Author Topic: Modified Accelerator Cable  (Read 1102 times)

Offline tsumini

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Re: Modified Accelerator Cable
« Reply #50 on: May 08, 2020, 01:14:32 PM »
There is a torsional spring. On the 50 mm TB there are six coils and strong return. I can't tell how many coils on this one as it is covered by the quadrant.
I keep coming bck to the torsional spring. Is it possible to strengthen it by permanently by winding/unwinding it maybe 1/4 turn? make a new one with thicker wire? IMO the return spring would be the simplest solution.

Offline tmsmini

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Re: Modified Accelerator Cable
« Reply #51 on: May 08, 2020, 01:30:29 PM »
None of this should be required as this is a system sold as a complete replacement. On the other hand I have made additional modifications and I am using a different intake manifold to make it fit better in a MK I engine bay.

I am going to start at the basics and replace my "replacements/modifications" where I can. If I can remove the adjustment to the air filter location and the filter still fits that will give me room to adjust the bracket that holds the cable end.

It is about 85 degrees and expected to hit and with the car in the driveway, it may wait until tomorrow to try somethings. Mail has not come yet.

I really appreciate all the suggestions and especially Willie for the ferrule!

Offline Jimini II

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Re: Modified Accelerator Cable
« Reply #52 on: May 08, 2020, 03:55:54 PM »
In this photo, are you suggesting moving it to the right? Or down?

Just my thoughts.

I do not know the specifics if the throttle shaft is bushed (I would assume and hope so) or is just turning in the body itself on your FI set up and it is the reason I suggested putting a small return spring on the accelerator pedal, this was the solution that Rover came up with on the MPI's the SPI's did not have this set up.
The problem I have run into several times over the years working on SU's is when owners had idle problems and decided to use a bigger spring to solve it on the Carb end, this resulted in increased wear mainly noticeable on HS2 and HS4 set ups.
Volvo had a mechanical linkage on their twin carbed 4 cylinders with way overrated return springs that would wear a set of carbs out in less than 30k.
The "bird cage" spring you are using is the same as BMC used in a set of 3 on Mini Coopers and S's and is not a powerful spring but will wear out a set of HS2's.

I am not saying it will wear out your throttle shaft like I said I don't know the specifics but I myself would rather risk a cheap throttle pedal assembly than that expensive FI set up.
The only other thing I would look into is getting the cable to run straight from the bulkhead instead of the 90 degree turn it currently has.
Great build btw and Good luck I hope you get it sorted.

Offline tmsmini

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Re: Modified Accelerator Cable
« Reply #53 on: May 12, 2020, 08:20:00 PM »
I was planning to start back at the beginning. I got side lined by a MPI sedan heater valve that need replacing.

I got around to removing the TB and installed one of the cable ends.
It does not line up very well.

Offline MPlayle

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Re: Modified Accelerator Cable
« Reply #54 on: May 12, 2020, 09:22:43 PM »
That is definitely a "Houston, we have a problem ..." type arrangement.

I imagine it is not any better when trying to use the 90* adapter you had on previously.


Offline tmsmini

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Re: Modified Accelerator Cable
« Reply #55 on: May 12, 2020, 11:00:57 PM »
Actually it is better, as the bend starts early enough to clear the fuel rail.
I will remove one of the spacers I added for the air filter. Then I will see if that allows me to bend or tweak the bracket to clear the fuel rail and get a straighter shot at the quadrant.

Offline tmsmini

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Re: Modified Accelerator Cable
« Reply #56 on: May 13, 2020, 01:23:28 PM »
The things I have done to fix things that may have made things worse
  • Modified plate for air filter to offset it away from the firewall
  • added spacers to move filter away from fire wall
  • used AN fittings on hoses which increased the diameter of the fitting
  • added fixed radius cable ends
« Last Edit: May 13, 2020, 03:28:07 PM by tmsmini »

Online John Gervais

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Re: Modified Accelerator Cable
« Reply #57 on: May 13, 2020, 05:18:57 PM »
Is there enough space under the bonnet to 'extend and/or invert the bracket' such that the bent cable end can be situated above the fuel rail instead of under it?
« Last Edit: May 13, 2020, 05:22:14 PM by John Gervais »
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Offline tmsmini

