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Hi guys,

My car doesn't start that great and doesn't run well until the engine is warm. My thoughts were that the carburator needs some work (revision). The best ofcourse is a revision of the carburator, but after calling a "carb revisor" I am looking for a different solution. The revision for my BAUR 320/6 Solex carb would cost €800 - €1000 euro's because the "parts were not available anymore".

What would you guys do? I am pretty technical but this is my first project car that is going to have a "full" revision.
I never disassembled a car carburator before, but would it be a option to do this yourself? Are they easy to take appart and then assemble again?
Are there revsion sets available?

Or is it easier and cheaper to look for a Weber carburator?

Cheers,
Roy

Hi Roy,

I have taken these carbs apart before. i am not sure what the weather is where you are but over here its very hot so my carb had problems with warping so i just threw it all away and went and plonked in an injection engine from an E30. that aside, taking these carbs apart is not rocket science. all you need to do is get yourself a overhaul kit. Walloth n Nesch still has it for about 49 euros but as Jeroen mentioned their quality might be questionable. there are a few guides online if you google them up. pretty simple and straight forward.

but before we go down taking it apart, maybe you may want to check on other components thats probably giving you an issue? bad cold start means choke problems probably. is yours and electric choke solex? if so fixing that part wouldnt mean dismantling the whole complete carb.. and when the engine is warm, any issues as you go up the revs? black smoke when you rev?
best to look for the simple possible solutions before taking it apart.

hope this helps.

Check with member Peter V. as well, he knows these 4A1's pretty well even though I agree to look for the simple solutions first:

- base gasket ok?
- intake manifold gaskets ok?
- base adjustment ok? >> it is very important to follow the 4A1 adjustment procedures step by step, the average garage won't be able to diagnose or adjust it properly without following these dedicated instructions

Unlike many other parts, there are no issues known to me with the WN rebuild kits for this carb btw.

If your German is ok, you can find a lot of info here: http://www.e30.de/solex/

I think the best way to go is buying a Weber carb. I did this myself (and PeterV aswell) an is pretty straight forward. The conversion to an 45 DGAS or DGES carb gives better fuel consumption, better performance and as a bonus a nice sound.

Fitting is very easy if you buy the complete kit for an 320/6 (because it has the adapter plate) and adjusting the carb is peanuts with some knowledge of carbs.

The Solex 4a1 will warp after some milleage, recreation the some problems over and over. So after revision, the problems will return. This is due to the construction of the carb. It is build up in layers, which are very sensitive to heat. And the M20 engine isn't exactly the best engine concerning engine temperature.

e21manic wrote:Hi Roy,

I have taken these carbs apart before. i am not sure what the weather is where you are but over here its very hot so my carb had problems with warping so i just threw it all away and went and plonked in an injection engine from an E30. that aside, taking these carbs apart is not rocket science. all you need to do is get yourself a overhaul kit. Walloth n Nesch still has it for about 49 euros but as Jeroen mentioned their quality might be questionable. there are a few guides online if you google them up. pretty simple and straight forward.

but before we go down taking it apart, maybe you may want to check on other components thats probably giving you an issue? bad cold start means choke problems probably. is yours and electric choke solex? if so fixing that part wouldnt mean dismantling the whole complete carb.. and when the engine is warm, any issues as you go up the revs? black smoke when you rev?
best to look for the simple possible solutions before taking it apart.

hope this helps.

@e21manic,

Thanks for your answer. I bought a can of carb cleaner some days ago and sprayed it inside the car with the engine running and it helped a little. Now the engine starts better but.. I always need to push the throttle once before it starts, after it started it revs to 3500 for 1 seconds and after that the engine runs pretty bad, it really shakes everywhere (stationairy) until it's warm. Even when driving it's like it's doesn't use all the cylinders for a few seconds until you rev it a bit more. I'm going to buy a new rotor and distributor to be sure that isn't the problem. I thinks it's a electrical choke by the way.

Your black smoke question, yes it does give some black smoke when you rev it a bit more, but ony the first time you rev it, if you do it again it's if the car or exhaust is clean again and doesn't smoke anymore, (could be a leak?). It also sometimes has some oil inside the lowest part of the airfilter. The exhaust fumes really smell like fuel, so I really think it's good for the carb to be cleaned and adjusted by someone that is good at it.

Regards,
Roy

Jeroen wrote:Check with member Peter V. as well, he knows these 4A1's pretty well even though I agree to look for the simple solutions first:

- base gasket ok?
- intake manifold gaskets ok?
- base adjustment ok? >> it is very important to follow the 4A1 adjustment procedures step by step, the average garage won't be able to diagnose or adjust it properly without following these dedicated instructions

Unlike many other parts, there are no issues known to me with the WN rebuild kits for this carb btw.

If your German is ok, you can find a lot of info here: http://www.e30.de/solex/

Hi Jeroen,
German reading and talking is no problem at all, writing on the other hand..
That website was already added to my favorites, very usefull information, alltough I can't find any information on how to adjust the carb.
I also found the website for the revision kit and sended them a mail to order the kit, but until today no answer, I think I will give them a call next week.

