10 replies to this topic

[RHDmini74]

So I set my advance at about 30 degrees with the engine at 4000 rpms with the vacuum advance tube blocked off at the carb. At idle the timing is at about 10-12 degrees. Runs okay with the tube kept blocked off. I decided to connect it and adjust my idle and realized that the timing now at idle is around 30 degrees. Is that how it’s supposed too be with the vacuum advance connected? Or should I re adjust it again. I have an electric dizzy hif44 carb. Thanks.

[nicklouse]

yes the vac increases the advance at high vac cases that is tick over.

 

but much has to do as to where you have the vac port on the car. and 10-12 sounds high for an engine running a vac advance.

 

so what does it say on the vac unit. it will say the pressure and the advance. also what dissy (original or from another spec) and what engine build/spec?

[RHDmini74]

yes the vac increases the advance at high vac cases that is tick over.
 
but much has to do as to where you have the vac port on the car. and 10-12 sounds high for an engine running a vac advance.
 
so what does it say on the vac unit. it will say the pressure and the advance. also what dissy (original or from another spec) and what engine build/spec?

I have this distributor https://www.7ent.com...ance-45d4e.html it isn’t marked anywhere. The engine is +040 flat top pistons aeg530 cam and big valve head with 1.5 rockers. It’s an old race motor.

Attached Files

•  C7606BD5-D412-42AC-AD30-9B23A57B4887.jpeg   34.72K   6 downloads
•  76A7F66D-9DB0-482A-A8DF-4A5F75058FF1.jpeg   48.12K   8 downloads

[timmy850]

It depends on which side of the throttle blade you are getting the vacuum signal from.

 

The standard place is before the throttle blade, at idle you should not get much vacuum here.

 

If you take the vacuum from the manifold side of the throttle blade you will get lots of vacuum signal at idle which will increase the timing. 

[RHDmini74]

It depends on which side of the throttle blade you are getting the vacuum signal from.

 

The standard place is before the throttle blade, at idle you should not get much vacuum here.

 

If you take the vacuum from the manifold side of the throttle blade you will get lots of vacuum signal at idle which will increase the timing. 

I have an hif44 and i know the standard port on it is after the throttle blade which is why the advance is increasing. I just need to know if I should re set my timing if I decide to leave the vacuum advance connected. Ive had it blocked off the last month or so. I heard that there's not much pros or cons to use it or leave it blocked.

[nicklouse]

 

yes the vac increases the advance at high vac cases that is tick over.
 
but much has to do as to where you have the vac port on the car. and 10-12 sounds high for an engine running a vac advance.
 
so what does it say on the vac unit. it will say the pressure and the advance. also what dissy (original or from another spec) and what engine build/spec?

I have this distributor https://www.7ent.com...ance-45d4e.html it isn’t marked anywhere. The engine is +040 flat top pistons aeg530 cam and big valve head with 1.5 rockers. It’s an old race motor.

 

not sure why you would even consider a vac advance dizzy on that cam.

[RHDmini74]

yes the vac increases the advance at high vac cases that is tick over.
 
but much has to do as to where you have the vac port on the car. and 10-12 sounds high for an engine running a vac advance.
 
so what does it say on the vac unit. it will say the pressure and the advance. also what dissy (original or from another spec) and what engine build/spec?

I have this distributor https://www.7ent.com...ance-45d4e.html it isn’t marked anywhere. The engine is +040 flat top pistons aeg530 cam and big valve head with 1.5 rockers. It’s an old race motor.

not sure why you would even consider a vac advance dizzy on that cam.

Should I just leave it blocked off then?

[mini13]

what are you using the motor for? thats a 300 degre cam ( its the 649 profile) so would not really be road freindly.

[nicklouse]

 

 

 

yes the vac increases the advance at high vac cases that is tick over.
 
but much has to do as to where you have the vac port on the car. and 10-12 sounds high for an engine running a vac advance.
 
so what does it say on the vac unit. it will say the pressure and the advance. also what dissy (original or from another spec) and what engine build/spec?

I have this distributor https://www.7ent.com...ance-45d4e.html it isn’t marked anywhere. The engine is +040 flat top pistons aeg530 cam and big valve head with 1.5 rockers. It’s an old race motor.

not sure why you would even consider a vac advance dizzy on that cam.

Should I just leave it blocked off then?

 

I would get a suitable dizzy and then get the advance curve modded to suit.

[Spider]

 

I have this distributor https://www.7ent.com...ance-45d4e.html it isn’t marked anywhere.

 

 

http://www.theminifo...s/#entry3550007

[RHDmini74]

what are you using the motor for? thats a 300 degre cam ( its the 649 profile) so would not really be road freindly.

It was in a mini given too me years ago. I rebuilt it and decided to put it in while I'm building another one on the side.