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PostPosted: July 28, 2021, 7:23 pm 
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All,

My plan is to drop the engine from a BMW K1200S into my 1973 Jensen Healey. The J-H had a cable operated clutch, but the K1200 has a hydraulic clutch. I would like to keep the pedals stock if at all possible (mostly for cost savings, not because I am a purist or anything) I have toyed with the idea of installing the levers from the bike somewhere, and operating the lever with the cable operated clutch in the J-H. I am worried about feel, but can probably overcome that with some stiff springs either in the clutch basket, or on the pedal itself, along with a pedal stop to keep from overdoing the clutch pull.

I have also considered modifying the clutch pedal, and using an after market clutch master cylinder like these (https://www.speedwaymotors.com/shop/clu ... 0-487-1996) or change just the clutch pedal to something like this. (https://www.mcleodracing.com/conversion-kits-chevy/p90)

Finally, and what I believe to be the most expensive route, it to change all the pedals to Willwood or similar all in one unit...floor mounted of course cause if i'm spending the money, might as well spend it right.

Anyone have any suggestions or opinions about the possibilities.


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PostPosted: July 29, 2021, 5:59 pm 
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Use the cable to pull the lever. You may want to make a new lighter duty and shorter cable with a smaller, threaded end.

Measure how much travel the cable has between the pedal on the floor and the pedal up against the stop. If there are no stops, you can make adjustable stops. You will probably need to limit total travel to prevent damage to the master and cable.

Shorten the lever and drill to accept the cable end or add a clamp around it and pin it so it won't slip or weld more material on.

Adequate pedal travel for modulation is more important than feel.

There should be spring that supports the pedal weight.

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PostPosted: July 29, 2021, 11:08 pm 
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Seems like a fairly heavy body for BEC.
Similar weight to MGB.
Just thinking out loud.

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PostPosted: July 30, 2021, 12:06 am 
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RichardSIA wrote:
Seems like a fairly heavy body for BEC.
Similar weight to MGB.
Just thinking out loud.


Thanks for the thought. Ya, considered the weight, but I think it will end up being about 2100 or so pounds after restoration/modification, especially with the loss of the transmission and engine and replaced with a much lighter bike engine/transmission. The stock Lotus 907 only puts out about 120HP, while the K1200S does about 170 or 180 HP. Sure, maybe not as good as a mini or fiberglass body, but I think the bike engine will really improve things.


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PostPosted: July 30, 2021, 12:07 am 
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Miatav8,MstrASE,A&P,F wrote:
Use the cable to pull the lever. You may want to make a new lighter duty and shorter cable with a smaller, threaded end.

Measure how much travel the cable has between the pedal on the floor and the pedal up against the stop. If there are no stops, you can make adjustable stops. You will probably need to limit total travel to prevent damage to the master and cable.

Shorten the lever and drill to accept the cable end or add a clamp around it and pin it so it won't slip or weld more material on.

Adequate pedal travel for modulation is more important than feel.

There should be spring that supports the pedal weight.


Thanks for the suggestions. I'll likely end up doing as you suggest.


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PostPosted: July 30, 2021, 12:45 am 
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Just connect a M/C plunger to the pedal. Use a rear master cylinder off a similar model bike. Lots of side by side and quad stuff also, pay attention to bore size and pedal ratio.

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PostPosted: July 30, 2021, 2:55 am 
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Use one of these to pull the clutch lever https://www.speedwaymotors.com/Speedway ... gJTSfD_BwE

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PostPosted: July 31, 2021, 9:49 pm 
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Kartracer47 wrote:
Use one of these to pull the clutch lever https://www.speedwaymotors.com/Speedway ... gJTSfD_BwE


What do you mean "to pull the clutch lever?" That appears to be a clutch slave cylinder.


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PostPosted: August 1, 2021, 1:28 am 
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https://www.speedwaymotors.com/Speedway ... gJTSfD_BwE

This is a PULL type clutch slave cylinder. The clutch lever on the MC engine is pulled by the clutch cable. Use this slave cylinder to pull on the lever. Originally designed to allow hydraulic actuation of the VW bug clutch lever which used a cable.

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PostPosted: August 1, 2021, 6:42 am 
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Kart, the MC engine uses a slave, not a cable. The Jensen uses a cable. Keeping the cable means no mods to the Jensen (though travel stops are a good idea), no additional hydraulics to buy and adapt, and the MC master can be placed anywhere the MC hose will reach.

As far as converting the Jensen to hydraulic, it would require a good bit of rework to the pedal assy. I doubt any aftermarket masters have a small enough bore to be compatible with the MC slave, plus a new hose and fittings, etc. I expect it would cost about $200 for parts not counting all the fab.

I designed a basic cable to hydraulic hand clutch adapter.


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Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12


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PostPosted: August 1, 2021, 11:28 am 
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My apologies - misread the post.

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PostPosted: August 1, 2021, 6:47 pm 
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Miatav8,MstrASE,A&P,F wrote:
Kart, the MC engine uses a slave, not a cable. The Jensen uses a cable. Keeping the cable means no mods to the Jensen (though travel stops are a good idea), no additional hydraulics to buy and adapt, and the MC master can be placed anywhere the MC hose will reach.

As far as converting the Jensen to hydraulic, it would require a good bit of rework to the pedal assy. I doubt any aftermarket masters have a small enough bore to be compatible with the MC slave, plus a new hose and fittings, etc. I expect it would cost about $200 for parts not counting all the fab.

I designed a basic cable to hydraulic hand clutch adapter.


Pretty much what I was planning to do. Do you by chance know where I can get the cables made. I once read a bike shop, but I am thinking I need something a little beefier.

No worries Kart, I often times don't write clearly. :lol:


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PostPosted: August 1, 2021, 7:43 pm 
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Nothing to apologize for Kart.

You could use marine steering cables for cheap. They come as short as two feet. I'd go 5/16.

Custom cables from these suppliers are another option:

http://www.flanderscables.com/

https://push-pull.com/custom-cables-brakes/

You may be able to make a pull rod that is about a foot long, fits the pedal pin, will work through the existing hole and bolt the clutch control adapter to the firewall.


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Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12


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PostPosted: August 3, 2021, 9:42 am 
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The wonderful thing about hydraulics is they work both ways. I wonder, if you used the "pull" slave cylinder mentioned earlier as a master? The Jensen cable clutch mechanism could pull the shaft and create the hydraulic pressure necessary to move the K1200 slave. If necessary a lever could be used to adjust the ratio. Just thinking out of the box with nothing but cobwebs in my head. May be worth an investigation?

TBH, some times I wonder too far and get lost. Maybe this is one of them? :roll:

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PostPosted: August 3, 2021, 12:24 pm 
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I'd say it will be considerably more difficult and expensive to do the cable monkey motion than it would to attach a Cycle rear master cylinder to the clutch pedal.
Most have a remote reservoir which makes the install that much easier.

You can't use a slave for a master as there is no fluid reservoir to draw from.

https://www.ebay.com/itm/352962135729

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