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> Reviving NOS Webers, Initial Settings?
bbrock
post Mar 20 2019, 08:55 PM
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I didn't want to hijack the other thread but have a question about my own Webers. They are Italian 40IDFs I bought in the late 80s or early 90s. Other than finger tight bolting them on to my engine to see how cool they looked, they have never been used. No fuel has touched them. I don't remember if I even opened them to set the float levels. BUT... they were stored in a humid basement for several years before I moved to a civilized climate. So, the magnesium housing is tarnished on the outside and the plating has deteriorated on a few of the levers and such. Pretty minor stuff from what I can see.

My question: is there is anything special I should do or check other than inspecting for corroded parts and normal setup as I prep these for service?
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914_7T3
post Mar 20 2019, 09:47 PM
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Are you really going to go through with it? After you have the "K" stamp on the suspension and 621 on the tin?

(IMG:style_emoticons/default/poke.gif)
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MarkV
post Mar 20 2019, 10:07 PM
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If nothing else I would take them apart and do a thorough cleaning and check the float levels. I have heard that they can have debris in them new out of the box.
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Mark Henry
post Mar 21 2019, 05:57 AM
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(IMG:style_emoticons/default/agree.gif) take them apart, clean, blow out*, etc.
Check the diaphragm it may have degraded.

*Note never blow out an assembled carb. It will destroy the float.
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rgalla9146
post Mar 21 2019, 06:04 AM
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QUOTE(Mark Henry @ Mar 21 2019, 07:57 AM) *

(IMG:style_emoticons/default/agree.gif) take them apart, clean, blow out*, etc.
Check the diaphragm it may have degraded.

*Note never blow out an assembled carb. It will destroy the float.


(IMG:style_emoticons/default/agree.gif) wrinkled floats
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Superhawk996
post Mar 21 2019, 07:45 AM
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Be brave. Put on and see what they do.

If stored cool and dry the accelerator pump diaphragms are probably OK.

There is very little to go wrong with carbs with respect to passages, jets and floats if they were stored dry.

If you want put some fuel in the bowl and then pump the throttles if you get fuel down the throats the diaphragm is fine.

There is more to go wrong or get lost by disassembling if you don’t have too. The chance of not having to fiddle and tune after install is slim under the best of circumstances.

But then again - you might be plating them anyway. (IMG:style_emoticons/default/screwy.gif) I’m jealous of your attention to detail. (IMG:style_emoticons/default/beerchug.gif)




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tmessenger
post Mar 21 2019, 07:53 AM
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The float needle tip can harden with age so I replace those along with pump diaphragms. Check your fuel pressure you'll want 3 ~ 3.5 psi.

Your 40 IDF's may have come with 28mm venturi, this is fine for a stock 1.7 or 1.8 if you have a 2L I would recommend 32mm venturi.

Note: The vintage IDF's are not drilled for port vacuum, they have manifold vacuum only (the vacuum port is below the throttle plate). Depending on which distributor you are running you may or may not be fine with a lot of vacuum advance at idle?

I wanted my vacuum advance to drop out at idle so I set up an electric vacuum switch and control it with a micro switch on the carb linkage.

Tim

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Superhawk996
post Mar 21 2019, 07:56 AM
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Just to add a little more context.

My car had been stored for at least a decade when I bought it. Im sure it was stored with fuel in it but it had evaporated long ago. i got it started without cleaning the carbs.

When getting things roughly tuned for my test drive I did diagnose and find a bad diaphragm on one accel pump and the diaphragm spring was long corroded away. I didn’t fix the diaphragm before I took the video in my thread of the car driving.

The moral of the story is carbs are more forgiving that most think.
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Superhawk996
post Mar 21 2019, 08:04 AM
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Not trying to start a (IMG:style_emoticons/default/stromberg.gif) storm but I don’t agree with the comment that needles will harden.

Needles are brass. There is no magic in material properties over time. Brass or stainless. Materials will work harden but even that is a stretch as needles are under no real load.

As I understood the situation these are basically new old stock and don’t even have any use.
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bbrock
post Mar 21 2019, 08:13 AM
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QUOTE(914_7T3 @ Mar 20 2019, 09:47 PM) *

Are you really going to go through with it? After you have the "K" stamp on the suspension and 621 on the tin?

