For the first three years my 3500S performed well. The engine was smooth running, powerful and reasonably economic on the open road. About two months ago it started to either surge or miss. I had the plugs changed, the points done and a new condensor. It ran OK but you could still feel that miss. It got steadily worse until it got so bad I was reluctant to drive it. It guzzles vast quantities of fuel, the exhaust stinks of petrol and it misses badly. I took off the HIf6 carbs and gave them to a retired man who specializes in SU carbs. He found that there was little wear in the butterfly spindles but fitted new floats, needle valves, seats and gaskets. I refitted thembut it was as bad as ever. A check of the spark plugs showed four were OK but plugs 2 and 8 onthe RH bank were oily and carboned up as were plugs 3 and 5 on the LH bank. I understand that one carb supplies fuel/air mixture to these cylinders but I do not know which one. Can some one advise. I mean LH or RH viewed from inside the car of course. Summer is now with us but I cannot use the car. Thanks
Serious V8 problems - Advice urgently sought
- Thread starter Classicus
- Start date
Each carb supplies the two cylinders opposite it, and the end two on the same side, so you have problems with the RH (Drivers side RHD)
IIRC there is a choke barrel and the seals on this can fail making it seem like it is running on full choke all the time.
If you've had the carbs done the easy way to prove the point is by substitution.
IIRC there is a choke barrel and the seals on this can fail making it seem like it is running on full choke all the time.
If you've had the carbs done the easy way to prove the point is by substitution.
Pilkie
Active Member
I had almost exactly this problem last year! It got really rough on my 2 day trip to devon and had a VERY severe drink problem!
It turned out to be the float chamber needle valve was stuck open,causing overfilling and the pumping of pure fuel into the cylinders!
I am surprised that I didnt blow the exhaust up with the amount of fuel it used!!
A tankfull got me 50 miles!!JUST!!
It ran rougher than a badgers arse!!
I had to slow down way before traffic light to hit them on green! It was scary!!
When I finally got to my mates for lunch,I took the plugs out of the offending cylinders,took the carb off and freed off the stuck valve and left it for 2hrs.
It ran sweeter than ever all the way home that evening,But I was just waiting for it to go wrong again!
It stuck one more time,and I gave the bottom of the carb by the valve/float chamber area a good few gentle but solid taps with a hammer and it freed the valve. And 18 months later its still fine! Its my Everyday car and doesnt get left to seize if not used! Even after I had drained the fuel and wrapped the car up for 6wks when I went to NZ, "sorry we didnt get to meet classicus!" On returning it was all fine!
Best remove the carb and check that valve ! It may need very fine adjustment!!
It turned out to be the float chamber needle valve was stuck open,causing overfilling and the pumping of pure fuel into the cylinders!
I am surprised that I didnt blow the exhaust up with the amount of fuel it used!!
A tankfull got me 50 miles!!JUST!!
It ran rougher than a badgers arse!!
I had to slow down way before traffic light to hit them on green! It was scary!!
When I finally got to my mates for lunch,I took the plugs out of the offending cylinders,took the carb off and freed off the stuck valve and left it for 2hrs.
It ran sweeter than ever all the way home that evening,But I was just waiting for it to go wrong again!
It stuck one more time,and I gave the bottom of the carb by the valve/float chamber area a good few gentle but solid taps with a hammer and it freed the valve. And 18 months later its still fine! Its my Everyday car and doesnt get left to seize if not used! Even after I had drained the fuel and wrapped the car up for 6wks when I went to NZ, "sorry we didnt get to meet classicus!" On returning it was all fine!
Best remove the carb and check that valve ! It may need very fine adjustment!!
Thank you harveyp6, you were spot on. I took the choke unit out of the RH carb and the inner seal had shrunk so much it might as well not been there at all. I fired up the engine and it was a vast improvement, although not perfect. I had to use an O ring with a circular cross-section unlike the ones Rover used which have a square cross-section. The square ones give you a greater sealing area. Are the Rover type and the end seal still available? Now I will have to do the LH carb. I will try to find the seals here in NZ from the Rover clubs but if I cannot I may have to go to the bank and buy some UK pounds and find someone to purchase them for me.