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Re: Modified Accelerator Cable
« Reply #58 on: May 13, 2020, 08:19:24 PM »
It might be possible, but it seems one change requires another.
With some bending and reorientation, I now have what the picture shows. Just a question of weather it will fit back in. It seems the quadrant is not circular.
The more I adjusted things to get the best angle at part throttle to closed throttle, the greater the angle became at WOT.
« Last Edit: May 13, 2020, 08:38:05 PM by tmsmini »

Offline Willie_B

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Offline tmsmini

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Re: Modified Accelerator Cable
« Reply #60 on: May 14, 2020, 09:25:39 AM »
I think I will just install one of these. Canepa offers rebuild service.



https://www.facebook.com/canepamotorsport/

Offline MiniDave

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Re: Modified Accelerator Cable
« Reply #61 on: May 14, 2020, 10:10:06 AM »
Wonder how much one of those weighs?

Surprised to see plastic fuel injection lines instead of metal.....
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Offline tmsmini

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Re: Modified Accelerator Cable
« Reply #62 on: May 14, 2020, 07:00:39 PM »
Looks like things are working, at least in the drive way. The cable offset in the cable end is more towards WOT, but the spring pressure is greater at that point.
And the air filter goes on and off easily.

I need to do a drive to really test it.
« Last Edit: May 15, 2020, 10:53:03 AM by tmsmini »

Offline tmsmini

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Re: Modified Accelerator Cable
« Reply #63 on: May 14, 2020, 07:08:06 PM »
Wiille's ferrule worked great. I used the clip on the firewall side.
So this picture is for really for Willie.

He gets his pick of any of these spare parts.
Bunch of stuff, valve cover, instrument pods, distributors A+, fans, HS2 elbows, sintered rockers, oil filter housing and pipe, etc.

Thanks Willie!!!!
« Last Edit: May 14, 2020, 10:18:36 PM by tmsmini »

Offline tmsmini

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Re: Modified Accelerator Cable
« Reply #64 on: May 16, 2020, 04:29:34 PM »
Quote

Just my thoughts.

I do not know the specifics if the throttle shaft is bushed (I would assume and hope so) or is just turning in the body itself on your FI set up and it is the reason I suggested putting a small return spring on the accelerator pedal, this was the solution that Rover came up with on the MPI's the SPI's did not have this set up.
The problem I have run into several times over the years working on SU's is when owners had idle problems and decided to use a bigger spring to solve it on the Carb end, this resulted in increased wear mainly noticeable on HS2 and HS4 set ups.
Volvo had a mechanical linkage on their twin carbed 4 cylinders with way overrated return springs that would wear a set of carbs out in less than 30k.
The "bird cage" spring you are using is the same as BMC used in a set of 3 on Mini Coopers and S's and is not a powerful spring but will wear out a set of HS2's.

I am not saying it will wear out your throttle shaft like I said I don't know the specifics but I myself would rather risk a cheap throttle pedal assembly than that expensive FI set up.
The only other thing I would look into is getting the cable to run straight from the bulkhead instead of the 90 degree turn it currently has.
Great build btw and Good luck I hope you get it sorted.


Solution is not in hand, but I wanted to respond to this.
This version of the TB has a unique design, "shaftless."


I am sure the side loading of the extra spring would eventually cause an issue.
I had a "half of Volvo HIF 44" on another engine and someone had engineered an extra spring solution. I had it rebuilt by Joe Curto and he said it was more trouble than it was worth to replace the existing linkage with Mini style linkage. All it needed was a proper spring replacement.

With the latest attempt I am running the cable with out the curved end at the firewall. This is a left hand drive car, so the cable can come close to the exhaust which is why I tried the curved cable end.
« Last Edit: May 16, 2020, 04:36:50 PM by tmsmini »

Offline tmsmini

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Re: Modified Accelerator Cable
« Reply #65 on: May 16, 2020, 05:50:38 PM »
So with some confidence that yesterday's changes seemed to work, I had my wife drive while I attempted to update the fuel MAP on the fly.
It was working pretty good, but it is hard to hold a station while driving. Other cars get in the way, etc.

But after 15 minutes or so the throttle was sticking again.

So for today attempt I took a 30 inch standard cable and cut one end off. This way I could use the brass end with the standard ferule on the firewall side.


I did have to remove a half inch or so of the sheath as it would not fit in the adjustable cable end.


With the extra length and to try to keep the cable away from the exhaust manifold(LHD car), I looped it through the master cylinder plate. Actually this is the way I originally had it with the 50 mm TB.


Bad picture but you can see the cable comes straight out of the firewall and clears the manifold to makes its turn towards the master cylinder plate.



