1973 LB. Non brake servo servo and no extra ports on the air filter. Stiiiil putting my LB together. I have various hose ports and no obvious place to connect to. The ports on the carb, inlet manifold and the t piece vent at the top of the engine bay, no idea. Also the dizzy vac can has a connector port on the rear Cheers John Sent from my iPhone using Tapatalk
You could start by poking a nail down III (manifold vacuum) to see if it's actually drilled through. If it isn't, you can ignore it.
There are four systems here.. 1. Fuel tank breather . Hose from T junction on roof of engine bay to spigot on the side of the air cleaner. 2. Vacuum advance (useful) . From port on carburettor to spigot on distributor on the side away from the distributor body. 3. Vacuum retard (not needed in UK) . From port on carburettor to spigot on distributor nearest distributor body. This one is usually omitted, leave connection on distributor open, block port on carburettor using short length of hose with a bolt in it or a rubber cap ( need to be creative on finding something) . 4. Vacuum feed for the hot air flap on the air cleaner. From II to vacuum flap thermostat on top of air cleaner and then from there onto the actuator that controls the hot air coming up through the tinware from beside no2 head fins. The difference between 2 and 3 is that the vacuum advance port on the carburettor does not suck at idle while the vacuum retard port sucks at idle. Easiest way to tell is block both ports I and III on the carburettor and set up idle timing (at below 1000 rpm or the centrifugal timing advance messes with settings!) Then with the engine running ... The vacuum retard port will suck if you unblock it, engine RPM will change maybe stop or speed up (depends on mixture setting) The vacuum advance port should not suck (much .. if your carburettor is misadjusted or worn it may suck in both senses) little change in engine speed when open. Connect the non sucky port to the vacuum advance , it should stay at 8 degrees advance at idle, and then rev up the engine and it should rise to 28 degrees. If it does, all is good. Otherwise, more issues maybe. Or try the other port out of I and III. Leave any unused ports on the carburettor blocked off as otherwise it will mess with setting the mixture and getting it to idle sensibly. You probably also want to check the rubber hose joiner in the fuel breather pipework hiding up high on the left hand side of the engine bay beside the spare wheel well, this one gets splashed with fuel internally from time to time and rots and splits causing fuel smells. The joiner on the right seems to last longer, just above the bracket for the diagnostics socket.
Wow, lots of info, thanks. What I ought to have also said is that I have built this bay from a jigsaw with not all the parts there, the engine I have built using new parts where necessary and used parts where necessary. The air filter being 1 of those. My air filter doesn’t have any spigots at all apart from the large 1 going to the port next to the oil filler. Perhaps I could add a port for the T piece vent from the top of the engine bay? Your point 2 do you mean to the port on the back side (flat) of the vacuum can? Also worth noting that I haven’t actually started the engine yet, I lease see my next post for more fun Sent from my iPhone using Tapatalk
The correct air cleaner either oil bath or boxed paper filter type should have two air inlets, with a flap that selects between the open air and a pipe coming up from the cylinder head through the tin. If it does not it maybe came off a Beetle If you dont have it, it will not prevent the engine running, maybe make it a bit hesitant or stop running properly at some times.
