Low gear band adjustment and over centering

[BobUkPipedream]

Hi All,

Well I have been enjoying taking my T on short trips since a complete engine rebuild. Most of the teething issues have been resolved, she starts well runs on batt or mag (better on mag). However I seem to have an issue with low gear. It works fine for a while, but when she gets hot, I run out of pedal travel, gear barely engages or not at all and even had the pedal over centre a couple of times, prompting a hasty pull of pedal to avoid calamity. I seem to get a nasty smell at the same time (not me scared of running into something, but smell from the car). I checked the drums and they are not blued, but as she has new Kevlar bands, I am trying to not over adjust and I am using new 10w30 oil in about 70 - 75 degrees Fahrenheit.

I have a good free neutral. I have lengthened the link from pedal to high gear pivot and now the pedal does not go over centre, but the low gear is still an issue. Otherwise she does have a lack of torque too. She has plenty of compression, but struggles on even slight inclines, but will make a good 35-40mph on the flat. Perhaps that is timing not being advanced enough as she starts well retarded, but needs full advance to run nice with no intermediate setting being useful.

So with low gear, I am wondering if I have issues with the low speed cam pins as I heard people have suffered them loosening off, but then this seems to present just when she is hot and returns to normal when cooled down - including low gear bite point and correct pedal travel. Interestingly amount of low gear use does not seem to affect it, it seems more related to engine temp. Should I just adjust the low speed band a bit more or are there any things I maybe missing?

[speedytinc]

"Should I just adjust the low speed band a bit more or are there any things I maybe missing?"
NO DO NOT EVER willie nillie tighten kevlar bands!!
The pedal distance to floor is not a factor.

That is affected by cam wear, improperly installed, not perfectly round with lining hi spot bands. Install with the Hogs head off.
Fitting thru the inspection cover produces an out of round band.

Adjust low as follows: Loosen the low adjuster jamb nut.
Start the motor. Back off then tighten the low adjuster untill you start to hear the triple gears song change, as in starting to engage.
This is the band creating friction on the low drum. Back off the adjuster 1/2 turn. You will not hear any more triple gear noise.
Your band is now adjusted correctly to its safe possible maximum.
If you dont have enough pedal travel for lockup before hitting the floor board see above possible band/cam issues.

@ this point, Get a look @ the low drum, full revolution to confirm it's not cracked. Just to be sure.

Regarding the difference in a hot motor & Kevlar band pedal travel changes - I also notice this.
Why, I dont know, but it does happen. The loss of or softer nature when hot has never been as severe as you describe by going over center.
I suspect you have an installation or band out of round situation.
Kevlar bands take several adjustments to set in. After set they wont need adjusting for a long time. Your new bands may not have completely set yet.
It's been more than 10K miles on one of my T's since I had to adjust.

Consult your service manual & check pedal/clutch linkage. Set to book spec.
Hope this helps.

[BobUkPipedream]

Thanks very much. I had not heard of that method of adjusting bands, so will give that a go first.
I suspect I may have to take hogshead off again and check band roundness. I cannot remember how I did the bands when I installed them. I would like to think I did make sure all was round and it is usually what I would do. I spent a huge amount of time getting the fourth main true in both up/down and side to side as well as square on, but can not remember what I did with the bands!

[Norman Kling]

I had a problem with bands on my first T. I had installed the lining wrong! I had started at one end and placed the rivets in order from one end to the other. I thought the lining was too long so cut off the overlap on the final end. The problem I had was that the lining was not tight to the drums between the rivets so would drag when the band was loose and wear out quickly. If your engine is running fast but the car will not move uphill, that might be your problem The proper way to install the lining is to start with the rivets at each end leaving about 3 16th inch beyond the end of the band. Then work the lining into the drum so it lays tight against the drum and place the other rivets. The band should also be checked for round by fitting around an extra drum to be sure it is not bent. Another problem you could have is addressed in another post about adjusting the low band.
When you go up a hill, if the engine is running but the car won't move, your problem is in the bands. But if the band is tight and the engine stalls going uphill, you have a problem with the the engine. There are some hills too steep to climb unless you get a good run in low gear before you start the steep part and keep going as fast as you can up the hill. Some hills cannot be climbed unless you use a Ruckstell or other compound low transmisson or go up in reverse. If your T is earlier than a 26-27 with a cowl tank you might need a full tank to climb a hill or go up in reverse.
Norm

[BobUkPipedream]

Thanks everyone for the help.

I tried the engine running method of adjusting the band today. I chickened out and after hearing the triples begin to engage, backed off one and a quarter turns. Then after another run realised that it was still loose and tightened again by half a turn and she seems a lot happier now. So the back off half a turn after triples start to engage seems right.

The drums all look really happy and the metal dust on the magnet in the strainer seems to have now reduced to virtually nothing. The sparks plugs have gone a nice shade of brown, although somehow three of them had loosened themselves out a bit and one had a biggish gap of 40 thou or so.

I also found some dirt in the fuel filter, richened the mixture a bit and she seemed a bit better up hill (we have quite a steep one). I then got up to some crazy speed probably close to 50mph. My boy and I looked like Beavis and butthead afterwards. Who needs hair stylists when you can race an open Speedster at speed down the road. She probably needs more higher speed runs as she is only 40miles out of a full rebuild and the rings are only just now seating I think.

[speedytinc]

"Dirt in the fuel filter"
Add on fuel filters on a gravity feed T, especially pre 26, can/will reduce fuel flow especially critical @ hi demand times like pulling a hill in low. Best to make sure your sediment "potato" has a good screen as designed.

[RVA23T]

I then got up to some crazy speed probably close to 50mph. My boy and I looked like Beavis and butthead afterwards.

Now that's my kind of T-model owner!
A Cornhoilo and vintage speed aficionado!
Congrats on the progress!

[BobUkPipedream]

Thanks very much!