Wide brake drum transmission.

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Model T Ford Forum: Forum 2015: Wide brake drum transmission.
Top of pagePrevious messageNext messageBottom of page Link to this message  By Allan Bennett - Australia on Thursday, July 23, 2015 - 09:27 pm:

Was the introduction of the wide brake drum transmission made at the same time as the four dip pan. Along with this would be the hogs head with ears and the threaded bosses on the engine block.

Or was there a transition period when the three dip pan was changed to accept the wider brake band and a hogs head with out ears was used, Prior to the four dip pan?

Allan from down under.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Treace, North FL on Thursday, July 23, 2015 - 09:57 pm:

Allan

July 1924 for the "4-dip" pan.

November 1925 for the new trans with ears and boss to the block along with straps from the ears to the frame on each side.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Allan Bennett - Australia on Friday, July 24, 2015 - 12:32 am:

Dan, the for dip pan came earlier than I thought. My 25 Canadian sourced roadster chassis has the standard 3 dip, but it is likely an earlier production than 25.

So, is this the time line? 4 dip pan first. Then the wide drum trans, along with the bulge in the pan and the ears on the hogs head and the wider pedals.

I was hoping to fit a wide brake drum into a 3 dip pan. Looks like I might have to settle for a machined down wide brake drum and driven plate, to replace the usual narrow drum with part of the driven plate making up the band surface.

Allan from down under.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wayne Sheldon, Grass Valley, CA on Friday, July 24, 2015 - 01:14 am:

If you want the wide brake drum because you have it, or even for the improved clutch guides? And if you are planning to use the earlier brake band, hogshead and pedals? The wide brake drum itself will fit into the earlier pan and hogshead and work with the earlier pedal and band just fine. It is the relaxed band that needs the dimples out on the pan to fit inside. As long as you don't have the wide band (and its position moved back about a quarter inch), the drum will fit inside the common three dip pan. I have not actually run a wide drum in a pre-'14 pan, but I did measure one and found that it should work. I have used a wide drum inside a 1920ish pan and hogshead and have spoken to several other people that have also. (I have also heard from one person that they did run a wide-drum transmission in a '12 pan, but never confirmed it)

Given the timeline of the four-dip pan being used in cars nearly a year before the wide-drum brake required the wider bulge in the pan for the band to clear (I first read about this a couple years ago myself)? I wonder, has anyone ever found a four-dip pan that did not have the bulges for the wider brake band? Has anyone ever gotten an engine mostly together and then found the pan wouldn't work without modifications?
Just curious.
On the plus side of things. That timeline almost makes my April '24 coupe nearly correct (sort of, kind of, almost, maybe) with its four-dip pan.
Drive carefully, and enjoy, W2


Top of pagePrevious messageNext messageBottom of page Link to this message  By Allan Bennett - Australia on Friday, July 24, 2015 - 03:22 am:

Wayne, I can go two ways with this. I have a wide drum with a chip at the rear, which would clean up quite well enough to run the usual narrow band. This drum has the replaceable lugs for the clutch plates. The rest of the trans will be a selection of the best parts I have, so I am anticipating some noise as the parts get to know one another.

I also have two complete wide drum trans assemblies still together. If one of those looks good on tear down, that would be the way to go, but I have never found a late trans without worn triple gears/drum gears.

Rather than a four dip pan without the bulges for the wider band that you enquired about, I was hoping for a three dip pan with the bulges, so I could use the wider band. I realise there would need to be some work done to align the pedal shafts, or I could resort to a late hogs head which already has a broken off ear.

The fellow who restored the running chassis under my 24 tourer, spent some time in this area. I should get it home again and lift the cover plate to see what he has done.

Too many cars to keep track of.

Allan from down under.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Trent Boggess on Friday, July 24, 2015 - 08:16 am:

I would like to offer a few points of clarification on the 4 dip and the improved car transmission.

First, the wider transmission brake drum was anticipated when the 4 dip pan was introduced. There are no 3 dip pans with the wider opening at the rear to clear the brake band.

Second, the improved cars were introduced about August 1, 1925, and they incorporated the wide brake drum, the new transmission cover with the ears for bolting the cover to the back of the block, and the wide clutch and brake pedals. Many other improvements and features were introduced at the same time. All in all, it was the largest revision of the Model T to occur since the introduction of the black era cars in 1917.

Finally, the development and introduction of the improved car was kept secret from the public and the rest of the company. When referring to the changes in the car and it's chassis the Ford engineers used a code name for the Improved Cars. They called it the "Australian Job", to suggest that the improvements were to used on cars built for the Australian market.

I thought you guys from down under would get a kick out of that third point.

Respectfully submitted,

Trent Boggess


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Treace, North FL on Friday, July 24, 2015 - 11:39 am:

Trent

Thanks for the correction.

Made that Nov date not thinking of the new engine intro. Quickly looking at Bruce's CD on changes, and made that error.

According to Bruce's documentations, Drawing date 7-2-1925 was for the new Improved block with the boss for the new transmission cover.

And July 27, 1925 was last production 'old design' engine, 12,218,728...after that and with the start of the third shift, the Improved engine with big brake drum, and other features began.


Service Bulletin announcement later.

As for that Nov 16, 1925 date, that is when "100% of production" got those straps to the frame from the engine block boss, according to Bruce. My Nov 25 Improved runabout 12,635,128 did have these straps. Guess the early Improved engines up to Nov 16 may or may not have had these straps?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Karlsson, southern Sweden on Friday, July 24, 2015 - 01:59 pm:

I've got one of the first improved style engines made july 27 1925 on the third shift - it didn't have any straps when I found it ( ok, it wasn't in a car)
There are at least one engine in Denmark and another in Sweden from that first day production still around, so there were likely a batch of them sent to the Copenhagen plant to give them a fast start for the changeover to the improved style.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Allan Bennett - Australia on Friday, July 24, 2015 - 08:25 pm:

Thanks Trent. Now I know I am looking for the impossible, and can get on with the job. The fellow who restored my 24 tourer spent a lot of time beating clearance for a wide brake band into a 3 dip pan, but I will have to lift the cover to see just how far he went with the installation.

Allan from down under.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Larry Smith on Saturday, July 25, 2015 - 08:31 am:

I had a '25 block once that had the '26 boss, but no bolt holes. Wish I would have kept it.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Trent Boggess on Saturday, July 25, 2015 - 10:35 am:

The reason the engine block to frame straps were added was to reduce crankcase arm breakage. According to Walter Fishleigh's papers (BFRC Acc. 94), the Model T had a problem with Frank case arm breakage because of the stresses put on the arms by the pressed steel running board arms. This was not a problem on the TT trucks because the used a much different design of running board arms that did not stress the crankcase arms. The Ford engineers found that by adding the engine to frame straps, they could pretty much clear up the crankcase arm breakage problem.

My October 1926 coupe did not come with the straps, but after reading about why the engineers added the straps, I have since added them to my car, even though they are not technically correct.

In the spring of 1926 the engineers found that the heavier bodies on the improved cars was causing a frame sag problem. The way they cured that problem was by going to a heavier gage steel on the frame side rails. Late '26 and 1927 Model T frame side rails are substantially thicker than post-2500 side rails.

Respectfully submitted,

Trent Boggess


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