Webers-good/Solex-bad (maybe)

[hamondrye]

I have had the original Solex carbs rebuilt on my '69 912...ran like crap. Bought another pair off Ebay, with better results. Great powerband, but will not idle smoothly. Attempting to start the car cold, (a week or so) requires about 100 pumps of the gas pedal to get it started. It seems that when adjusted to idle well, higher RPM performance is compromised. When I park the car in the garage, after it has set awhile, it has a very strong gas smell. Nothing on the floor. The repair guy has thrown his arms up in the air for answers, and suggests that I get new carbs. So I have made up my mind to go with Webers.

The motor has about 700 miles on a total rebuild. Big bore japanese kit (1750). Stock muffler. Stock rebuilt fuel pump. New distributor...everything!

My question is should I go with the 40 idf, and does it make a difference weather I use new manifolds, or adaptors for the new carbs. Suggestions on where to pick them up? Thanks in advance.

[ron69912t]

I converted to Weber 40IDF's on my 69. I used adaptor plates base on the comments of the Maiestro that the adapler plates raise the carbs up and make it easier to get at the spark plugs.

Also, the original intake manifolds are supposedily Teflon coated on the inside (in 69) which helped meet the Emissions tests without the air pump etc.

The choke mechanism must be removed on the right Weber so it clears the fan shroud, be aware of this, they give you a little plate to cover up the choke lever cavity.

Bought my Webers from CBP and the plates from PMO.

The car ran 1000% better with the Webers, no more sputtering, popping or stalling, what a dream come true. Nothing else I have done to the car has made a more dramatic improvement. It was embarassing to drive before that and especially at stop lights when it stalled and cars drove around me.

Good Luck
Ron D

[craign]

I have weber 40's on my 69 big bore and love them. Once dialed in they stay that way for quite a while. Adaptor plate is required but I have heard there is a weber manifold for the 912 but never seen one.

Look on Ebay for a good used set unless you want to spring for new ones.

Here are a couple links you might find handy.

http://www.webercarburetors.com/

http://www.piercemanifolds.com/

Craign

[Hoffman912]

what did you guys do with your solexes? you still have em with all the bits and equipment? i have a friend looking to get rid of webbers and get a set of solexes.

[ron69912t]

Harry:
I put them in a storage box in case the next owner of my car wants to go original. I figure I'll be 100 by then and maybe too old and weak to shift it or put the clutch down.

thanks,
Ron D

[hamondrye]

Hey Ron,
Thanks for the great info! Glad to hear things worked out well for you. I'm pretty convineced that this is the thing to do. Did the choke covers that came with the kit not fit properly? Are the PMO covers better? Thanks again.

[hamondrye]

Harry, I will have a set w/air cleaners available. Split shaft. I'll keep you posted.

[Hoffman912]

thanks hamondrye, let me know and ill pass the info along

[ron69912t]

The manual choke on the 40IDF is a manual lever mechanism that sticks out the side of the carb body ready to be connected to a choke cable. I left the right choke lever on because it was clear of anything but the right lever hits the fan shroud and cocked the carb so it would not sit flat. I removed the choke lever mechanism from the carb body and covered the hole with the cover that came with the Weber conversion kit, it then fit flat and was clear of the shroud. No problem with the choke cover(s) in the kit.

My carbs were on 1/2" thick adapters so they sit higher but the right one still did not clear the shroud. I got a set of Weber intake manifolds with my kit buy decided to go with adapter plates instead. I sold the Weber intakes on e-bay.

Good Luck
Ron D

[ron69912t]

I forgot to mention the PMO Adapter Plates fit perfectly - no problems at all & easy to install.

Ron D

[69 Soft Targa]

Solex-bad (maybe)

You definitely have a 'problem' of some sort with the Solex's. Perhaps they need to be bored and bushed or just aren't set up right.

Properly set up Solex's should run better than Weber's on our engines. The Solex was designed for the engine and the Weber was adapted to the engine. Don Marks and Gary Emory both prefer Solex. Don sez "you're always chasing a flat spot somewhere with Weber's"

Having said that, both of my cars came with Webers which run fine. I haven't bothered to convert them back to Solex.

The adapter plate for the Solex manifold will give you a consistent 40mm port from carb to head. Weber manifolds are 44mm and will therefore introduce a lip to the flow. Use the adapters if possible and be sure to jet the carbs for your engine as they may be set up for VW.

[craign]

Here is a weber with choke, the plate is laying down below.

[ron69912t]

When you order your Weber 40IDF's tell CBP that they are for a 69 912 and they will set them up accordingly. You can buy the Kit with or without intake manifolds. They don't have the adapter plates.

