948cc with poor acceleration...

[coronetv000]

Over the years my little 1960 saloon has been gradually suffereing from lack of power which is really noticable when accelerating up hills. If you rev the car in neutral it sounds like it should go like a bomb, just when the engine is under load it shows reluctance.
For example on a flat road in 4th gear it can take over 20 seconds to change from 40mph to 50mph.

The car is booked into the garage on Tuesday so if anyone has some pointers I would be extremely grateful.

[beero]

If it is tuned up properly and still suffers I think you need a compression test. How many miles has it done on that engine?

[bmcecosse]

Could be many things of course - but first check will be the valve gaps. Set 12 thou inlets and 15 thou exhausts. And if you run the hot engine at idle, and remove the oil filler cap - and rev up, is there a plume of smoke/fume from the opening? Next a compression test will be a good idea. And of course - is the air cleaner element 'clean' - not choked with oil and flies.......? Dizzy mechanical advance may be seized, and/or the vacuum advance may have given up, and perhaps the timing needs to be optimised by advancing till pinking is heard - and then taking it back slightly. Report back with compression test findings!

[JOWETTJAVELIN]

Has it been showing any other symptoms, i.e. stuttering, reluctance to start?

From the description so far it could be binding brakes, maladjusted ignition timing or restricted air flow into the engine perhaps?

As beero says is it tuned up correctly? All gaps set, oil and filters renewed?

[coronetv000]

Thanks for all the comments!

Tuning has been checked and re-checked before and this has not really changed the performance in the past but will have this looked at again. There has been no other symptoms and the car starts like a dream every time. The engine has only done 20k miles since it was rebuilt.

I will certainly ask my garage to do a compression test and report back the results - if anyone can think of any other issues which might cause this type of sluggish behaviour do let me know.

[Fingolfin]

May be worth checking the fuel pump. If it's somehow operating inadequately, it won't be supplying as much fuel as the engine needs for higher revs -- so the engine will be fine at lower speeds and struggle at higher ones.

[bmcecosse]

But worth checking JJs comment re possible binding brakes. Does the car roll easily when you release the brakes?

[coronetv000]

I think the car has adequate fuel - it revs very well when stationary but will have this checked out just incase.

Re: Binding brakes - the car is easy to push and car does freewheel ok in neutral.

[mike.perry]

Have you put a heavy tool box in the boot???????

[bmcecosse]

Or a box full of spare coils.......

[MarkyB]

Tuning has been checked and re-checked

By the garage or by you?
Have you checked the vacuum advance yet?
Also does the piston in the carb lift up easily and fall with a clunk?

[coronetv000]

By the garage (changing a car battery is about my mechanical limit!) - I will be giving them a summary of everyones tips on Tuesday which I am hoping will result in a healthier car.

[bmcecosse]

Do the 'garage' have any idea about Minors......or are they just emptying your pockets....... If you post up your location (in your profile) there may be someone nearby willing to come and have a look.

[coronetv000]

My little car is going under the spanner tomorrow. Results to follow shortly...

[coronetv000]

Well I got my car back from the garage last week and it's now a totally different beast! They said that the tappets were not adjusted correctly and now the power has dramatically increased - good acceleration and the ability to go uphill in 4th without slowing down has returned
They've suggested that the car might be even better after a de-coke so am thinking of having that done sometime soon.
Thanks everyone for your comments, much appreciated!

[bmcecosse]

Way back on May 3 I advised to check the valve gaps (they are not 'tappets') - but glad you got it fixed. Did they run a compression test?? Modern fuels do not require the engine to be 'de-coked' - a compression check would tell if the valves needed grinding in - which is a possibility.

[JOWETTJAVELIN]

There is EVERY need for a decoke - especially if it hasn't been for donkey's years, if at all.

I agree, however, that modern fuels reduce or even eliminate the need for decarbonizing. All depends on whether you use supermarket or quality grades.

[bmcecosse]

It all comes out of the one refinery........... If you think you have carbon in the chambers (running on..) - then run some water through the system - hot engine revving above idle - put the dizzy vacuum lead in to a jar of water and let the carb suck it in.....

[JOWETTJAVELIN]

So you are saying that Shell is the exact same blend as Asda's????

[bmcecosse]

Of course! There is only one refinery in central Scotland and it supplies everyone......