Throttle cross shaft improvement

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Kevster
Posts: 42
Joined: Thu Jan 08, 2015 5:38 am
Location: West Wickham, Kent. UK.

Throttle cross shaft improvement

Post by Kevster »

Hi,
I thought I would share a simple fix I did on my throttle shaft. After I rebuilt my engine I was having real trouble getting the idle speed down without it stalling. If you let the revs drop slowly it idled too fast, if you let it drop quickly it would stall.
I soon realised it was the slop in the linkage that was causing the problems, so set about fixing it. Now I know there are other solutions out there, but being in the uk, anything specific to a corvair has to be imported and costs a fortune.

I started off with buying these bushes, £4/$5 for the pair. They are 3/8 x 1/2 x 1/2.
New bush
New bush
I then filed down the brazing until I could remove the end. I believe you may be able to heat up an old braze but I don't have anything that will get that hot, and it doesn't sound easy, so I went with the mechanical technique.
Before you take it completly off, you need to mark both pieces to ensure you put them back on the correct alignment.
Brazed end
Brazed end
Having removed the bracket, drill out the centre to 1/2", then press in the bushing as shown.
image.jpeg
Now make sure you put the bracket back on the right way, line up the arm with your marks and weld or braze it back on.
Weld end
Weld end
That is the first end completed and it should look like this.
One end completed
One end completed
Now mark the other arm position and file away the braze until you can remove the arm.
Other end
Other end
Drill out the centre to 1/2" again, but this time the bush pushes in from the other side. You wil also need to drill a hole for a cotter pin to stop it moving side to side. The original fixing will be covered by the bush.
Second bracket
Second bracket
Put the bracket on the shaft, line up the arm with your marks and weld or braze it on.
Paint it up, and you are done. No more play from the shaft, but I can now feel the slop in the bent rods, so will be replacing them with ball joint linkages.
image.jpeg
image.jpeg
image.jpeg
Hope that is some help to anyone who wants to do something similar, cheap to do and only took an hour to do.

Kev.
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toytron
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Joined: Mon Dec 28, 2015 4:30 am

Re: Throttle cross shaft improvement

Post by toytron »

Hey Kev, thanks for the info! Looks good. Are those bearings brass or bronze? If bronze what alloy are they?
Thank you, Ed

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Edwin Stevenson
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65 corvair corsa convertible turbo
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wbabst
Posts: 313
Joined: Mon Oct 27, 2014 8:03 pm
Location: Lake Elsinore, California

Re: Throttle cross shaft improvement

Post by wbabst »

I wanted to improve my cross shaft performance also. I like the bronze bushings, yours look great, but I didn't want to take my shafts apart. I built bushing blocks that fit over the shaft arms, and then made delron bushings that fit nice, I spit them and then the bushing blocks hold them in place. I am lucky to have access to a lathe and mill at work so I made these.
Image

Image

Image
Current owner
61(x2) Monza Cpe
55 Pontiac Chieftain Wagon


61 Progress here
https://www.facebook.com/pages/Chevrole ... 7898185672
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Kevster
Posts: 42
Joined: Thu Jan 08, 2015 5:38 am
Location: West Wickham, Kent. UK.

Re: Throttle cross shaft improvement

Post by Kevster »

Hi
The bushes are oil filled bronze, similar to oilite if you have tham over their?
http://www.ebay.co.uk/itm/131666950472? ... EBIDX%3AIT

I thought about using the Clark brass blocks, similar to yours, but the cost was fairly high and I preferred the look of only having the bush. It did involve taking things apart, which was a little worrying, but actually was really quiet easy. If it had all gone wrong I would have just ordered the Clark complete shafts, and I wouldn't have cared about the core value as the postage would be more than I got back!

Anyway, all went well in the end and really easy. I guess it depends how well they were brazed at the factory, mine were only done in a couple of spots, so no trouble.
Kev
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wbabst
Posts: 313
Joined: Mon Oct 27, 2014 8:03 pm
Location: Lake Elsinore, California

Re: Throttle cross shaft improvement

Post by wbabst »

Kev, your bushings look great, we buy the Oilite material in sticks of different diameters and make our own bushings at the shop. Your find on Ebay seems like a very simple and easy solution.

I too thought that Clarks brass blocks were a bit expensive, but not too bad for what they are. I just like making things my self when I can and often do since I have the shop to do it in. I can promise you that it doesn't mean I get away for doing it for less. I needed new shafts for my carburetors and I made them in the shop, by the time you count the material I purchased and my time to make them, I had a lot more into them then the $10 Clarks gets for them :doh:
Image
Current owner
61(x2) Monza Cpe
55 Pontiac Chieftain Wagon


61 Progress here
https://www.facebook.com/pages/Chevrole ... 7898185672
https://www.facebook.com/pages/Goose-N6 ... 8869056897
Kevster
Posts: 42
Joined: Thu Jan 08, 2015 5:38 am
Location: West Wickham, Kent. UK.

Re: Throttle cross shaft improvement

Post by Kevster »

Nice work on those shafts.
I bought the clarks ones and replaced mine, and must say, while they were made in China, I couldn't find anything wrong with them! Nice if you can do it yourself though.
I was offered a milling machine for free a month or so ago, but I really don't have the space, and as you say, I probably couldn't afford to make bits with it!
Kev.
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cad-kid
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Location: Kronenwetter, WI
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Re: Throttle cross shaft improvement

Post by cad-kid »

Great throttle shaft solutions, both of you :tu:
Jeremy (cad-kid)
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