i recently acquired a '66 amazon wagon, and on a trip from minneapolis to chicago and back i realized my weber isn't pulling on the dist. advance; needless to say it was a loooong trip. so if i recall from my vw days, when i threw the weber conversion on my bus i had to also add a bosch "009" dist(mechanical advance). so will a B18 dist fit in a B20? or is a mechanical advance dist available for my new road-warrior?

the dizzy from the B18 fits, no problem. But the vacumm on your present dizzy is a retard vacumm, that uses the lack of vacumm to advance the timing when you are idling (anti pollution) or put the other way, retards the timing when vacumm is present. Generally I don't hook it up to the engine, that way the timming is just mechanical and has about the same curve as the b18. The manuals all say to set the timing with the vacumm disconnected. I suggest you open up the dizzy, make sure all the linkages are free moving and then if you want you can even keep the vacumm retard providing it's not jamming. Keep it simple. Congrats on the wagon, they are the toughest of the bunch.

Perhaps the vac. retard on my 1800E isn't working very well, but when it is connected the engine has a huge dead spot coming off idle. It just seems to take a second or so to come to life, which makes certain traffic situations a little more exciting than they need to be. With it disconnected it has immediate pep off the line, no delayed reaction.

For a true mechanical advance only dist try scrounging up a Mallory unit - I saw one (a dual point) on eBay just yesterday. Although the vacuum retard ones work perfectly fine with no vacuum attached.

John,
Those sound like all the vacuum *advance* distributors I've driven (what, two maybe?).

If it really is an advance dizzy, setting the timing depends on where it's connected. If it hooks directly to the manifold vacuum, set the timing with the vacuum disconnect, and ignore the fact that it jumps way up at idle. If it doesn't ping, don't retard it. When you hit the gas, the vacuum advance will back off and actually retard the timing -- to where it needs to be. If you set the timing with the vacuum connected, it'll go WAY retarded when you try to accelerate, giving you a nasty bog.

If it's hooked to a port outboard of the throttle plates (Weber downdrafts have a port there, for instance), the vacuum advance is basically inop at idle and it doesn't matter whether you time it connected or not. It cannot contribute to bogging in that case; it can only quicken the advance curve (which may or may not be a good thing).

Most vacuum dizzies on the old Volvos are retard units, which the consensus seems to be are best left disconnected.

Yep, yep. I thought good performance from those ADVANCE units depended on where one sources vacuum.

well i disconnected it and she runs pretty good in comparison; she doesn't heat up as bad as she did so i think we found it; even my buddy from germany said how nice she sounded, course he did hear a couple of valves he thought were a little tight(that guy has the BEST ear i've ever seen). i just wanted to say thanx to everyone..thanx.

hey thanx everyone, i'll pull that line off in about 30 seconds and see how she responds. John Mc- you don't know which model mallory that is, or is there only one? well as you might guess i'm REAL new to volvos, but i already love this little sucker, got me to chicago and back, maybe a few coughs and spits, but she made it better than half of the old buses i used to drive cross-country, man i couldn't believe all the looks i got. 'course mine's got a narrowed windshield visor from a '49 Chrysler attached it, no one really knows what they're lookin at til they get up close...

Try these links.

Mallory #1

and

Mallory #2. These show up every couple weeks so don't put a lien on your house to buy what you think may be the last one ever or anything.
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Justin 66 122E, 71 145S
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