So I'm trying to figure out if my vacuum lines are connected correctly or not, it's an FE 390. In the picture, the hose coming from the back of the block (on a multi-port block) goes to the rusty bit on the distributor (I've googled it and it says this is vacuum advance) and the retard pipe (on the top) is going to carb, and the PCV valve from the back of the carb to the valve cover. Have I got these the right way round or am I just going crazy and mixing things up?
? where is line that runs to distributor go? what is the line the from next to distributor to carb for? take another pic from p***enger side of motor, showing lower half of carb
Disconnect and remove the 'retard' hose; this was for emissions purposes and not needed. Plus if it is used, the distributor vacuum hoses should be connected/controlled through a temperature-controlled valve that probably was originally mounted in the thermostat housing where you now have a threaded plug. After removing the hose, plug the connection at the manifold but DON'T plug the hose ****** on the distributor; this needs to be left open to allow the advance diaphragm to move freely. If you're worried about 'stuff' getting in this opening, use a small bit of open-cell foam on the ****** as a 'filter'. Or better yet, replace the advance unit with a single-diaphragm unit.
So I've done as you say, so now I have the vacuum advance line going to my carb, and that's it, and left the retard port open to air, I don't need any other lines as it's a manual transmission? I have the PCV from the back of the carb to the valve cover and that's it, and I've blocked the manifold port off that my other line was originally connected to, only trouble now is it runs like ****, it idles fine, but it sounds like the carb or somewhere else is popping, definitely not exhaust, and the revs climb a bit on their own, I'm ***uming this is from a vacuum leak or is the carb running too lean?
You'll need to check the timing and readjust the carb, probably both idle mixture and idle speed. Start with initial timing of around 6-8 degrees BTDC with the vacuum advance disconnected. Make sure you don't have vacuum on that unused ****** on the vacuum advance, if you do the advance is bad. If that doesn't help, look for vacuum leaks.
Thought as much, when I adjust the mixture can I leave the advance pipe off? as the fitting on the carb will be the only place I can source vacuum now, or is it crucial that I leave the advance connected, I could always go off the PCV at the back I suppose?
Set the timing with the advance disconnected, reconnect it to adjust the carb. Now, you may want to try the two different vacuum sources at both the carb and the manifold for the advance. The carb may be ported vacuum (no or little vacuum until the throttle is opened), although I've personally had the best results on Ford motors using manifold vacuum. Generally speaking, using manifold vacuum will help keep low-speed engine temps down but can cause off-idle pinging in some cases. If you're using a vacuum gauge to set idle mixture, use manifold vacuum.
Yeah, I think I'll try putting my vacuum tree thingie in the back of the manifold when I do the carb, it'll be far easier than disconnecting and reconnecting hoses all the time. As for the timing, would it be best to also check my distributor for mechanical advance before I do anything, as I'd rather not set my initial timing and then have too much mech. advance after And this might sound stupid but when I connect the vacuum advance line, the timing will advance yes? Say from inital at 8 degrees (which is what it's set at) to whatever it'll jump to?
It's probably a good idea to check the mechanical advance; you're looking for something around 32-36 degrees total (without the vacuum) and it should be all in by 3K rpm or a bit less. This is a horseback guess, but should be close. And yes, hooking the vacuum up will advance the timing if it's hooked to manifold vacuum.
I've heard on other threads that if you move the distributer to the back of the motor it will run better and be faster.
Right, sorry it's been a week but work and stuff got in the way this week Anyways, I fitted the vac advance line to the carb and it started up sweet as, running about 14* with the line on, however when I removed the line from the distributor the timing dropped to like -20ATC, so I put the pipe back on but didn't make much difference so I shut the engine down, what on earth has happened there? I've ordered a single diaphragm unit and that should be here soon, so would it be best to leave it until I can fit that?
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