Anyone have any idea how to cure a big flat spot on my HF when accelerating quickly through 2500 rpm. The engine falters badly and if 2 people in the car and on an incline can be very noticable and sometimes leads to a stall. However you can drive slowly through this and definately there is no flat spot after 3000 rpm. I have checked everything re ignition, valve clearances, manifold rubbers/gaskets. I am sure that this appeared after I rebuilt the carburettors earlier this year to clean them out and replace the pump diaphram gaskets etc. All 4 accellerator pumps work at about the same capacity but I have not checked actual volume. I thought I would ask for ideas before tearing down the carbs again.
Tim
1600HF solex 42's flat spot
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Huib
Re: 1600HF solex 42's flat spot
Send your carbs to Gugliemo Portelli for full modification. You will have a different car.
C.D.M. snc
Via Superga 52
I-10042 Nichelino (TO)
Sig. Gugliemo Portelli
tel + fax +39 011 68909247
C.D.M. snc
Via Superga 52
I-10042 Nichelino (TO)
Sig. Gugliemo Portelli
tel + fax +39 011 68909247
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william
Re: 1600HF solex 42's flat spot
What will he charge for modifying a set? And will he also repair and modify the known Solex spindle wear problem?
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Huib
Re: 1600HF solex 42's flat spot
You have to talk to him about the cost.
He will certainly repair any wear in the only correct way, which is boring to oversize and installing oversize valves and spindles. If he can modify them to avoid wear I don't know.
He will certainly repair any wear in the only correct way, which is boring to oversize and installing oversize valves and spindles. If he can modify them to avoid wear I don't know.
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P. de R. Leclercq
Re: 1600HF solex 42's flat spot
Well the tragedy of the Solex is the fact that unlike Weber or Dell'Orto, there are no ball bearings, perhaps because of the limited width.
Flat spots are a regular complaint with the 42s. When I was running a (clapped out!) pair, I remember curing the problem by substantially enlarging the idle jets. These of course provide the fuel for the pick-up phase where the problem always occurs. Unfortunately I was running about 10% CO at idle, but it went well enough!
Paul
Flat spots are a regular complaint with the 42s. When I was running a (clapped out!) pair, I remember curing the problem by substantially enlarging the idle jets. These of course provide the fuel for the pick-up phase where the problem always occurs. Unfortunately I was running about 10% CO at idle, but it went well enough!
Paul
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Huib
Re: 1600HF solex 42's flat spot
You can of course fiddle around a bit and improve things. I understand however from Signor Portelli that substantial modification is required including very different acceleration pumps to really make them top of class.
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m!
Re: 1600HF solex 42's flat spot & seasons greetings
Hello Huib
Just to start out just want to wish you, PdeR all all other Fulvistii a very happy holiday season
The second thing, I'd like to ask your opinion, if I may.
With the rather awful flat spots of the Solex's, what would you recommend to do? Perform the work to make them top class? Replace them and with what? Or just stick with them with flat spots and all? And why you would chose that option?
Many thanks to everyone for the last year. I enjoy this site very very much and look forward too another year.
All the best
m!
Just to start out just want to wish you, PdeR all all other Fulvistii a very happy holiday season
The second thing, I'd like to ask your opinion, if I may.
With the rather awful flat spots of the Solex's, what would you recommend to do? Perform the work to make them top class? Replace them and with what? Or just stick with them with flat spots and all? And why you would chose that option?
Many thanks to everyone for the last year. I enjoy this site very very much and look forward too another year.
All the best
m!
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P. de R. Leclercq
Re: 1600HF solex 42's flat spot & seasons greetings
And a Merry Christmas to you!
Whilst admittedly flat spots on 1600s are usually the fault of the carburettors, there are other possibilities which should be looked into. For example, the ignition system must be spot on - check the sutomatic advance system . for stiffness or general slack. And of course the points gap, plug gaps and static advance must be set correctly.
A good clean out of the carbs can sometimes help; white owder can form in carbs that are not used for a while and block the small passages. Also there can be a build up of gum and fuel residues which will affect performance. And of course the dreaded spindle bush wear - Huib has mentioned the ultimate solution, but an economical improvement can be achieved using small Viton O rings to restrict the entry of air past the spindles. The point is that the "pick up" phase i.e. small throttle opening is covered by small drillings near the butterflies. These receive fuel from the idle circuit. The drillings are uncovered just as the butterfly moves from the idle position so air entering past the spindles has a notable effect. Of course once the throttles are more open the influence of a leak past the spindles is small.
Good luck
Paul
Whilst admittedly flat spots on 1600s are usually the fault of the carburettors, there are other possibilities which should be looked into. For example, the ignition system must be spot on - check the sutomatic advance system . for stiffness or general slack. And of course the points gap, plug gaps and static advance must be set correctly.