The cable barely sits below the bonnet.


I was thinking of trying a valve cover bracket to hold it in place, like RHD cars with the longer cable. It appears the master cylinder plate holds things in a large radius loop.

With Willie's custom ferrule, it makes changing the cable petty easy.
But you still have to adjust the cable, reset the TPS, adjust idle, adjust lambda...

I did order a pedal spring as a back though.

All of this should not be necessary with a kit design to be used in MK I cars, unless I am missing something.





« Last Edit: May 16, 2020, 05:52:53 PM by tmsmini »

Online John Gervais

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Re: Modified Accelerator Cable
« Reply #66 on: May 16, 2020, 06:17:33 PM »
If you could twist the notched end of the cable bracket, perhaps the cable could sit under the fuel rail (on the side closest to the bonnet rather than the firewall side).  As it sits now, I suspect that the cable will develop a kink smack-dab above the adjuster.
« Last Edit: May 16, 2020, 06:21:04 PM by John Gervais »
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Offline Jimini II

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Re: Modified Accelerator Cable
« Reply #67 on: May 16, 2020, 11:12:08 PM »
Thanks for the reply.
It seems like you have tried just about every way to cure this issue.
As it is now sticking after the car has been driven for a while maybe it is a heat issue which i would assume would be affecting the throttle body area of the cable.
Maybe a heat shield or remove the tb and heat it up to see if the linkage in the body itself is sticking.

Offline LarryLebel

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Re: Modified Accelerator Cable
« Reply #68 on: May 17, 2020, 01:31:15 PM »
Like I said before you need to chamfer the hole in the ferrule in the firewall. The pedal pulls down on the cable as well as out and the drag of the cable on a sharp edge causes the restriction.

Offline tmsmini

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Re: Modified Accelerator Cable
« Reply #69 on: May 17, 2020, 01:46:08 PM »
I used a hand reamer to do this on all the cable ends I have tried to far.

I need to go for the longer drive to test it. I have repositioned the cable within the master cylinder bracket, so the cable does not interfere with the bonnet. It almost touches the block as it comes out of the firewall before turning.

It looks like it has stopped raining, so I may go for a drive.

Online John Gervais

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Re: Modified Accelerator Cable
« Reply #70 on: May 17, 2020, 04:19:04 PM »
I'm envisioning something like this, as it would give the cable arc enough to 'flow' under the bonnet without snaking (baggy) and too close to the engine, though in my modified image I cannot rotate the cable adjuster (copied & pasted) counter-clockwise to line up to the exposed cable or black cable sheath.  Imagine it to be rotated 25° - 30° (+/-) counter clockwise to clear the fuel rail.
« Last Edit: May 17, 2020, 08:33:50 PM by John Gervais »
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Offline tmsmini

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Re: Modified Accelerator Cable
« Reply #71 on: May 20, 2020, 03:19:09 PM »
I took a few drives and the issue was still present intermittently.
I do think I need to look at the throttle body itself, as I can touch the cable when it is stuck and it is loose. I think this means even a pedal spring wont help.

I could try bending the bracket at some other angles , but a problem is getting parts from S.C. I am afraid if I bend things too much I won’t be able to get a replacement.

This is such a simple issue, but I seem incapable of resolving it.
I also need to get it fully mapped as there are some settings that “street” mapping can’t help with.
Car also needs alignment, but I don’t want to take it in with a sticking throttle.

Offline MiniDave

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Re: Modified Accelerator Cable
« Reply #72 on: May 20, 2020, 04:33:26 PM »
After thinking about it I don't think a spring on the pedal is the right answer, as it pulls the wrong direction. My bad....
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Offline tmsmini

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Re: Modified Accelerator Cable
« Reply #73 on: May 20, 2020, 06:12:49 PM »
If the problem was with the cable, it is possible that the pedal spring would help.
This is how the pedal on the MPi uses a spring, I am guessing SPi are similar.
« Last Edit: May 20, 2020, 06:14:54 PM by tmsmini »

Offline tmsmini

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Re: Modified Accelerator Cable
« Reply #74 on: May 22, 2020, 02:37:28 PM »
My box from Sommerford should come today and it has a pedal spring. I will give that a try.
I did hear back from SC and they are asking if it sticks with no cable. I cannot seem to get it to do that, but if heat affect it, by the time I open the hood and get a camera setup, take the cable off, it does not stick.