SU Carb jet assembly
SU Carb jet assembly
I was trying to remove the nylon fuel pipe that connects the jet assebmly to the base of the fuel chamber (don't ask1) - the fuel pipe came out with the nut and a metal washer but I think there is meant to be some sort of rubber 'olive' on the end? I think this is still inside the fitting in the base of the fuel chamber. If we can get this out is it possible to reattach all the parts to reconnect the fitting or will we need a new jet assembly?!
Thanks.
Thanks.
Felicity and Sam, Owners of 'Nelly', 1955 Black 4-Door A30
Owner and Club Member Since 2014
Southampton & New Forest Club Member
Owner and Club Member Since 2014
Southampton & New Forest Club Member
Re: SU Carb jet assembly
Managed to get the rubber olive out and attach the nylon pipe back on, hopefully no leaks! Now just having trouble undoing the lock nut for centring the jet - lots of plusgas now sprayed on and looking for a better fitting 18mm socket (seems the closest metric size for a difficult to find imperial size nut!) Any tips?
Felicity and Sam, Owners of 'Nelly', 1955 Black 4-Door A30
Owner and Club Member Since 2014
Southampton & New Forest Club Member
Owner and Club Member Since 2014
Southampton & New Forest Club Member
Re: SU Carb jet assembly
Well a new 18mm socket from Halfords and about half an hour of straining(!!) and the locking nut came free. Surprisingly nothing else seemed to be damaged in the process!
Now to the next problem. The SU we bought was a used one but in good condition. It came from a newer A35 van so had an AN needle in. We bought a GG needle (as specified for the 803cc). However, even after an afternoon of attempting to centre the jet, the needle still sticks. It just doesn't seem to want to centre. I don't think there's enough play in the jet and the needle just won't line up. We tried starting the engine with the best we could get it but the piston just got stuck when the engine was running.
Going back to the AN needle and all is fine. Is it safe to use this needle temporarily - I assume the mixture will be slightly too rich?
What is the next step? New needle in case this one is bent (looks ok to the eye)? New jet bearing? New jet?
Thanks for any suggestions!
Now to the next problem. The SU we bought was a used one but in good condition. It came from a newer A35 van so had an AN needle in. We bought a GG needle (as specified for the 803cc). However, even after an afternoon of attempting to centre the jet, the needle still sticks. It just doesn't seem to want to centre. I don't think there's enough play in the jet and the needle just won't line up. We tried starting the engine with the best we could get it but the piston just got stuck when the engine was running.
Going back to the AN needle and all is fine. Is it safe to use this needle temporarily - I assume the mixture will be slightly too rich?
What is the next step? New needle in case this one is bent (looks ok to the eye)? New jet bearing? New jet?
Thanks for any suggestions!
Felicity and Sam, Owners of 'Nelly', 1955 Black 4-Door A30
Owner and Club Member Since 2014
Southampton & New Forest Club Member
Owner and Club Member Since 2014
Southampton & New Forest Club Member
Re: SU Carb jet assembly
Does the engine run ok with the AN needle? If it does I'd stick with the AN. Assuming the piston moves smoothly and the spring is in position the SU is a very forgiving carb. The standard setting for the jet is 12/13 flats down from when it is level with the 'bridge'. You can use SAE20 oil in the damper.
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Re: SU Carb jet assembly
an 'AN' is a 1098cc standard needlePaulc wrote:Does the engine run ok with the AN needle? If it does I'd stick with the AN. Assuming the piston moves smoothly and the spring is in position the SU is a very forgiving carb. The standard setting for the jet is 12/13 flats down from when it is level with the 'bridge'. You can use SAE20 oil in the damper.
Nick Bayliss
Club's A35 (Saloon) Registrar, South Midlands Area Contact
Email, a35@austina30a35ownersclub.co.uk
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Re: SU Carb jet assembly
Indeed, hence why I think it'll be too rich. We haven't tested the carb with the AN needle yet but she idles nicely on the drive with it! (weather too wet last couple of days!). We have a new GG needle on order so that might solve the problem. I know that fuels have changed a lot so might not be the perfect needle but got to start somewhere!A40FARINAGURU wrote:an 'AN' is a 1098cc standard needlePaulc wrote:Does the engine run ok with the AN needle? If it does I'd stick with the AN. Assuming the piston moves smoothly and the spring is in position the SU is a very forgiving carb. The standard setting for the jet is 12/13 flats down from when it is level with the 'bridge'. You can use SAE20 oil in the damper.