Thegs wrote:I think the best way to go is buying a Weber carb. I did this myself (and PeterV aswell) an is pretty straight forward. The conversion to an 45 DGAS or DGES carb gives better fuel consumption, better performance and as a bonus a nice sound.

Fitting is very easy if you buy the complete kit for an 320/6 (because it has the adapter plate) and adjusting the carb is peanuts with some knowledge of carbs.

The Solex 4a1 will warp after some milleage, recreation the some problems over and over. So after revision, the problems will return. This is due to the construction of the carb. It is build up in layers, which are very sensitive to heat. And the M20 engine isn't exactly the best engine concerning engine temperature.

Hi Thegs,

Sounds pretty good so I really have ears for your story. Do you have some information about this Weber carb and the cost about buying a new one or maybe a good second hand?

Dakloos wrote:...I can't find any information on how to adjust the carb.

It's on that very same website: http://www.e30.de/solex/018/018.htm

The solex 4A1 is a very nice carb untill the problems start. The biggest issue is that it is actuelly two carbs in one. They must be perfectly balanced or the engine will not run smoothly.

Indeed i do have the weber mounted at the car and it runs perfect but i will place the 4A1 back as soon as i have the carb ready. That is a personal choice and i know that i will not have the same throttle respons as with the weber but i am an originalfreak.

I know you are from Holland so we can check your solex carb sometime but the basic of the engine must be good.
If you want to check your carb i do have a nice link for you.

http://www.ruddies.business.t-online.de/se4a1b.htm

If you look at the following website, you'll see the complete kit for the 320/6:

http://www.redlineweber.com/carb-kits/auto/bmw/

This is bassicly the kit you want to buy, because it includes the adapter plate for the 320 intake manifold. It replaces the automatic choke for a manual one (buy the cable yourself), which work a lot better than de Solex choke.

I bought my set in The Netherlands from a Ford enthausiast, they use the 38 DGAS and DGES carburators on the Capri, Taunus, Granada...

You can buy this set with a new or revised carb for around 500-600 euro's. When I find one I will contact you

Peter V. wrote:The solex 4A1 is a very nice carb untill the problems start. The biggest issue is that it is actuelly two carbs in one. They must be perfectly balanced or the engine will not run smoothly.

Indeed i do have the weber mounted at the car and it runs perfect but i will place the 4A1 back as soon as i have the carb ready. That is a personal choice and i know that i will not have the same throttle respons as with the weber but i am an originalfreak.

I know you are from Holland so we can check your solex carb sometime but the basic of the engine must be good.
If you want to check your carb i do have a nice link for you.

http://www.ruddies.business.t-online.de/se4a1b.htm

Hi Peter,

That's a good idea, maybe after your evaluation of the Solex I know if it's better to revise the Solex or buy a Weber, I agree with you that the original carb is more "classic".

This summer the whole car will be taken apart and the engine also will be taken out, it then would be great to know upfront from a "expert" if the Solex is at the end of it's life or just needs some work. Buying the Weber can always be a second option.

Thegs wrote:If you look at the following website, you'll see the complete kit for the 320/6:

http://www.redlineweber.com/carb-kits/auto/bmw/

This is bassicly the kit you want to buy, because it includes the adapter plate for the 320 intake manifold. It replaces the automatic choke for a manual one (buy the cable yourself), which work a lot better than de Solex choke.

I bought my set in The Netherlands from a Ford enthausiast, they use the 38 DGAS and DGES carburators on the Capri, Taunus, Granada...

You can buy this set with a new or revised carb for around 500-600 euro's. When I find one I will contact you

Hi Thegs,

Thanks for your information and thanks for looking around, I appreciate you looking for me!

The classic look of the solex is not visible with the airfilter on it. I used the original airfilter with my weber so from the outside it looks the same. The only difference is indeed that i have a manual chokeknob at my dashboard.

When the time is right for you i am willing to check your carb offcourse. Make sure that the engine can run then because othewise it is difficult to check.

Hi guys,

Last the week the revision set from WallothNesch arrived and today was a good day to start dismantling the carburetor and hopefully giving it a second life.


After taking the engine bonnet off I had more light and easy to get to all the wires and hoses. Some hoses gave me some trouble because the were hard, old and rotten, so I had to cut them.


Shes really needs a good clean and revision, hopefully it will also stop the "cold start" problems.


After all the hoses and wires were disconnected I was able to get the carb off, with the result below.


It was time to go inside with the carb and start with dismantling the three layers of the Solex.



After taking all the layers apart it was time to give them a boil into a big cooking pot with lemon water.
When boiling all the dirt comes of pretty easy, after that it's then easy to finish it with a tooth brush.
The result after cleaning, I'm pretty happy with it.








All other parts have been cleaned by hand and look like new again.
Hopefully tomorrow I can start with assembling the carburetor back together and still remember what goes where.


Will keep you up-to-date with pictures when doing so!

That looks good. I never tried to boil the parts but it goes very well. Toptip i think.