Discussion
I'd be interested to hear whether any of you chaps experience this with your cars.
Basically, mine was running too slow at tickover, dropping oil pressure below a 'comfortable' level. So, I adjusted it.
Needless to say, this has to be done with the rear canopy up. I set it to about 800rpm.
Now, the thing is, when I close the canopy, the tickover drops by 200 revs or so. I'm assuming that this is due to a combination of hotter intake air and a more restricted space from which it can be 'sucked' into the carb.
Not a great problem, just that it makes the car run rather rich (so nerr, nerr, ne nerrr to all those saying it would run lean
) Makes my eyes water I can tell you, although, I can lean it off with the adjuster screws.
Just wondered whether you'd get the same effect with a 'standard' installation with the tall filters?
Basically, mine was running too slow at tickover, dropping oil pressure below a 'comfortable' level. So, I adjusted it.
Needless to say, this has to be done with the rear canopy up. I set it to about 800rpm.
Now, the thing is, when I close the canopy, the tickover drops by 200 revs or so. I'm assuming that this is due to a combination of hotter intake air and a more restricted space from which it can be 'sucked' into the carb.
Not a great problem, just that it makes the car run rather rich (so nerr, nerr, ne nerrr to all those saying it would run lean
) Makes my eyes water I can tell you, although, I can lean it off with the adjuster screws. Just wondered whether you'd get the same effect with a 'standard' installation with the tall filters?
You get that effect with a dirty filter restricting the airflow.
You could try taking the filter off and seeing if the same effect occurs. If it does it is temperature related if not it is a restriction.
On the subject of a rich idle, it is totally unrelated to max power running. Mine does the same. You might find the power valve in the carb is rated too high.
Attach a vacuum gauge to the carb and note the idle vacuum. The power valve should be sized about 2" Hg less to ensure the enrichment circuit remains closed at idle. The stinging eyes is a classic symptom of the enrichment circuit in operation.
You could try taking the filter off and seeing if the same effect occurs. If it does it is temperature related if not it is a restriction.
On the subject of a rich idle, it is totally unrelated to max power running. Mine does the same. You might find the power valve in the carb is rated too high.
Attach a vacuum gauge to the carb and note the idle vacuum. The power valve should be sized about 2" Hg less to ensure the enrichment circuit remains closed at idle. The stinging eyes is a classic symptom of the enrichment circuit in operation.
adequatespeed said: You get that effect with a dirty filter restricting the airflow.
You could try taking the filter off and seeing if the same effect occurs. If it does it is temperature related if not it is a restriction.
On the subject of a rich idle, it is totally unrelated to max power running. Mine does the same. You might find the power valve in the carb is rated too high.
Attach a vacuum gauge to the carb and note the idle vacuum. The power valve should be sized about 2" Hg less to ensure the enrichment circuit remains closed at idle. The stinging eyes is a classic symptom of the enrichment circuit in operation.
Mark,
Extremely unlikely to be a dirty filter seeing as it's brand new (well, except for 300 miles). Will check again with the filter off to see what difference it makes (if any). Couldn't test for long as the alternator had given up the ghost!
Will investigate carb further - ta!
Mine definately changes with heat, but goes the other way. If I set the idle with the engine 'cool' not stone cold, then run the car up the road for a while, the tickover goes up by about 100-200 rpm.
Are you sure that belt ain't rubbing? Try climbing in and then closing the canopy and see if you can spot any problems Maybe it gets sad all alone in there 
Are you sure that belt ain't rubbing? Try climbing in and then closing the canopy and see if you can spot any problems
Maybe it gets sad all alone in there 
james said: Did you remember to leave a hole in the canopy for air to get in? That might be the cause of your problem.
I now have this image of stigs car imploding as that engine sucks in all the available air.
Doh! Forgot holes!
Try standing there lifting & shutting the canopy untill you catch it out
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