Yes. Tap handle. Christmas is coming.
I'm impressed you had the room to tap the end of that throttle shaft. Looks pretty tiny.
Yes. Tap handle. Christmas is coming.
I'm impressed you had the room to tap the end of that throttle shaft. Looks pretty tiny.
In reply to TVR Scott (Forum Supporter) :
It's a round shaft that is ground roughly rectangular for maybe 1/4" on the end, just enough to provide anti-rotation for a couple of stamped pieces. I must have used my off-center punch, because the hole is slightly closer to one side of the rectangle than the other, but still plenty of wall thickness to take a thread. And like I said, after that first 1/4" it becomes round at a diameter a little bigger than the diagonal of that rectangular end.
and now, on to tonight's fun. Step 1: fire up the heater!
I need to secure the cable sheath near the throttle cam. The OE bracket didn't look like it would be much help, but I remembered there was a similar end on the vacuum thing from the cruise control. Good thing I still have a couple boxes of random crap from the C4.
I couldn't picture how to efficiently tie it to any available mounting points, so i threaded some 3/8" bolts into the end of the head and that got some ideas going.
That bracket won't be much good as-is, but I love my band saw! A couple quick cuts and a couple stubs of round tubing and I've got a pretty good idea of how to hack it together.
tomorrow night, I hope, the hacking will continue.
Did the factory set up have any type of adjustment for the cable?
In reply to NOT A TA :
I don't think so. Nothing like the barrel on a bicycle cable anyway. It looks very one size fits all.
AngryCorvair (Forum Supporter) said:Next up is to weld mounts to gas tank, which has been leak-free for 10 days now. I kinda feel like I should pressurize it a little just to be sure, so thinking about how to do that. I've got a pretty good idea, just need to make a plate with a Shrader in the center, to bolt in place of the pump assembly.
Instead of putting positive pressure on it - just pull a vacuum on it? If it holds vacuum it's not likely to let go with non-pressurized contents inside. I'm leery of putting positive pressure in, because it may hold the pressure, but that pressure may also cause cracks to form where you can't see them. Conversely, vacuum will more likely cause cracks and leaks on the outside of the tank (just think about which direction the force is being applied).
What cable are you using? How long is it overall. I will need one for the LMP360 and could use some tips on where to look for cheap long ones.
In reply to RevolverRob :
I think it will be slightly pressurized in normal operation, so I think pressurizing for leak check is the right way to go, yes?
In reply to nocones :
Stock C4 throttle cable. It's not very long, maybe 18" or so. I can measure it for you.
The Corvair pedal has a short lever on it, with a rod from there to a bell crank at the side of the OE trans, about 6 ft long. I'm going to shorten that rod and redrill the bell crank, and attach the free end of the C4 cable to it.
I recommend these Tap Socket Set over a tap handle.
In reply to AngryCorvair (Forum Supporter) :
Probably is best to go with a positive pressure test then. What are you expecting pressure wise 3-5psi? I'd probably pick 10-15psi as my target.
In reply to RevolverRob :
I'm going to ask a couple friends at GM for a ballpark operating pressure and test it a couple psi higher than that. Google tells me there's a relief valve as part of the evap system that pops off at 0.7 psi
Wouldn't take much psi for that thing to blow out. That's a lot of surface area. And those sharp corners are pretty good stress-risers.
If you can verify the existence of the relief valve, maybe just test it until that pops.
I started this evening by clamping that tiny bit of bracket to the tube on the upper bolt and hit it with a tack of flux core. No pic.
then I split a leftover scrap of rosette-ready angle, trimmed it to fit, and tacked it between the tubes on upper and lower bolt:
then trimmed the other side of that scrap of angle and tacked it in to complete the triangle:
I was working on this while on the GRM Zoom call, and when I showed the result it was unanimous: two 3/8" bolts and 1/8"-wall tubing are overkill for a throttle cable bracket. ;-) but at least it's got speed holes. :-) it works a treat! still need to trim overhang from top piece, finish weld, and (maybe) paint.
In reply to AngryCorvair (Forum Supporter) :
Convenience trumps overkill complaint. You will get full throttle every time. Might not with a flimsy one.
Tonight I only had about an hour in the garage.
finish welded the throttle cable bracket, then weighed it with its bolts:
180 grams. Compared to the OE C4 bracket and bolts:
126 grams. ermagerd, the new part is almost 2 ounces heavier! Now I feel like I need to find a place to get those 2 ounces back. And I found it without looking too hard: my cattle gate shift coupler. Here's the before:
280 grams. I didn't have time to put it on a diet yet, so that'll be coming up in the next few days.
Eh, two ounces is nothing. Just make sure to have a good turd before the drags, and you'll do fine.
AngryCorvair (Forum Supporter) said:In reply to RevolverRob :
I think it will be slightly pressurized in normal operation, so I think pressurizing for leak check is the right way to go, yes?
All the fuel tanks I was ever involved in working on got pressure tested under water. No more than 3-5PSI and then just look for bubbles.
AngryCorvair (Forum Supporter) said:Tonight I only had about an hour in the ga
finish welded the throttle cable bracket, then weighed it with its bolts:
180 grams.
I see about an ounce of welding buggers on there. That plus speed holes in the third leg of your triangle should get you there.
I spent some time in a chemical plant. It's really amazing how little vacuum it takes to collapse a tank. Even a 10,000 gal one. (Yep. That's the voice of experience)
Tanks that are designed for pressure don't resist vacuum at all.
SVreX (Forum Supporter) said:I spent some time in a chemical plant. It's really amazing how little vacuum it takes to collapse a tank. Even a 10,000 gal one. (Yep. That's the voice of experience)
Tanks that are designed for pressure don't resist vacuum at all.
PSI gets bad fast when your SI measurement is large.
Also, stampie, I think you meant boogers. I mean this as constructive criticism only of course.
In reply to Robbie (Forum Supporter) :
You are correct. Seeing how I never talk about such crass things I of course didn’t know the correct spelling.
Fart in it, seal it, put it in your wife's car. If you don't get in trouble for a day, then you're good to go.
After a busy week at work, it was good to spend some quality time in the garage. Goals for today were to:
result:
And a bunch of pix of the steps in between. I forgot I had turned on the heater so I thought Satan came to visit:
I measured the molded plastic end of the C4 cable as accurately as I could:
transferred measurements to CAD:
then to a scrap of a scrap of rectangle tube leftover from engine crossmember fab:
this gave me a nice vertical surface for the cable end and a horizontal surface for attaching to the underside of the floor:
the Corvair pedal rod and bellcrank were still under the car, so I cut some slots in a scrap of 1" square tube and tacked it to the bellcrank, then drilled a hole in the floor for the pivot bolt. I will weld a nut to the topside after I test the linkage.
the pedal rod is just a round steel tube with the ends flattened, then drilled and bushed to fit over a 1/4" pin with a snap ring for retention. so I cut the pedal rod and duplicated the flattened and drilled end, and hooked it all up. the result can be seen in the video embedded above. I'm not gonna lie, I sat in the drivers seat and floored the gas and made quadrajet noises a bunch of times.
I need to modify the bellcrank again, to let the cable end rotate instead of bend when the throttle moves. but for now I'm pretty happy with what I accomplished today.
That's awesome! If you find a Qjet guru they can likely tune out that tip-in lean bog I heard.
gumby (Forum Supporter) said:That's awesome! If you find a Qjet guru they can likely tune out that tip-in lean bog I heard.
I changed the rods but I'm still using the stock hanger.
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