Bushings for carb butterfly shaft?

[Vanapplebomb]

The biggest problem with Delrin is it’s nature to cold flow under consistent pressure. It won’t hold its shape well and will go oval over time from the return spring on the throttle, resulting in leaky bushings. This is true of UHMW, Teflon, Nylon, etc… great natural lubricity, and pretty good west resistance, but won’t retain its shape long term due to cold flow.
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1800 Type 4 Berrien 295

http://www.thesamba.com/vw/forum/viewtopic.php?t=487021

[raygreenwood]

[Brian_e]

Or you could just use short piece of an old push rod, or chunk of a valve guide and machine it to size and be done. It will long outlast the rest of the carb or the engine its going on. It may not be the most exotic, but we ain't going to the moon here.

Brian
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www.type-emotorsports.com

[Chickensoup]

sorry, but im not seeing how using old worn engine parts is cheaper. I dont have an unlimited stash of push rods and valve guides.

If customers found out I install "used" parts, they will freak. Carb buyers are not easy to deal with.
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-'85 c10 5.3 LS, 222 cam, long tubes, x pipe, 3 inch spin tech's
-'05 B5.5 TDI Wagon 17in sport rims ;EGR + BSM + ASV Delete, Stage-2 Tune, straight pipe
'65 Tourist Delivery Build
'66 RIP
'69 RIP
Hosea 4:6 "My people are destroyed for lack of knowledge"

[Brian_e]

You have never taken a piece of good material from the scrap bucket, and turned it into something very useful for a different application?

My point is....you don't need to re-invent the wheel with questionable space age materials, when a small piece of aluminum, or brass, or bronze will work 100% and most likely be cheaper and easier. With one old push rod tube, you can probably re-bush 6-8 Kads. Sleeve bearings from Mcmaster are less than $1 each and they also last forever.

I have been re-bushing and O-ringing Kads and other carbs for 12+ years, and never had an issue with non-plastic bushings. They work 100% every time, and I have yet to see one wear out.

Brian
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www.type-emotorsports.com

[Lingwendil]

[modok]

We have been recycling metal for 2000 years
your valve guides might have some bronze from the "bronze age" in there, used to be a hatchet, used to be a cannon, used to be a church bell?

you prefer nu-metal?
Aluminum is very "new"

[liquidrush]

I do a lot of Quadrajets for guys and I use silicon bronze bushings from mc master. Measure your shafts OD for the bushing ID, then look for a chucking reamer about .1 or .150 or so over. Search mc master for bushings in that size and there you go. Their bushings have .0005 over for a tap in fit. I chuck my reamer in the drill by the flutes leaving the length of the bushing exposed, then let the shaft of the reamer act as a guide in the T-body and spin the drill in reverse to ream the hole. Works perfectly every time. I put the bushing on a 5/16 x 4" bolt and tap it in again using the center holes as my guide. Done. I know this is a Q-jet but the principle applies.

[Chickensoup]

The valve guide idea, im concerned about proper fit when using used guides. Obviously i will adjust the OD/crush, but for the ID, Results would be inconsistent right? Since the ID already is 8mm.

As for push rods, for me at least, finding non bent examples has been a challenge. I can chuck a few up in the lathe and watch how blurry they spin. Although, if I cut them into smaller chunks before hand...

new valve guides go for 5-7 bucks a piece. that could make about 4ish bushings?

I can get push rods for 3 bucks a pop. And they can make a billion per push rod.

Igus... well idk. Their website has been down.

[Chickensoup]

ok new idea. What are yalls opinions on pushrod grade aluminum bushings, and nickel plated shafts? Would the nickle plating be a better option that polished steel? zinc plate is also an option. I guess what im asking is what happens when the two metals contact each other over time?
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-'85 c10 5.3 LS, 222 cam, long tubes, x pipe, 3 inch spin tech's
-'05 B5.5 TDI Wagon 17in sport rims ;EGR + BSM + ASV Delete, Stage-2 Tune, straight pipe
'65 Tourist Delivery Build
'66 RIP
'69 RIP
Hosea 4:6 "My people are destroyed for lack of knowledge"

[Vanapplebomb]

There is a good reason you don’t see aluminum bushings and aluminum faced bearings. Aluminum is sticky, gummy, and galls easily to harder materials.

Also, the aluminum will wear out fast, no matter what grade it is. It’s soft with no natural lubricity in and of itself.

If you want to see how metals react with each other, look up tables of the galvanic series. More cathodic elements “galvanize” more anodic materials. This is why magnesium, aluminum, (raw) beryllium, and zinc protect steel components for corrosion.
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1800 Type 4 Berrien 295

http://www.thesamba.com/vw/forum/viewtopic.php?t=487021

[modok]

So why are most engine bearings aluminum then?

Ok to be fair there are lots of different kinds of aluminum, and lots of different kinds of bronze.
Some are soft, some contain hard particles like silicon, some are SUPER hard, some are alloyed with tin or lead.

If you want to buy something universal look up....
660 aka 932 bronze, or phosphor bearing bronze
That's the classic for low speed bearing on a soft steel shaft.

You don't HAVE to make the bushings to fit, but it is handy because.....
You can make the bushing to fit whatever size the hole comes out, and fit whatever size the shaft IS after it's polished up.

[modok]

I don't know about nickel plating, sounds good but i wonder why isn't it used?

[Brian_e]

Make it easy on yourself and order a 7/16OD x 5/16ID oil impregnated bronze sleeve bearing from McMaster for less than $1 each. Use a 7/16 end mill to bore the hole, put a drop of sleeve retainer on it, tap it in, and then run a long .314” reamer through both bushings. Polish the shaft, reassemble, and go drive.

Easy peasy. No need to make it harder than it needs to be.

Brian
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www.type-emotorsports.com

[raygreenwood]

[tisius]

[Vanapplebomb]

[modok]

Yes I agree that is not an ideal material to use but it does NOT need to be ideal to work.
the zinc alloy the carburetor is made from is a bad bearing material also, but yet it worked good enough for most people.

I think most ideas discussed here would work well.
Bearing bronze and hard aluminum are a joy to work with, but some of the others are more troublesome.

My scrap bin currently has lots of 6&7mm id bronze guides from vw and bmw, actually 8mm is getting a bit rare, but I have a few left in the bottom perhaps.

[esde]

Or, here is the really easy answer
https://www.thesamba.com/vw/classifieds/detail.php?id=2324257
https://www.thesamba.com/vw/classifieds/detail.php?id=1929455
I know that in the VW community claiming you fixed something better than new with leftover bits for no money is a point of pride. And I get it, my dad was never one to spend if he could DIY a thing, consequently everything we owned needed work, and we made a lot of our own tools and parts. SO surely these throttle shafts are not the cheapest or thriftiest way to do the job, but it does cut it down to one operation. Surely being the fastest option is worth something? I used these on a 30pict and two 28pci carbs, and man it was easy.
SD
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modok wrote:
Bent cranks are silent but gather no moss. I mean, ah, something like that.

[raygreenwood]