Flat spot under acceleration

[Andy Jones]

Hi

A month or so ago I bought a Lancia beta spider. Very nice. Very tidy. The only issue I have with it is that it has a real stuttery flat spot under acceleration. I can either drive it carefully, slowly accelerating (a bit dull), or I can absolutely floor it. Anything between and it gets very lumpy. I know it has twin barrels on the carb, and i gather the second cuts in under acceleration. Could there be a problem here, or is it likely to be something else? Anyoen experienced anything like this before?

Cheers

AJ (Lancia Newby)

[Alan Cooper]

all cars cars tend to be a little that way when cold (except for vx's) but should be ok when hot. difficult to pin point faults as carb will be simply getting generally 'old' however I would favour carefully removing and blowing through all the jets preferably with an airline/compressor and maybe go so far as to remove the idle adjusting screw and do the same there I had a 1600 berlina about 3 years ago 23000 miles but had lots of running probs which were not cured until I had thoroughly cleaned the carb I had to remove it in the end to do a proper job of it...needless to say but I'll mention anyway don't poke at anything or push objects into the jets to clear them as carbs are very precise instruments. I would also make sure that you are using decent spark plugs. The second choke on betas always cuts in with a little bit of a thrust I suspect it is designed to give an illusion of power!

[jimcraib]

Hi Andy

Yes I agree with Allan on this one very difficult to pin point. A few years ago my 1300 coupe started showing signs of poor running. Fortunately for me in Shrewsbury there was a small garage who was also a Weber agent I think the carb was a 32DATR. You can get service kits for these carbs thats what happened with mine. Don't touch anything like Allan says they are very tough and will hold their tune for a very long time as the owner of Price Motors told me sometimes when they get them they have been mistreated. If in doubt leave it alone.

[Jim Keller]

Have you checked the vacuum advance and advance weights?, the vac advance could be bad or the weights could be rusted stuck, this would cause the problem, also, bad vacuum lines can cause these symptoms

[Andy Jones]

Thanks all for replies, very useful.

As it happens, I am now on the search for front suspension bushes (at wishbones). Any ideas where these can be obtained?

Thanks

will keep you posted re carb problems!

AJ

[Keith Turner]

This is a common problem with Betas they are very sensitive to ignition timing the more advance you can get the better but be careful, especially with modern fuels.
the usual trick is to advance the ignition a little at a time until the engine just pinks in the 'wrong' gear ie pulling up hill in 4th or 5th at slow speed. dont just set the ignition to the 'factory' setting experiment a little I have generally found this works - I've had 8 Betas including a VX.
Wishbone bushes try Betacar or other suppliers they were still available or - I made some from Nylatron wth a stainless steel sleeve over the centre bolt worked a treat no noticeable increase in road noise & much better wishbone location think i still have the sketches somewhere if you are interested.
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[andy Jones]

I actually managed to get the bushes from evo cars in london - very helpful. Am planning a removal of carb to clean as suggested. Now need to track down relevant gaskets before starting!

Andy