James Harris Posted May 31, 2009 Posted May 31, 2009 I have just changed my 1971 2000 automatic estate from Strombergs to a professionally reconditioned set of SUs + the associated air filter required for the long reach inlet manifold. New gaskets, filters, as far as I'm aware everything necessary.Took it up the road for a test drive and brokedown after a mile. Once it is up to running temperature it looses all power and put it into drive, it stalls. Got towed home by my Dad in his 2000 saloon.Stripped the whole lot down, Traces of oil mist in the two back barrels of the inlet manifold. Presumed that air was getting sucked in somewhere so replaced the manifold to head gasket, torqued it all up and set off down the road again. Much better this time, lots more power, did a couple of miles up and down the gears, lots of different speeds, kickdown worked very well, up to 75 mph, got home, flipped the bonnet to check for any leaks bearing in mind the amount of new plumbing but all was well. The car was still ticking over so suggested to Dad that he take it down the road to see what a great job I had done this second time . . . back to square one! Put it into drive and it stalls again. Cannot get the bugger to move.My initial thoughts are that either there could be a crack in the inlet manifold or that the second gasket is not upto scratch either.The manifold has been sandblasted, the carbs, blasted, rebuilt, everything you would expect.Does anyone have any ideas please? It looks lovely under the bonnet but my little baby just doesn't want to go.CheersJames
piman Posted May 31, 2009 Posted May 31, 2009 Hello James, why are you certain that the carburettors are at fault? In my experience, air leaks don't happen very often, in fact I've never ever had one in donkeys years of building cars.Alec
James Harris Posted May 31, 2009 Author Posted May 31, 2009 Fellas thanks for the replies. No I do not think it is fuel starvation. I have checked both carb reservoirs and found no problems. I think and I say 'I think' that it is the carbs as it was fine before I started the exercise. Was at its worst when I first did it and road tested it. It was much better the second time, and the only thing different that time was the manifold to head gasket. But I really am not sure, which is why I am asking. Is there something obvious I have missed? Any GOOD advice to get this little baby going again would be great!Thanks James
beefertoo Posted May 31, 2009 Posted May 31, 2009 got to ask what was wrong with the old carbs? i presume it didnt do it before the change...if so it would be worth going over the ignition. if the only fault now is cutting out have you got the idle set too low,from memory autos are slightly higher(used to have a rover auto with su's and that was a total pain to set giving similar probs,,). are you sure they are the correct needles etc? craig
James Harris Posted May 31, 2009 Author Posted May 31, 2009 Strombergs were getting tired and I prefer SUs but that has nothing to do with it. It was fine before change. Now once up to running temperature and a bit it will not run in anything other than 'park'. In fact once it gets to that point it will not even start again until it has cooled down.
rotoflex Posted June 1, 2009 Posted June 1, 2009 What do the plugs look like?Also, I had a weird problem coming back on a trip where the car would start to sputter and die after warming up. Cold, started again, cruising down the road, reached operating temperature, it started to sputter & die again. After the next cool-&-restart, I noticed that when it started to sputter it would even out & continue for a while if engine speed was increased slightly until the next sputter, then an increase in engine speed again kept it going a while longer. Made it to with 15 miles of home before getting a brutal speeding ticket. The problem turned out to be the points were disintegrating.
James Harris Posted June 1, 2009 Author Posted June 1, 2009 I haven't had the plugs out yet. It is the old story of focusing too much on one thing. Because all was well before the carn swap I automatically put it down to something related to that. You may well be right though. I have just had a chat with Andrew Turner the specialist that built my SUs and he suggested the condensor and/or coil, so I will give the ignition system and good seeing to.Does anyone have or know where I can get decent old stock of Lucas items as most classic car parts suppliers only seem to have the crap produced in the far east, which I have only had bad experiences with?!If anyone has any other ideas about the bad running at working temperature I would be pleased to hear.ThanksJames
piman Posted June 1, 2009 Posted June 1, 2009 Hello James, I presume that the carburettors were set up by the specialist, i.e jet height?Incidentally the needle selection will have no real effect on your idle performance. Cars that are difficult to start from hot may be indicative of incorrect mixture but it is by no means the only reason.Alec
James Harris Posted June 1, 2009 Author Posted June 1, 2009 Yes he set everything up to suit the engine. I have had carbs from him before and thoroughly recommend him. Good work at a fair price. With both cars that I have done, the carbs have been great, starting up first time. Just this one doesn't like carrying on down the road. But I am going to have a good look at the ignition system and see if I can get this sorted out asap.
James Harris Posted June 1, 2009 Author Posted June 1, 2009 Just had a thought after trawling the internet for prices and info for suitable coils . . . my car is 1971 originally fitted with Strombergs and associated ignition system. Now it has a set of HS6 SUs fitted with the long reach manifold. Looking at Chris Witors website there are specific distributors used with specific carb set-ups. Is it that I now have the incorrect ignition system combination for the HS6 SUs? Anyone got any views?
bodders1 Posted June 1, 2009 Posted June 1, 2009 05209 wrote:Just had a thought after trawling the internet for prices and info for suitable coils . . . my car is 1971 originally fitted with Strombergs and associated ignition system. Now it has a set of HS6 SUs fitted with the long reach manifold. Looking at Chris Witors website there are specific distributors used with specific carb set-ups. Is it that I now have the incorrect ignition system combination for the HS6 SUs? Anyone got any views?Unlikely. All the distributor does is make sure that the spark arrives at the correct spark plug at more or less the right time.Changing the carbs with no other changes to the engine would not require a different distributor. If you go for a different camshaft and/or head modifications, then it is conceivable that you may require a distributor with a different advance curve to get the best out of your engine but, even then, it would not give the symptoms you describe.
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