good writeup about the various problems to encounter regarding the 352/365 box shift linkage. I was looking for this exact page when I wrote here the last time, but only stumbled upon it today as a mirror on Jerry's Europa Page:
http://www.lotus-europa.com/manuals/misc/transmission/tc_shifter.html :coolpic:
Peter Boedker
3904R Special
Denmark

Offline andy harwood

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Re: GEAR LINKAGE QUESTIONS 1974 TCS and tire recommendations.
« Reply #8 on: Sunday,November 17, 2013, 12:27:13 PM »
not sure if this will apply in your case - but- I was having a hard time engaging 5th gear. found shift tube was slightly rubbing header.  had to move the pivot eye bolt out a bit.