tr6tuga Posted September 14, 2020 Report Share Posted September 14, 2020 Dear forum Need some advice on the best way to set up AFR . Brown book section19.20.05 states that we should use pair 5/6 as reference airflow and set pairs 3/4 2/1 to the same flow rate. Green book from service and training, states otherwise, use central pair 3/4 as master then set the other pairs Wich way is the best? It makes sense use center pair? Never got a good spark colour using bb instructions Thankyou all Quote Link to post Share on other sites
John L Posted September 15, 2020 Report Share Posted September 15, 2020 Do you have an air bleed screw on the front inlet manifold? Are the 3 nylon bushes on the throttle shaft under the throttle bodies new if not renew them first. What are the linkages on the 3 throttle bodies like, worn perhaps? Do you have an air flow meter? You will need these items to get it set up correctly John Quote Link to post Share on other sites
tr6tuga Posted September 15, 2020 Author Report Share Posted September 15, 2020 Hi John I have a air bleed (bb says turn 5 times before setting) Nylon bushes new Linkages renewed Have a flow meter Wich steps to folow BB or green book? Quote Link to post Share on other sites
John L Posted September 15, 2020 Report Share Posted September 15, 2020 I would just get the engine to idle once warm at around 900 rpm and check the air flow, in 2, 4, 6 bodies with the flow meter and get the flow the same by adjusting the link to the throttle butterfly shaft, if you need to increase/decrease idle speed use the air bleed screw in or out to fine tune the speed. You may have use some asbestos gloves as the links are close to the manifold! You are aiming to get all the butterfly shafts to open at the same time. I choose the 2,4,6 as these are the ones that the butterfly shaft can have the most air if the bodies are a little bit worn, it may mean that 1,3,5 will be slightly less air flow, but you have to put up with that a bit, and finish with an idle speed around 800/900rpm. John Quote Link to post Share on other sites
ntc Posted September 15, 2020 Report Share Posted September 15, 2020 All should be set at 3 air valve in the middle Quote Link to post Share on other sites
Waldi Posted September 15, 2020 Report Share Posted September 15, 2020 I used the BB just as a guidance on my CP. I used the 3 idle screws for idle, this is very easy, and then the 3 rods for 1500-1800 rpm. I replaced the original linkages by ball-type linkages (mine came from Moss). Both speeds should be “sync“, not just idle. This worked for me. The basis should be sound first: plugs, timing from Ignition and valves, and engine warm. And as John says, a good linkage system and the TB’s in good condition. If not, it will not be as good as it could be. Waldi Quote Link to post Share on other sites
tr6tuga Posted September 15, 2020 Author Report Share Posted September 15, 2020 Thankyou I'll take the midle pair as master,, looks to be consensual and folow the notes for idle setting, air screw and minimum screw Take the path this weekend, still have to buy the abestos gloves it really gets hot.. Quote Link to post Share on other sites
Waldi Posted September 15, 2020 Report Share Posted September 15, 2020 I don’t think “the middle pair” makes much difference, it is an iterative process until you are satisfied (at least, that’s how I did it). The car should be able to stall when you close the air idle valve. In other words: do not open the butterfly too much. Cheers, Waldi Quote Link to post Share on other sites
ntc Posted September 15, 2020 Report Share Posted September 15, 2020 All six should read three if not there is a issue with the linkage or twisted spindles Quote Link to post Share on other sites
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