I am rebuilding the transmission of my November 1913 engine. According to the books, I would have to change everything but I am not looking for a perfect transmission only something to run 500 miles per year for the next 20 years !
I measured the triple pins:
# 1 is between 0.6760 and 0.6468
# 2 is between 0.6756 and 0.6776
# 3 is between 0.6744 and 0.6760
I measured the clearance this way by pushing and pulling the gear(is it correct ?) and found
# 1 : between 0.003 and 0.0055
# 2 : between 0.004 and 0.0055
# 3 : 0.005
(instrument is in 1/100 of mm)
Should I change something ? I wish to avoid changing the pins because of the risk of breaking the flywheel. Replacement pins are 0.003 oversize, I agree that pressing in and out the pin will increase the hole in the flywheel but 0.003 seems a lot and it will be a very tight fit with the risk.
I then measured the clearance for the bushing of reverse and low drum with same method. I found 0.008 for reverse and 0.005 for Low. I think I have to change ?
Although the new bush kits are all set to clearance, once pressed in they will all need to be re-reamed, I've seen trans bushing far worse than yours and work fine, I think your cracked drums would be the priority repair.
New bushing will make you transmission making less noise but the bushing need the right clearance to make the oil go between them. Very important is to check if the triple gears don't run in the flywheel there for you need to check the condition of the brass part of the bushing on the back of the triple gear.
As Kerry say take also care of the cracked drums they can explode wail you are running the car.
Kerry, are you seeing cracks in the reverse drum web? A good many drums look like that one and the "crack" is not really a crack. Rather it is a flaw which occurs as the casting is poured. It looks like the metal has cooled a little before flowing completely through the mould. These can be quite sound, evidenced by their succesful use over many years. That does not mean that I would use one if I had a replacement. On a recent re-build one of the brand new repro drums showed this flaw and i returned it for replacement.
Philippe, I would use the transmission you have as it is. Those components have gotten to know each other and will operate sweetly. I would not disturb them, especially given you are not looking to put a lot of mile on the car.
Just my opinion.
Allan from down under.
Just my opinion.
I would put it back together. It is in great shape. Anything you do to it will not be better.
Was the pin #1 measurement a misprint?
The clearances don't bother me. You probably should press out the triple gear bushings enough to wrap one circle of wire around under the flange and press it back in. I use Loctite too. Book says 6 thou proud, I go for 10 or 12.
Royce is correct. Rebushing will make a noisy transmission. The transmission is the most rugged item in the driveline. Andre is incorrect about new bushings resulting in a quieter transmission.
From what I have read on the forum the last few years rebushing a transmission and getting all the clearences 'real close' usually results in more trouble. Not always but more than you might think.
I am sorry but mine makes less noise as before the rebuild and is very quiet now but I also changed the clutch to a Jack Rabbit and the Kevlar lining to Wood.
Thanks for your advice
Chuck: Yes the measure for #1 should be 0.6768
Richard : instead of pushing out the bushing if the flange is used, can I put a hard steel shim ?
What about the clearance of the bushing of the drums ? Are there OK even if much more than hat book says ?
My apologies, this was not my experience and congratulations on your achievement.
Philippe, yes you can place a hard steel shim behind the flange, but you'll have to split the shim to work it behind the flange. You shouldn't simply place a steel shim between the flange and flywheel, it won't hold up. You don't remove the bushing, you just push it out enough to get a shim or wrap of wire behind the flange and then push it back in. The shim or wire will keep it raised a bit so you have the right amount of flange height. Kinda hard to explain, easy if you saw it done.
The bushing clearances for the slow and reverse drums are fine. The quietest transmission I ever had was in a Rip Van Winkle car and each measured 12 thou clearance. Folks rebush transmission drums way more than needed.