Home Forums General Technical Help Speedometer @ gearbox cover

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  • #76452
    Hatchy rmbf
    Participant
    Club Member

    Speedometer drive cover

    I’m fitting a 105e four speed gear box in my DLM
    The chassis is 1935 Standard 9 with crusiform cross members
    The gearbox mount will be in the centre of the X and the speedo drive cover might not fit as it foul the chassis rail
    Not fitted everything into the chassis yet but asking incase

    ? My question is, if there is no cover or speedometer cable fitted will there be a possible oil leak.? or is it sealed?

    The old spedometer drive was belt driven off the prop shaft but for accuracy I was using a push bike computer
    The old speedo was eratic, and never the same each journey, and reading about 5-10 MPH out, and it was a case of somewhere between 25-35, 50-60 and flat out 20mph out.

    Will be trying everything for size in the next few days.

    #76454
    JAN
    Participant

    The cable forms no part of an oil seal to its drive. There is an O ring between the drive housing and the extension housing, but the driven gear shaft merely has a scroll to maintain oil tightness, which is never a hundred per cent achieved. There is a gasket between the cable’s flange and housing, but I’ve never seen one in situ. The driven gear must be in place, but the cable need not be connected.

    #76455
    Hatchy rmbf
    Participant
    Club Member

    Thank you Jan
    Will be trying everything out soon,
    I have had the engine and gearbox in place to check mount and how much needed cutting off the old propshaft
    It looked a bit close but might be enough room as I have trimmed away some of the web plate over the X
    I have thought about a GPS speedometer if it wont fit, almost the same price as a 90 degree adapter
    I use a pushbike computer as well as my normal speedo is way way out and eratic.
    20MPH out at 80hMPH, 5MPH out at 30mph or somewhere up to 10 mph either side as the needle waves to you lol

    #76464
    member2617
    Participant

    Could always stick a blanking plug to cover the hole.

    #76468
    JAN
    Participant

    You’d struggle to make a seal. The driven gear housing goes inside the gearbox casing and the main seal is the O ring and you would need to provide something similar but solid; nor couldn’t you simply provide a flat plate outside the hole, especially as there is only a single screw to secure it.

    #76469
    member2617
    Participant

    speedo drive plug (alloy)

    Should do the trick.

    #76470
    Hatchy rmbf
    Participant
    Club Member

    I’m going to have to posr a photo of the speedo drive as it is at the moment
    Not sure if I have it right, as it is at the moment there is a drive spindle exiting the gearbox and a flat piece flush/ish with the casting.
    I seem to be thinking that there should be a cover over the spindle with the speedo cable in place, is this right.
    Not having seen one in place a car and only exploded images I’m not too sure of the set up.
    Anyway at the last resort that plug looks like it’ll do the job

    Thanks for the help so far.
    Got everything in place so now it’s time to take it all down and check everything is tight-n-torqued, final clean up-n-paint
    Shame I cant see how to post photos but there all on my facebook page.

    #76471
    Hatchy rmbf
    Participant
    Club Member

    I think Ive found a good image of the gearbox end of the drive
    I take it the drive cable just pushes onto the spindle and the spring clip with screw holds it in place?
    If so I’m home-n-dry.

    #76472
    JAN
    Participant

    Apart from that the clip isn’t sprung, yes. That’s how it works.

    #76477
    Hatchy rmbf
    Participant
    Club Member

    Thanks for the help
    I see now, will have room for a normal speedo drive.
    Got engine and gearbox back out of the car to check everything over, double checking everything is tight etc.
    clean up and paint, send the propshaft of for balancing,

    Thanks again

    #76478
    JAN
    Participant

    What axle ratio / wheel size are you using? There is a range of speedo driving and driven gears to suit the different ratios Ford offered. These were generally with 5.20×13 or 5.60×13 tyres. The teeth on the colour coded driven gears are – Natural 22 – 4.125; Black 23 – 4.429/4.444, both with 6 teeth on the driving gear mounted on the mainshaft. For a different driving gear there are driven gears with: Green 24 and Blue 25 teeth. I don’t know the ratios (3.9 is one) or details of the driving gear. Perhaps someone else on here might know. Retro Dick?

    #76479
    Hatchy rmbf
    Participant
    Club Member

    Hi Jan
    The car is the DLM 1 Special, a one of bitza.
    Chassis is 1935 Standard nine, Engine is a 100e and will soon be with a 105e gearbox.
    The rear axle is also 100e, I believe there is only one ratio for the 100e box.
    The Wheels are 16 inch with 5.5×16 tyres giving 85 inch circumference (217cm)

    #76482
    JAN
    Participant

    Yes, all 100Es used 4.429:1 which, with 5.20×13 tyres, gives a circumference of about 187cm so your speedo is going to under-read quite a lot.

    #76483
    member2617
    Participant

    Jan, the other ratio is 3.5, but I can never remember if it’s the blue or green one.

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