New mystery running problem!!

O

operaroverman

Member
Help Guys!!

I recently had my V8 auto rolling-road tuned. My replacement carb (due to another previous problem) was found to have been, at some point in the past sealed with silicone. This suddenly caused major running issues (maybe brought on by the workout on the rolling road), and the carb was removed to flush out loads of orange bits! I collected the car this week and she runs superbly, BUT will only start on choke even when hot and left for a few minutes! That is, she starts but just dies if you don't keep revving... Once on the move she runs perfectly and smoothly with loads of power. She also stalls frequently when stopping for lights, round-a-bouts etc. The car runs well down through the gears, draws to a halt, then the revs just drop right off and she dies! Start-up again is no problem if it's immediate. I have increased the tick-over, but the same things happens.

Suggestions gratefully received!

John
 
Hi John,

The only problem with taking it back to the person who carried out the work is that they will likely make a mess of it, given that it has been set far too lean to begin with. Even if they used exhaust gas analysis, what might be fine for a modern car fitted with catalytic converters is not going to correct for the Rover. You really need to find someone who KNOWS how to set carburettors correctly.

You could set the idle mixture yourself if you want to?

Ron.
 
Thanks for the advice.

The company who did the rolling-road tune is CCK Historic. They only deal with classics, and have vast experience with all manner of cars from the '50s thru to more modern stuff,mostly restoring and setting up cars for historic racing (they are quite major players at Goodwood). It seems strange for them to get the mixture quite this wrong, or are we only talking a minor adjustment? I feel I should go back, as the rolling road tune plus the carb dismantling (for the silicone) and re-assembly set me back more than £200!

John
 
The idle mixture is set by a single screw on each carburettor. It isn't difficult which makes me wonder why they didn't realise that they had made a mistake while they had your Rover with them. Still, you have paid a lot of money, so on that front they should rectify the problem quick smart.

Ron.
 
Again, thanks for the comments!

I felt I was taking a 'belt and braces' approach by shelling out to have the car tuned on a rolling road, but maybe it was an error...
In theory tho, this type of tuning should achieve a good result?

Does anyone know of an old-fashioned mechanic in the Bromley, south-east London area who would be able to sort this out if I don't get a satisfactory outcome from CCK?

Many thanks,

John
 
operaroverman wrote,...
In theory tho, this type of tuning should achieve a good result?
Click to expand...

Provided the operator knows what they are doing, then absolutely. The trouble though is finding that someone.

Ron.
 
Good evening friends,

I am taking my V8 back to CCK to have this running problem looked at and hopefully solved. They are very apologetic about my troubles and have suggested the following:

"...the HIF carburettor is fitted with an automatic choke function in the form of a bimetallic strip that reacts to heat, bending upwards to 'lean out' the mixture as the engine warms. These do wear out over time. If one carb is changed and one remains original (as in my car) then you may find that the carbs are reacting differently as the engine warms. One carb may be 'leaning out' too far due to a worn out bimetallic strip..."

Is this true, and a possible cause of my problem?

Thanks,

John
 
Quiet likely, I believe they were problematic however you had no trouble prior.

Graeme
 
operaroverman said:
"...the HIF carburettor is fitted with an automatic choke function in the form of a bimetallic strip that reacts to heat, bending upwards to 'lean out' the mixture as the engine warms. These do wear out over time. If one carb is changed and one remains original (as in my car) then you may find that the carbs are reacting differently as the engine warms. One carb may be 'leaning out' too far due to a worn out bimetallic strip..."

Is this true, and a possible cause of my problem?
Click to expand...

It has a bimetallic strip, fitted to the bottom of the jet tube, but it isn't an automatic choke, it's for emission control, and whether it's effective even for that is open to question. I can't see it having that much effect if it fails.
 
Used to run lovely that engine. Can't be much wrong. I'm sure they'll sort you out :wink:
 
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