Triumph Repair: Vacuum Line Diagram for 1978 Spitfire, haynes manual, vacuum lines

Question
Hi Howard,
 I recently purchased a '78 Spitfire. The previous owners have done some modifications and I am trying to get everything back proper. At the moment I am in need of a vacuum hose diagram and can't seem to find one online. Are you familiar enough with this model to describe the routing of the vacuum lines? Also, is there a reference manual that you would recommend for this car? I'm looking at Haynes but am worried that it might not be detailed enough to really guide me in restoring this car.

Thanks,
Chris

Answer
Hi Chris,

The Haynes manual is ok and has some of the emission hoses but not a full diagram. You may be able to figure out how to rout each hose with the few diagrams and text. However the Bentley manual is more extensive. I did not find a full hose diagram in either book but if you have some time I will see if I can assemble what I can find and post them on my web site for you. It may take me a couple of days but I will let you know as soon as I have them posted so you can just go to my web site and copy them.

I think Bentley is a little better then the Haynes but more expensive. I keep both on most British cars as sometimes Bentley will miss important information and Haynes will have it and vise-versa.

Howard

The vacuum hoses on the 78 are for the vacuum unit on the distributor and the EGR valve and the charcoal canister. Look at the distributor vacuum unit and if the pipe connection is on the distributor side of the unit it is a vacuum retard unit and if it is on the out side of the vacuum unit it is a vacuum advance unit. Vacuum advance units must get "Ported" vacuum which will come from the mounting base of the carburetor, either on top or on the bottom.

On some models that have a CAT (like yours) there is a "T" in the vacuum line from the carburetor (ported vacuum) to a vacuum switch on the throttle linkage and to the EGR valve.

Some models that were built for different parts of the country have different routing. It is difficult to get it exactly as the factory had it because even the factory manuals were very lax in printing vacuum hose diagrams. So it was then difficult for any of the other manuals to print any. I worked in several dealerships back then and it was a large problem for us too. We often had to look at another car to get the routing of hoses.

We often had to just connect up what we knew would operate each item.

Howard