(IMG:style_emoticons/default/poke.gif)


Nobody is going to notice carbs or FI if they have that beautiful '621' stamp to catch their eye. (IMG:style_emoticons/default/smile.gif)

Thanks everyone for the help. I think I remember Tomlinsons stressing the need to clean even brand new carbs in his book and will check the diaphragm. It's been so long since I've worked on carbs that I couldn't remember what might deteriorate with age.
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bbrock
post Mar 21 2019, 08:21 AM
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QUOTE(tmessenger @ Mar 21 2019, 07:53 AM) *

The float needle tip can harden with age so I replace those along with pump diaphragms. Check your fuel pressure you'll want 3 ~ 3.5 psi.

Your 40 IDF's may have come with 28mm venturi, this is fine for a stock 1.7 or 1.8 if you have a 2L I would recommend 32mm venturi.

Note: The vintage IDF's are not drilled for port vacuum, they have manifold vacuum only (the vacuum port is below the throttle plate). Depending on which distributor you are running you may or may not be fine with a lot of vacuum advance at idle?

I wanted my vacuum advance to drop out at idle so I set up an electric vacuum switch and control it with a micro switch on the carb linkage.

Tim
QUOTE(Superhawk996 @ Mar 21 2019, 08:04 AM) *

Not trying to start a (IMG:style_emoticons/default/stromberg.gif) storm but I don’t agree with the comment that needles will harden.

Needles are brass. There is no magic in material properties over time. Brass or stainless. Materials will work harden but even that is a stretch as needles are under no real load.

As I understood the situation these are basically new old stock and don’t even have any use.


Yes, no use. None of the parts have even touched fuel. Only taken out of the box to see how they looked. But thanks for the tips on setup. That will be another bunch of questions as I get closer to test final assembly on the engine. (IMG:style_emoticons/default/beerchug.gif)
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tmessenger
post Mar 21 2019, 09:15 AM
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Here's a photo of the needle that came out of my vintage IDF's, the ones I got with the new kit have Vinton tips. Can't hurt to check yours and see what's in there and the condition? You'll want to check the float levels anyway they are typically off from the factory.

Tim

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QUOTE(Superhawk996 @ Mar 21 2019, 09:04 AM) *

Not trying to start a (IMG:style_emoticons/default/stromberg.gif) storm but I don’t agree with the comment that needles will harden.

Needles are brass. There is no magic in material properties over time. Brass or stainless. Materials will work harden but even that is a stretch as needles are under no real load.

As I understood the situation these are basically new old stock and don’t even have any use.
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dr914@autoatlanta.com
post Mar 21 2019, 09:28 AM
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Richard at PMO is a great sounding board for any weber carb rebuild, and he does not hesitate to lend advice. You could call him.


QUOTE(tmessenger @ Mar 21 2019, 08:15 AM) *

Here's a photo of the needle that came out of my vintage IDF's, the ones I got with the new kit have Vinton tips. Can't hurt to check yours and see what's in there and the condition? You'll want to check the float levels anyway they are typically off from the factory.

Tim

Attached Image






QUOTE(Superhawk996 @ Mar 21 2019, 09:04 AM) *

Not trying to start a (IMG:style_emoticons/default/stromberg.gif) storm but I don’t agree with the comment that needles will harden.

Needles are brass. There is no magic in material properties over time. Brass or stainless. Materials will work harden but even that is a stretch as needles are under no real load.

As I understood the situation these are basically new old stock and don’t even have any use.


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Superhawk996
post Mar 21 2019, 09:37 AM
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(IMG:style_emoticons/default/pray.gif)

I learned something. Thank you.

My old IDFs from 80s had solid brass float needles and seats. When did they change to rubber tips? I see your point and I do agree rubber WILL harden with age.

I’ll double down though. Personally I would still just try them without disassembly.
Worst case you get a slight seepage past the needle, which runs up the bowl fuel level and it runs a bit rich. Other potential downside would be continual weepage past needle IF the fuel tank were higher than the carb resulting in gravity feed. This would lead to long term bowl flooding and continued fuel weeping into manifolds during storage which wouldn’t be cool: This isn’t possible in a 914 since tank is below carbs.
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Chi-town
post Mar 21 2019, 09:55 AM
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You'll want to replace all the original rubber parts with the newer Viton stuff due to ethanol in current gas. If you don't an old probably already degrading seal will fail quickly.
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MarkV
post Mar 21 2019, 08:13 PM
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If you are putting them on a fresh engine with fresh rings you are going to want to make sure that they are close to jetted and set up right before you fire your engine for the first time. Mine were set up all wrong and were sitting for a long time before I used them. If they are pig rich you are going to have a harder time getting your rings to seat properly.