Felicity and Sam, Owners of 'Nelly', 1955 Black 4-Door A30
Owner and Club Member Since 2014
Southampton & New Forest Club Member
Owner and Club Member Since 2014
Southampton & New Forest Club Member
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Re: SU Carb jet assembly
a 'M' needle is standard for a 948, i've never had problems with that needle
Nick Bayliss
Club's A35 (Saloon) Registrar, South Midlands Area Contact
Email, a35@austina30a35ownersclub.co.uk
Connected with A30/A35's for 63 years
A30/A35 Member A1372 (since 1981)
Club's A35 (Saloon) Registrar, South Midlands Area Contact
Email, a35@austina30a35ownersclub.co.uk
Connected with A30/A35's for 63 years
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Re: SU Carb jet assembly
From another post by Edosan
"Think you need to go at least EB, following advice on here I recently changed from standard AN on my 1098 to Weak EB and what an amazing difference, engine running better right through rev range and its the sweetest tickover I've ever had. Reason is basically modern fuels. Needles relatively cheap and so easy to change so suggest you simply experiment and find which one it runs best with"
"Think you need to go at least EB, following advice on here I recently changed from standard AN on my 1098 to Weak EB and what an amazing difference, engine running better right through rev range and its the sweetest tickover I've ever had. Reason is basically modern fuels. Needles relatively cheap and so easy to change so suggest you simply experiment and find which one it runs best with"
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Re: SU Carb jet assembly
'EB' i think is 848cc standardPaulc wrote:From another post by Edosan
"Think you need to go at least EB, following advice on here I recently changed from standard AN on my 1098 to Weak EB and what an amazing difference, engine running better right through rev range and its the sweetest tickover I've ever had. Reason is basically modern fuels. Needles relatively cheap and so easy to change so suggest you simply experiment and find which one it runs best with"
Nick Bayliss
Club's A35 (Saloon) Registrar, South Midlands Area Contact
Email, a35@austina30a35ownersclub.co.uk
Connected with A30/A35's for 63 years
A30/A35 Member A1372 (since 1981)
Club's A35 (Saloon) Registrar, South Midlands Area Contact
Email, a35@austina30a35ownersclub.co.uk
Connected with A30/A35's for 63 years
A30/A35 Member A1372 (since 1981)
Re: SU Carb jet assembly
Yes it is, according to your book that you mentioned in a post a while agoA40FARINAGURU wrote:'EB' i think is 848cc standardPaulc wrote:From another post by Edosan
"Think you need to go at least EB, following advice on here I recently changed from standard AN on my 1098 to Weak EB and what an amazing difference, engine running better right through rev range and its the sweetest tickover I've ever had. Reason is basically modern fuels. Needles relatively cheap and so easy to change so suggest you simply experiment and find which one it runs best with"
Very week needle on a 1098 then. We will try to get a new GG needle working when it arrives then might experiment with other, weeker, needles to compare.
Thanks all.
Felicity and Sam, Owners of 'Nelly', 1955 Black 4-Door A30
Owner and Club Member Since 2014
Southampton & New Forest Club Member
Owner and Club Member Since 2014
Southampton & New Forest Club Member
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Re: SU Carb jet assembly
I recommend you get a new jet assembly and centre it properly as the jet is almost certainly worn as well... They are a trial and error process that you may get right first time or might take a hundred attempts...Nelly wrote: We will try to get a new GG needle...
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Re: SU Carb jet assembly
Yup, agree with Neil, each time I have fitted a new needle, I have always replaced the jet. Makes life much easier if both bits are brand new. Just make sure the new needle isn't bent though!Neil Evans wrote:I recommend you get a new jet assembly and centre it properly as the jet is almost certainly worn as well... They are a trial and error process that you may get right first time or might take a hundred attempts...Nelly wrote: We will try to get a new GG needle...
Mark Bouskill
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Re: SU Carb jet assembly
Took Nelly out for the first decent length drive with the GG needle (now working). How do these plugs look?
Felicity and Sam, Owners of 'Nelly', 1955 Black 4-Door A30
Owner and Club Member Since 2014
Southampton & New Forest Club Member
Owner and Club Member Since 2014
Southampton & New Forest Club Member
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Re: SU Carb jet assembly
middle one looks normal, the other two look a tad weakNelly wrote:Took Nelly out for the first decent length drive with the GG needle (now working). How do these plugs look?
Nick Bayliss
Club's A35 (Saloon) Registrar, South Midlands Area Contact
Email, a35@austina30a35ownersclub.co.uk
Connected with A30/A35's for 63 years
A30/A35 Member A1372 (since 1981)
Club's A35 (Saloon) Registrar, South Midlands Area Contact
Email, a35@austina30a35ownersclub.co.uk
Connected with A30/A35's for 63 years
A30/A35 Member A1372 (since 1981)