Dist vacume advance. - Steel Soldiers::Military Vehicles Supersite

ken · 02-25-2010, 16:07

There are two metal lines comming from the dist to the air intake tube before the carb. Are both of these nessary for timing advance? Or just one? We are planning on installing a open air filter in the hopes of helping fuel milage. And keeping the orginal oilbath filter for shows and parades. So i'll need to plumb the vacume somewhere else. We are shooting for 12MPG.

G-Force · 02-25-2010, 16:16

Got pictures??? If both lines run to the tube before the carb and in between theair cleaner then no they aren't for vacuum advance. A vacuum advance has to hook up below the carb to access the vacuum of the engine. The easiest way I would say to definitely find out is to disconnect the lines and remove the distributor cap and apply some vacuum to each line. You should see the rotor move. Chances are they are just vents but I'n not absolutely sure.
Hope this helps

Mike_L · 02-25-2010, 17:15

No, they aren't. They are there for venting purposes. Some folks take them off and plug them, others leave them on.

You can run the truck without them. I ran my truck without them for some time when I had a civilian carb on it. I re-attached them when I put the military carb back on.

Bill W · 02-25-2010, 17:20

The stock distibutor on a M-37 is centrifical advance not vacuum, the two lines the run to the (stock) dist are vent lines which circulate the air in the cap to flush out the gas that builds up from the arching of the points. In the air horn where the two vents from the dist run to you'll find two short 1/8" angled tubes, one facing towards the air filter and one facing the carb this promotes airflow in the dist through a venchuri effect

NDT · 02-25-2010, 21:14

The vent lines are there for a reason: the distributor will fail without the ventilation!

Capt.Marion · 02-26-2010, 02:12

With the exception of lines coming off the vacuum pump side of the fuel pump, almost all metal lines going straight to the intake air horn are vent lines... and since the ole '37 was designed to be forded with minimum preparation, there are a LOT of vent lines.

ken · 02-26-2010, 15:19

They guys thanks for the quick responses. that's what i needed to know. They are the vent lines. Now if i could only find a fan clutch that will work.

Wolf.Dose · 02-28-2010, 20:49

Anything less than 8 mpg is low fuel consumption, 9,3 mpg is a dream value. If you are to low in fuel consumption, you will run into cooling problems.
The carbs of that time are that poor in vaporizing the fuel that the engine heat is needed to vaporize the fuel completely for propper ignition. This takes heat out of the engine and helps the cooling. This cost about 1 gallon per 60 miles.
You better check for propper assembly of the carb, for we found out that even new carbs are not neccessarily correctly assembled.
Try hard! Keep it running!

Wolf

ken · 03-01-2010, 09:52

We installed the new air filter saturday. Now you can hear air rushing into the carb when you push the throttle. It has a noticible increase in power. Not that it's fast or anything. But it sure has more seat of the pants acceleration. We replaced the 160 thermostat for a 180 two months ago. The heater just wouldn't warm up the cab before. The carb isn't icing anymore since the thermostat change.