(IMG:style_emoticons/default/smash.gif)
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Superhawk996
post Mar 22 2019, 10:13 AM
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QUOTE(MarkV @ Mar 21 2019, 10:13 PM) *

If you are putting them on a fresh engine with fresh rings you are going to want to make sure that they are close to jetted and set up right before you fire your engine for the first time. Mine were set up all wrong and were sitting for a long time before I used them. If they are pig rich you are going to have a harder time getting your rings to seat properly.

(IMG:style_emoticons/default/smash.gif)



Good Point that I hadn't considered. (IMG:style_emoticons/default/blink.gif)

However, I don't think they would ever end up that rich from a leaky float needle though. That would be the more likely case if the jets and emulsion (air) tubes are grossly wrong. A quick plug pull after a brief start up will show where the mixture is and should be done anyway regardless.

This whole thing comes down to personality types. I'm a risk taker (see my signature). If you're a risk adverse person, I completely see the perspective of complete rebuild 1st.

Honestly the concern I have is that in taking apart NOS carbs you risk losing little things like accelerator pump check balls and/or getting the accelerator pump linkage adjusted properly again once it has been disassembled.

Likewise the risk of ethanol attacking the rubber is a longer term use vs. time degradation thing. Rubber stored in cool, dry dark, conditions ages pretty well.

My main point of the initial push back on the desire to rebuild 1st is:

1) Carbs are more robust than people give them credit for. Especially in an age of fuel injection, carbs are now viewed with mystery and mythology that just isn't warranted.

2) Do you take apart NOS parts (never used) as an OCD thing just to "make sure". The crazy extension of this is -- do you take apart your new_______ (place item here, car, TV, washing machine) to make sure it was put together right before you use it for the 1st time. What if you could get a NOS Transmission? Would you take it apart to make sure the gaskets and/or O-ring seals hadn't dried out or would you run it for a bit and then go from there.


Bottom line: Brent is fastidious and his attention to detail is top notch. He clearly has the ability to disassemble and reassemble with care. My money is betting that he's already ordered complete rebuild kits and has them apart on the bench already. (IMG:style_emoticons/default/biggrin.gif)
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bbrock
post Mar 22 2019, 11:46 AM
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QUOTE(Superhawk996 @ Mar 22 2019, 10:13 AM) *

Bottom line: Brent is fastidious and his attention to detail is top notch. He clearly has the ability to disassemble and reassemble with care. My money is betting that he's already ordered complete rebuild kits and has them apart on the bench already. (IMG:style_emoticons/default/biggrin.gif)


Thanks for the vote of confidence. I'm also a risk taker by nature but the reason I parked the car for 35 years was because I was tired of the frequent unscheduled roadside repairs and needed more reliable transportation. Now is the time to put it back together right.

One point about whether it is worth opening them up is that you have to open them to set the float level before first use anyway. Replacing diaphragms etc. is, of course, more work but I don't mind. That said, I just opened one of the carbs and it isn't pretty. Fing Midwest humidity! Nasty inside and every bit of plated hardware needs re-plating. I'm going to tear these down and may just take the bodies in for boiling out.

Attached Image

Now for setup, I was going to start a new thread on this down the road but since we are talking about it anyway... Here's what I have. Mostly stock GA 2.0 engine. The only mods are a reground carb cam and Mahle flat top (Euro) spec pistons. I've been unsuccessful tracking down the cam specs but it was done through the old Automotion and I suspect was actually farmed out to Web Cam and is their 86 street carb grind.

A few important notes before digging into the carbs.

- My house is at 6,000 ft. elevation and the majority of my driving will be between 4,000 and 10,000 ft.

- I will be install a bung for an O2 sensor for dialing in the carbs.

- Within reason, mpg and reliability/longevity are more important to me than hp. I'm not looking for a hyper-mileing dog but like 30+ mpg highway and don't want to sacrifice fuel economy just to squeeze ever last muscle fiber out of the engine.

You may ask why I am going with carbs then but that is another story and FI may be a future project. For now, it is these carbs.

The carbs:
I have the following:

Venturi - 28
Emulsion tubes - F11
Main jet - 115
Correction Jet - 200

Any other numbers I should post? What can you tell me about initial setup?

Also, these carbs actually did come set up with port vacuum. They are drilled and blanked on both the port and manifold sides and the port side already has a tube fitting installed. (IMG:style_emoticons/default/piratenanner.gif)

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Superhawk996
post Mar 22 2019, 12:34 PM
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(IMG:style_emoticons/default/unsure.gif)

Wow. I'm looking for the eating crow emoji.

Not what I had envisioned as NOS. Were they stored outdoors?
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Superhawk996
post Mar 22 2019, 12:37 PM
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How about this one

I got (IMG:style_emoticons/default/owned.gif)
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