Vacuum Spark Advance

[Guest gmorse]

Hello. Does anyone know what the maximum amount of vacuum you can expect with the ported vacuum line on a '39 248 with Carter WDO carb? I realize that there will be none at idle, but has anyone measured what the maximum would be? Any info will be appreciated.

Gary

[FLYER15015]

I got 19" on my '40 LTD (320cid) one time.

Scared me to death.............

My book says 18-20" at 7-8 mph, but my son can't run 8mph for very long and hold the gage steady...........

Mike in Colorado

[Guest gmorse]

Hello Mike. Thanks for the reply, but I am looking for the ported vacuum that goes to the spark advance on the distributor. I also get 19 to 20 in. vacuum at the manifold take-off.

Thanks.

Gary

[FLYER15015]

Gary,

One thing you might do is to check your vacuum advance system. Noticing a sluggish take off this last summer, I hooked up a vacuum brake bleeder pump to the carb side of the vacuum advance tube and immediately found that I could not make the breaker point plate move (no vacuum advance). I replaced the vacuum can (2 screws) on the distributor and boy does she run a whole lot better. Found it on e-bay as NOS from Delco. (P/N 681-H) for my '40 Buick LTD.

One thing to be aware of, is that the little brass nuts at the ends are NOT the standard ferrule and nut set up. the nut actually swages down on the copper tube, so to reinstall takes some messaging and a bit of lube to get them to open up a bit and spin on the tube.

By the way, we will be comming to the Eastern meet in Lakeland in February, and staying @ my sister-in-law's house in Groveland. Can't bring the "Baby" down this time, but look forward to seeing all the Buick guys again, and of course , their cars.

Mike in Colorado