Good luck
Ron D

[Ed in Sac]

One reason why you have a strong fuel smell may be that you are leaking fuel out of the pump housing. Its in the middle of each carb, facing outwards, roughly a squarish 1 1/2 inches, held in by 6 screws. That housing can be subject to warpage. You need to pull and flat file it. It doesn't need to be screwed in real tight. Also that is why you need to pump it a bunch of times after it has sat for a week. It could be a problem with both carbs. I have had webers on the car, but they were the 44 IDFs, too large, but they did have the Weber manifolds not adapter plates. It runs much better with the solexes. Another consideration of rough idling could be your distributor if it is stock. Many 912s have been converted over to the 050 distributer with positive results. I understand the 050 to be in short supply, with an increase in price.

[Hoffman912]

great point ed! dizzy problems masquarade themselves as carb problems. not all stock dizzy's are crap. some 912s came with 022's and some came with 031's originally. John Benton 912 engine and solex carburetor guru who was one of the leading guests at the 912 rendezvous tech session more or less said that the 022 is junk and causes too many probs. the 031 is the best one for the job, but are hard to find, and expensive. if you have an 031 and its broke, get it fixed, or sell it to someone who would want to get it fixed.

there are 2 aftermarket distributors; the 009 and 050, both are VW distributors. the 009 will work, but does not have enough advance curve for comfortable street use. it can be used in race cars though, as John thornton uses one in his 912R vintage racer.

the 050 has enough advance curve for street use, and if you have an 009, it is recomended you find an 050, and throw the 009 as far as you can. the 050 set up at 33 degrees BTDC at 3000 RPM is the right timing, and set up like this will make the car drive like a dream (although not as well as the 031 i hear).

bosh has discontinued the 050, and you can find them, but prices are going up as availability drops. if you want one contact gabe at strasse or will at csp.

im very pleased with my 050.

[tronman]

Everyone is correct about the dizzy giving the false impression of carb problems. My 69 had bugged me for nearly a year with little pops and sputters either cold or hot(weber 40s, with weber intakes), depending how I had the carbs adjusted. Could never get it to be nice both ways. I finally pulled the 031 and dropped in an 050 and all of that cleared up immediately! Car runs smooth as silk now. But , with the 050 there is a definite difference in the seat of the pants dyno just doesn't seem to pull quite as hard as it did. I plan on rebuilding my 031 and keeping it to drop in for playdays...

[papi]

tronman(Kevin),

Who are you going to have rebuild your distributor. I am considering getting mine rebuilt, but I have been told that I need to go to someone that has a good reputation in rebuilding Porsche distributors. Your thought or anyone elses on this thread. Thanks in advance for input.

[papi]

I have the solexes on my 1969 912 and it "spuders and pops until the engine warms up. It is somewhat embarassing, I would agree. I just had these carbs professionally rebuilt and balanced. My engine also has the 009 'D' with new wires points, plugs, etc. I would think that it would run smooth. Did these vehicles do this off the factor floor? I find it hard to believe that there would be a lot of happy customers with these vehicles sounding like a popcorn machine for the first 3 minutes.

I must say the car hauls butt with these carbs. It tops out at 115 mph and it accelerates very quickly. The speedometer was checked out by AAA awhile back so I believe I am getting good readings. Is there anybody out there that has the solexes that do not run into the 'snap', 'crackle', 'pop' sounds?

[jpamental]

I have the original Solex's in my '68, and it usually is just fine - although the super-frigid air in New England right now messes with things a bit. All summer/fall it was fine without any hesitation, popping or backfiring. I've got a pretty new (less than a year) 050 dizzy and I rebuilt the carbs with new gaskets, etc. Once I got them dialed in (lots of trial and error, and a little help from Eric Smith here in RI) it has run beautifully. I wouldn't think of changing them.

I'm sure that either is fine, but if you have solex's that are in good shape (bores/butterflies in good shape, no play in the shafts), it should only be a matter of tuning and upkeep to get it running like the day it was born. (OK, maybe oversimplifying a little, but you get the idea...)

Jason

ps - the accellerator pump suggestion was a good one - make sure that cover is flat and there's a new gasket there, and another thing to check is to make sure the bases are flat as well. Pull the carbs and check -sometimes previous owners have been know to overtighten them to the manifold unevenly which can lead to a vacuum leak that will make it hard to adjust as well. You can (very carefully) file the bases flat again while you have them out.

[tronman]

papi,

I haven't actually done any research into who I want to send it out to yet. At the moment I know it does work,just with the nice spits and pops when cold, and I keep it in the trunk as a back-up. As soon as I find someone to do the work on it I'll post the details and give feedback on how it performs after the rebuild.