2500s sort of powerless

[_uwe_]

I registered my 2500s estate last friday and happily did ca. 150mls in it. Starts first time, never misses a beat and drives quite well, except that it feels very powerless and wont rev past 3.500-4000.
On very low revs you can feel the grunt that comes from the capacity but over ca. 2500rpm that´s pretty much gone. Top speed is about 120-130km/h=80mp/h
I can feel a very slight vibration at speeds over ca. 40-50mp/h and there is a grinding/whinig noise from time to time (for a fraction of a second only) but quite frequently. I think that might be the clutch plate somehow. It hasn´t changed in the time I drove her and doesn´t seem to affect anything engine, speed and drivewise.
Oh and it has a lumenition fitted by the previous owner

[CAR]

It will be quite interesting to see what other people think here. Our estate is a little flat and hesitant at similar revs of 3500-4000, don't know about it topping out at 80mph though, I think it would go past that (RBRR this weekend could be a chance to test, it certainly did more than that near Salisbury two years ago!)
In the lower gears the S seems to need a big amount of throttle to really go, it's natural way is to gain speed rather than accelerate. The CW 6-3-1 manifold has certainly endowed the car with more torque at anything above 2000rpm, with down changes out of o/d on long inclines being unneccessary now.

We also have a Lumenition fitted and I have always felt that the unwillingness to rev beyond 4000 was made worse by fitting this.

Sadly, comparisons with the pi always make you think, how can two very similar engines have such different characteristics?

Colin.

[_uwe_]

I used to have both a PI and a 2000. The PI was alot faster and the 2000 felt pretty much the same if not abit faster at hi revs with a little less grunt at 2000rpm

[owen1183]

the characteristics of the 2500 make it a relaxing drive at low revs.

It has the same bore size as the 2000, but with a longer stroke, hence why it will never rev like the 2000.

I have never got mine to rev over 4000RPM and to be honest I don't think its needed?

It will happily accelerate to 70MPH briskly enough for what the car is.... an executive saloon

As for top speed, I don't know it was about 106MPH when new, mine will hit 80MPH with a bit more to go, but never been faster than that.

[owen1183]

I can feel a very slight vibration at speeds over ca. 40-50mp/h and there is a grinding/whinig noise from time to time (for a fraction of a second only) but quite frequently.

Could well be the viscous coupling on the cooling fan. if the bearings have gone it makes a horrible grinding / knocking sound

as it is connected to the crank shaft it can feel like it is clutch / bottom end related.

Take the fan & coupling off and fit an electric fan... will also aid fuel economy

[_uwe_]

Owen, thanks for that great advice.
I should have came up with that myself.
That is exactly what I'll do as two friends of mine had to get new radiators as the fan got loose ...

[_uwe_]

Oh and it is impossible to rev it past 4k as it starts to miss alot of beats then and the engine is not runnig well anymore!
It can't be that slow, uphills my Panda 45 is faster than the 2500!
Even if hills are not that steep you can really feel the car getting alot slower immediately.

[dallliiisss]

I registered my 2500s estate last friday and happily did ca. 150mls in it. Starts first time, never misses a beat and drives quite well, except that it feels very powerless and wont rev past 3.500-4000.
On very low revs you can feel the grunt that comes from the capacity but over ca. 2500rpm that´s pretty much gone. Top speed is about 120-130km/h=80mp/h
I can feel a very slight vibration at speeds over ca. 40-50mp/h and there is a grinding/whinig noise from time to time (for a fraction of a second only) but quite frequently. I think that might be the clutch plate somehow. It hasn´t changed in the time I drove her and doesn´t seem to affect anything engine, speed and drivewise.
Oh and it has a lumenition fitted by the previous owner

Hello,
After having owned a 2500S saloon many years ago I can comment on the fact that a standard 2500 is no road burner. But also, it shouldn't be sluggish. Mine had the 4-speed overdrive gearbox, and it suited the car very well, with good turn of acceleration with effortless high speed cruising.

I would hazard a guess and say that your car may need a thorough ignition service and tune-up before any more judgement is passed. Also viscous fan problems can reduce power drastically.

Also, some of the aftermarket breakerless ignition systems can actually reduce power, but be more reliable in use. My Pi has been fitted with breakerless ignition and I actually prefer points as they're more responsive somehow

[Raider]

I am no expert but it sounds like an ignition/timing problem to me.

Good idea to ditch the viscous fan though.

[Mike Stevens]

Another possibility could be fuel starvation at higher revs. Colin (CRAJ) had an issue like this with his PI. If I remember correctly, crud in petrol tank was sometimes partially blocking the outlet.

Have you got an in-line filter? As standard, there wasn't a separate one on the carburettor cars, relying on the filter screen in the pump itself. It might also be worth taking the pump top off and looking at its filter.

Have you checked that the advance mechanism in the distributor is not seized?

Cheers,
Mike.