Where to do the vacuum advance and retard pipes connect to?

[paul83]

Hi,

 

I've recently bought a USA TR6, CC series. The distributor has a vacuum advance and a vacuum retard - both without the vacuum pipes connected (I missed it when checking over the car, as previous experience was with a PI).

 

Where do the vacuum pipes connect to? - I cannot find any diagrams in the books or parts catalogues.

 

Where are the vacuum pipes listed in the parts catalogues (e.g Rimmer Bros)? I can't find them!

 

Thank you,

 

Paul

[foster461]

Hi,

 

I've recently bought a USA TR6, CC series. The distributor has a vacuum advance and a vacuum retard - both without the vacuum pipes connected (I missed it when checking over the car, as previous experience was with a PI).

 

Where do the vacuum pipes connect to? - I cannot find any diagrams in the books or parts catalogues.

 

Where are the vacuum pipes listed in the parts catalogues (e.g Rimmer Bros)? I can't find them!

 

Thank you,

 

Paul

 

Paul, what year is this TR6 ?. The configuration seems to have changed for almost every year and it is important to know what year and if the carbs and the dizzy match as some people (like me) chose to run the earlier dizzy in the later engine and may have modified the carb vacuum port configuration.

 

For the 69 for example this had the dizzy with both vacuum advance and retard. The advance port is on the upper side of the front carb on the manifold flange. The retard port is on the lower side of the front carb (on the left I think), described in the TRF blue book as "on the bell crank support bracket".

 

For 1970 the vacuum advance stays on the top of the front carb but the retard port is on the underside of the rear carb.

 

The later cars only had a vacuum retard and the port for that is located under the rear carb. However the dizzy retard unit is connected indirectly to that port via a thermal switch in the top hose.

 

You probably dont have the TRF parts books but I can scan in the relevant pages when we figure out what you have.

 

Lets get the year sorted out and then we can start figuring out what carbs and dizzy you have. This may take a few iterations..

 

Stan

[foster461]

Paul, what year is this TR6 ?. The configuration seems to have changed for almost every year and it is important to know what year and if the carbs and the dizzy match as some people (like me) chose to run the earlier dizzy in the later engine and may have modified the carb vacuum port configuration.

 

For the 69 for example this had the dizzy with both vacuum advance and retard. The advance port is on the upper side of the front carb on the manifold flange. The retard port is on the lower side of the front carb (on the left I think), described in the TRF blue book as "on the bell crank support bracket".

 

For 1970 the vacuum advance stays on the top of the front carb but the retard port is on the underside of the rear carb.

 

The later cars only had a vacuum retard and the port for that is located under the rear carb. However the dizzy retard unit is connected indirectly to that port via a thermal switch in the top hose.

 

You probably dont have the TRF parts books but I can scan in the relevant pages when we figure out what you have.

 

Lets get the year sorted out and then we can start figuring out what carbs and dizzy you have. This may take a few iterations..

 

Stan

 

Here we go, Moss has a picture of all the different flavors:

 

http://www.mossmotors.com/Shop/ViewProduct...teIndexID=32761

[stuart]

Shame that a lot of it isnt available new.

Stuart.

[paul83]

Stan,

 

You are spot on - the year of manufacture is 1969 and there is indeed a short rubber pipe in the top of the manifold flange which someone has 'blocked' with a bolt. I'll have to check where the retard pipe is connected to, but from memory I suspect that it is the bottom of the front carb.

 

I'm travelling at the moment, so it will take a few days before I can report back the exact spec of the carbs and the dizzy.

 

Thank you also for the link to the parts catalogue.

 

Paul

[vanflyer]

Paul,

The retard pipe is not necessary, as it was there to aid in emissions on the over run, it also went through a small one way valve arrangement that worked off of the throttle plate cam, opening the retard port when the throttle was closed. If the valve was faulty then the manifold pulls a vacuum on to both tubes simultaneously this has the effect of cancelling out one another and you get no vacuum advance. Block the retard one and you get correct advance without any other adverse effects. The valves are no longer available.

[Tom Fremont]

When I ran a standard TR250 I found much improvement from disabling the vacuum advance - smoother and no pinking noises - and set the static timing to 6 degrees BTDC.

 

As noted in the post prior, the retard function is only supposed to operate at idle ( it does make for a nice purr of an idle ) but depends on a valve, and the remote type fixed to the bell crank bracket is NLA. Later smog carbs seem to have them on board. Either way, it isn't at all necessary. I've seen a good number of these set up incorrectly. What's really rare is a properly functioning dual-vacuum set-up, and when I ran mine it was the only one I knew of

[foster461]

When I ran a standard TR250 I found much improvement from disabling the vacuum advance - smoother and no pinking noises - and set the static timing to 6 degrees BTDC.

 

As noted in the post prior, the retard function is only supposed to operate at idle ( it does make for a nice purr of an idle ) but depends on a valve, and the remote type fixed to the bell crank bracket is NLA. Later smog carbs seem to have them on board. Either way, it isn't at all necessary. I've seen a good number of these set up incorrectly. What's really rare is a properly functioning dual-vacuum set-up, and when I ran mine it was the only one I knew of

 

 

Agreed. I removed most of this **** off my 74.5 just to simplify things and clean up the engine bay of all that spaghitti and to eliminate the potential for vacuum leaks.. I think the 74 was the pinnacle of the spaghetti tubing era but was before the air pump era. I did keep the vacuum advance from the earlier dizzy, I understood that it would help with fuel economy. Very important when you drive less than 1000 miles a year :-)

 

Stan