Weber jetting
Posted: Tue Jan 26, 2016 2:50 pm
I've read the numerous previous posts on this subject, but remain confused (my regular state these day ) about my particular problem. You will all have read my restoration thread on my 65 S2 (EOK) that I posted ad nausium over the last 2 years, ( you haven't ? ....then better get to it ) This car was restored from boxes of bits after being stored for the previous 40 odd years. The engine that came with the car was not original, being I suspect from a Plus2 of '67 vintage. When I had the head restored I found that one of the cams was an SE and after advice I fitted this to the inlet side and at the same time had the larger inlet valves fitted. The carbs (DCOE 18s) were very gummed up and were eventually ultrasonically cleaned and the car tuned on a rolling road. However I have have never been totally satisfied with their performance. There is a stuttering hesitation from a steady idle at 900 rpm to when the main jets come into play. At the same time, and possibly unconnected with this issue, cylinders 2 and 3 aren't pulling their weight as a plug lead pulled from these two makes little difference to engine revs. Accuspark ignition, new ht leads, dizzy cap, rotor and plugs.
The car is going back to the tuner on Thursday for him to take another look.
The hesitation at small throttle openings would probably be due to the carbs still having the original Slow running jets, and would hopefully respond to a larger jet. We will look at that on Thursday. I'm assuming that the current jets are standard i.e. 45 F.9, but I don't know how to determine this. Examining the jets shows the number 35 stamped on them, but nothing else. Does this mean the jets are even smaller than 45s? In view of the SE cam and the larger inlet valve, should we go to the SE spec idle jets of 50 F.8 ? Also Air Corrector jets are I assume standard i.e. 200 rather than 150 for the SE and choke size is 30 not 32 for the SE
Regarding the cylinders 2 and 3 not pulling their weight. I've noticed on a few occasions that I can get a loss of power when driving normally, as if it's running on 3 cylinders. This "feels" electrical, though not sure. Checked everything electrical but no improvement.
So, can anyone make helpful suggestions re: what does the 35 signify stamped on the idle jets?
Would going to 50F8 be a sensible step to take? (can't go down the route of trying every conceivable combination of jet size at this point.
What effect of not reducing size of air corrector jet?
Would these carb issues be the source of the problem for the poor performance of 2 and 3? ( bearing in mind the old adage that most carb problems turn out to be electrically based)
Any other useful suggestions gratefully received
Apologies for the length of this post, I do go on a bit
Not competent enough to rule out the possibility that these two things may be connected in some way.
The car is going back to the tuner on Thursday for him to take another look.
The hesitation at small throttle openings would probably be due to the carbs still having the original Slow running jets, and would hopefully respond to a larger jet. We will look at that on Thursday. I'm assuming that the current jets are standard i.e. 45 F.9, but I don't know how to determine this. Examining the jets shows the number 35 stamped on them, but nothing else. Does this mean the jets are even smaller than 45s? In view of the SE cam and the larger inlet valve, should we go to the SE spec idle jets of 50 F.8 ? Also Air Corrector jets are I assume standard i.e. 200 rather than 150 for the SE and choke size is 30 not 32 for the SE
Regarding the cylinders 2 and 3 not pulling their weight. I've noticed on a few occasions that I can get a loss of power when driving normally, as if it's running on 3 cylinders. This "feels" electrical, though not sure. Checked everything electrical but no improvement.
So, can anyone make helpful suggestions re: what does the 35 signify stamped on the idle jets?
Would going to 50F8 be a sensible step to take? (can't go down the route of trying every conceivable combination of jet size at this point.
What effect of not reducing size of air corrector jet?
Would these carb issues be the source of the problem for the poor performance of 2 and 3? ( bearing in mind the old adage that most carb problems turn out to be electrically based)
Any other useful suggestions gratefully received
Apologies for the length of this post, I do go on a bit
Not competent enough to rule out the possibility that these two things may be connected in some way.