Thread: Vacuum advance
View Single Post
  #4  
Old 03-02-2008, 03:55 PM
paul J's Avatar
paul J paul J is offline
AF Newbie
 
Join Date: Feb 2008
Posts: 81
Thanks: 0
Thanked 0 Times in 0 Posts
Re: Vacuum advance

Quote:
Originally Posted by beedlejpott
Yes, that's what I mean. This car is connected to manifold vacuum, but I suspect that is wrong as all other "B's" that I have seen have ported vacuum. I cannot find a vacuum diagram to confirm this however.
Not all "B"s are ported vacuum! What carburetters are on your car? 74 MGBs came with a 25D4 distributor. 75s and later came with a 45D4 or 43 D4. If you have HIF carbs on your car, look at the rear carb on the firewall side next to the manifold flange and see if there is a blanked off tube the size of the vacuum line. Some carbs had one and some didn't. If your car has it, and the distributor hasn't been changed, more than likely it is ported vacuum. If not it is probably manifold vacuum. But, the vacuum advance diaphragm has to match one or the other. Give me a little more info. Is the dizzy a 25D4 or a 45D4? What carbs do you have? Also, is your car a chrome bumper 74 or a rubber bumper 74 1/2? I run manafold vacuum on my 72. Jeff at Advanced Distributors set it up for me that way. PJ

Contact Jeff at www.advanceddistributors.com or email him at [email protected] .

He has a top knotch distributor repair and replacement service.

Last edited by paul J; 03-03-2008 at 03:54 AM.
Reply With Quote