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3 questions about weber carb upgrade from solex.


jparker6
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I bought this Weber 38 carb. for my '74 o2 offline and they sent me the wrong installation guide paperwork :( Numerous attempts by phone with them and I still have no promise of 1 in the mail or PDF file via email. Any

help here would be greatly appreciated, Thanks.

1. Off of the old Solex there were two lines that went to the radiator (or so i believed they did????).

solex.jpg

Do they or something attach to the new Weber 38/38 that i installed? couldn't find a spot for them or mention of them in any installation guide. If not should i just plug the ones from the Solex?

2. There were a few electric wires coming off the Solex. i believe they were the idler, choke, and one near the throttle lever. wondering if both the idler and choke ones are the same +12v? the one that came off the Solex idler is the only one long enough to reach the weber choke. AND i believe this is the only electrical connection on the weber????

3. The Vacumm Advance Port. Does this need to be attached to something or plugged? I read several things about it not being a necessity to attach and just wanted to be sure. If i recall correctly the Solex one attached to the base of the carburetor, in which my Weber does not have a nipple there.

WeberDGEV.jpg

Thanks all. ready to try this thing out first thing in morning and trying to cover all bases before first crank and first starting.

~JP

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How do you open the intake manifold ports to match

the opening bores of the new 38/38 ?

~ give that some thought. What's the point of

installing a 'larger' carburetor if the intake manifold

is not optimized ?? The larger carburetor also

would like it very much if it had an improved

exhaust manifold/header to breath through.

Air flow needs a smooth efficient exit or it doesn't flow.

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1. Off of the old Solex there were two lines that went to the radiator (or so i believed they did????).

Do they or something attach to the new Weber 38/38 that i installed? couldn't find a spot for them or mention of them in any installation guide. If not should i just plug the ones from the Solex?

2. There were a few electric wires coming off the Solex. i believe they were the idler, choke, and one near the throttle lever. wondering if both the idler and choke ones are the same +12v? the one that came off the Solex idler is the only one long enough to reach the weber choke. AND i believe this is the only electrical connection on the weber????

3. The Vacumm Advance Port. Does this need to be attached to something or plugged? I read several things about it not being a necessity to attach and just wanted to be sure. If i recall correctly the Solex one attached to the base of the carburetor, in which my Weber does not have a nipple there.

On question # 1 - that's a water actuated choke housing. The two hoses come off of that side of the choke and attach to fittings on the block. Water circulating through the block then goes through the choke, causing a bi-metallic spring to expand and contract, which opens and closes the choke.

On question # 2 - If the water choke was on your solex, then there was only 1 electric line coming off of it - that's to the 12v solenoid. That's a safety feature (car won't start if solenoid isn't energized). The weber you have a picture of looks like it has an electric choke.

On question 3 - check the base of the carb again. The vac port might be plugged. If not, I have had my vac advace plugged into my intake since I bought my car - and I think it's fine. I'm sure a bunch will chirp up and say it is sub-optimum, but it's worked for me for years. If you have a vac advance dizzy, you are going to need something.

Good Luck. Like CD says - if you want to use the 38 to the fullest - you are going to have to open up the throat on the intake.

Ken

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I may be mistaken, but I think that Weber looks like a 32/36, not a 38/38. The idle adjustment screws are on the center base of each side on a 38/38, not in the passengers rear quarter as in this pic. Take a close look at the markings (I think they're near the base) and see what is stamped into the body of the carb. Also, if it's a 38 it'll have two gear units on the back, bottom of the carb about the size of a portion of a silver dollar. If you decide to continue to use the 32/36 you will not be required to "hog out" the inlet of the intake manifold, and, if your engine has not been modifided, your car will probably run better than with a 38.

Bob Napier

Additionally, make sure you have an approx. ¼" thick isolation block, with a gasket top and bottom, between the carb and the intake manifold. This keeps heat from the manifold from transfering into the carb body and causing gas in the float bowl to boil.

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that's set up for a Datsun 510 or 521 pickup truck--thus the pulley sheave-like connection to the accelerator pedal. You'll need to use the linkage pieces currently on your car (may need some modifying) to connect with your 02's accelerator linkage.

You'll also need to check the jetting on this carb--if it is in fact jetted for a Datsun, you'll need to rejet so it'll work properly with your larger 02 engine (2 liters vs 1600cc).

You can use the electric connection from the solex to power your electric choke; just doublecheck that the wire is hot only with the ign on. The other wire that is there wasn't used on US version cars; tape it up out of the way, or use it if you fit an solenoid idle valve to your Weber.

You can also remove the water hose nipples from the block and plug 'em with an appropriately threaded bolt. Be sure and use an aluminum or copper crush washer and either teflon tape or anti-sieze paste on the threads.

Check the archives for many many postings on every phase of installing and jetting Weber carbs...

cheers from Nicaragua

mike

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I may be mistaken, but I think that Weber looks like a 32/36, not a 38/38. The idle adjustment screws are on the center base of each side on a 38/38, not in the passengers rear quarter as in this pic. Take a close look at the markings (I think they're near the base) and see what is stamped into the body of the carb. Also, if it's a 38 it'll have two gear units on the back, bottom of the carb about the size of a portion of a silver dollar. If you decide to continue to use the 32/36 you will not be required to "hog out" the inlet of the intake manifold, and, if your engine has not been modifided, your car will probably run better than with a 38.

Bob Napier

Additionally, make sure you have an approx. ¼" thick isolation block, with a gasket top and bottom, between the carb and the intake manifold. This keeps heat from the manifold from transfering into the carb body and causing gas in the float bowl to boil.

I'm w/Bob, check the base of that carb. from that angle it's iffy it's a 38/38 or 32/36, but at the base face of the carb you'll see it and the gear units are a solid give away.

Until i put my 38/38/ on there, i didn't know about the isolation block. JAM engineering told me about it and encouraged me to get one. He has them for like 8 bucks i think. The added bonus is that you can put that on your stock double barrell manifold to 'test run' the 38/38 until you get time to either hog that one out, or buy a cannon manifold and install it.

Setting up the 38/38 was, at least for me, easier than the 32/36. And it will suck down some more gas, but man, you step on that thing you better be holding on cuz it's going to go!!! For me the fun factor was well worth the extra bit of gas.

Enjoy!

David

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thanks for all the solid advice. I'M TERRIBLY sorry that i was lazy and found

a picture online of a weber that "looked" similar to mine. I just wanted the picture to show the same vacuum port setup, which is the one nipple and not one on the base. I do indeed have a weber 38/38.

I did not add an isolation block and didn't "hog out" the manifold. so both of those things are def. on my list. i'll get to those asap.

Thanks for the info on those water hoses, i'll plug them at the block.

AND get those extra electric wires pulled out of the way.

Just didn't know this going to be so simple. :)

I know this will probably be a little waste of time, but i'm going to have to tune it and get this thing on the road until i can get the isolation block and the tools to "hog out" the manifold intake. And then re-tune the carb.

thanks again all ~

JParker in Portland, OR.

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Hey here is what is cool.

if you just get the isolation block you can use the carb and get it tuned while you figure out when you can hog it out. The extra space will give the butterflies enough room to fully open. It'll be a bit restricted w/the smaller intake holes, but will give you a good taste of what is to come.

my car time get's eatin up by kid, house and 'honey do' time, so i bought a cannon from JAM for a b-day gift. now i just need to get the time to get it on there over the winter! LOL!!!

Honestly i couldn't believe the power difference vs. the 32/36.

let us know how it goes.

Dave

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