Power loss/ odd running

[v8classic]

Evening all. I have a 1985 rrc with a 3.5 rover v8 with twin su carbs. I have only just recently got the car up and running and it has never been quite right. It starts and ticks over fine. It will rev fine when stationery. Once I take it out it will be fine in 1st and 2nd when pulling away but then when changing into 3rd to gain a constant speed or if I start to go up a hill it just dies and the power disappears! To make it to the top I have to gear down and rev the engine more just to move forward. Would it be the timing that isn't correct? Any help would be much appreciated. I have read around trying to find the cause and haven't had much joy! Thanks in advance.

[Bowie69]

Should to me more like a fuel issue -what state is the pump in?

Checking timing is readily done with a gun, get one and do it, you could ruin the engine if it is very advanced.

[Davo]

As it's of 1985 vintage, unless you know for sure what work has been done on it lately, you really have to rebuild the carbies, replace the fuel pump, and replace the spark plugs, distributor cap, leads, rotor, and points, (if that's what you've got), and check the vacuum advance. Without the fuel and ignition in top condition, the problem could be anything and usually what happens is people tear their hair out trying to guess what it is instead of doing the above and starting with a clean slate. It's a bit of work, but not that much, and will be worth it in the long run. A Range Rover from the '80s is a great car once it's sorted out, as they are from that time before piles of electronics made used cars so complicated. 

[FridgeFreezer]

All the ignition bits want to be genuine too, aftermarket are often totally awful.

[Quagmire]

10 hours ago, Davo said:

As it's of 1985 vintage, unless you know for sure what work has been done on it lately, you really have to rebuild the carbies, replace the fuel pump, and replace the spark plugs, distributor cap, leads, rotor, and points, (if that's what you've got), and check the vacuum advance. Without the fuel and ignition in top condition, the problem could be anything and usually what happens is people tear their hair out trying to guess what it is instead of doing the above and starting with a clean slate. It's a bit of work, but not that much, and will be worth it in the long run. A Range Rover from the '80s is a great car once it's sorted out, as they are from that time before piles of electronics made used cars so complicated. 

Just to contradict this (that's what forums are for eh? )- changing everything at once is a good way to not be able to figure out what did/didn't work, or if you have actually introduced a new problem.

Do everything one step at a time and check the results as you go. Be methodical and follow the factory settings.

Before you replace anything - check everything is clean (plugs, points, rotor arm, cap, leads, filters, carb dashpots clean and pistons move smoothly etc) and correctly adjusted (plug gaps, points, timing).

I got my old Rover running after it had sat for 10 and a bit years after changing the SU's for a known working set, the originals had dried up and leaked like sieves. Ignition-wise all i did was clean and gap everything. It got pressed into service as my daily doing a fair few miles everyday and ran fine on the original ignition system until I got fed up of adjusting the points every couple of months and fitted Megajolt.

14 hours ago, Bowie69 said:

Should to me more like a fuel issue -what state is the pump in?

Checking timing is readily done with a gun, get one and do it, you could ruin the engine if it is very advanced.

 +1 on this being fuel - my 90 would starve on fuel when I first converted it from 2.25 petrol to 3.5 power. The fuel filter was full of crud, and the poor little 2.25 had never demanded enough fuel to make it apparent. 

[Davo]

You're right that lots of new parts at once can cause trouble, but these ignitions are notorious for not working well unless everything is right. They don't tolerate very much, though they'll keep going, but performance always suffers. Yours must have had some decent ignition parts already. Usually everything is completely worn out!