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ichthos
06-23-2008, 02:34 PM
I own a 69 TR6. On my particular year, there is a vacuum control valve just underneath the front carb. Can someone explain what this does, and how it should function if working properly? Does anyone know where I can buy one? I checked the big three, and none of them carry these. Any help would greatly be appreciated.
Kevin

Tinster
06-23-2008, 02:55 PM
Kevin,

I'm not sure if this will help you or not.

My car is a 1969 and that valve was removed.
A vacuum line was then direct connected to the two "ears"
on my 1969 distributor.

Front carb vacuum line connected the dizzy ear pointing to front.

Rear carb connected to rear pointing dizzy ear.

Hope this helps ya,

tinster

Tosh
06-23-2008, 03:04 PM
That little guy is a diverter valve for vacuum for the push/pull type distributor. It is the one with a vacuum capsule on each side of the distributor (front and rear).

Inside is a shuttle valve that moves forward or back in response to throttle position and allows vacuum to advance or retard the timing.

It is actuated by a cam type of lever on the carb linkage. Press pedal to accelerate (shuttle moves rearward via return spring inside) and you get advance. Release pedal (to coast) and the aforementioned cam contacts the shuttle; moves it forward; and you get retard.

Pretty confusing if you ask me. Was all done in the name of emissions compliance back in the day.

Have used both kinds of distributors and can't see a bit of difference in performance.

Keep on.

TR3driver
06-23-2008, 04:12 PM
A vacuum line was then direct connected to the two "ears" on my 1969 distributor.Dale, that may well be part of why your car runs poorly !

As Tosh notes, the valve admits vacuum to the vacuum retard module; only when the throttle is closed. In theory, it reduces emission of unburned hydrocarbons when idling, as the abnormally late timing gets matched by having the throttle open farther (to keep the idle rpm the same) which leads to higher chamber pressure and, at least in theory, more complete combustion.

But since it also increases CO2 emissions (not to mention wasting fuel), my suggestion is to disconnect and cap the retard line; set your ignition timing to 10 BTDC; and adjust the idle rpm as necessary.

ichthos
06-23-2008, 10:34 PM
Thanks for all the information. Does anyone know who still sells these? I noticed that they were listed in TRF about a year ago.There has got to be someone who still has some NOS or some of the reproduced ones.
Kevin

ichthos
06-23-2008, 10:47 PM
I forgot to ask, is this valve known by any other name? Thanks, Kevin

Tinster
06-24-2008, 04:52 AM
A vacuum line was then direct connected to the two "ears" on my 1969 distributor.my suggestion is to disconnect and cap the retard line; set your ignition timing to 10 BTDC; and adjust the idle rpm as necessary.

<span style="color: #990000">Thanks Randall!

Should I remove the retard vacuum line totally and then
plug both the carb nipple as well as plug the retard "ear"
on my distributor?

I was going to back off my timing to 10* BTDC this morning.

I'll play w/ various settings, install a fuel filter and see
if the Beast might make it for a mile or so around the hood.

</span>

<span style="color: #000099">I have to tell ya these Triumphs are strange machines.
One day roaring down the road at 75 mph, the next day broke down
in the driveway needing major repairs. BLARRRRGH!

regards,

dale</span>

angelfj1
06-24-2008, 07:34 AM
If memory serves, this little vacuum valve is actually a US made component, I believe Ford or GM. I will try to find my notes. You might want to try 6-Pack or give Dave H at TRF a call.

TR3driver
06-24-2008, 02:53 PM
Should I remove the retard vacuum line totally and then
plug both the carb nipple as well as plug the retard "ear"
on my distributor?Pretty much up to you, Dale. The carb nipple needs to be capped off (otherwise it will leak vacuum), but it doesn't matter if you do that at the carb, or leave the line and cap it at the other end. The distributor 'ear' can be left open.<div class="ubbcode-block"><div class="ubbcode-header">Quote:]
<span style="color: #000099">I have to tell ya these Triumphs are strange machines.
One day roaring down the road at 75 mph, the next day broke down
in the driveway needing major repairs. BLARRRRGH!

regards,

dale</span> [/QUOTE]You certainly do seem to have awful luck in that department. There's certainly no reason a TR6 should be any less reliable than a TR3A, and I rolled the odometer over twice on mine in nearly 20 years of daily driving; while only coming home on a wrecker twice. Once was when a broken lock tab got into the oil pump and caused the shaft to shear off, the second time was when the Toyota behind me didn't bother stopping until he was in my trunk !

Certainly 'Pedro' has played a part in that ... but I literally bought my TR3A (actually late wife bought it, as a Bday present) in "non-running condition" and drove it home. It had it's share of problems, including both rear springs broken and broken piston rings. But there is a certain art to herding old cars down the road; which I think you're learning !

Anyway Good Luck !