A good clean out of the carbs can sometimes help; white owder can form in carbs that are not used for a while and block the small passages. Also there can be a build up of gum and fuel residues which will affect performance. And of course the dreaded spindle bush wear - Huib has mentioned the ultimate solution, but an economical improvement can be achieved using small Viton O rings to restrict the entry of air past the spindles. The point is that the "pick up" phase i.e. small throttle opening is covered by small drillings near the butterflies. These receive fuel from the idle circuit. The drillings are uncovered just as the butterfly moves from the idle position so air entering past the spindles has a notable effect. Of course once the throttles are more open the influence of a leak past the spindles is small.
Good luck
Paul
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Huib
Re: 1600HF solex 42's flat spot & seasons greetings
Many thanks and best wishes to you too.
I don't have a 1600 myself. I cannot say what I have done with my 42's.
The two of my Fulvia's I prefer are both rallye 1.3 coupe's of 1967. One (Elena) is currently my daily driver. It does nearly 40.000 km per year. I have covered 200.000 km with it. The other one (Celestina) is under restoration (soon to be finished). I will then use Celestina daily and restore Elena. Both have Dellorto DHLB35's. Not the original Solexes. I would not have changed carbs if the Dellorto's would not have been completely compatible.
The 42 Solexes share the problem of spindle and butterfly wear with the other Solexes. In addition they are not well designed. Probably a quick job for a very limited production. Just to sell enough cars for the qualifications. The factory rally team itself probably had their mind on a different set up from the start.
There is no direct replacement for the 42's. However, there are still people around who worked on the carbs then. If I had any I would send them to above gentleman. I am not going to say what the cost will be. He has to do that himself. I can say that it is modest, very modest. What you get back is total perfection.
I don't have a 1600 myself. I cannot say what I have done with my 42's.
The two of my Fulvia's I prefer are both rallye 1.3 coupe's of 1967. One (Elena) is currently my daily driver. It does nearly 40.000 km per year. I have covered 200.000 km with it. The other one (Celestina) is under restoration (soon to be finished). I will then use Celestina daily and restore Elena. Both have Dellorto DHLB35's. Not the original Solexes. I would not have changed carbs if the Dellorto's would not have been completely compatible.
The 42 Solexes share the problem of spindle and butterfly wear with the other Solexes. In addition they are not well designed. Probably a quick job for a very limited production. Just to sell enough cars for the qualifications. The factory rally team itself probably had their mind on a different set up from the start.
There is no direct replacement for the 42's. However, there are still people around who worked on the carbs then. If I had any I would send them to above gentleman. I am not going to say what the cost will be. He has to do that himself. I can say that it is modest, very modest. What you get back is total perfection.
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Michael Beattie
Re: 1600HF solex 42's flat spot & seasons greetings
Tim
Having "upped" my carb spec to 45 Webers for hillclimb & sprint events, I know some of the pitfalls involved. I have since reverted back to my Solex 42s, which have proved to be better in the initial pick up phase and are "good enough" for the road rally use I am currenly using the car for.
The cost of the Weber/Dellorto alternative.
I paid £350 for a set of Webers on eBay, they are finefrom 2700 on and will idle at 1000. Beware, mine are the type designed for a single 45 carb use ( i.e. BMC A or B series) which means that the progression holes that Paul talks about on the Solex carbs, on these Webers are slightly different on each of the pairs of barrels. This gives probs at low revs. So make sure any carbs you get are suitable for single choke per cylinder useage. A new set is £600 and hopefully the supplier might fit /change the setting to sort you out
Obviously, on the 2nd hand carbs you may need to rejet, change emulsion tubes and even chokes. and you could spend nearly £200 if you are not lucky.
This plus the cost of a manifold or carb adaptor can see it all pushing towards £600 - 700 !!!!
As I said I have gone back to the Solex ( I was lucky mine are in good condition) they are more economic, a lot quieter and it is only at the very top of the rev range that you notice any difference.
Cheers
Michael
Having "upped" my carb spec to 45 Webers for hillclimb & sprint events, I know some of the pitfalls involved. I have since reverted back to my Solex 42s, which have proved to be better in the initial pick up phase and are "good enough" for the road rally use I am currenly using the car for.
The cost of the Weber/Dellorto alternative.
I paid £350 for a set of Webers on eBay, they are finefrom 2700 on and will idle at 1000. Beware, mine are the type designed for a single 45 carb use ( i.e. BMC A or B series) which means that the progression holes that Paul talks about on the Solex carbs, on these Webers are slightly different on each of the pairs of barrels. This gives probs at low revs. So make sure any carbs you get are suitable for single choke per cylinder useage. A new set is £600 and hopefully the supplier might fit /change the setting to sort you out
Obviously, on the 2nd hand carbs you may need to rejet, change emulsion tubes and even chokes. and you could spend nearly £200 if you are not lucky.
This plus the cost of a manifold or carb adaptor can see it all pushing towards £600 - 700 !!!!
As I said I have gone back to the Solex ( I was lucky mine are in good condition) they are more economic, a lot quieter and it is only at the very top of the rev range that you notice any difference.
Cheers
Michael