Lack of power, hesitaiton, lean running problem

[Tintin]

wondering where I can get hold of a vac advance unit if poss before Friday.

I have had good results and very helpful advice from Martin Jay at

http://www.distributordoctor.com/

Whether he can come up with anything by Friday...………

Robbie

[alan12666]

Folks,

After all the help and advice given I thought I should revive this topic to let you know how I got on. I bought and fitted a 123 distributor; that made some improvement but not a full fix. So I failed in the target to fix it before Goodwood Revival - never mind, used the daily driver and still enjoyed the event. That was followed by about 1.5 weeks with a cold so I didn't get back to the car until last weekend (it's not kept at home).

I'm pleased to say the issue now seems to be sorted. The car is back to what is was before the whole engine- and box-out job. So what have I done to fix it? Well I went back to basics and double and triple checked various things.
- fuel filters checking (including the one in-tank). All OK.
- carbs removed, ultrasonically cleaned (no problems found), and reassembled with al base settings (floats, jets, slow running screw) all set to correct start points.
- correct SAE20 oil used in the carb dampers for the first time (so handy that there was a big SU stand were at Goodwood!)
- purchased a snychrometer and fittings so I could properly balance the carbs. that seemd to make a big difference; gives so much finer adjustment than listening to pipes.
- set the 123 to a less aggressive advance curve
- checked both rpm and vacuum advance were working as expected
- set the mixture on boths carbs using the "maximum idle speed" method on each carb.

The result: the mixture was 4 - 4.5% CO at idle on both exhausts; the car drives nicely now with no hesitation, up to more than normal motorway cruising speeds. One happy owner.

Next plans?
1. use the car for running around in the rest of this week while the weather is good, to put a smile on my face and remind myself that all the effort is worth it!
2. get the original distributor rebuilt by Distributor Doctor then refit it ... I want to keep the car standard if possible.
3. rolling road tune early next year to check it all over completely; never had it done since I bought the car nearly 3 years ago.
4. attend the regional meet in Coventry next Wednesday? I just might, work permitting.

Thanks again for all the ideas and help.

Alan

[piman]

Hello Alan,

nic eto hear that it's running much better.
I have a little theory about balancing carburettor air flow, it really only matters at idle to low speed, open the throttle wide and it make slittle or no difference to performance?

Alec

[3.8etypephil]

Hello Alan,

nic eto hear that it's running much better.
I have a little theory about balancing carburettor air flow, it really only matters at idle to low speed, open the throttle wide and it make slittle or no difference to performance?

Alec

Nail on the head; far more important is synchronisation of all butterflies at the full throttle position.