13 b runs better w/o vacuum hoses???

bowjangles · 10-22-2013, 05:33 AM

Since my 13B runs smoother at idle w/o the vacuum hoses from the carb to the distributor attached, I am pleased. However can anyone think of a reason NOT to do this? Many thanks

Garfinkles Motor Works · 10-30-2013, 09:10 PM

If the timing is set correctly and all vacuum parts are not leaking then the idle should be good if every thing else is correct .When the static timing is set then the engine should start easy. When you tip in the timing will be a little retarded and the RPM will build a little slow until the timing is advanced ( automatic ) When the engine is at idle there is full vacuum .So the design uses the vacuum to advance the timing at idle so tip in will build RPM quickly before the distributor can advance the timing as needed . In the real world if you set every thing correctly and block the vacuum lines then the car will start well but rev slowly at tip in until the distributor advances .

Rotary Evolution · 10-31-2013, 11:18 AM

a vacuum leak would offset a rich condition, so your idle mixture setting is off(carb is running rich).

it could also be an indication of an issue within the engine, such as a weak front rotor(where the port would cause the lean out).

10-22-2013, 05:33 AM	#1
bowjangles Rotary Fan in Training Join Date: Sep 2013 Posts: 62 Rep Power: 13	13 b runs better w/o vacuum hoses??? Since my 13B runs smoother at idle w/o the vacuum hoses from the carb to the distributor attached, I am pleased. However can anyone think of a reason NOT to do this? Many thanks

10-31-2013, 11:18 AM	#3
Rotary Evolution rotaryevolution.net Join Date: Feb 2011 Location: Las Vegas, NV Posts: 248 Rep Power: 15	a vacuum leak would offset a rich condition, so your idle mixture setting is off(carb is running rich). it could also be an indication of an issue within the engine, such as a weak front rotor(where the port would cause the lean out). __________________ http://rotaryevolution.net Last edited by Rotary Evolution; 10-31-2013 at 11:21 AM.

10-30-2013, 09:10 PM	#2
Garfinkles Motor Works RCC Contributor Join Date: Mar 2008 Posts: 535 Rep Power: 18	If the timing is set correctly and all vacuum parts are not leaking then the idle should be good if every thing else is correct .When the static timing is set then the engine should start easy. When you tip in the timing will be a little retarded and the RPM will build a little slow until the timing is advanced ( automatic ) When the engine is at idle there is full vacuum .So the design uses the vacuum to advance the timing at idle so tip in will build RPM quickly before the distributor can advance the timing as needed . In the real world if you set every thing correctly and block the vacuum lines then the car will start well but rev slowly at tip in until the distributor advances .