Author Topic: 336 speedometer drive solutions?  (Read 121 times)

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Offline Richard48Y

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336 speedometer drive solutions?
« on: Sunday,March 03, 2024, 10:46:08 PM »
Tried search but could not find the answer I remember seeing.
Someone had been able to mount a pulse generator directly to the transmission.

With that solved this becomes my preferred solution as I do want to be rid of the long failure-prone cable but also want my original speedo.
https://www.summitracing.com/parts/dak-ecd-200bt-1
Dakota Digital unit that would mount behind the dash and drive the mechanical speedometer via a short cable.
I used one in my chevy pickup and it worked well.

I do not have any original transmission speedometer drive parts but I do have an R16 drive piece, which has no right angle.

Offline kram350kram

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Re: 336 speedometer drive solutions?
« Reply #1 on: Monday,March 04, 2024, 06:43:00 AM »
I used a direct drive speedometer 12vdc motor affair to drive the stock speedo in my TCS. Uses GPS. Buddy use same unit in his Elan. I have some pictures of the install and the manufacturers data. Need to dig it out. Will post later.

Online Bryan Boyle

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Re: 336 speedometer drive solutions?
« Reply #2 on: Monday,March 04, 2024, 07:48:49 AM »
Tried search but could not find the answer I remember seeing.
Someone had been able to mount a pulse generator directly to the transmission.

With that solved this becomes my preferred solution as I do want to be rid of the long failure-prone cable but also want my original speedo.
https://www.summitracing.com/parts/dak-ecd-200bt-1
Dakota Digital unit that would mount behind the dash and drive the mechanical speedometer via a short cable.
I used one in my chevy pickup and it worked well.

I do not have any original transmission speedometer drive parts but I do have an R16 drive piece, which has no right angle.

I think in 40+ years of Europa ownership, I've only replaced one speedo cable along the way.  Key to keeping it working is removing as much stiction in the rotation as you can (new cables are teflon lined, so it helps, but hanging it up by one of the ferules and filling with a thin oil and letting it drain through helps) and having as WIDE a bending radius both at the back where it hooks into the tranny and at the front where it comes up from the tunnel and has to make a 180 degree bend to get into the back of the speedo is also necessary. 

When I did 693R back when...I sourced an MGB right angle speedo adapter (their drive is picked off the tail of the tranny and poke through the tunnel and loop up to the driver side (LHD); on the back of their speedo (at least the pre-'67 or so) was a gear box that translated the drive 90 degrees.  Of course, their cable is only 24" or so...ours have a longer distance...but, it was a simple fix (693R's was the only cable I replaced) that reduced the number of radii the cable had to have to get from the front to the back. 

Just a thought...afaik, the current owner still has a working speedo...17 years later...
Bryan Boyle
Fall River MA
Morrisville PA
Commercial Pilot/CFII/FAA Safety Team
Amateur Extra Class Operator & FCC Volunteer Examiner
Currently working on 3291R, ex 444R, 693R, 65/2163, 004R, 65/2678
http://www.lotuseuropa.us for mirror of lotus-europa.com manual site.

Offline jbcollier

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Re: 336 speedometer drive solutions?
« Reply #3 on: Monday,March 04, 2024, 04:05:51 PM »
You can use a commonly available ford part that does the trick.  Just slides right in.  I’ve mentioned it before so you should be able to search the archives.  I’m travelling right now but will post it when I get back if you haven’t already found it by then.

Offline kram350kram

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Re: 336 speedometer drive solutions?
« Reply #4 on: Monday,March 04, 2024, 06:49:03 PM »
Richard 48Y... I used the Speedbox by SpeedHut, same type unit you posted. I could not use a  straight cable and bending the cable 90 degrees seemed to acute, because of my gas tank placement. So I placed the drive motor directly behind the speedo thru the firewall with a cover. Fabricated a short coupling to connect the speedo to the drive unit.  Used a Polaris speedometer drive part# 3280017 , 2.25” long from a snowmobile. Best I can do with photos as it's all inplace now.   

Offline BDA

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Re: 336 speedometer drive solutions?
« Reply #5 on: Monday,March 04, 2024, 08:04:25 PM »
I replaced my original speedo with an electronic Smiths speedo. I ended up driving it with a GPS antenna mounted in my engine compartment (along with some other electronics). It works great but there is a downside. It takes a couple of minutes to acquire enough satellites after I leave my garage before it can register my speed (and mileage) and when I start under tree cover, it can't acquire the satellites till I get into a clearing for a long enough period of time to acquire them. There is some logic in the antenna that remembers (for a limited time) where the last satellites were so when I park, it doesn't take any time to acquire them so it's really only a problem when I first drive away.

Over all, I'm really happy with it. As you've found out, there are many ways to skin this cat. The electronic driver driven by the speedo gear in the tranny is maybe a better alternative but I shredded my speedo gear so that wasn't an option.

Offline Richard48Y

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Re: 336 speedometer drive solutions?
« Reply #6 on: Monday,March 04, 2024, 08:08:52 PM »
I think I found the discussion of the Ford impulse sender.
Should work fine so long as the 336 and 365 are the same?
I also saw new 12T drive gears at R16 shop.
Hoping to pull parts and delve into this a bit more in the morning.
I know my 336 transmission has an empty hole with a plastic cover over it.