FI Scorpion throttle cable

[chris obert]

Hi,
I have been brought a 1977 Scorpion that has had a 1982 Beta fuel injected engine installed. Most of the conversion has been completed (a lot of it in not the way I would have done it...), I assume in the way pioneered by Mark Rawlings and improved upon by others. But the thing still will not run.

The throttle cable sticks because someone has rigged a pull system on the FI throttle body made out of fishing line hardware, and it has a real sharp bend from the housing stop attached to an intake cam box bolt. Someone has somehow attached a throttle position switch to the heater side of the throttle body with what appears to be tin can parts, and the position switch moves all around when the throttle is actuated. The switch has failed, either because of the funky mount, or because it was just it's time.

Instead of reinventing the wheel, I am curious what set up works. Is there a "standard" way of rigging the throttle cable? Of course my client is on a budget, but this needs to get fixed.

I also have no idea why the stock 1982 Beta throttle system has been deleted, but I think I have most if not all of it in storage on an old FI engine we parted. Is there any reason I just can't go back to 'what the factory used'?

Hope to hear from someone soon as I would like to get a start ASAP. This thing has been sitting, but the client wants it completed soon.

Chris Obert

[DJ]

Hi, Chris

Welcome to our little corner of the web.

The throttle connection is always one of the biggest challenges for most folks with a Scorpion FI conversion. The stock Beta assembly simply won't fit under the parcel shelf on the Scorpion.

This is what I've done for my throttle assembly. John Allen has done something similar.

The base plate, cam/cable connector, and cable holder were used parts/materials I had laying around. The uprights were cut and fashioned from a piece of aluminum angle. The bronze bushes, keepers, and shaft are from Ace Hardware.

The shaft was simply drilled and tapped to thread onto the throttle-body shaft and then drilled/tapped again for a set screw on each side. This is likely the weakest part of the whole thing and should be done carefully and precisely for as a good a fit as possible. If I ever need to re-do this I'll use a carbon steel shaft instead of the softer stainless that I have now. The other end was formed by hand with a file to fit the cam, then threaded for the nut.

This works really well so far. The only problem I have with throttle now is the sloppy foot pedal which is on my list of fixes to do soon.

As for the TPS mount, by far the easiest way to do it is to find an aftermarket Weber "Big Throat" (60 mm) TB which has a mount and extended shaft to allow mounting to the side of the TB. These pop up on eBay routinely as new and used units. Most used ones are off Datsun Z-cars. Redline also made an aftermarket performance kit for VWs. There's one here (http://cgi.ebay.com/ebaymotors/Weber-60mm-Throttle-Body-Datsun-Nissan-240-260-280-Z-ZX_W0QQcmdZViewItemQQ_trkparmsZ72Q3a570Q7c66Q3a2Q7 c65Q3a12Q7c39Q3a1Q7c240Q3a1318Q7c301Q3a1Q7c293Q3a1 Q7c294Q3a50QQ_trksidZp3286Q2ec0Q2em14QQhashZitem32 0337357864QQitemZ320337357864QQptZMotorsQ5fCarQ5fT ruckQ5fPartsQ5fAccessories#ht_500wt_1213) on eBay right now.

If you have to stick with the stock Beta TB, you can still mount the TPS on the side but you'd need to extend the throttle shaft.

http://lancisti.net/forum/picture.php?albumid=19&pictureid=226

[chris obert]

Hi, Chris

Welcome to our little corner of the web.

The throttle connection is always one of the biggest challenges for most folks with a Scorpion FI conversion. The stock Beta assembly simply won't fit under the parcel shelf on the Scorpion.

This is what I've done for my throttle assembly. John Allen has done something similar.

The base plate, cam/cable connector, and cable holder were used parts/materials I had laying around. The uprights were cut and fashioned from a piece of aluminum angle. The bronze bushes, keepers, and shaft are from Ace Hardware.

The shaft was simply drilled and tapped to thread onto the throttle-body shaft and then drilled/tapped again for a set screw on each side. This is likely the weakest part of the whole thing and should be done carefully and precisely for as a good a fit as possible. If I ever need to re-do this I'll use a carbon steel shaft instead of the softer stainless that I have now. The other end was formed by hand with a file to fit the cam, then threaded for the nut.

This works really well so far. The only problem I have with throttle now is the sloppy foot pedal which is on my list of fixes to do soon.

As for the TPS mount, by far the easiest way to do it is to find an aftermarket Weber "Big Throat" (60 mm) TB which has a mount and extended shaft to allow mounting to the side of the TB. These pop up on eBay routinely as new and used units. Most used ones are off Datsun Z-cars. Redline also made an aftermarket performance kit for VWs. There's one here (http://cgi.ebay.com/ebaymotors/Weber-60mm-Throttle-Body-Datsun-Nissan-240-260-280-Z-ZX_W0QQcmdZViewItemQQ_trkparmsZ72Q3a570Q7c66Q3a2Q7 c65Q3a12Q7c39Q3a1Q7c240Q3a1318Q7c301Q3a1Q7c293Q3a1 Q7c294Q3a50QQ_trksidZp3286Q2ec0Q2em14QQhashZitem32 0337357864QQitemZ320337357864QQptZMotorsQ5fCarQ5fT ruckQ5fPartsQ5fAccessories#ht_500wt_1213) on eBay right now.

If you have to stick with the stock Beta TB, you can still mount the TPS on the side but you'd need to extend the throttle shaft.

http://lancisti.net/forum/picture.php?albumid=19&pictureid=226

Thanks for the suggestion & the picture. I just completed something very similar to yours, and it works great!

Two Weber items that came in very useful for me was a throttle body TB8380 (which gave me a throttle shaft I needed along with other misc parts) & a throttle cable cam 45041.063 (which gave me something to connect a throttle cable to).

The most frustrating part of this job is the set screws I purchased at the hardware store where in the incorrect bin so they would not screw into my throttle shaft extension! I went back this morning & traded them. This morning they where in the correct bin...

If I could determine how to post pictures I would, but since I can't...

Now all I got to do is hope the client authorizes me to fix some or all of the rest of the things that are wrong with this car. Who knows, possibly some day he may get the car to the point he could visit the California referee and try to register the car.

Chris Obert

[DJ]

If I could determine how to post pictures I would, but since I can't...

Two easy ways to post pictures, Chris.

The first is to simply attach them directly to your post by using the "Attach Files -> Manage Attachments" button in the "Additional Options" box below the message entry screen. It allows you to search your computer and select files for attachment. This attaches the photo(s) as small thumbnails at the bottom of the post that will open up when a user clicks on them.

The other way is to click this icon http://lancisti.net/forum/images/editor/insertimage.gif just above the message entry window. A small window will open up that allows you to paste in a URL link to either a picture on another site or to a picture you've uploaded to your personal photo albums here at Lancisti ("Your Photo Albums" on the left-side Main Menu). This displays the picture(s) directly inline within the message.